JP2016168077A - Treatment planning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment planning device which can appropriately determine whether a dose distribution to be formed is within an allowable range as treatment in a treatment plan even when an irradiation object is moved or deformed due to different causes.SOLUTION: The treatment planning device includes: a movement deformation instruction unit instructing a condition for an irradiation object to be moved or deformed; a movement deformation calculation unit calculating movement deformation irradiation object image data by moving or deforming the irradiation object expressed by treatment planning time irradiation object image data based on the condition instructed by the movement deformation instruction unit; a dose distribution calculation unit calculating a movement deformation dose distribution which is a dose distribution to be formed in the irradiation object in irradiating the irradiating object with radiation, the irradiation object expressed by the movement deformation irradiation object image data, by using treatment plan data created by a treatment plan data creation unit; and a dose distribution information display unit displaying dose distribution information based on the movement deformation dose distribution.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a suitable treatment planning apparatus for performing a treatment plan in radiation therapy in which treatment is performed by irradiating a lesion site of a patient with radiation, a particle beam or the like.

  In radiotherapy, first, 3D CT data for treatment planning obtained by imaging an affected area of a patient using an X-ray CT (Computed Tomography) apparatus is acquired, and a treatment plan is made based on the diagnosis result of the CT data. At this time, the position and shape of the tumor affected part are specified based on the three-dimensional CT data, and the irradiation direction and radiation dose are determined. Next, radiation therapy is performed based on the determined treatment plan. However, if a considerable amount of time has passed between CT imaging and radiation therapy, the position and position of the patient on the treatment table at the time of treatment may be different from the position and position of the patient at the time of treatment planning. Many. Therefore, before performing radiotherapy, irradiation is performed by correcting the deviation between the current patient position and the patient position at the time of treatment planning.

  There are cases in which it is not possible to sufficiently cope with the deformation of the affected area, which is the irradiation target, or the change in the body position, simply by correcting the displacement of the patient position. As a technique for solving such a problem, Patent Document 1 discloses irradiation at the planning stage so that the irradiation field at the irradiation stage is adapted to the irradiation stage, that is, the target volume (affected part) of the patient moved or deformed at the time of treatment. A technique for converting and irradiating a field is disclosed. Further, in Patent Document 2, an irradiation target that moves due to breathing or the like is monitored by a laser rangefinder or a fluoroscopic image, and a gate signal is output when the amount of movement is within a certain range, and the gate signal is output. A technique for forming a uniform irradiation field in a short time by determining the number of times of repainting to irradiate one surface during the period is disclosed.

  Patent Document 3 discloses a technique for estimating an irradiation error due to an irradiation system and determining an irradiation parameter in consideration of the estimated irradiation error. Further, in Patent Document 4, for the purpose of facilitating the radiation irradiation plan in the so-called spot scanning irradiation method in which irradiation is performed while moving the irradiation spot, in particular, the quantitative determination of the irradiation time, the elapsed time and the irradiation position are determined. A technique is disclosed in which information is calculated and the influence on the dose distribution is actually calculated while knowing the spot irradiated at a certain timing when the organ moves due to fluctuation due to respiration.

JP 2008-68093 A JP 2010-253250 A JP 2008-136523 A JP 2008-178568 A

  As described above, depending on the part, the affected part may move or deform due to respiration. In addition, if the patient's posture is different during treatment, the shape of the affected part may be deformed at the time of treatment planning. Further, depending on the site of the affected area, the shape and position of the affected area may change depending on, for example, the state of intestinal gas or the state of the bladder. Further, the position of the affected area at the time of treatment planning and the position at the time of treatment may be shifted due to the positioning accuracy of the apparatus. Alternatively, as described in Patent Document 3, an irradiation error caused by the irradiation system is also conceivable.

  As described above, during treatment, that is, at the time of irradiation, the cause of movement and deformation may differ depending on the irradiated region, and the patient who is the irradiation target due to various factors such as positioning accuracy and irradiation error of the irradiation system. In some cases, a radiation field different from the treatment plan is formed in the body, that is, a dose distribution different from the treatment plan is formed. Each of the prior arts described in Patent Documents 1 to 4 is a technique for eliminating the dose distribution that is formed from a dose distribution different from the treatment plan based on one factor. For example, as in Patent Document 3, even if the irradiation parameter is determined in consideration of the irradiation error caused by the irradiation system, if the irradiation target moves or deforms, a dose distribution as planned is formed on the irradiation target. I can't.

  On the other hand, by irradiating with the irradiation parameters created in the treatment plan, the formed dose distribution may fall within the allowable range for treatment even if the irradiation target moves or deforms.

  The present invention has been made to solve the above-described problems. When irradiation is performed according to a certain treatment plan, the formed dose distribution is treated as a treatment even if the factors that move or deform vary depending on the irradiation target. It is an object of the present invention to provide a treatment planning apparatus that can appropriately determine whether a treatment plan is within an allowable range.

  The treatment planning apparatus according to the present invention creates treatment plan data for obtaining irradiation parameter of radiation at the time of treatment based on the irradiation target image data obtained by imaging the irradiation target at the time of treatment planning. Based on the condition instructed by the movement / deformation instructing unit, the movement / deformation instructing unit for instructing a condition for moving or deforming the irradiation target, and the irradiation target represented by the irradiation target image data at the time of treatment planning A moving deformation calculation unit that obtains moving deformation irradiation target image data by moving or deforming, and an irradiation target expressed by the moving deformation irradiation target image data using the treatment plan data created by the treatment plan data creation unit A dose distribution calculation unit for obtaining a moving deformation dose distribution which is a dose distribution formed on the irradiation target when irradiated with radiation; It is obtained by so and a dose distribution information display section for displaying the dose distribution information based on.

  According to the present invention, it is possible to provide a treatment planning apparatus that can appropriately determine whether or not the dose distribution to be formed is within a range that is acceptable as a treatment even if the factors that move or deform vary depending on the irradiation target.

It is a block diagram which shows the structure of the treatment plan apparatus by Embodiment 1 of this invention. It is a block diagram which shows the structure of the radiotherapy system containing the treatment plan apparatus of this invention. It is a flowchart which shows operation | movement of the treatment planning apparatus by Embodiment 1 of this invention. It is a figure which shows an example of the dose distribution information which the dose distribution information display part of the treatment planning apparatus by Embodiment 1 of this invention displays. It is a block diagram which shows the structure of the treatment planning apparatus by Embodiment 2 of this invention. It is a block diagram which shows the structure of the treatment planning apparatus by Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 2 is a block diagram showing the overall configuration of a particle beam therapy system including the treatment planning apparatus of the present invention. The treatment planning device 1, the image data transmitting device 3, and the treatment plan data receiving device 4 which are the objects of the present invention are connected by a network 2 for communication between the devices. The image data transmission device 3 transmits image data 31 for treatment planning to the treatment planning device 1. The image data transmission device 3 includes an image data storage device 32 and an image photographing device 33, for example. The image data 31 is, for example, CT / MR / PET or the like, image data of an irradiation target irradiated with radiation, that is, a patient including an affected area of a patient to be treated and a periphery of the affected area.

  The treatment plan data 41 created by the treatment planning device 1 is transmitted to the treatment plan data receiving device 4 as output data of the treatment planning device 1. The treatment plan data receiving device 4 includes, for example, a treatment plan data storage device 42 and a treatment device 43. The treatment plan computer 11 performs the main processing in the treatment plan apparatus 1. The treatment planning apparatus 1 is provided with an input device 12 for giving an instruction to the treatment plan computer 11 and a display device 13 for presenting information processed by the treatment plan computer 11 to the user. The input device 12 may be any input device such as a keyboard, a mouse, and a pen tablet as long as it is assumed to use a computer. The display device 13 may be any display device such as a liquid crystal display, a touch panel type tablet display, or a projector as long as it is assumed to use a computer.

  FIG. 1 is a block diagram showing a configuration of a treatment plan computer 11 of the treatment plan apparatus 1 according to Embodiment 1 of the present invention. The image data input unit P1 captures the image data 31 into the treatment plan computer 11. The image data 31 taken into the treatment plan computer 11 is stored in the image data storage unit P2 in the treatment plan computer 11. The user selects image data stored in the image data storage unit P2 in the image data selection unit P3 (image data selection operation). Here, the selected image data is referred to as irradiation target image data during treatment planning. The user uses the contour data creation unit P4 to create contour data so as to be superimposed on the treatment target irradiation target image data (contour data creation work). The contour data includes contour data necessary for a treatment plan, such as a target indicating a treatment target, an important organ that needs to avoid irradiation in treatment, and a body contour indicating the shape of a patient's body. In the treatment plan, using the contour data, for example, an irradiation parameter is determined such that the dose is concentrated on the affected area and the dose of the important organ is lowered. Further, in the present invention, contour data is also used when evaluating the dose of the affected area and the dose of the important organ when the irradiation object that has been moved and deformed as described below is irradiated. The contour data created by the contour data creation unit P4 is stored in the contour data storage unit P5.

  The treatment plan data creation unit P6 creates treatment plan data using treatment target irradiation target image data / contour data. At this time, if there is a condition to be input by the user in preparation of the treatment plan, it is entered (treatment plan data creation work). The treatment plan data includes the radiation parameters necessary for the treatment plan, such as the type of beam to be irradiated, such as the type of particle, the beam energy, the beam direction, such as the gantry angle, the prescription dose, and the number of divisions. . The treatment plan data created by the treatment plan data creation unit P6 is stored in the treatment plan data storage unit P7.

  The movement / deformation instructing unit P8 instructs on the assumption that the treatment site is moved or deformed when actually treating. Since the cause of movement / deformation and the state of movement / deformation vary depending on the treatment site, the movement / deformation instruction unit P8 instructs the movement and deformation of the organ according to the treatment site. The movement / deformation instruction by the movement / deformation instructing unit P8 may include input of the amount of movement of the contour data as a numerical value, the user specifying the movement destination / deformed shape of the contour data with a drawing tool, or the like. Included in the geometric information of the contour data, the geometric information of the image data, or the image data, such as instructing to automatically calculate the movement amount / deformation amount from a plurality of image data taken in accordance with the respiratory phase This includes using meta information such as respiratory phase (moving deformation amount instruction work). In the movement / deformation calculation unit P9, the movement amount / deformation amount is calculated for the contour data by the method specified by the movement / deformation instruction unit P8. Image data obtained by moving and deforming the data is temporarily created on the memory as moving deformation irradiation target image data. As described above, the moving deformation irradiation target image data includes image data obtained by moving and deforming the irradiation target image data at the time of treatment planning, and contour data subjected to moving deformation.

  In the dose distribution calculation unit P10, using the treatment plan data and the moving deformation irradiation target image data, the movement deformed irradiation target represented by the moving deformation irradiation target image data is irradiated with radiation according to the irradiation parameters of the treatment plan data. In this case, a moving deformation dose distribution which is a dose distribution formed on the irradiation target is calculated. The moving deformation dose distribution obtained by the dose distribution calculation unit P10 is displayed on the dose distribution information display unit P11. As the display in the dose distribution information display part P11, a distribution display by color according to the intensity of the dose, which is generally assumed to display the dose distribution as a treatment planning apparatus, or a dose volume histogram (DVH, Dose Volume). Any display may be used as long as the display is based on dose distribution information assumed as a treatment planning apparatus, such as a display by Histogram). The treatment plan data 41 is transmitted from the treatment plan data output unit P12 to the treatment plan data receiving device 4.

  FIG. 3 is a flowchart showing a procedure for creating treatment plan data by the treatment planning apparatus according to the first embodiment of the present invention. Creation of treatment plan data starts from image data selection S1. In the image data selection part P3, treatment target irradiation target image data for which treatment plan data is to be created is selected (step S1). As a method of selecting the irradiation target image data at the time of treatment planning, an image data list of a specific patient is acquired from the image data storage unit P2, and the user is allowed to select image data, or the image photographing device 33 is sent to the treatment planning device 1. For example, a method generally used at the time of creating a treatment plan, such as transmitting the image data 31 directly, is adopted.

  Next, the contour data creating unit P4 creates contour data to be superimposed on the selected treatment plan irradiation target image data (step S2). After the contour data is created, the treatment plan data creation unit P6 creates treatment plan data corresponding to the contour data (step S3). Since the treatment plan data is created corresponding to the contour data created based on the irradiation target image data at the time of treatment planning, the treatment plan data is eventually created based on the irradiation target image data at the time of treatment planning. Become. Steps S1 to S3 so far are the same as the conventional treatment planning method. Next, in the movement / deformation instructing section P8, the contour data is instructed as to the assumed movement / deformation (movement / deformation caused by the patient's breathing, movement / deformation caused by the influence of gravity such as the inclination of the patient's body position). Moving deformation irradiation target image data, which is a result of moving / deforming the treatment plan irradiation target image data including the contour data and moving / deforming the treatment planning irradiation target image data including the contour data. Is obtained in the memory (step S4). As the moving deformation irradiation target image data, the image data obtained by moving and deforming the irradiation target image data not including the contour data and the contour data subjected to the movement deformation may be separately stored in the memory. The image data may be stored as image data including the contour data, and the data format may be any.

  The movement / deformation instructed by the movement / deformation instruction unit P8 may instruct a plurality of movement / deformation. When a plurality of movement deformations are instructed, the movement deformation calculation unit P9 obtains movement deformation irradiation target image data for each movement deformation, that is, obtains a plurality of movement deformation irradiation target image data.

  In the dose distribution calculation unit P10, the various conditions given in step S4 (treatment target irradiation target image data, contour data, treatment plan data, moving deformation irradiation target image data, etc.) are used, and the dose distribution of each condition is calculated. Calculation is performed (step S5), and the result is displayed on the dose distribution information display section P11. As described above, what is displayed on the dose distribution information display part P11 is for the user to determine the validity / validity of the treatment plan data such as distribution display by color according to the intensity of the dose or DVH. Dose distribution information. An example in which DVH is displayed as dose distribution information is shown in FIG. In FIG. 4, for example, the dose distribution information obtained by estimating the dose distribution obtained by estimating the movement when the organ moves due to respiration is expressed in DVH is moved 1, and the dose obtained by estimating the case where the organ is deformed depending on the posture of the patient. The dose distribution information expressing the distribution in DVH is shown as modification 1. In the display, DVH when there is no movement deformation from the treatment plan is also displayed as a treatment plan. By displaying in this way, the user can determine whether this treatment plan is appropriate, depending on whether the dose to the important organ is within an acceptable range or whether the dose to the treated organ is a dose required for treatment. Judgment can be made.

  As described above, in steps S <b> 1 to S <b> 3, treatment plan data is created based on treatment plan irradiation target image data including, for example, CT data including an affected part of a patient imaged during treatment planning. That is, an irradiation parameter for giving an optimal dose distribution to the affected area when imaged at the time of treatment planning is created as treatment plan data. Since actual irradiation is performed at a different time and at a different place from the treatment plan, it is assumed that the affected part of the patient moves or deforms at the time of the treatment plan due to various causes. If the affected area of the patient, that is, the organ to be treated has moved or deformed from the time of the treatment planning, when irradiation is performed according to the treatment plan data created in steps S1 to S3, it is formed in the patient to be irradiated. The dose distribution is not the dose distribution set at the time of treatment planning. The dose distribution calculation unit P10 calculates the dose distribution when irradiation according to the treatment plan data is performed on an organ that has moved or deformed, assuming movement or deformation of the organ, and the dose distribution itself or By presenting the dose distribution information such as DVH to the user, the dose distribution is evaluated based on the dose distribution information presented by the user, and the validity and validity of the treatment plan data is evaluated (step S6). When the effectiveness / relevance of the treatment plan data is insufficient and the user determines that replanning is necessary (YES in step S6), the treatment plan data creation in step S3 can be performed again. When it is determined that the validity / validity of the treatment plan data is sufficient (NO in step S6), the treatment plan data is output to the treatment plan data receiving device (step S7). This completes the procedure for creating treatment plan data.

  According to the treatment planning apparatus according to the first embodiment of the present invention, the process of estimating the dose distribution error due to the movement or deformation of the organ is provided in the process of planning the treatment plan. And the effect on deformation can be evaluated. Scanning irradiation is an irradiation method that obtains a three-dimensional dose distribution by irradiating a small-sized beam for each spot. Therefore, if an organ moves or deforms during irradiation, It is likely that errors will occur from the dose distribution, and the assessment of effects is particularly important. With the treatment planning apparatus according to Embodiment 1 of the present invention, it is possible to evaluate the influence on organ movement and deformation, and a more appropriate treatment plan can be made.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing the configuration of the treatment plan computer 111 of the treatment plan apparatus according to Embodiment 2 of the present invention. The treatment plan computer 111 according to the second embodiment has a configuration in which a CT value error calculation unit P13 is added to the configuration of the treatment plan computer 11 according to the first embodiment.

  When radiation, particularly particle beams, is irradiated, the proportion of absorbed particle beams is related to the so-called CT value of the irradiation object. The CT value is a value corresponding to the electron density obtained from the X-ray CT image. The relationship between the CT value and the rate at which particle beams are absorbed may contain errors depending on the organ, so it is closer to the dose distribution as a physical phenomenon by considering the CT value error in the dose distribution calculation. The dose distribution can be presented to the user. For example, by specifying the CT value error to be considered in the movement deformation instruction unit P8, the movement deformation irradiation obtained in the movement deformation calculation unit P9 based on the designated CT value error in the CT value error calculation unit P13. A CT value error is given to the target image data. The dose distribution calculation unit P10 obtains a dose distribution in consideration of a given CT value error, and presents dose distribution information including the CT value error, thereby assisting in creating highly accurate treatment plan data. Can be done.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing the configuration of the treatment plan calculator 211 of the treatment plan apparatus according to Embodiment 3 of the present invention. The treatment plan computer 211 according to the third embodiment has a configuration in which a patient positioning error calculation unit P14 is added to the configuration of the treatment plan computer 11 according to the first embodiment.

  For example, by designating a patient positioning error to be considered in the movement deformation instruction section P8, the movement deformation irradiation obtained by the movement deformation calculation section P9 based on the designated patient positioning error in the patient positioning error calculation section P14. An error due to positioning error is given to the target image data. In the dose distribution calculation unit P10, a dose distribution is calculated in consideration of a given positioning error, and dose distribution information including the positioning error is presented. In this way, by considering patient positioning errors, dose distribution information when patient positioning errors occur can be presented to the user, and support for creating more robust treatment plan data can be provided Is possible.

  In the present invention, the respective embodiments can be appropriately modified or omitted within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Treatment plan apparatus, 31 Treatment plan data, P6 Treatment plan data preparation part, P8 Movement deformation instruction part, P9 Movement deformation calculation part, P10 Dose distribution calculation part, P11 Dose distribution information display part, P13 CT value error calculation part, P14 Patient positioning error calculator

Claims (5)

A treatment planning device for creating a plan related to radiation irradiation at the time of radiation treatment,
Based on the irradiation target image data obtained by imaging the irradiation target at the time of the treatment plan, a treatment plan data creation unit that calculates the irradiation parameters of the radiation at the time of the treatment and generates the treatment plan data, and the irradiation target moves Or a movement / deformation instructing unit for instructing conditions for deformation;
A movement / deformation calculation unit that obtains moving deformation irradiation target image data by moving or deforming the irradiation target expressed by the irradiation target image data at the time of treatment planning based on the conditions instructed by the movement / deformation instruction unit;
Moving deformation that is a dose distribution formed on the irradiation target when the irradiation target represented by the moving deformation irradiation target image data is irradiated with radiation using the treatment plan data created by the treatment plan data creation unit A dose distribution calculation unit for obtaining a dose distribution;
A treatment planning apparatus comprising: a dose distribution information display unit that displays dose distribution information based on the moving deformed dose distribution. The movement deformation instruction unit instructs a plurality of movement or deformation conditions based on an operator input,
The movement deformation calculation unit obtains a plurality of movement deformation irradiation target image data based on each condition of the plurality of movement or deformation conditions,
In the dose distribution calculation unit, for each irradiation target represented by each of the plurality of moving deformation irradiation target image data, each moving deformation dose distribution is obtained,
2. The treatment planning apparatus according to claim 1, wherein the dose distribution information display unit displays each of the dose distribution information based on the moving deformation dose distribution obtained in the dose distribution calculation unit.   The treatment planning apparatus according to claim 1, further comprising a CT value error calculation unit that gives a CT value error of the irradiation target and obtains moving deformation irradiation target image data including the CT value error. .   2. A patient positioning error calculation unit that gives a patient positioning error when positioning a patient during treatment and obtains moving deformation irradiation target image data including the given patient positioning error. 4. The treatment planning device according to any one of 3.   The treatment planning apparatus according to claim 1, wherein the dose distribution information displayed in the dose distribution information display unit is a dose volume histogram.

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