JP2018042831A - Medical image processing apparatus, treatment system, and medical image processing program - Google Patents

Abstract

A medical image processing apparatus, a medical treatment system, and a medical image processing program capable of adjusting the position of a patient so that planned energy of radiation is given to a lesion. According to one embodiment, a medical image processing apparatus includes a first image acquisition unit, a second image acquisition unit, a route acquisition unit, and a search unit. The first image acquisition unit acquires a three-dimensional first image of the subject. The second image acquisition unit acquires a three-dimensional second image of the subject captured at a different time from the first image. The path acquisition unit acquires the radiation path set for the first image. The search unit is configured to integrate a first integrated value obtained by integrating a pixel value of a three-dimensional first pixel included in the first image and passing through the radiation path, and a three-dimensional pixel passing through a path corresponding to the radiation path in the second image. Movement of the second image for adjusting the position of the subject shown in the second image to the position of the subject shown in the first image based on the second integrated value obtained by integrating the pixel value of the second pixel. A movement amount signal representing the amount is output. [Selection diagram] Fig. 1

Description

  Embodiments described herein relate generally to a medical image processing apparatus, a treatment system, and a medical image processing program.

  Radiotherapy is a treatment method that destroys a lesion by irradiating the lesion in the body of the patient. In radiation therapy, it is necessary to accurately irradiate radiation at the position of a lesion. This is because if normal tissue in the patient's body is irradiated with radiation, the normal tissue will be damaged. Therefore, when performing radiotherapy, first, in the stage of treatment planning, computer tomography (CT) is performed in advance to grasp the position of the lesion in the patient's body three-dimensionally. Then, based on the grasped position of the lesion, the direction when irradiating the radiation and the intensity of the irradiating radiation are planned so as to reduce the irradiation to the normal tissue. Thereafter, in the treatment stage, the patient is arranged so as to match the position of the patient in the treatment planning stage, and the lesion is irradiated with radiation according to the irradiation direction and irradiation intensity planned in the treatment planning stage.

  In the patient alignment in the treatment stage, the patient is virtually seen through a fluoroscopic image of the patient's body taken while the patient is lying on the bed immediately before the start of treatment and a three-dimensional CT image taken at the time of treatment planning. Image matching with a digitally reconstructed radiograph (DRR) image obtained by reconstructing the image is performed, and a shift in the position of the patient between the images is obtained. Then, by moving the bed based on the obtained deviation, the position of the lesion, bone, etc. in the patient's body is matched with those in the treatment plan.

  The patient position shift is obtained by searching for a position in the CT image so that a DRR image most similar to the fluoroscopic image is reconstructed. A number of methods have been proposed for automating the search for a patient's location by a computer. The result of the automatic search is confirmed by a user (such as a doctor) comparing the fluoroscopic image and the DRR image.

  At this time, it may be difficult to visually confirm the position of the lesion imaged in the fluoroscopic image. This is because the lesion has a higher X-ray permeability than bones and the like, and the lesion is not clearly visible in the fluoroscopic image. Therefore, when performing treatment, a CT image is taken instead of a fluoroscopic image to confirm the position of a lesion. In this case, the position shift of the patient is obtained by performing image matching between the CT image taken at the time of the treatment plan and the CT image taken at the treatment stage, that is, by image matching between the CT images.

  In image collation between CT images, a position most similar to the other CT image is obtained while shifting the position of one CT image. As an example of a method for performing image matching between CT images, for example, there is a method disclosed in Patent Document 1. In the method disclosed in Patent Document 1, an image around a lesion included in a CT image taken at the time of treatment planning is prepared as a template. In the method disclosed in Patent Document 1, the position of the most similar image is searched as the position of the lesion by performing template matching on the CT image captured in the treatment stage. Then, based on the searched position, a shift in the position of the patient is obtained, and the bed is moved in accordance with the shift in the same manner as described above, and the position of the patient is adjusted to the same position as in the treatment plan.

  By the way, radiation used in radiotherapy loses energy when passing through a substance. Therefore, in the treatment plan, a radiation irradiation method is determined by virtually calculating the amount of energy loss of radiation to be irradiated based on the captured CT image. And when aligning a patient's position in a treatment stage, it is important that the tissues in the patient's body in the path through which the radiation to be irradiated also match.

  However, in the method disclosed in Patent Document 1, it is important to align the position around the focus of interest with the CT image around the focus prepared as a template. For this reason, in the method disclosed in Patent Document 1, the position of the patient's body tissue does not always match even outside the vicinity of the lesion. In other words, when the position of the patient is aligned by the method disclosed in Patent Document 1, even if the irradiated radiation reaches the lesion, it is planned depending on the tissue in the patient's body in the path through which the radiation passes. In some cases, the energy of radiation could not be given to the lesion.

Japanese Patent No. 5669388

  The problem to be solved by the present invention is to provide a medical image processing apparatus, a treatment system, and a medical image processing program capable of aligning a patient so that planned radiation energy can be applied to a lesion.

  The medical image processing apparatus according to the embodiment includes a first image acquisition unit, a second image acquisition unit, a route acquisition unit, and a search unit. The first image acquisition unit acquires a three-dimensional first image of the subject imaged by the imaging device. The second image acquisition unit acquires a three-dimensional second image of the subject imaged by the imaging device at a time different from the first image. The path acquisition unit acquires a radiation path set in the first image. The search unit includes a first integration value obtained by integrating pixel values of a three-dimensional first pixel included in the first image and passing through the radiation path, and a path corresponding to the radiation path in the second image. Based on the second integrated value obtained by integrating the pixel values of the three-dimensional second pixels, the position of the subject imaged in the second image is changed to the position of the object imaged in the first image. A movement amount signal representing the movement amount of the second image for matching is output.

The block diagram which showed schematic structure of the treatment system provided with the medical image processing device of 1st Embodiment. 1 is a block diagram showing a schematic configuration of a medical image processing apparatus according to a first embodiment. 3 is a flowchart showing a flow of search processing in the medical image processing apparatus according to the first embodiment. The figure explaining an example of the relationship between radiation | emission emission and the irradiation target in the treatment system provided with the medical image processing apparatus of 1st Embodiment. The block diagram which showed schematic structure of the medical image processing apparatus of 2nd Embodiment. The block diagram which showed schematic structure of the medical image processing apparatus of 3rd Embodiment.

  Hereinafter, a medical image processing apparatus, a treatment system, and a medical image processing program according to embodiments will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of a treatment system including the medical image processing apparatus according to the first embodiment. The treatment system 1 illustrated in FIG. 1 includes a medical image processing apparatus 100 and a treatment apparatus 10.

  First, the treatment apparatus 10 constituting the treatment system 1 will be described. The treatment apparatus 10 includes a treatment table 11, a computed tomography (CT) apparatus 12 (hereinafter referred to as “CT imaging apparatus 12”), and a treatment beam irradiation gate 13.

  The treatment table 11 is a bed on which a subject (patient) P to be treated with radiation is fixed in a state in which it is laid with a fixing tool or the like. The treatment table 11 can move into an annular CT imaging device 12 having an opening with the patient P fixed. In FIG. 1, illustration of a treatment table control unit that controls movement of the treatment table 11 is omitted.

  The CT imaging device 12 is an imaging device for performing three-dimensional computer tomography. The CT imaging device 12 has a plurality of radiation sources arranged inside an annular opening, and emits radiation for seeing through the body of the patient P from each radiation source. That is, the CT imaging device 12 emits radiation from around the patient P. The radiation irradiated from each radiation source in the CT imaging device 12 is, for example, X-rays. The CT imaging device 12 detects radiation that has been irradiated from a radiation source and reached through the body of the patient P by a plurality of radiation detectors arranged inside the annular opening, and the detected radiation A CT image in the body of the patient P is generated based on the magnitude of energy. The CT image of the patient P generated by the CT imaging device 12 is a three-dimensional digital image in which the magnitude of radiation energy is represented by a digital value. The CT imaging device 12 outputs the generated CT image to the medical image processing device 100. In FIG. 1, radiation from each radiation source provided in the CT imaging device 12 and generation of a CT image based on the radiation detected by each radiation detector, that is, 3 inside the patient P Illustration of a control unit for three-dimensional imaging is omitted.

  The treatment beam irradiation gate 13 emits radiation for destroying an irradiation target (a lesion present in the patient P) inside the patient P as the treatment beam B. The treatment beam B is, for example, an X-ray, γ-ray, electron beam, proton beam, neutron beam, heavy particle beam, or the like. In FIG. 1, illustration of a control unit that controls irradiation of the treatment beam B by the treatment beam irradiation gate 13 is omitted.

  In addition, in FIG. 1, the structure of the treatment apparatus 10 provided with one treatment beam irradiation gate 13 was shown. However, the treatment apparatus 10 is not limited to a configuration including only one treatment beam irradiation gate 13 and may be configured to include a plurality of treatment beam irradiation gates. For example, FIG. 1 shows the configuration of the treatment apparatus 10 including the treatment beam irradiation gate 13 that irradiates the patient P with the treatment beam B from the vertical direction, but the treatment beam that irradiates the patient P with the treatment beam from the horizontal direction. You may comprise the treatment system 1 including the treatment apparatus further provided with the irradiation gate.

  The medical image processing apparatus 100 performs processing for aligning the position of the patient P when performing radiotherapy based on the CT image output from the CT imaging apparatus 12. More specifically, the medical image processing apparatus 100 outputs information for aligning the position of a lesion or tissue in the body of the patient P who is treated in radiation therapy. In the medical image processing apparatus 100, the lesion and tissue alignment processing is performed on the CT image of the patient P taken before the radiotherapy, such as the stage of treatment planning, and the current patient P output from the CT imaging apparatus 12. Based on the CT image.

  At this time, the medical image processing apparatus 100 virtually moves the position of the lesion or tissue in the body of the patient P, and then determines the tissue on the path until the treatment beam B reaches the lesion. That is, the medical image processing apparatus 100 determines whether or not the tissues inside the patient P in the path (radiation path) through which the treatment beam B passes are matched. This is because the amount of energy lost when the irradiated treatment beam B passes through the tissue in the patient P (energy loss amount) is within an allowable range with respect to the energy loss amount calculated at the stage of treatment planning. This is to notify whether or not. In other words, this is to notify that the position of the maximum portion (Bragg peak) in the Bragg curve of the irradiated treatment beam B is not deviated from the position of the lesion to be treated. In the medical image processing apparatus 100, the tissue on the path through which the treatment beam B passes is determined by comparing the tissue up to the lesion included in the CT image of the patient P imaged before the radiotherapy and the CT of the current patient P. This is done by comparing the tissue up to the lesion included in the image. The medical image processing apparatus 100 outputs information representing the result of comparing the tissues on the path through which the treatment beam B passes.

  The medical image processing apparatus 100 and the CT imaging apparatus 12 included in the treatment apparatus 10 may be connected via a LAN (Local Area Network) or a WAN (Wide Area Network).

  Hereinafter, the configuration of the medical image processing apparatus 100 configuring the treatment system 1 will be described. FIG. 2 is a block diagram illustrating a schematic configuration of the medical image processing apparatus 100 according to the first embodiment. The medical image processing apparatus 100 illustrated in FIG. 2 includes a first image acquisition unit 101, a second image acquisition unit 102, a route acquisition unit 110, and a search unit 120. In addition, the search unit 120 includes an integrated image calculation unit 121, a comparison unit 122, a determination unit 123, and a movement unit 124.

  The first image acquisition unit 101 acquires a first image related to the patient P before treatment. The first image acquisition unit 101 outputs the acquired first image to the search unit 120. Here, the first image is a CT image used to determine the direction (path including tilt, distance, etc.) and intensity of the treatment beam B to be irradiated at the stage of the treatment plan when performing radiotherapy. The first image is taken in a state where the posture of the patient P is kept constant by being fixed to the treatment table 11. In the treatment planning stage, the direction and intensity of irradiation of the treatment beam B are planned so as to reduce the irradiation of the treatment beam B to normal tissues in the body of the patient P. Note that the first image acquisition unit 101 may include an interface for connecting to the CT imaging device 12 included in the treatment device 10.

  The 2nd image acquisition part 102 acquires the 2nd image regarding the patient P just before starting a treatment. The second image acquisition unit 102 outputs the acquired second image to the search unit 120. Here, the second image is a CT image in the body of the patient P taken immediately before the treatment is started in order to align the position of the patient P. That is, the second image is a CT image generated by the CT imaging device 12 in a state where the treatment beam irradiation gate 13 is not irradiating the treatment beam B. The second image is taken in a state in which the second image is close to the same posture as when the first image was taken. Note that the second image acquisition unit 102 may include an interface for connecting to the CT imaging device 12 included in the treatment device 10.

  The route acquisition unit 110 acquires information on a route for irradiating the treatment beam B determined in the treatment planning stage. In addition, the information of the path | route which irradiates the treatment beam B is the information represented on the basis of the three-dimensional coordinate of the reference position preset in the treatment room where the treatment system 1 is installed, for example. The treatment beam B exists in the body of the patient P by scanning (raster scan) one radiation beam (hereinafter referred to as “treatment beam b”) or irradiating a plurality of treatment beams b. Irradiated to the area (range) of the lesion. In other words, there are a plurality of paths for irradiating the treatment beam B for each treatment beam b that actually irradiates the lesion in the body of the patient P. The route acquisition unit 110 acquires information on each route of the treatment beam b representing the treatment beam B irradiated to the lesion in the body of the patient P. The route acquisition unit 110 outputs the acquired route information of the treatment beam b to the search unit 120. Further, the route acquisition unit 110 may acquire information on the intensity of each treatment beam b planned in the treatment planning stage.

  The search unit 120 includes information on each path of the treatment beam b output from the path acquisition unit 110, the first image output from the first image acquisition unit 101, and the first image output from the second image acquisition unit 102. Based on the two images, a movement amount for matching the current position of the patient P with the position of the stage of the treatment plan is searched. The search unit 120 searches for a movement amount for aligning the position of the patient P so that the energy given to the lesion in the body of the patient P by the irradiated treatment beam B approaches the energy planned in the treatment planning stage.

  The integrated image calculation unit 121 generates an integrated image representing the irradiation range of the treatment beam B based on the information on each route of the treatment beam b output from the route acquisition unit 110. The integral image calculation unit 121 includes an integral image corresponding to the first image output from the first image acquisition unit 101 (hereinafter referred to as “first integral image”) and a second image output from the second image acquisition unit 102. Each of the integrated images corresponding to the images (hereinafter referred to as “second integrated image”) is generated. The integral image calculation unit 121 outputs each generated integral image to the comparison unit 122.

  Here, an outline method in which the integral image calculation unit 121 generates an integral image will be described by taking as an example a case where a first integral image corresponding to the first image is generated. In the generation of the first integral image by the integral image calculation unit 121, first, a path through which the treatment beam b passes from among the three-dimensional pixels (voxels) included in the first image output from the first image acquisition unit 101. The upper voxel is extracted. Here, the pixel value of the voxel is a value that varies depending on tissues (substances) such as meat and bone constituting the patient P. When air is contained in the body of the patient P, the pixel value of the voxel is different from a tissue (substance) such as meat or bone. The integrated image calculation unit 121 extracts the voxels located on the route for each route of the treatment beam b based on the information on the route of the treatment beam b output from the route acquisition unit 110. Then, the integral image calculation unit 121 integrates (line integrals) the extracted voxel pixel values (hereinafter referred to as “CT values”) for each path of the treatment beam b. The integrated image calculation unit 121 may integrate (line integration) the CT value of the voxel up to the position of the Bragg peak according to the intensity of each treatment beam b planned in the treatment planning stage. Then, the integrated image calculation unit 121 generates a first integrated image by arranging (arranging) the CT values integrated for each path of the treatment beam b at corresponding positions within the irradiation range of the treatment beam B. To do. In this manner, the integral image calculation unit 121 integrates (line integral) values of CT values obtained by integrating (line integral) the pixel values of the pixels constituting the integral image for each path of the treatment beam b. A first integrated image of the irradiation range of the treatment beam B is generated (hereinafter referred to as “voxel data”). Similarly, the integral image calculation unit 121 arranges the voxel data obtained by integrating (line integration) the CT values of the voxels on the respective paths of the treatment beam b extracted from the second image in the irradiation range of the treatment beam B. Two integral images are generated. In this way, the integral image calculation unit 121 integrates (line integral) the voxel data of only the voxels through which each of the treatment beams b passes when the treatment beam B is irradiated with the intensity planned in the treatment planning stage. Each integral image including is generated.

  In addition, when the integral image calculation part 121 produces | generates each integral image, the case where the path | route of any treatment beam b passes the boundary of a voxel is also considered. In this case, for example, the integral image calculation unit 121 uses the CT value of any one voxel adjacent in the path of the treatment beam b as the CT value of the voxel on the path of the treatment beam b to generate the CT when the integral image is generated. Value integration (line integration), that is, calculation of voxel data may be used. In addition, the integral image calculation unit 121 generates an integral image using, for example, a CT value obtained by averaging the CT values of two adjacent voxels in the treatment beam b path as a CT value of the voxel on the treatment beam b path. You may use for calculation of the voxel data at the time of doing.

  In addition, although the integral image calculation part 121 demonstrated the structure which produces | generates and outputs an integral image by arranging voxel data in the irradiation range of the treatment beam B, the integral image calculation part 121 converts the voxel data in the form of an image. It is not limited to the structure to output. For example, the integral image calculation unit 121 may output each voxel data itself, that is, an integrated value obtained by integrating (line integrating) the CT value for each path of the treatment beam b.

  When generating each integral image, the integral image calculation unit 121 uses the CT value of each voxel located on the path of the treatment beam b as the water equivalent thickness obtained by converting the amount of radiation energy loss into the water thickness. Is used to generate each integral image. As described above, the treatment beam b (treatment beam B) loses energy when passing through the substance (tissue). At this time, the amount of energy lost by each of the treatment beams b is an amount of energy corresponding to the CT value of the voxel through which the treatment beam b passes, and is different for each path of the treatment beam b. That is, the amount of energy loss in the treatment beam B is not uniform, and a different amount of energy is lost for each treatment beam b path. The water equivalent thickness is a value representing the amount of radiation energy loss that differs for each tissue (substance) as the thickness of water that is the same substance, and can be converted based on the CT value of the voxel. For example, when the CT value is a value representing bone, the amount of energy loss when radiation passes through the bone is large, so the water equivalent thickness is a large value. For example, when the CT value is a value representing air, the amount of energy loss when the radiation passes through the air is small, so the water equivalent thickness is a small value. When the integral image calculation unit 121 generates the integral image, the CT value of the voxel is converted into a water equivalent thickness, whereby the energy loss amount for each path through which each of the treatment beams b passes in the treatment beam B is set to the same reference. Can be expressed as

  Further, the integral image calculation unit 121 converts the CT value of the voxel located on the path of the treatment beam b into a water equivalent thickness for each path, and then integrates (equivalents) the water equivalent thickness to each of them. Voxel data is calculated to generate an integral image. The water equivalent thickness can express the depth of water (water conversion depth) by integration (line integration). In the integrated image, the water equivalent depth represents the distance from the body surface of the patient P to the lesion. In other words, the integral image calculation unit 121 converts the CT value of the voxel on each path of the treatment beam b extracted from the first image into a water equivalent thickness, and then integrates (line integration), thereby at the treatment planning stage. The confirmed distance (water conversion depth) from the body surface of the patient P to the lesion can be represented by the first integral image. Further, the integral image calculation unit 121 converts the CT value of the voxel on each path of the treatment beam b extracted from the second image into a water equivalent thickness, and then integrates (line integration), thereby obtaining a treatment stage, that is, The distance (water conversion depth) from the body surface of the patient P confirmed at the current position of the patient P to the lesion can be represented by the second integrated image.

  By comparing the distance (water equivalent depth) from the body surface of the patient P to the lesion represented by each of the first integrated image and the second integrated image, the irradiation is performed within the irradiation range of the treatment beam B. It can be determined whether each treatment beam b can give the planned energy to the lesion in the body of the patient P in the treatment planning stage. If any of the treatment beams b cannot give the energy planned in the treatment planning stage to the lesion in the patient P, appropriate measures such as changing the path of the treatment beam b are taken. be able to. For example, if air that was not present at the stage of the treatment plan is currently present in the path of any treatment beam b, the amount of energy lost when radiation passes through the air is small as described above. For this reason, the water equivalent thickness becomes a small value, and accordingly, the value of the water equivalent depth becomes a small value. In this case, the voxel data of the second integral image in the path of the treatment beam b is smaller than the corresponding voxel data of the first integral image. That is, the position of the Bragg peak in the path of the treatment beam b is deeper than the stage of the treatment plan. When the position of the Bragg peak in the path of the treatment beam b is deeper than the stage of the treatment plan, it is an important organ that is located deeper than the lesion in the body of the patient P and is not desired to be destroyed by radiation called a dangerous organ. It is conceivable that the treatment beam b arrives. In such a case, it is necessary to take appropriate measures so that the treatment beam b does not reach the dangerous organ. In such a case, the medical image processing apparatus 100 irradiates the treatment beam b by bypassing the path. In other words, the medical beam b avoids the path where air that did not exist at the stage of the treatment plan exists. Thus, it is possible to take appropriate measures for allowing the energy planned in the treatment planning stage to be given to the lesion in the body of the patient P. In the medical image processing apparatus 100, the comparison unit 122 compares the first integrated image and the second integrated image. Further, in the medical image processing apparatus 100, whether or not each of the treatment beams b irradiated within the irradiation range of the treatment beam B can give the energy planned in the treatment planning stage to the lesion in the body of the patient P. Is determined by the determination unit 123. Further, in the medical image processing apparatus 100, the amount of change when changing the path of the treatment beam b is determined by the moving unit 124.

  The integral image calculation unit 121 compares each of the first integral image and the second integral image configured by voxel data representing the value of the water equivalent depth for each path through which the treatment beam b passes through the comparison unit 122. Output to. In other words, the integral image calculation unit 121 is a first integral image of the irradiation range of the treatment beam B that represents information on the distance from the body surface of the patient P to the lesion calculated from the first image for each path of the treatment beam b. And a second integrated image of the irradiation range of the treatment beam B in which the information on the distance from the body surface of the patient P calculated from the second image to the lesion is represented for each path of the treatment beam b. It outputs to 122.

  In addition, by applying the range data, which is the reach distance of the treatment beam b obtained from the Bragg curve corresponding to the intensity of the treatment beam b to be irradiated, to the water equivalent depth, the treatment beam b of each path is obtained. The irradiation amount, that is, the irradiation amount of the treatment beam b on the lesion can also be calculated. For this reason, the integral image calculation unit 121 is configured to output each of the first integral image and the second integral image in which the irradiation amount of the treatment beam b in the irradiation range of the treatment beam B is voxel data to the comparison unit 122. There may be.

  The comparison unit 122 compares the first integral image and the second integral image output from the integral image calculation unit 121 and outputs information representing the comparison result to the determination unit 123. Here, the comparison unit 122 compares the voxel data at the same position in the first integrated image and the second integrated image, that is, the distance from the body surface of the patient P to the lesion in the path of the same treatment beam b (water equivalent depth). ) Information representing a comparison result obtained by comparing each other is output to the determination unit 123. More specifically, the comparison unit 122 performs voxel data (water conversion depth value) of a path of a certain treatment beam b included in the first integral image and the same corresponding treatment beam b included in the second integral image. The difference from the voxel data (value of water equivalent depth) of the path of is calculated. The comparison unit 122 outputs the difference in the voxel data calculated in the path of each treatment beam b (the difference in water equivalent depth) to the determination unit 123 as a comparison result. In other words, the comparison unit 122 calculates the energy loss amount for each treatment beam b path in the treatment beam B calculated from the first image and the energy loss amount for each treatment beam b route in the treatment beam B calculated from the second image. The comparison result obtained by comparing is output to the determination unit 123.

  The determination unit 123 determines a shift between the first integrated image and the second integrated image based on the information on the comparison result output from the comparison unit 122. Here, the determination of the shift between the first integrated image and the second integrated image in the determination unit 123 is performed for each path of the treatment beam b in the first integrated image and the second integrated image. More specifically, the determination unit 123 checks whether or not the difference in the voxel data represented by the comparison result output from the comparison unit 122 is within a predetermined allowable range. That is, the determination unit 123 determines, for each path of the treatment beam b, whether or not the difference in water conversion depth represented by the comparison result output from the comparison unit 122 is a difference within a predetermined allowable range. In other words, the determination unit 123 determines that the energy loss amount for each treatment beam b path in the treatment beam B calculated from the second image is the energy loss amount for each treatment beam b route in the treatment beam B calculated from the first image. It is determined whether or not it is within a predetermined allowable range. Here, the determination unit 123 does not deviate from the first integral image and the second integral image when all the differences in the voxel data within the irradiation range of the treatment beam B are within a predetermined allowable range. That is, it is determined that the current position of the patient P matches the position of the stage of the treatment plan. On the other hand, if any of the voxel data differences within the irradiation range of the treatment beam B is not within a predetermined allowable range, the determination unit 123 deviates from the first integral image, that is, the second integral image. It is determined that the current position of the patient P does not match the position of the stage of the treatment plan. And the determination part 123 outputs the determination signal showing the result of having determined the shift | offset | difference of a 1st integral image and a 2nd integral image. The determination signal is output, for example, to a result presentation device (not shown) that presents the determination result, and presented to a user (such as a doctor) of the treatment system 1. Further, the determination unit 123 outputs information on the determination result for each path of the treatment beam b to the moving unit 124.

  The moving unit 124 determines the amount of movement for moving the current position of the patient P based on the determination result information for each path of the treatment beam b output from the determining unit 123. More specifically, the moving unit 124 has a difference in water equivalent depth based on the difference in water equivalent depth expressed in the determination result of the path of each treatment beam b output from the determining unit 123. A movement amount including a direction (inclination) for moving the current position of the patient P (that is, the second image) in a predetermined three-dimensional space is determined so as to be moved in a small direction. Then, the moving unit 124 outputs information representing the determined moving amount to the integrated image calculating unit 121. In other words, the moving unit 124 calculates the position and direction of the patient P for the treatment beam b (treatment beam B) to reach the lesion with an energy loss amount within a predetermined allowable range, and moves the calculated position and direction to the calculated position and direction. Information on the amount of movement for aligning (moving) the position of the patient P is output to the integral image calculation unit 121. Accordingly, the integral image calculation unit 121 virtually moves the second image based on the movement amount information output from the movement unit 124, generates a second integral image in this state, and sends the second integral image to the comparison unit 122. Output.

  The search unit 120 generates the second integrated image by the integrated image calculation unit 121 as described above, the comparison unit 122, and the determination until it is determined that the current position of the patient P matches the position of the stage of the treatment plan. The determination of the difference between the second integrated image and the first integrated image by the unit 123 and the determination of the moving amount by which the moving unit 124 moves the position of the patient P are repeated. Then, in the search unit 120, when the determination unit 123 determines that the current position of the patient P matches the position of the stage of the treatment plan, the final movement amount (tilt, distance, etc.) determined by the movement unit 124 is determined. The movement amount signal indicating the position of the patient is actually moved, and the position of the patient P is adjusted to the position of the stage of the treatment plan. That is, the search unit 120 sets the energy loss amount for each treatment beam b path in the treatment beam B calculated from the second image to the energy loss amount for each treatment beam b path in the treatment beam B calculated from the first image. On the other hand, when it is within a predetermined allowable range, information for finally adjusting the position of the patient P to the position is output. The movement amount signal is output to, for example, a treatment table control unit (not shown) that controls the movement of the treatment table 11, and the treatment table control unit (not shown) moves the treatment table 11 based on the movement amount signal. The position of the patient P is actually moved.

  With such a configuration, the medical image processing apparatus 100 converts the first image of the patient P taken at the stage of treatment planning and the second image of the patient P taken before performing radiation therapy at the treatment stage. Based on this, the difference between the position of the patient P at the stage of the treatment plan and the current position of the patient P is determined. The medical image processing apparatus 100 outputs a result of determining the difference between the position of the patient P at the stage of the treatment plan and the current position of the patient P as a determination signal. Further, the medical image processing apparatus 100 determines a moving amount for moving the position of the patient P based on the result of determining the deviation, and virtually moves the current position of the patient P. The medical image processing apparatus 100 outputs a movement amount signal for moving the current position of the patient P to a position that is finally determined to match the stage of the treatment plan. Thereby, in the treatment system 1 provided with the medical image processing apparatus 100, for example, a treatment table control unit (not shown) that controls the movement of the treatment table 11 moves the treatment table 11 based on the movement amount signal. The position of the patient P is actually moved. Thereby, in the treatment system 1 including the medical image processing apparatus 100, the current position of the patient P is set in a state where the treatment beam B of the energy planned in the treatment planning stage can be irradiated to the lesion in the body of the patient P. In combination, radiation therapy can be performed.

  Some of the functional units included in the medical image processing apparatus 100 described above execute a program stored in a storage device by a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). It may be a software function unit that functions according to the above. Here, the storage device may be realized by a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), a flash memory, or the like. Note that a program executed by a processor such as a CPU or GPU may be stored in advance in a storage device of the medical image processing apparatus 100, or may be downloaded from another computer apparatus via a network. A program stored in the portable storage device may be installed in the medical image processing apparatus 100. In addition, a part or all of the functional units included in the medical image processing apparatus 100 described above is a hardware unit such as an FPGA (Field Programmable Gate Array), an LSI (Large Scale Integration), or an ASIC (Application Specific Integrated Circuit). It may be.

  Hereinafter, a flow of processing (search processing) for determining the amount of movement to be performed in order to match the current position of the patient P with the position of the stage of the treatment plan in the medical image processing apparatus 100 configuring the treatment system 1 will be described. The search processing in the medical image processing apparatus 100 is a patient who can focus on the treatment beam B of energy planned in the treatment planning stage by generating a first integrated image and a second integrated image and determining a deviation. This is a process of searching for the position of P. FIG. 3 is an example of a flowchart illustrating a flow of search processing in the medical image processing apparatus 100 according to the first embodiment. Note that before the medical image processing apparatus 100 performs the search process, that is, before the radiation therapy is performed (for example, about one week before), a treatment plan is made based on the captured first image. Further, the second image is taken immediately before the medical image processing apparatus 100 performs the search process, that is, immediately before the start of radiation therapy. In the following description, it is assumed that the second image is already captured in the treatment system 1, the first image acquisition unit 101 acquires the first image, and the second image acquisition unit 102 acquires the second image. To do. Further, description will be made assuming that the route acquisition unit 110 acquires a route for irradiating the treatment beam b (treatment beam B) determined at the stage of the treatment plan.

  In the radiation therapy, in order to treat the same patient P, the treatment beam B may be irradiated a plurality of times (including when not on the same day). For this reason, when the radiation treatment for the same patient P is performed for the second time or later, the second image obtained by aligning the position of the patient P in the previous treatment is used as the first image, and the treatment beam b in the previous treatment is used. The path of (treatment beam B) may be used as the path of treatment beam b (treatment beam B) in the current treatment.

  First, when the medical image processing apparatus 100 starts a search process, the integral image calculation unit 121 included in the search unit 120 acquires information on each path of the treatment beam b output from the path acquisition unit 110 (step S100). ).

  Next, the integrated image calculation unit 121 applies the information of each path of the treatment beam b acquired from the path acquisition unit 110 to the first image, and generates a first integrated image representing the irradiation range of the treatment beam B ( Step S200). Here, the integral image calculation unit 121 uses the water equivalent thickness obtained by converting the CT value of each voxel located on the treatment beam b path in the first image for each path through which the treatment beam b passes. A first integrated image representing the value of the water equivalent depth is generated. In addition, the detailed description regarding the method in which the integral image calculation part 121 produces | generates a 1st integral image using the water equivalent thickness which converted CT value is mentioned later. The integral image calculation unit 121 outputs the generated first integral image to the comparison unit 122.

  Next, the integral image calculation unit 121 sets each path of the treatment beam b acquired from the path acquisition unit 110 as a second image (step S300). At this time, the integral image calculation unit 121 does not first move the second image virtually, for example, with reference to the three-dimensional coordinates of the reference position set in advance in the treatment room in which the treatment system 1 is installed. A three-dimensional direction represented by the path of the treatment beam b is set in the second image. That is, the path of each treatment beam b is set for the current state of the patient P (the body position including the position and direction).

  Next, the integral image calculation unit 121 generates a second integral image representing the irradiation range of the treatment beam B based on each set path of the treatment beam b (step S400). Here, the integrated image calculation unit 121 uses the water equivalent thickness obtained by converting the CT value of each voxel located on the path of each treatment beam b set in the second image, and the set treatment beam b passes therethrough. A second integral image representing the value of the water equivalent depth is generated for each route. In the second image, it is conceivable that the CT values of the respective voxels located on the path of each treatment beam b are different. However, the method of generating the second integrated image by the integrated image calculating unit 121 is the integrated image. The calculation unit 121 is similar to the method for generating the first integral image. Therefore, the detailed description regarding the method for the integrated image calculation unit 121 to generate the second integrated image will be described later together with the method for generating the first integrated image. The integral image calculation unit 121 outputs the generated second integral image to the comparison unit 122.

  Next, the comparison unit 122 compares the first integral image and the second integral image output from the integral image calculation unit 121, and outputs information representing the comparison result to the determination unit 123 (step S500). Here, the comparison part 122 compares the comparison result (the difference of water conversion depth) which compared the value of the water conversion depth corresponding to the treatment beam b of the same position in a 1st integral image and a 2nd integral image, respectively. Is output to the determination unit 123 as a comparison result corresponding to the treatment beam b.

  Next, based on the comparison result for each treatment beam b output from the comparison unit 122, the determination unit 123 has a deviation between the first integral image and the second integral image within a predetermined allowable range. Is determined for each treatment beam b (step S600).

  As a result of the determination in step S600, when it is determined that there is a shift between the first integral image and the second integral image (“NO” in step S600), the determination unit 123 determines whether the first integral image and the second integral image are the same. A determination signal indicating that there is a deviation, that is, the current position of the patient P does not match the position of the stage of the treatment plan is output. In addition, the determination unit 123 outputs information on the determination result for each path of the treatment beam b (including the difference in water conversion depth) to the moving unit 124.

  Next, the moving unit 124 determines the moving amount of the second image based on the determination result information for each path of the treatment beam b output from the determining unit 123 (step S610). More specifically, as described above, based on the difference in water equivalent depth included in the determination result for each path of each treatment beam b output from the determination unit 123, the path of each treatment beam b The amount of movement of the second image (including the amount of rotation), that is, the amount of movement for moving the current position of the patient P is determined so that the difference in water conversion depth becomes smaller. The moving unit 124 outputs the determined movement amount of the second image to the integrated image calculating unit 121. When the second image is centered, that is, when the second image is a fixed position, the movement amount of the second image determined by the moving unit 124 in step S610 is the direction in which each treatment beam b is irradiated. This corresponds to the amount of change of the route including (tilt etc.) and strength (distance etc.).

  Next, the integrated image calculation unit 121 virtually moves the second image based on the movement amount of the second image output from the movement unit 124, and then obtains it from the route acquisition unit 110 in the same manner as in step S300. Each path of the treated beam b is set in the second image after movement (step S620). In addition, when the change amount of the path | route of each treatment beam b is output from the moving part 124, the path | route which irradiates the treatment beam b was virtually changed, ie, the state (position and direction) of the present patient P Each of the paths of the treatment beam b after being changed with respect to the body position including, etc. is set in the second image.

  Thereafter, the search processing of the medical image processing apparatus 100 returns to step S400 and repeats the processing from step S400 to step S600. That is, in the search process of the medical image processing apparatus 100, generation of a new second integral image corresponding to the second image after movement, comparison between the first integral image and the new second integral image, and determination of deviation are repeated. .

  On the other hand, when it is determined that there is no deviation between the first integrated image and the second integrated image (or a new second integrated image) as a result of the determination in step S600 (“YES” in step S600), the determination unit 123 A determination signal is output indicating that there is no deviation between the first integrated image and the second integrated image, that is, the current position of the patient P matches the position of the stage of the treatment plan. Further, the determination unit 123 outputs information on a determination result indicating that there is no deviation between the first integrated image and the second integrated image to the moving unit 124.

  Next, the moving unit 124 outputs a movement amount signal representing the final movement amount of the second image (step S700). Here, since the movement amount signal output by the moving unit 124 does not move the second image acquired by the second image acquiring unit 102 when the moving unit 124 has not performed the process of step S610, the shooting is performed. It is a signal including information indicating that the second image is not moved. On the other hand, when the movement unit 124 performs the process of step S610, the movement amount signal output from the movement unit 124 includes information indicating the movement amount of the second image determined in the last process of step S610. Signal. In the process of step S610 in the moving unit 124, when the movement amount of the second image is always determined based on the preset three-dimensional coordinates of the reference position, the determination is performed in the last process of step S610. The information on the movement amount of the second image is information represented by the movement amount signal. However, in the process of step S610 in the moving unit 124, for example, when the movement amount of the second image is further determined based on the movement amount of the second image determined in the previous process of step S610, Information on the movement amount of the second image, which is the sum of the movement amounts of the images, is information represented by the movement amount signal.

  Thereafter, in the treatment system 1, a treatment table control unit (not shown) treats the treatment table based on the movement amount signal output from the medical image processing apparatus 100 (more specifically, the movement unit 124 included in the search unit 120). 11 is moved, and the position of the patient P is actually moved.

  Here, an example of processing (processing method) performed by the components included in the medical image processing apparatus 100 in the search processing of the medical image processing apparatus 100 configuring the treatment system 1 will be described.

  First, a treatment plan performed before the search process is performed in the medical image processing apparatus 100 will be described. In the treatment plan, the energy of the treatment beam B (radiation) irradiated to the patient P, the irradiation direction, the shape of the irradiation range, the distribution of the dose when the treatment beam B is irradiated in multiple times, and the like are determined. More specifically, first, a treatment planner (such as a doctor) performs a tumor (lesion) region and a normal tissue region on a CT image (first image) taken at the stage of the treatment plan. Specify the boundary of the tumor, the boundary between the tumor and important organs around it. In the treatment plan, the direction (path) of the treatment beam B to be irradiated, based on the depth from the body surface of the patient P to the position of the tumor, the size of the tumor, calculated from information on the designated tumor, Determine the strength.

  The designation of the boundary between the tumor area and the normal tissue area described above corresponds to designation of the tumor position and volume. The volume of this tumor is the gross tumor volume (GTV), clinical target volume (CTV), internal target volume (ITV), planning target volume (Planning Target Volume: PTV). GTV is a volume of a tumor that can be confirmed with the naked eye from an image. In radiotherapy, GTV is a volume that needs to be irradiated with a therapeutic beam B having a sufficient dose. CTV is the volume containing GTV and the potential tumor to be treated. The ITV is a volume obtained by adding a predetermined margin to the CTV in consideration of the movement of the CTV due to the predicted movement of the physiological patient P or the like. The PTV is a volume obtained by adding a margin to the ITV in consideration of an error in the alignment of the patient P performed when performing the treatment. The relationship of the following formula (1) is established in these volumes.

  On the other hand, the volume of an important organ located around a tumor that is highly sensitive to radiation and strongly influenced by the dose of irradiated radiation is called a dangerous organ (Organ At Risk: OAR). As a volume obtained by adding a predetermined margin (margin) to this OAR, a planning dangerous organ volume (PRV) is designated. These volumes have the relationship of the following formula (2).

  At the stage of treatment planning, the direction (path) and intensity of the treatment beam B (radiation) irradiated to the patient P are determined based on a margin that takes into account errors that may occur in actual treatment.

  Then, when performing a search process in the medical image processing apparatus 100, the first image acquisition unit 101 first acquires the first image and outputs it to the integrated image calculation unit 121 provided in the search unit 120. In addition, the second image acquisition unit 102 acquires a second image related to the patient P immediately before starting the treatment, and outputs the second image to the integrated image calculation unit 121 included in the search unit 120. As described above, the first image and the second image are both CT images. When the second image is captured, the posture of the patient P is brought close to the same posture as when the first image is captured. However, it is difficult to capture the second image in the same posture as when the first image was captured. That is, it is difficult to suppress a change in the state of the body of the patient P or to fix the same position even if a fixture is used. For this reason, even if each of the first image and the second image is virtually arranged in the predetermined three-dimensional space, a slight shift (for example, several mm) occurs, and the second image is It is difficult to reproduce the posture of the patient P when the first image is photographed only by photographing. Therefore, in the medical image processing apparatus 100, the search unit 120 uses the water equivalent thickness to align the positions of the first image and the second image (to reduce the difference between the images), that is, for the current patient P. The movement amount for matching the posture to the posture when the first image is taken is searched. The predetermined three-dimensional space is a space based on the three-dimensional coordinates serving as a reference position preset in the treatment room, such as the treatment beam irradiation gate 13 and the treatment table 11.

  Further, when performing a search process in the medical image processing apparatus 100, the route acquisition unit 110 acquires information on a route for irradiating the treatment beam B (radiation) determined based on the first image in the treatment planning stage. Output to the integrated image calculation unit 121 included in the search unit 120. The direction in which the treatment beam B is irradiated is a direction in a three-dimensional space from the exit of the treatment beam irradiation gate 13 toward the tumor (lesion) in the body of the patient P. Therefore, if the position of the exit of the treatment beam irradiation gate 13 in a predetermined three-dimensional space is known, the treatment beam that passes through the respective voxels in the first image and the second image with the position of the exit as a starting point. The route of B can be obtained. The path of the treatment beam B can be represented by three-dimensional coordinates. Note that the path of the treatment beam B may be represented by a three-dimensional vector with the position of the exit port as the starting point of three-dimensional coordinates.

  Here, the treatment beam B irradiated from the treatment beam irradiation gate 13 in the treatment system 1 will be described. In the following description, it is assumed that the path of the treatment beam B is represented by a three-dimensional vector.

  As described above, the treatment beam B scans a single treatment beam b or irradiates a plurality of treatment beams b, so that the entire region (range) of the lesion existing in the body of the patient P is obtained. Irradiated. FIG. 4 shows radiation (treatment beam B) emission and radiation (treatment beam B) irradiation targets (lesions existing in the body of the patient P) in the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment. It is a figure explaining an example of the relationship. FIG. 4 shows an example of a route through which the treatment beam B irradiated from the treatment beam irradiation gate 13 reaches the irradiation target lesion. 4A shows an example of the treatment beam B in the case where the treatment beam irradiation gate 13 is configured to emit a plurality of treatment beams b, and FIG. 4B shows the treatment beam irradiation. An example of the treatment beam B in the case where the gate 13 is configured to emit and scan one treatment beam b is shown.

When the treatment beam irradiation gate 13 emits a plurality of treatment beams b in the treatment system 1, the treatment beam irradiation gate 13 has a planar emission port as shown in FIG. Yes. Each treatment beam b emitted from the treatment beam irradiation gate 13 reaches the irradiation target lesion via the collimator 13-1. That is, only the treatment beam b that has passed through the collimator 13-1 among the plurality of treatment beams b simultaneously emitted from the treatment beam irradiation gate 13 reaches the irradiation target lesion. Here, the collimator 13-1 is a metal instrument for blocking the unnecessary treatment beam b. As the collimator, there is a multi-leaf collimator that can mechanically change an area where the unnecessary treatment beam b is blocked, in addition to a metal instrument. The irradiation range of the treatment beam B irradiated from the treatment beam irradiation gate 13 in the treatment system 1 is set such that, for example, any treatment beam b is not irradiated to a region other than the lesion existing in the body of the patient P. The region through which the treatment beam b passes in accordance with the shape of the lesion is adjusted by the collimator 13-1. FIG. 4A schematically illustrates an example in which the treatment beam b of the treatment beam b ₁ to the treatment beam b _N passes through the collimator 13-1 and is irradiated to the lesion to be irradiated in the first image. It shows. In this case, the starting point in each path of the treatment beam b ₁ to the treatment beam b _N is the position of the exit point of each treatment beam b located within the range of the planar exit of the treatment beam irradiation gate 13. Note that the three-dimensional position of the treatment beam irradiation gate 13 having this configuration is, for example, the position (coordinates) of the center of the plane of the emission port.

The path acquisition unit 110 uses, as a starting point, the position of the exit point of the treatment beam b to obtain information about the path through which each of the treatment beams b ₁ to b _N reaches the irradiation target lesion in the first image for a predetermined 3 It is acquired as information on the path of each treatment beam b in the treatment beam B irradiated in the dimensional space. In this case, the path of each treatment beam b in the treatment beam B can be discretely expressed by a set of three-dimensional vectors as shown in the following equation (3).

On the other hand, in the treatment system 1, when the treatment beam irradiation gate 13 is configured to emit and scan one treatment beam b, the treatment beam irradiation gate 13 includes the collimator 13 as shown in FIG. -1 is not provided, and one exit port is provided. Then, the direction of one treatment beam b emitted from one exit of the treatment beam irradiation gate 13 is bent by, for example, a magnet so as to fill (scan) the entire region of the lesion to be irradiated. Are scanned and irradiated. FIG. 4B schematically illustrates an example of a case where one treatment beam b is bent so as to be the treatment beam b ₁ to the treatment beam b _N and irradiated to the irradiation target lesion in the first image. Is shown. In this case, the starting point in each path of the treatment beam b ₁ to the treatment beam b _N is the position of the exit of the treatment beam irradiation gate 13. Note that the three-dimensional position of the treatment beam irradiation gate 13 having this configuration is the position (coordinates) of one exit port.

The path acquisition unit 110 starts from the position of the exit of the treatment beam irradiation gate 13 and starts from each of the treatment beams b ₁ to b _N that are bent from the start position and reach the lesion to be irradiated in the first image. Is obtained as information on the path of each treatment beam b in the treatment beam B irradiated in a predetermined three-dimensional space. In this case, the path of each treatment beam b in the treatment beam B can also be discretely expressed by a set of three-dimensional vectors as shown in the above equation (3).

(Integration image generation method)
Next, a method in which the integral image calculation unit 121 generates the first integral image and the second integral image in the search process in the medical image processing apparatus 100 will be described. First, an integrated image generation method in the integrated image calculation unit 121 will be described.

In the following description, one point in the predetermined three-dimensional space is represented as a point x. A pixel value (CT value) of a three-dimensional pixel (voxel) corresponding to the point x included in the first image virtually arranged in a predetermined three-dimensional space is represented as I ₁ (x, θ). Similarly, the pixel value (CT value) of the three-dimensional pixel (voxel) corresponding to the point x included in the second image virtually arranged in the predetermined three-dimensional space is represented by I ₂ (x, θ). It expresses. Note that the CT value is “0” when there is no voxel corresponding to the point x in the first image or the second image. Here, θ is a parameter representing the position and orientation of the first image or the second image in the three-dimensional space. The position of the exit of the treatment beam irradiation gate 13 in the treatment beam B, that is, the vector from the starting point = 0 to the point x can be expressed by the following equation (4).

In this case, the pixel value (voxel data) s ₁ (x, θ) of the pixel of the first integrated image obtained by integrating the CT values of the respective voxels located on the treatment beam B path up to the point x in the first image is And can be calculated by the following equation (5).

  In the above equation (5), t is a parameter.

Similarly, the pixel value (voxel data) s ₂ (x, θ) of the pixel of the second integrated image obtained by integrating the CT values of the respective voxels located on the path of the treatment beam B up to the point x in the second image is And can be calculated by the following equation (6).

Now, if the integrated image of the first image corresponding to a certain treatment beam b _i is S _{1, i} (θ), this integrated image S _{1, i} (θ) is expressed by the following equation (7).

Here, the following equation (8) is a set of coordinate positions in the three-dimensional space through which the treatment beam b _i passes.

In this way, the integrated image S _{1, i} (θ) is expressed as a vector in which M _i integrated pixel values are arranged. The first integrated image S ₁ (θ) can be expressed by the following equation (9) by integrating the integrated images S _{1, i} (θ) of the first image corresponding to the N treatment beams b _i. .

Similarly, the second integral image S ₂ (θ) can be expressed by the following equation (10).

Here, the set X _i is a set of pixel positions corresponding to the PTV, for example. Note that the set X _i may include a range of a predetermined margin (margin) included in the volume designated at the stage of the treatment plan such as PRV, for example. The set X _i may include all positions where the treatment beam b _i passes through the body of the patient P. The set X _i may be until the treatment beam b _i reaches the irradiation target lesion in the first image and the second image.

  With such an integral image generation method, the integral image calculation unit 121 sends the first integral image and the second integral image represented by the above equations (9) and (10) to the comparison unit 122. Output.

  In addition, when the integral image calculation unit 121 generates each integral image, as described above, the CT value of each voxel positioned on the treatment beam b path in the first image or the second image is used as the radiation. A first integral image and a second integral image are generated using a water equivalent thickness obtained by converting the amount of energy loss of water into a water thickness. Here, as an example of the conversion method for converting the CT value of each voxel included in the first image and the second image into a water equivalent thickness, the integral image calculation unit 121 is as shown in Reference Document 1 below. A regression equation based on non-linear conversion data obtained experimentally is used. As another method, the integral image calculation unit 121 may prepare a conversion table, for example, and convert the CT value into a water equivalent thickness using the conversion table. In addition, as described above, the water equivalent thickness is obtained by integrating (line integration) to obtain the depth of water (water equivalent depth), that is, the distance from the body surface of the patient P to the tumor (lesion). Can do. Reference 1 also shows that the relationship between the depth (= water thickness) when a heavy particle beam passes through an aqueous medium and the applied dose is experimentally obtained. The integrated image calculation unit 121 may convert each voxel data in the integrated image into an applied dose at each pixel position using the relationship between the water thickness and the applied dose shown in Reference Document 1. .

[Reference 1] O.D. Jakel, et al. "Relation between carbon ion ranges and x-ray CT numbers", Med. Phys. 28 (4), 701-703, 2001

  The integrated image calculation unit 121 is represented by a water conversion depth obtained by converting the CT value of each voxel located on the treatment beam b path included in the first image and the second image into a water equivalent thickness and integrating. The integrated image or an integrated image obtained by converting each voxel data in the integrated image into a given dose is output to the comparison unit 122.

  Next, a method in which the comparison unit 122 compares the first integral image and the second integral image in the search process in the medical image processing apparatus 100 will be described.

  The comparison unit 122 uses a cost function as shown in the following equation (11) in order to compare the first integral image and the second integral image.

  The comparison unit 122 obtains Δθ that minimizes the square error of the pixel value (voxel data) of the integral image by the above equation (11). Then, the comparison unit 122 minimizes the cost function using an optimization method such as a gradient method, a Newton method, or a Lucas-Kanade method (LK method). The comparison unit 122 outputs the minimized cost function value E and Δθ to the determination unit 123 as information of a comparison result obtained by comparing the first integral image and the second integral image.

  Further, the cost function used for the comparison unit 122 to compare the first integral image and the second integral image may be a cost function as shown in the following equation (12).

In the above equation (12), E _PTV represents the square error of the integral image consisting only of the pixel positions included in the PTV, and E _PRV represents the square error of the integral image consisting only of the pixel positions included in the PRV. . In the above equation (12), λ is a parameter, and when comparison is made with emphasis on alignment in PTV, for example, λ = 0.5 or more. Even when the comparison is performed using the cost function as shown in the above equation (12), the comparison unit 122 compares the cost function value E and Δθ with information on the comparison result comparing the first integral image and the second integral image. To the determination unit 123.

  By such a comparison method, the comparison unit 122 outputs information of a comparison result obtained by comparing the first integral image and the second integral image to the determination unit 123.

  Next, a method in which the determination unit 123 determines the difference between the first integrated image and the second integrated image in the search process in the medical image processing apparatus 100 will be described.

  The determination unit 123 determines whether the comparison result output from the comparison unit 122 is within a predetermined allowable range. In the determination unit 123, the following determination conditions are set.

(Determination condition 1): Δθ included in the comparison result output from the comparison unit 122 is equal to or less than a predetermined threshold value.
(Determination condition 2): The cost function value E included in the comparison result output from the comparison unit 122 is equal to or less than a predetermined threshold.

  In addition, the following determination conditions are set in the determination unit 123.

(Determination condition 3): The number of determinations for the comparison result output from the comparison unit 122 is equal to or greater than a predetermined number.

  The determination unit 123 performs determination based on the above-described determination conditions 1 to 3, and if there is at least one determination condition, there is no deviation between the first integrated image and the second integrated image. judge. Moreover, the determination part 123 determines with there being a shift | offset | difference of a 1st integral image and a 2nd integral image, when not meeting all the determination conditions of the determination conditions 1-determination conditions 3 mentioned above. And the determination part 123 outputs the determination signal showing the result of having determined the shift | offset | difference of a 1st integral image and a 2nd integral image.

  In addition, the determination unit 123 calculates a difference between the threshold values in the above-described determination condition 1 and determination condition 2 and the comparison result output from the comparison unit 122, that is, a shift amount. It outputs to 124.

  Accordingly, the moving unit 124 moves the second image in the three-dimensional space so as to move the current position of the patient P in the direction in which the shift amount is larger based on the shift amount information output from the determination unit 123. The amount of movement (including the amount of rotation) to be moved is determined. Then, the moving unit 124 outputs information indicating the determined amount of movement of the second image to the integrated image calculating unit 121. Thereby, the integral image calculation part 121 produces | generates a new 2nd integral image with the production | generation method of the integral image mentioned above.

  By such processing, in the search processing of the medical image processing apparatus 100, the patient P at the stage of treatment planning is based on the first integrated image generated from the first image and the second integrated image generated from the second image. And the current position of the patient P are determined. That is, in the search process of the medical image processing apparatus 100, the path of the treatment beam B is determined based on the first integrated image and the second integrated image. In the search process of the medical image processing apparatus 100, based on the determined shift amount, a movement amount for moving the posture of the patient P so that the current posture of the patient P approaches the posture of the patient P at the stage of the treatment plan. To decide. In other words, in the search process of the medical image processing apparatus 100, the position of the patient P is set so that the treatment beam B having an energy amount close to the energy determined in the stage of the treatment plan can be irradiated to the lesion in the patient P. Determine the amount of movement to match. Thereby, in the treatment system 1 including the medical image processing apparatus 100, the patient P is actually moved according to the movement amount determined by the search process of the medical image processing apparatus 100, and the treatment of the energy amount determined in the treatment plan is performed. The lesion can be irradiated with the beam B, and radiation treatment can be performed as planned.

  As described above, in the medical image processing apparatus 100 according to the first embodiment, the first image acquisition unit 101 acquires the first image of the patient P imaged before the treatment, and the second image acquisition unit 102 performs the treatment. A second image of the patient P taken immediately before starting is acquired. In the medical image processing apparatus 100 according to the first embodiment, the route acquisition unit 110 acquires information on a route for irradiating the treatment beam B determined in the treatment plan stage based on the first image. In the medical image processing apparatus 100 according to the first embodiment, the search unit 120 (integrated image calculation unit 121) includes a first integrated image corresponding to the first image based on information on the path of the treatment beam B, and A second integrated image corresponding to the second image is generated. In the medical image processing apparatus 100 according to the first embodiment, the search unit 120 (the comparison unit 122 and the determination unit 123) determines a shift in the path of the treatment beam B between the first integrated image and the second integrated image. The determination signal representing the determination result is output. In the medical image processing apparatus 100 according to the first embodiment, the search unit 120 (the moving unit 124) changes the posture of the current patient P to the posture of the patient P at the stage of the treatment plan based on the determined shift amount. The movement amount for approaching is determined, and when the deviation of the path of the treatment beam B in the first integral image and the second integral image is within a predetermined allowable range, the final movement amount of the patient P is expressed. Output travel distance signal. Thereby, in the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment, for example, a treatment table control unit (not illustrated) that controls movement of the treatment table 11 performs treatment table 11 based on the movement amount signal. The position of the patient P is actually moved. Thereby, in the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment, the lesion in the body of the patient P can be irradiated with the treatment beam B having an energy amount close to the energy determined in the treatment planning stage. By aligning the current position of the patient P with the ready state, radiation therapy can be performed as planned.

  As described above, the medical image processing apparatus 100 includes the first image acquisition unit 101 that acquires the three-dimensional first image of the patient P imaged by the CT imaging apparatus 12 and the CT image at a time different from the first image. A second image acquisition unit 102 that acquires a three-dimensional second image of the patient P imaged by the imaging device 12, and a radiation path set in the first image (a path through which the irradiated treatment beam B (treatment beam b) passes) ) And a first integrated value (first integrated image) obtained by integrating pixel values (CT values) of three-dimensional first pixels (voxels) included in the first image and passing through the radiation path. And a second integrated value (second integrated image) obtained by integrating pixel values (CT values) of three-dimensional second pixels (voxels) through which a path corresponding to the radiation path in the second image passes, The position of the patient P shown in the second image is the first Includes a search unit 120 for outputting a shift amount signal indicating an amount of movement of the second image to match the position of the patient P which is photographed in the image, the. Accordingly, the medical image processing apparatus 100 includes the first image acquired by the first image acquisition unit 101, the second image acquired by the second image acquisition unit 102, and the treatment beam B (treatment by the path acquisition unit 110). Based on the path (radiation path) for irradiating the beam b), it is possible to search for a movement amount for adjusting the current position of the patient P to the position when the first image is taken.

  In addition, as described above, the search unit 120 calculates the first integral value, and displays the calculated first integral value in the irradiation range in which the treatment beam B (treatment beam b) is irradiated, , An integrated image calculation unit 121 that calculates a second integrated value and generates a second integrated image representing the calculated second integrated value within the irradiation range; and a first integrated value (voxel) included in the first integrated image Data) and a second integral value (voxel data) corresponding to the first integral value (voxel data) included in the second integral image, respectively, and a comparison result of the comparison unit 122 A determination unit 123 that determines the deviation of the radiation path represented in the first integral image and the second integral image, a movement amount is determined based on the determination result of the determination unit 123, and a movement amount signal that represents the determined movement amount is obtained. And a moving part 124 for outputting. . As a result, the medical image processing apparatus 100 obtains a comparison result between the first integrated value obtained by integrating the CT value of the voxel included in the first image and the second integrated value obtained by integrating the CT value of the voxel included in the second image. Based on this, the deviation between the virtually moved position of the current patient P and the position of the patient P when the first image is taken is determined, and finally the amount of movement for moving the patient P is determined. be able to.

  In addition, as described above, the integral image calculation unit 121 includes the pixel value (CT value) of the first pixel (voxel) located on the radiation path and the second pixel (voxel) located on the path corresponding to the radiation path. ) And the pixel value (CT value) are converted by a predetermined nonlinear conversion (an experimentally obtained nonlinear conversion data) and then integrated, and the first integrated value and the second integrated value are respectively integrated. It may be calculated. As a result, the medical image processing apparatus 100 experimentally calculates the CT value of the voxel included in the first image and the CT value of the voxel included in the second image, for example, as shown in Reference Document 1 above. The amount of movement for moving the current position of the patient P can be determined based on the first integrated image and the second integrated image that are integrated after conversion by a regression equation based on the obtained nonlinear conversion data. .

  Further, as described above, the integral image calculation unit 121 calculates the pixel value (CT value) of the first pixel (voxel) located on the radiation path by nonlinear conversion (nonlinear conversion data obtained experimentally). Each pixel value (CT value) of the second pixel (voxel) located on the path corresponding to the radiation path is converted into a value (for example, water equivalent thickness) representing the amount of energy loss when the radiation passes. May be. As a result, the medical image processing apparatus 100 integrates the CT value of the voxel included in the first image and the CT value of the voxel included in the second image after, for example, conversion into a water equivalent thickness and the first integrated image. Based on the two integrated images, a moving amount for moving the current position of the patient P can be determined.

  In addition, as described above, the integral image calculation unit 121 includes the first pixel (voxel) on the radiation path that is located before the treatment beam B (treatment beam b) reaches the irradiation target region (lesion). Energy converted from the pixel value (CT value) of the second pixel (voxel) located before reaching the irradiation target region on the path corresponding to the radiation path The first integral value and the second integral value may be calculated by integrating the loss amount value (water equivalent thickness). Accordingly, the medical image processing apparatus 100 can reduce the processing amount (calculation amount) when generating the first integrated image and the second integrated image.

  Further, as described above, the movement amount signal may be transmitted to a treatment table control unit (not shown) that controls the movement of the treatment table 11 provided in the treatment apparatus 10. Thereby, based on the movement amount signal output from the medical image processing apparatus 100, the treatment table control unit (not shown) can control the movement of the treatment table 11, and the position of the patient P can be actually moved.

  Moreover, as described above, the region (lesion) to be irradiated with radiation is a region of a tumor (lesion) existing in the body of the patient P, and the radiation path may include a region of the tumor (lesion).

  Further, as described above, the route corresponding to the radiation route is a region that avoids irradiation of the treatment beam B (treatment beam b) when the second image is moved by the amount of movement searched by the search unit 120 (for example, May include areas of air that were not present at the stage of treatment planning. As a result, the medical image processing apparatus 100 changes the position of the Bragg peak of the treatment beam B (treatment beam b), so that the irradiated treatment beam B (treatment beam b) uses the energy planned in the treatment planning stage. Appropriate measures can be taken against the possibility that P cannot be given to the lesion in the body of P, or that a dangerous organ (OAR) that does not want to be irradiated with treatment beam B (treatment beam b) may be irradiated.

  Further, as described above, the treatment system 1 includes the medical image processing apparatus 100, the irradiation unit (treatment beam irradiation gate 13) that irradiates the patient P with the treatment beam B (treatment beam b), the first image, and the first image. A treatment apparatus 10 including a CT imaging device 12 that captures two images and a treatment table control unit (not shown) that controls movement of the treatment table 11 on which the patient P is fixed in accordance with a movement amount signal; May be. Thereby, the treatment system 1 is able to irradiate the lesion in the body of the patient P with the treatment beam B (treatment beam b) having an energy amount close to the energy determined in the treatment planning stage. In combination, the radiation therapy can be performed as planned.

  The medical image processing apparatus 100 includes a processor such as a CPU and a GPU and a storage device such as a ROM, a RAM, an HDD, and a flash memory. The storage device captures the processor P by the CT imaging device 12. A first image acquisition unit 101 for acquiring a three-dimensional first image of the first and a second image acquisition for acquiring a three-dimensional second image of the patient P imaged by the CT imaging device 12 at a time different from the first image Unit 102, a path acquisition unit 110 that acquires a radiation path set in the first image (a path through which the irradiated treatment beam B (treatment beam b) passes), and a three-dimensional path that is included in the first image and through which the radiation path passes. A first integrated value (first integrated image) obtained by integrating the pixel value (CT value) of the first pixel (voxel) of the first pixel (voxel), and a three-dimensional second pixel (pass through a path corresponding to the radiation path in the second image). I The position of the patient P imaged in the second image based on the second integrated value (second integrated image) obtained by integrating the pixel value (CT value) of It may be an apparatus that stores a program for causing it to function as the search unit 120 that outputs a movement amount signal representing a result of searching for the movement amount of the second image for matching with the second image.

  The medical image processing apparatus 100 includes a processor such as a CPU or GPU and a storage device such as a ROM, RAM, HDD, or flash memory. The storage device includes a processor, and the search unit 120 includes a first integral value. , A first integrated image in which the calculated first integral value is represented within the irradiation range in which radiation is irradiated, a second integral value is calculated, and a second second value in which the calculated second integral value is represented in the irradiation range is calculated. An integrated image calculation unit 121 that generates an integrated image, and a first integrated value (voxel data) that is an integrated (line integrated) value of a pixel value (CT value) of a first pixel (voxel) included in the first integrated image. And a second integral value (voxel data) that is an integral (line integral) value of the pixel value (CT value) of the second pixel (voxel) corresponding to the first integral value (voxel data) included in the second integral image. And a comparison unit 12 for comparing And a determination unit 123 that determines the deviation of the radiation path represented in the first integral image and the second integral image based on the comparison result of the comparison unit 122, and the movement amount is determined based on the determination result of the determination unit 123. In addition, it may be a device that stores a program for functioning as the moving unit 124 that outputs a movement amount signal representing the determined movement amount.

(Second Embodiment)
Hereinafter, the second embodiment will be described. The configuration of the treatment system including the medical image processing apparatus according to the second embodiment is the same as that of the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment shown in FIG. The apparatus 100 is configured to replace the medical image processing apparatus of the second embodiment (hereinafter referred to as “medical image processing apparatus 200”). In the following description, the treatment system including the medical image processing apparatus 200 is referred to as “treatment system 2”.

  In the following description, the components of the treatment system 2 including the medical image processing apparatus 200 are the same as the components of the treatment system 1 including the medical image processing apparatus 100 of the first embodiment. Are given the same reference numerals, and detailed description of each component is omitted. In the following description, only the configuration, operation, and processing of the medical image processing apparatus 200 that is a different component from the medical image processing apparatus 100 of the first embodiment will be described.

  Similarly to the medical image processing apparatus 100 of the first embodiment, the medical image processing apparatus 200 is based on the CT image output from the CT imaging apparatus 12 and the posture of the patient P at the stage of the treatment plan and the current patient P A determination signal representing the result of determining the deviation from the body position is output. Similarly to the medical image processing apparatus 100 of the first embodiment, the medical image processing apparatus 200 determines the state (position) of the patient P when performing radiation therapy based on the result of determining the shift of the patient P's body position. And a movement amount signal representing a movement amount for moving the posture so as to approach the posture of the patient P at the stage of the treatment plan. However, the medical image processing apparatus 200 speeds up the search process for searching for the amount of movement for moving the posture of the patient P so as to approach the stage of the treatment plan as compared with the medical image processing apparatus 100 of the first embodiment.

  Hereinafter, the configuration of the medical image processing apparatus 200 constituting the treatment system 2 will be described. FIG. 5 is a block diagram illustrating a schematic configuration of the medical image processing apparatus 200 according to the second embodiment. The medical image processing apparatus 200 illustrated in FIG. 5 includes a first image acquisition unit 101, a second image acquisition unit 102, a route acquisition unit 110, and a search unit 220. The search unit 220 includes a temporary positioning unit 225, an integrated image calculation unit 121, a comparison unit 122, a determination unit 123, and a movement unit 224.

  The medical image processing apparatus 200 has a configuration in which the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment is replaced with a search unit 220. The search unit 220 has a configuration in which a temporary positioning unit 225 is added to the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment. Accordingly, in the medical image processing apparatus 200, the moving unit 124 in the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment is replaced with the moving unit 224. The other components provided in the medical image processing apparatus 200 are the same as the components provided in the medical image processing apparatus 100 of the first embodiment. Therefore, in the following description, in the constituent elements of the medical image processing apparatus 200, the same constituent elements as those included in the medical image processing apparatus 100 of the first embodiment are given the same reference numerals, A detailed description of the components will be omitted. In the following description, only components that are different from the medical image processing apparatus 100 of the first embodiment will be described.

  Similar to the search unit 120 included in the medical image processing apparatus 100 of the first embodiment, the search unit 220 includes information on each path of the treatment beam b output from the path acquisition unit 110 and the first image acquisition unit. Based on the first image output from 101 and the second image output from the second image acquisition unit 102, a movement amount for matching the current position of the patient P to the position of the stage of the treatment plan is searched. . Similarly to the search unit 120 included in the medical image processing apparatus 100 of the first embodiment, the search unit 220 plans the energy that the treatment beam B to be irradiated gives to the lesion in the body of the patient P at the stage of the treatment plan. A movement amount for adjusting the position of the patient P is searched so as to approach the energy.

  However, in the medical image processing apparatus 200, as described above, the search process for searching for the movement amount for aligning the position of the patient P is performed faster than the medical image processing apparatus 100 of the first embodiment. In the medical image processing apparatus 100 according to the first embodiment, the search unit 120 searches for a movement amount for adjusting the current position of the patient P to the position of the stage of the treatment plan. However, in the medical image processing apparatus 100 according to the first embodiment, the shift between the first image and the second image, that is, the shift between the position of the patient P at the stage of the treatment plan and the current position of the patient P is large. This is because the search process in the search unit 120 may take time. More specifically, in the flowchart of the search process in the medical image processing apparatus 100 of the first embodiment shown in FIG. 3, the processes in steps S400 to S600 for searching for the final movement amount of the second image. This is because it is considered that the number of repetitions of increases. Therefore, the search unit 220 includes a temporary positioning unit 225. In the medical image processing apparatus 200, the temporary positioning unit 225 temporarily determines the movement amount of the second image so that the shift between the first image and the second image is reduced to a predetermined shift amount. By searching for the movement amount for adjusting the current position of the patient P to the position of the stage of the treatment plan from the state, the time required for the search process is shortened. In other words, the medical image processing apparatus 200 determines a deviation between the first integrated image and the second integrated image in the search process by virtually moving the second image in advance based on the temporarily determined movement amount. The search range is narrowed down in advance around the irradiation target (the lesion existing in the body of the patient P) to be irradiated with the treatment beam B (radiation), thereby speeding up the search process.

  The temporary positioning unit 225 determines the current position of the patient P based on the first image output from the first image acquisition unit 101 and the second image output from the second image acquisition unit 102 at the stage of the treatment plan. The amount of movement for adjusting to the position of is temporarily determined. More specifically, the temporary positioning unit 225 moves the second image in a predetermined three-dimensional space (inclination so that the deviation between the first image and the second image is reduced to a predetermined deviation amount. ) Is temporarily determined. Then, the temporary positioning unit 225 outputs the second image after moving based on the temporarily determined movement amount to the integrated image calculating unit 121. In addition, the temporary positioning unit 225 outputs information representing the temporarily determined movement amount to the moving unit 224.

  The integrated image calculation unit 121 outputs the second image after the temporary movement (hereinafter referred to as the second image) output from the temporary positioning unit 225 instead of the second integrated image corresponding to the second image output from the second image acquisition unit 102. , “Second provisional image”), and outputs the second integrated image to the comparison unit 122.

  Similar to the moving unit 124 in the search unit 120 included in the medical image processing apparatus 100 of the first embodiment, the moving unit 224 uses the determination result information for each path of the treatment beam b output from the determining unit 123. Based on this, a moving amount for moving the temporary moving second image in a predetermined three-dimensional space is determined, and information representing the determined moving amount is output to the integral image calculating unit 121. However, the moving unit 224 is output from the temporary positioning unit 225 when outputting a movement amount signal for moving the current position of the patient P to a position that is finally determined to match the stage of the treatment plan. Along with the amount of movement that was recorded. That is, the moving unit 224 uses the movement amount that has already been applied to the temporary moving second image for which the integrated image calculating unit 121 generates the second integrated image as the final moving amount of the second image. The movement amount signal is output.

  Here, a method in which the temporary positioning unit 225 provided in the search unit 220 in the medical image processing apparatus 200 temporarily determines the movement amount of the second image will be described. In the following description, one point in the predetermined three-dimensional space is represented as a point x.

  The temporary positioning unit 225 uses a cost function as shown in the following equation (13) in order to compare the first integrated image and the second integrated image.

In the above equation (13), I ₁ (x, θ) is a CT value of a three-dimensional voxel corresponding to a point x included in the first image virtually arranged in a predetermined three-dimensional space, I ₂ ( x, θ) represents the CT value of the three-dimensional voxel corresponding to the point x included in the second image virtually arranged in the predetermined three-dimensional space. In the above equation (13), X is a set of pixel positions. In the above equation (13), the set X includes CT values at the positions of all the pixels included in the first image and the second image. Note that the set X may be limited to pixel positions corresponding to, for example, PTV and PRV, as in the case where the integral image calculation unit 121 generates the first integral image and the second integral image.

The temporary positioning unit 225 obtains Δθ for minimizing the square error of the difference between the pixel values (CT values) of the voxels included in each of the first image and the second image by the above equation (13). The temporary positioning unit 225 minimizes the cost function using an optimization method such as a gradient method, a Newton method, or an LK method. The temporary positioning unit 225 determines a temporary movement amount ρ for moving the second image based on the cost function value E _k and Δθ minimized by comparing the first image and the second image.

  The cost function used by the temporary positioning unit 225 for comparing the first integrated image and the second integrated image may be a cost function as shown in the following equation (14).

In the above equation (14), _{X 1} is, for example, the set of pixels included in the PTV, _{X 2,} for example, represent the set of pixels included in the PRV. Further, in the above equation (14), λ is a parameter, and when comparison is made with emphasis on alignment in PTV, for example, a value of λ = 0.5 or more is set. Even when the first image and the second image are compared using the cost function as shown in the above equation (14), the temporary positioning unit 225 determines the second image based on the cost function value E _k and Δθ. A temporary movement amount ρ for movement is determined.

  The temporary positioning unit 225 outputs the second image moved based on the determined temporary movement amount ρ to the integrated image calculation unit 121 as the temporary movement second image. The temporary movement second image output from the temporary positioning unit 225 to the integrated image calculation unit 121 is represented by the following expression (15).

  By such a comparison method, the temporary positioning unit 225 compares the first image and the second image, and the temporary movement second image obtained by moving the second image based on the provisionally determined temporary movement amount ρ is obtained as an integral image. Output to the calculation unit 121. Thereafter, the search unit 220 performs a search process in the same manner as the search unit 120 included in the medical image processing apparatus 100 of the first embodiment, and outputs a movement amount signal representing the final movement amount of the patient P.

  With such a configuration and operation, the medical image processing apparatus 200 causes the first image of the patient P captured at the stage of treatment planning and the second image of the patient P captured before performing radiation therapy at the treatment stage. Based on the above, the result of determining the difference between the position of the patient P at the stage of the treatment plan and the current position of the patient P is output as a determination signal. Further, the medical image processing apparatus 200 outputs a movement amount signal for moving the current position of the patient P to a position finally determined based on the result of determining the deviation. Thereby, in the treatment system 2 provided with the medical image processing apparatus 200, for example, as in the treatment system 1 provided with the medical image processing apparatus 100 of the first embodiment, for example, the movement of the treatment table 11 is controlled (not illustrated). The treatment table control unit moves the treatment table 11 based on the movement amount signal, so that the position of the patient P is actually moved. Thereby, in the treatment system 2 provided with the medical image processing apparatus 200, the treatment beam B of the energy planned in the stage of the treatment plan is provided as in the treatment system 1 provided with the medical image processing apparatus 100 of the first embodiment. Radiation therapy can be performed as planned by matching the actual state (position) of the patient P with the state (position) where the lesion in the body of the patient P can be irradiated.

  In addition, in the medical image processing apparatus 200, the temporary positioning unit 225 included in the search unit 220 has a temporary movement amount that is temporarily determined so that the shift between the first image and the second image is reduced to a predetermined shift amount. By moving the second image, it is possible to perform the search process from a state in which the range in which the search process is performed is narrowed down in advance around the lesion in the body of the patient P to which the treatment beam B is irradiated. Thereby, in the medical image processing apparatus 200, a search process for searching for a movement amount for moving the state (position) of the patient P so as to approach the stage of the treatment plan is performed. It can be faster than.

  The search process in the medical image processing apparatus 200 can be easily considered by adding a process by the temporary positioning unit 225 to the search process in the medical image processing apparatus 100 of the first embodiment shown in FIG. . More specifically, in the search process of the medical image processing apparatus 100 of the first embodiment shown in FIG. 3, the temporary positioning unit 225 is the second before the step S100 or between the steps S200 and S300. This can be easily considered by adding a process of determining and moving the image movement amount. Therefore, detailed description regarding the flow of search processing in the medical image processing apparatus 200 is omitted.

  As described above, in the medical image processing apparatus 200 of the second embodiment, the first image acquisition unit 101 acquires the first image of the patient P taken before the treatment, and the second image acquisition unit 102 performs the treatment. A second image of the patient P taken immediately before starting is acquired. Further, in the medical image processing apparatus 200 of the second embodiment, the route acquisition unit 110 acquires information on a route for irradiating the treatment beam B determined in the treatment plan stage based on the first image. In the medical image processing apparatus 200 according to the second embodiment, after the search unit 220 (temporary positioning unit 225) temporarily moves the second image so as to reduce the deviation between the first image and the second image. The search unit 220 (integrated image calculation unit 121) generates a first integrated image corresponding to the first image and a second integrated image corresponding to the second image based on the information on the path of the treatment beam B. . In the medical image processing apparatus 200 according to the second embodiment, the search unit 220 (the comparison unit 122 and the determination unit 123) determines a shift in the path of the treatment beam B between the first integrated image and the second integrated image. The determination signal representing the determination result is output. Further, in the medical image processing apparatus 200 of the second embodiment, the search unit 220 (moving unit 224) changes the current posture of the patient P to the posture of the patient P at the stage of the treatment plan based on the determined shift amount. The amount of movement to be approached is determined, and the amount of movement already applied is adjusted when the deviation of the path of the treatment beam B in the first integral image and the second integral image is within a predetermined allowable range. A movement amount signal representing the final movement amount of the patient P is output. Accordingly, in the treatment system 2 including the medical image processing apparatus 200 according to the second embodiment, for example, the movement of the treatment table 11 is performed in the same manner as the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment. A treatment table controller (not shown) that controls the movement of the treatment table 11 based on the movement amount signal actually moves the position of the patient P. Thereby, in the treatment system 2 provided with the medical image processing apparatus 200 of the second embodiment, it is determined at the stage of the treatment plan, similarly to the treatment system 1 provided with the medical image processing apparatus 100 of the first embodiment. The current position of the patient P can be adjusted to a state in which the treatment beam B having an energy amount close to the energy can be irradiated on the lesion in the body of the patient P, and the radiation therapy can be performed as planned. In addition, in the treatment system 2 including the medical image processing apparatus 200 according to the second embodiment, the radiation of the patient P is adjusted earlier than the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment. Can be treated.

  As described above, in the medical image processing apparatus 200, the search unit 220 includes the pixel value (CT value) of the first pixel (voxel) included in the first image and the second pixel (voxel) included in the second image. ) Based on the difference between the pixel value (CT value) and the first image and the second image, and based on the temporary movement amount (temporarily determined movement amount) determined based on the determined result. The integrated image calculating unit 121 further includes a temporary positioning unit 225 that outputs a temporary moving second image in which the position of the patient P imaged in the second image is matched with the position of the patient P imaged in the first image in advance. Generates a first integrated image corresponding to the first image and a second integrated image corresponding to the provisional movement second image. Accordingly, the medical image processing apparatus 200 adjusts the current position of the patient P to the position when the first image is captured from the state in which the temporary positioning unit 225 virtually moves the position of the patient P in advance. Therefore, it is possible to search for the movement amount for the search, and to shorten the time required for the search process.

(Third embodiment)
Hereinafter, a third embodiment will be described. The configuration of the treatment system including the medical image processing apparatus according to the third embodiment is the same as that of the treatment system 1 including the medical image processing apparatus 100 according to the first embodiment illustrated in FIG. The apparatus 100 is configured to replace the medical image processing apparatus of the third embodiment (hereinafter referred to as “medical image processing apparatus 300”). In the following description, the treatment system including the medical image processing apparatus 300 is referred to as “treatment system 3”.

  In the following description, the components of the treatment system 3 including the medical image processing device 300 are the same as the components of the treatment system 1 including the medical image processing device 100 of the first embodiment. Are given the same reference numerals, and detailed description of each component is omitted. In the following description, only the configuration, operation, and processing of the medical image processing apparatus 300 that is a different component from the medical image processing apparatus 100 of the first embodiment will be described.

  Similarly to the medical image processing apparatus 100 of the first embodiment, the medical image processing apparatus 300 is based on the CT image output from the CT imaging apparatus 12 and the posture of the patient P at the stage of the treatment plan and the current patient P. A determination signal representing the result of determining the deviation from the body position is output. In addition, the medical image processing apparatus 300 presents the result of determining the position shift of the patient P to a user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300. In addition, the medical image processing apparatus 300 determines the position shift of the patient P according to the setting by the user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300. Similarly to the medical image processing apparatus 100 of the first embodiment, the medical image processing apparatus 300 is based on the result of determining the position shift of the patient P, and the state (position) of the patient P when performing radiation therapy. And a movement amount signal representing a movement amount for moving the posture so as to approach the posture of the patient P at the stage of the treatment plan.

  Hereinafter, the configuration of the medical image processing apparatus 300 constituting the treatment system 3 will be described. FIG. 6 is a block diagram illustrating a schematic configuration of a medical image processing apparatus 300 according to the third embodiment. The medical image processing apparatus 300 illustrated in FIG. 6 includes a first image acquisition unit 101, a second image acquisition unit 102, a route acquisition unit 110, a search unit 320, and a user interface unit 330. In addition, the search unit 320 includes an integrated image calculation unit 321, a comparison unit 322, a determination unit 323, and a moving unit 124.

  The medical image processing apparatus 300 has a configuration in which a user interface unit 330 is added to the medical image processing apparatus 100 of the first embodiment. Accordingly, in the medical image processing apparatus 300, the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment replaces the search unit 320. In the search unit 320, the integrated image calculation unit 121 provided in the search unit 120 is replaced with the integrated image calculation unit 321, the comparison unit 122 is replaced with the comparison unit 322, and the determination unit 123 is replaced with the determination unit 323. The other components provided in the medical image processing apparatus 300 are the same as the components provided in the medical image processing apparatus 100 of the first embodiment. Therefore, in the following description, in the constituent elements of the medical image processing apparatus 300, the same constituent elements as those included in the medical image processing apparatus 100 of the first embodiment are given the same reference numerals, A detailed description of the components will be omitted. In the following description, only components that are different from the medical image processing apparatus 100 of the first embodiment will be described.

  Similar to the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment, the search unit 320 includes information on each path of the treatment beam b output from the path acquisition unit 110 and the first image acquisition unit. Based on the first image output from 101 and the second image output from the second image acquisition unit 102, a movement amount for matching the current position of the patient P to the position of the stage of the treatment plan is searched. . Similarly to the search unit 120 included in the medical image processing apparatus 100 of the first embodiment, the search unit 320 also plans the energy that the treatment beam B to be irradiated gives to the lesion in the body of the patient P at the stage of the treatment plan. A movement amount for adjusting the position of the patient P is searched so as to approach the energy.

  However, as described above, the medical image processing apparatus 300 presents the result of determining the position shift of the patient P to a user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300. Further, in the medical image processing apparatus 300, as described above, determination of the position shift of the patient P according to the setting by the user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300 is performed.

  Similarly to the integrated image calculation unit 121 in the search unit 120 included in the medical image processing apparatus 100 according to the first embodiment, the integral image calculation unit 321 includes each path of the treatment beam b output from the path acquisition unit 110. Based on the information, a first integrated image corresponding to the first image and a second integrated image corresponding to the second image are generated and output to the comparison unit 322. Furthermore, the integral image calculation unit 321 outputs each of the generated first integral image and second integral image to the user interface unit 330. Note that the integral image calculation unit 321 generates each of the first image and the second image virtually arranged in a predetermined three-dimensional space when generating each of the first integral image and the second integral image. , It may be output to the user interface unit 330.

  Similar to the comparison unit 122 in the search unit 120 provided in the medical image processing apparatus 100 of the first embodiment, the comparison unit 322 includes the first integrated image and the second integrated image output from the integrated image calculation unit 321. Compare At this time, the comparison unit 322 compares the first integral image and the second integral image based on the setting output from the user interface unit 330. More specifically, the comparison unit 322 includes a first integration in a region corresponding to a region of interest (ROI) output from the user interface unit 330 in response to an operation for setting a partial image region by the user. The image is compared with the second integral image. In addition, the comparison unit 322 uses the parameters output from the user interface unit 330 in response to an operation for setting the parameters of the cost function by the user, for example, the cost function shown in the above equation (11) or the above equation (12). The first integrated image and the second integrated image are compared with each other. The comparison unit 322 outputs information of a comparison result obtained by comparing the first integral image and the second integral image to the determination unit 323.

  Similar to the determination unit 123 in the search unit 120 included in the medical image processing apparatus 100 according to the first embodiment, the determination unit 323 determines the first integrated image based on the comparison result information output from the comparison unit 322. And a second integrated image are determined, and a determination signal representing the determined result is output. At this time, the determination unit 323 outputs information on the determination result of the deviation between the first integrated image and the second integrated image represented by the output determination signal to the user interface unit 330. In addition, the determination unit 323 determines a shift between the first integrated image and the second integrated image according to an instruction represented by a user determination signal output from the user interface unit 330 in response to an operation by the user. That is, the determination unit 323 determines a shift between the first integrated image and the second integrated image at a timing according to the operation of the user interface unit 330 by the user. For example, when the user determination signal output from the user interface unit 330 indicates that the next determination process is instructed, the determination unit 323 outputs information of the determination result to the moving unit 124 to output the determination result. The amount of movement of the two images is determined, and a process of determining a shift between the first integrated image and the new second integrated image generated by the integrated image calculation unit 321 is executed. Further, for example, when the user determination signal output from the user interface unit 330 indicates that the determination process is to be terminated, the determination unit 323 newly adds a first integrated image, a second integrated image, and the like. The determination of the shift between the first integrated image and the second integrated image currently being performed is not performed, and the determination result output last time to the user interface unit 330 is maintained. Since the user may adopt the previous determination result, the determination unit 323 stores a history of information on the determination result obtained by determining the deviation between the first integrated image and the second integrated image. The moving amount of the second image determined by the moving unit 124 may be restored. The moving unit 124 stores a history of the determined movement amount of the second image so that the user can reproduce the movement amount of the second image from which the adopted determination result can be obtained. Good.

  The user interface unit 330 displays a result of determining the displacement of the patient P's posture to a user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300, and inputs various operations by the user. And an input device for receiving. A display device constituting the user interface unit is, for example, a liquid crystal display (LCD). The user interface unit 330 includes information on a determination result of a shift between the first integrated image and the second integrated image output from the integrated image calculation unit 321 and a shift between the first integrated image and the second integrated image output from the determination unit 323. An image for presentation is displayed on a display device. In addition, when each of the first image and the second image is output from the integral image calculation unit 321, the first integral image or the second integral image corresponding to each of the first image and the second image. You may display the image which superimposed on the display apparatus.

  The input device constituting the user interface unit is an input device such as a keyboard, a pointing device such as a mouse and a pen-type stylus, and an operation device such as buttons and switches. The user interface unit 330 accepts the operation of the input device by the user, more specifically, the setting of the region of interest ROI, the setting of the parameter of the cost function, the instruction represented by the user determination signal, and the information represented by the accepted operation To the comparison unit 322 and the determination unit 323. Note that the user interface unit 330 may include a pressure sensor as an input device, and may be configured as a touch panel combined with a display device. In this case, the user interface unit 330 detects various touch operations (such as taps and flicks) performed by the user on the first integral image and the second integral image displayed on the display device by the press sensor. Information received and received by the input operation of the received user is output to the corresponding comparison unit 322 and determination unit 323.

  Here, the display of each information in the user interface unit 330 and the input method of each setting and instruction will be described. Since the first integral image and the second integral image are three-dimensional images, they cannot be directly displayed on a display device that performs two-dimensional display. Therefore, the user interface unit 330 generates one or a plurality of cross-sectional images corresponding to the first integrated image and the second integrated image, and displays them on the display device. At this time, the user interface unit 330 displays a difference image of each cross-sectional image in order to facilitate visual comparison between the first integral image and the second integral image. Further, the user interface unit 330 may perform a color map display in which colors are classified according to the difference values of the respective cross-sectional images. In addition, the user interface unit 330 may display an outline such as PTV or PRV in a superimposed manner. Further, the user interface unit 330 may display the value of the cost function for each PTV or PRV as information. Thereby, the user confirms the cross-sectional images of the first integrated image and the second integrated image displayed on the display device, and determines the deviation between the first integrated image and the second integrated image, that is, the patient P It is possible to determine whether or not to end the determination for aligning the positions. When the user inputs a result determined by operating the input device, the user interface unit 330 outputs a user determination signal representing information input by the input device to the determination unit 323. Further, the user can set the region of interest ROI and the cost function parameters on the cross-sectional images of the first integrated image and the second integrated image displayed on the display device. When the user operates the input device to input the region of interest ROI setting or the cost function parameter setting, the user interface unit 330 sets the region of interest ROI or the cost function parameter input by the input device. The information is output to the comparison unit 322.

Here, a method in which the comparison unit 322 compares the first integrated image and the second integrated image in the region corresponding to the region of interest ROI in the search processing in the medical image processing apparatus 300 will be described. In the following description, a set of positions Y of pixels (voxels) in a predetermined three-dimensional space included in the region of interest ROI output from the user interface unit 330 is referred to as Y _ROI . In this case, the cost function shown in the above equation (11) is expressed as the following equation (16), where Y = Y _ROI .

In the above equation (16), E _ROI represents the square error of the integral image consisting only of pixel positions included in the set Y _ROI .

  The comparison unit 322 obtains Δθ for minimizing the square error of the difference between the pixel values (voxel data) of the integral image in the region corresponding to the region of interest ROI by the above equation (16). Then, the comparison unit 322 minimizes the cost function using an optimization method such as a gradient method, a Newton method, or an LK method. The comparison unit 322 outputs the minimized cost function value E and Δθ to the determination unit 323 as information of a comparison result obtained by comparing the first integrated image and the second integrated image in the region corresponding to the region of interest ROI. To do.

  Further, when the comparison unit 322 compares the first integral image and the second integral image in the region corresponding to the region of interest ROI, the position Y of the pixel (voxel) in the three-dimensional space is expressed by the following equation (17). It may be.

  In the above equation (17), the set X is, for example, a set of pixel positions corresponding to the PTV. When the position Y is compared with the first integrated image and the second integrated image in the region corresponding to the region of interest ROI as shown in the above equation (17), the comparison unit 322 also calculates the cost function value E and Δθ. The information is output to the determination unit 323 as information of a comparison result obtained by comparing the first integrated image and the second integrated image in the region corresponding to the region of interest ROI.

  By such a comparison method, the comparison unit 322 outputs information on a comparison result obtained by comparing the first integrated image and the second integrated image in the region corresponding to the region of interest ROI to the determination unit 323.

  With such a configuration and operation, the medical image processing apparatus 300 causes the first image of the patient P captured at the stage of treatment planning and the second image of the patient P captured before performing radiation therapy at the stage of treatment. Based on the above, the result of determining the difference between the position of the patient P at the stage of the treatment plan and the current position of the patient P is output as a determination signal. Moreover, the medical image processing apparatus 300 displays the result of determining the difference between the position of the patient P at the stage of the treatment plan and the current position of the patient P on the display device constituting the user interface unit 330, thereby The information is presented to a user (such as a doctor) of the treatment system 3 including the image processing apparatus 300. Thereby, the user of the treatment system 3 including the medical image processing apparatus 300 determines whether or not to end the determination of the deviation between the position of the patient P and the current position of the patient P at the stage of the treatment plan. Can do.

  In addition, the medical image processing apparatus 300 is a first image displayed on a display device by a user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300 operating an input device constituting the user interface unit 330. The region of interest ROI and the cost function parameters can be set on the cross-sectional images of the integral image and the second integral image. Thereby, the medical image processing apparatus 300 compares the first integrated image and the second integrated image in a method set by the user, that is, the position of the patient P at the stage of the treatment plan and the current position of the patient P. Can be determined.

  In addition, the medical image processing apparatus 300 outputs a movement amount signal for moving the current position of the patient P to a position finally determined based on the result of determining the deviation. Thereby, in the treatment system 3 provided with the medical image processing apparatus 300, for example, a treatment table control unit (not shown) that controls the movement of the treatment table 11 moves the treatment table 11 based on the movement amount signal. The position of the patient P is actually moved. Thereby, in the treatment system 3 provided with the medical image processing apparatus 300, the current position of the patient P can be moved to a position according to the user's judgment and instruction. Thereby, in the treatment system 3 provided with the medical image processing apparatus 300, the treatment beam B of the energy planned in the treatment plan stage is supplied to the patient P in the state (position) of the patient P according to the judgment and instruction of the user. Radiation therapy can be performed to irradiate lesions in the body.

  The search process in the medical image processing apparatus 300 is the same as the search process in the medical image processing apparatus 100 of the first embodiment shown in FIG. 3 except that the display and input in the user interface unit 330 are different. is there. More specifically, the integrated image calculation unit 321 presents each integrated image, and the determination unit 323 outputs information of the determination result represented by the determination signal to the user interface unit 330 to present to the user. Further, the comparison process in the comparison unit 322 is performed by a method set by the user by the user interface unit 330. Also. Execution and termination of the determination process in the determination unit 323 are controlled according to the determination result of the user input to the user interface unit 330. These are the same as the search processing in the medical image processing apparatus 100 of the first embodiment shown in FIG. 3 except that these are performed in the search processing in the medical image processing apparatus 300. Therefore, detailed description regarding the flow of search processing in the medical image processing apparatus 300 is omitted.

  As described above, in the medical image processing apparatus 300 according to the third embodiment, the search unit 320 (integrated image calculation unit 321) uses the path of the treatment beam B as in the medical image processing apparatus 100 according to the first embodiment. Based on this information, a first integrated image corresponding to the first image and a second integrated image corresponding to the second image are generated. At this time, in the medical image processing apparatus 300 according to the third embodiment, each of the generated first integrated image and second integrated image is output to the user interface unit 330, so that the treatment including the medical image processing apparatus 300 is performed. Presented to system 3 users (such as doctors). In the medical image processing apparatus 300 according to the third embodiment, the search unit 320 (the comparison unit 322 and the determination unit 323) performs the first integral image and the first integration image similarly to the medical image processing apparatus 100 according to the first embodiment. The deviation of the path of the treatment beam B in the two integrated images is determined, and a determination signal representing the determined result is output. At this time, in the medical image processing apparatus 300 according to the third embodiment, the determination is performed according to the setting from the user input to the user interface unit 330. In the medical image processing apparatus 300 according to the third embodiment, information indicating the determination result is output to the user interface unit 330 and presented to the user. In the medical image processing apparatus 300 according to the third embodiment, in accordance with an instruction from the user input to the user interface unit 330, determination of a shift in the path of the treatment beam B between the first integrated image and the second integrated image. Execute or exit. In the medical image processing apparatus 300 according to the third embodiment, the movement amount signal indicating the movement amount determined by the moving unit 124 based on the determination result when the determination of the deviation is finished is placed at the finally determined position. This is output as a movement amount signal for moving the current position of the patient P. Accordingly, in the treatment system 3 including the medical image processing apparatus 300 according to the third embodiment, for example, a treatment table control unit (not illustrated) that controls movement of the treatment table 11 performs treatment table 11 based on the movement amount signal. The position of the patient P is actually moved. Thereby, in the treatment system 3 provided with the medical image processing apparatus 300 of the third embodiment, the current position of the patient P can be moved to a position desired by the user, and the patient P desired by the user can be moved. In the state (position), it is possible to perform radiotherapy that irradiates the lesion in the body of the patient P with the treatment beam B of the energy planned in the treatment planning stage.

  The user interface unit 330 is not limited to the configuration provided in the medical image processing apparatus 300 according to the third embodiment, and the configuration provided in the treatment system 3 including the medical image processing apparatus 300 according to the third embodiment. It may be. Further, the user interface unit 330 is not limited to the configuration added to the medical image processing apparatus 100 of the first embodiment or the treatment system 1 including the medical image processing apparatus 100 of the first embodiment. The medical image processing apparatus 200 according to the second embodiment and the treatment system 2 including the medical image processing apparatus 200 according to the second embodiment may be added.

  In the medical image processing apparatus 300 according to the third embodiment, in the configuration of the medical image processing apparatus 300 illustrated in FIG. 6, the user interface unit 330 is a component in the search unit 320 included in the medical image processing apparatus 300. The case has been described where the image is generated according to the information output from the image and displayed (superimposed) on the display device. However, the image to be displayed (superimposed) on the display device that constitutes the user interface unit 330 is not limited to the configuration generated in the user interface unit 330, but is configured to be generated by each component that outputs information. There may be. For example, in the medical image processing apparatus 300, the integrated image calculation unit 321 in the search unit 320 generates cross-sectional images corresponding to the first integrated image and the second integrated image, and each of the generated cross-sectional images is converted to the first one. The configuration may be such that the first integrated image and the second integrated image are output to the user interface unit 330, respectively. In this case, the user interface unit 330 is configured to display each cross-sectional image output from the integral image calculation unit 321 as it is. Further, for example, in the medical image processing apparatus 300, the determination unit 323 in the search unit 320 displays a piece of information for displaying information on the determination result of the deviation between the first integrated image and the second integrated image represented by the determination signal. The information display image may be generated, and the generated information display image may be output to the user interface unit 330 as determination result information represented by the determination signal. In this case, the user interface unit 330 is configured to superimpose the single information display image output from the determination unit 323 directly on the cross-sectional image.

  As described above, the medical image processing apparatus 300 further includes the user interface unit 330 including a display device that displays at least the result determined by the determination unit 323. As a result, the medical image processing apparatus 300 determines that the deviation between the current position of the patient P virtually moved and the position of the patient P when the first image is taken is determined. It can be presented to a user (such as a doctor) of the treatment system 3 having 300.

  Further, as described above, in the medical image processing apparatus 300, the user interface unit 330 includes at least a comparison region (region of interest ROI, region of interest) within the irradiation range in which the comparison unit 322 compares the first integral value and the second integral value. The comparison unit 322 includes a first integration value and a second integration value in the comparison region corresponding to the region of interest ROI set by the input device. May be compared. Thereby, the medical image processing apparatus 300 is a method set by a user (such as a doctor) of the treatment system 3 including the medical image processing apparatus 300 when the first image of the current position of the patient P is captured. A search process for searching for a movement amount to match the position can be performed.

  Further, as described above, the treatment system 3 may further include the user interface unit 330 including a display device that displays information when the search unit 320 searches for the movement amount of the second image. Thereby, the treatment system 1 determines the shift between the current position of the patient P virtually moved and the position of the patient P when the first image is taken, and the processing state of the medical image processing apparatus 300 Can be presented to a user (such as a doctor) of the treatment system 3.

  As described above, in the treatment system 3, the user interface unit 330 searches for a search region (a region of interest ROI or a cost function parameter) in which the search unit 320 searches for the movement amount of the second image. The search unit 320 further includes an input device to be set, and the search unit 320 searches for the movement amount of the second image based on the first integral value and the second integral value corresponding to the region of interest ROI set by the input device. Good. Thereby, the treatment system 1 uses the method set by the user (such as a doctor) to adjust the movement amount for adjusting the current position of the patient P by the medical image processing apparatus 300 to the position when the first image is captured. Search processing for searching can be performed.

  As described above, in the medical image processing apparatus of each embodiment, the first image that is a three-dimensional CT image of the patient P imaged before treatment and the three-dimensional CT image of the patient P that is currently imaged. Each of the certain second image and information on the path for irradiating the treatment beam B determined based on the first image are acquired. In the medical image processing apparatus according to each embodiment, in the first image and the second image, the pixel value (CT value) of a three-dimensional pixel (voxel) located on the path of the treatment beam B is used as the energy loss of radiation. A first integrated image corresponding to the first image and a second integrated image corresponding to the second image, which are integrated (line integration) after the amount is converted into the water equivalent thickness converted into the water thickness, are generated. In the medical image processing apparatus according to each embodiment, the current state of the patient P (the position including the position, the direction, and the like) is determined by determining the deviation of the path of the treatment beam B between the first integrated image and the second integrated image. ) Is searched for the amount of movement to match the state of the treatment plan. And in the medical image processing apparatus of each embodiment, the 2nd image according to the deviation | shift amount when the deviation | shift of the path | route of the treatment beam B in a 1st integral image and a 2nd integral image becomes in the predetermined tolerance. Is determined as the final movement amount of the patient P for adjusting the current state of the patient P to the state of the patient P in the stage of the treatment plan. In the medical image processing apparatus of each embodiment, a movement amount signal representing the determined final movement amount of the patient P is output. Thereby, in the treatment system provided with the medical image processing apparatus of each embodiment, for example, the treatment table control unit that controls the movement of the treatment table moves the treatment table based on the movement amount signal, thereby Actually move the state. Thereby, in the treatment system provided with the medical image processing apparatus of each embodiment, the treatment beam B having an energy amount close to the energy determined in the treatment planning stage can be irradiated to the lesion in the patient P at present. In accordance with the condition of the patient P, radiation therapy can be performed as planned.

  In the second embodiment and the third embodiment, the configuration in which the constituent elements that are characteristic in each embodiment are added to the medical image processing apparatus 100 of the first embodiment has been described. However, the constituent elements that are characteristic in each embodiment are not limited to the configurations that are exclusively provided in the medical image processing apparatus. That is, the constituent elements that are characteristic in each embodiment may be provided simultaneously in the medical image processing apparatus. For example, a medical image processing apparatus provided with the temporary positioning unit 225 provided in the medical image processing apparatus 200 of the second embodiment and the user interface unit 330 provided in the medical image processing apparatus 300 of the third embodiment at the same time. It may be configured. In this case, other components included in the medical image processing apparatus are changed as appropriate to realize functions corresponding to the respective components.

  In each embodiment, the configuration in which each of the medical image processing apparatus and the treatment apparatus 10 is a separate apparatus has been described. However, the medical image processing apparatus and the treatment apparatus 10 are not limited to configurations that are separate apparatuses, and may be configured such that the medical image processing apparatus and the treatment apparatus 10 are integrated.

  In each embodiment, the comparison unit and the determination unit determine the displacement of the pixel value on the treatment beam b path between the first integral image and the second integral image, and as a result, the body tissue on the treatment beam b path is In the case where there is a large deviation, a case has been described in which appropriate measures are taken to move the current patient P so that the body tissues match. However, measures when the pixel values on the path of the treatment beam b are greatly deviated are not limited to the methods described in the embodiments. For example, when the intensity of the treatment beam b irradiated in the treatment stage can be changed, instead of moving the current patient P, a measure for changing the intensity of the treatment beam b may be taken. More specifically, as a result of comparing the distance (water equivalent depth) from the body surface of the patient P to the lesion represented by each of the first integral image and the second integral image, When the position of the Bragg peak in the path is shifted in a direction deeper than the stage of the treatment plan, a measure for reducing the intensity of the treatment beam b may be taken. On the other hand, as a result of comparing the distance (water equivalent depth) from the body surface of the patient P to the lesion represented by each of the first integral image and the second integral image, the Bragg peak in the path of any treatment beam b If the position is shifted in a direction shallower than the stage of the treatment plan, a measure for increasing the intensity of the treatment beam b may be taken. In this case, the intensity of the treatment beam b in the medical image processing apparatus may be changed by a component corresponding to the moving unit.

  The medical image processing program used in the treatment system described in the above embodiment includes a computer, a first image acquisition unit that acquires a first three-dimensional image of a subject imaged by an imaging device, and a first image Included in the first image is a second image acquisition unit that acquires a three-dimensional second image of the subject imaged by the imaging device at different times, a path acquisition unit that acquires a radiation path set in the first image, and A first integrated value obtained by integrating the pixel values of the three-dimensional first pixel through which the radiation path passes and a pixel value of the three-dimensional second pixel through which the path corresponding to the radiation path in the second image passes are integrated. A search for outputting a movement amount signal representing a movement amount of the second image for matching the position of the subject imaged in the second image with the position of the object imaged in the first image based on the two integral values. A medical image processing apparatus comprising: A medical image processing program for functioning as a.

  According to at least one embodiment described above, a first image acquisition unit (101) that acquires a three-dimensional first image of a subject (patient P) imaged by an imaging device (CT imaging device 12); A second image acquisition unit (102) that acquires a three-dimensional second image of the subject (patient P) imaged by the imaging device (CT imaging device 12) at a time different from the first image; A path acquisition unit (110) that acquires a set radiation path (a path through which the irradiated treatment beam B (treatment beam b) passes), and a three-dimensional first pixel (voxel) that is included in the first image and passes through the radiation path ) And the pixel value (CT value) of the three-dimensional second pixel (voxel) through which the path corresponding to the radiation path in the second image passes is integrated. Based on the second integral value, the second image A search unit (120) for outputting a movement amount signal representing a movement amount of the second image for adjusting the position of the subject (patient P) to the position of the subject (patient P) imaged in the first image; The patient can be positioned so that the planned radiation energy can be applied to the lesion.

  Note that, for example, the search unit 120 illustrated in FIG. 2, the integrated image calculation unit 121 that configures the search unit 120, the comparison unit 122, the determination unit 123, the moving unit 124, and the like The program for realizing the functions is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed, thereby executing the above-described treatment system according to the present embodiment. Various functions may be realized. Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

  Further, the “computer-readable recording medium” refers to a volatile memory (for example, DRAM (Dynamic) in a computer system serving as a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Random Access Memory)) that holds a program for a certain period of time is also included. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what implement | achieves the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1, 2, 3 ... treatment system, 10 ... treatment device, 11 ... treatment table, 12 ... CT imaging device, 13 ... treatment beam irradiation gate, 13-1 ... collimator, DESCRIPTION OF SYMBOLS 100, 200, 300 ... Medical image processing apparatus, 101 ... 1st image acquisition part, 102 ... 2nd image acquisition part, 110 ... Path | route acquisition part, 120, 220, 320 ... Search , 121, 321... Integral image calculation unit, 122, 322... Comparison unit, 123, 323... Determination unit, 124, 224. ..User interface part

Claims (15)

A first image acquisition unit for acquiring a three-dimensional first image of the subject imaged by the imaging device;
A second image acquisition unit that acquires a three-dimensional second image of the subject imaged by the imaging device at a time different from the first image;
A route acquisition unit for acquiring a radiation route set in the first image;
A first integrated value obtained by integrating pixel values of three-dimensional first pixels included in the first image and passing through the radiation path; and a three-dimensional path through which a path corresponding to the radiation path in the second image passes. Based on the second integrated value obtained by integrating the pixel value of the second pixel, the position of the subject imaged in the second image is matched with the position of the object imaged in the first image. A search unit for outputting a movement amount signal representing the movement amount of the second image;
A medical image processing apparatus comprising: The search unit
The first integral value is calculated, the calculated first integral value is represented within an irradiation range in which radiation is irradiated, the second integral value is calculated, and the calculated second integral value is calculated. An integrated image calculation unit for generating a second integrated image represented in the irradiation range;
A comparison unit that compares the first integral value included in the first integral image with the second integral value corresponding to the first integral value included in the second integral image;
A determination unit for determining a shift of the radiation path represented in the first integral image and the second integral image based on a comparison result of the comparison unit;
A movement unit that determines the movement amount based on a determination result of the determination unit, and outputs the movement amount signal representing the determined movement amount;
Comprising
The medical image processing apparatus according to claim 1. The search unit
Based on a difference between a pixel value of the first pixel included in the first image and a pixel value of the second pixel included in the second image, a shift between the first image and the second image is determined. Based on the provisional movement amount determined based on the determination result, the position of the subject imaged in the second image is adjusted in advance to the position of the object imaged in the first image A temporary positioning unit that outputs the temporary movement second image;
The integral image calculation unit includes:
Generating the first integrated image corresponding to the first image and the second integrated image corresponding to the temporary moving second image;
The medical image processing apparatus according to claim 2. A user interface unit including a display device that displays at least the determination result of the determination unit;
The medical image processing apparatus according to claim 2 or 3. The user interface unit includes:
An input device for setting a comparison region within the irradiation range in which at least the comparison unit compares the first integral value and the second integral value;
The comparison unit includes:
Comparing the first integral value and the second integral value in the comparison region set by the input device;
The medical image processing apparatus according to claim 4. The integral image calculation unit includes:
The pixel value of the first pixel located on the radiation path and the pixel value of the second pixel located on the path corresponding to the radiation path are integrated after being converted by a predetermined nonlinear conversion. Calculating each of the first integral value and the second integral value;
The medical image processing apparatus according to any one of claims 2 to 5. The integral image calculation unit includes:
When the radiation passes through the pixel value of the first pixel located on the radiation path and the pixel value of the second pixel located on the path corresponding to the radiation path by the nonlinear conversion. Convert to a value that represents the amount of energy loss,
The medical image processing apparatus according to claim 6. The integral image calculation unit includes:
The pixel value of the first pixel on the radiation path located before the radiation reaches the irradiation target area and the time until the irradiation target area is reached on the path corresponding to the radiation path Integrating the value of the energy loss amount obtained by converting each of the pixel values of the second pixels located at a position, and calculating each of the first integral value and the second integral value;
The medical image processing apparatus according to claim 7. The movement amount signal is:
Transmitted to the treatment table controller that controls the treatment device,
The medical image processing apparatus according to any one of claims 1 to 8. The target area of radiation is
A region of a tumor present in the subject,
The radiation path is
Including the area of the tumor,
The medical image processing apparatus according to any one of claims 1 to 9. The path corresponding to the radiation path is
When the second image is moved by the movement amount searched by the search unit, including a region that avoids radiation irradiation,
The medical image processing apparatus according to any one of claims 1 to 10. The medical image processing apparatus according to any one of claims 1 to 11,
Control of movement of an irradiation unit that irradiates the subject with radiation, the imaging device that captures the first image and the second image, and a treatment table on which the subject is mounted and fixed according to the movement amount signal A treatment device comprising a treatment table controller that
A treatment system comprising: A user interface unit including a display device that displays information when the search unit searches for a movement amount of the second image;
The treatment system according to claim 12. The user interface unit includes:
An input device for setting a search area for searching for a movement amount of the second image by the search unit;
The search unit
Searching the moving amount of the second image based on the first integral value and the second integral value corresponding to the search area set by the input device;
The treatment system according to claim 13. Computer
A first image acquisition unit for acquiring a three-dimensional first image of the subject imaged by the imaging device;
A second image acquisition unit that acquires a three-dimensional second image of the subject imaged by the imaging device at a time different from the first image;
A route acquisition unit for acquiring a radiation route set in the first image;
A first integrated value obtained by integrating pixel values of three-dimensional first pixels included in the first image and passing through the radiation path; and a three-dimensional path through which a path corresponding to the radiation path in the second image passes. Based on the second integrated value obtained by integrating the pixel value of the second pixel, the position of the subject imaged in the second image is matched with the position of the object imaged in the first image. A search unit for outputting a movement amount signal representing the movement amount of the second image;
A medical image processing program for causing a medical image processing apparatus to function.

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