JP2012030005A - Radiotherapy equipment controller and radiotherapy equipment control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more easily position a subject.SOLUTION: A radiotherapy equipment control method comprises the steps of: calculating a plurality of luminance gradations on the basis of a first image in which a subject is photographed; extracting from the first image a plurality of display parts 63-1 to 63-n displayed in a plurality of display areas respectively on the basis of the plurality of luminance gradations; and generating a display image 61 in which the plurality of display parts 63-1 to 63-na are displayed in a plurality of display areas respectively, and a second image 62 is displayed in another area. The display image 61 allows a user to easily view how the subject is displaced from a first time of day when the first image is photographed to a second time of day when the second image is photographed. Thus, the user uses the display image 61 to easily position the subject 35.

Description

  The present invention relates to a radiotherapy apparatus control method and a radiotherapy apparatus control apparatus, and more particularly to a radiotherapy apparatus control method and a radiotherapy apparatus control apparatus used when performing radiotherapy on a tumor affected part inside a human body.

  Radiotherapy is known in which a patient is treated by exposing therapeutic radiation to the tumor site. A radiotherapy apparatus that performs the radiotherapy includes an imager system that captures an X-ray image of a patient lying on a couch, and a therapeutic radiation irradiation apparatus that exposes the patient to therapeutic radiation. The radiotherapy apparatus is arranged so that the affected area of the patient is arranged at a predetermined position based on the CT image of the patient imaged in advance and the X-ray image of the patient imaged immediately before by the imager system. After the position of the couch is adjusted, the therapeutic radiation is exposed to the affected area by the therapeutic radiation irradiation device. In the radiotherapy, it is desired to arrange the affected part of the patient at a predetermined position with higher accuracy.

  Japanese Unexamined Patent Application Publication No. 2007-143627 discloses an image diagnostic apparatus that can improve diagnostic efficiency. The diagnostic imaging apparatus includes a display unit that superimposes a second image on a subject on a first image on the subject and displays the second image on the display screen. The diagnostic imaging apparatus includes a first transparency setting unit that sets a transparency when the first image is transmitted and displayed on the display unit, and a second image that is transmitted and displayed on the display unit. A second transparency setting unit for setting the transparency of the first image, and the display unit transmits and displays the first image so as to correspond to the transparency set by the first transparency setting unit. At the same time, the second image is transmitted and displayed so as to correspond to the transparency set by the second transparency setting unit.

JP 2007-143627 A

An object of the present invention is to provide a radiotherapy apparatus control method and a radiotherapy apparatus control apparatus that adjust the position of a subject with higher accuracy.
Another object of the present invention is to provide a radiotherapy apparatus control method and a radiotherapy apparatus control apparatus that adjust the position of a subject at higher speed.

  In the following, means for solving the problems will be described using the reference numerals used in the modes and examples for carrying out the invention in parentheses. This symbol is added to clarify the correspondence between the description of the claims and the description of the modes and embodiments for carrying out the invention. Do not use to interpret the technical scope.

  The radiotherapy apparatus control apparatus (10) according to the present invention includes a first image collection unit (42, 43), a luminance gradient calculation unit (44), an alignment display area calculation unit (45), and a second image collection unit (43, 42) and a display image creation unit (46). The first image collection unit (42, 43) collects the first images (51) (91) obtained by photographing the subject (35). The first images (51) (91) show a plurality of first luminances corresponding to a plurality of display element positions. A luminance gradient calculation unit (44) calculates a plurality of luminance gradients corresponding to a plurality of gradient calculation positions based on the first images (51) (91). The luminance gradient corresponding to an arbitrary position among the plurality of luminance gradients is a gradient direction in which the plurality of first luminances change most at the arbitrary position, and the plurality of first luminances at the arbitrary position. The degree of change in the gradient direction is shown. Based on the plurality of luminance gradients, the alignment display area calculation unit (45) displays a plurality of display parts (56-) respectively displayed in a plurality of different display areas of the first images (51) (91). 1-56-n) are extracted. The second image collection unit (43, 42) collects a second image obtained by photographing the subject (35) at a second time different from the first time when the first images (51) (91) are photographed. The second image shows a plurality of second luminances corresponding to the plurality of display element positions. The display image creation unit (46) creates a display image (61) based on the second image and the plurality of display areas. In the display image (61), a plurality of display portions (56-1 to 56-n) are respectively displayed in the plurality of display areas of the display image (61), and the plurality of display images (61) are displayed. The second image is displayed in a region other than the display region.

  As for such a display image (61), the 2nd image was image | photographed with respect to the position where the subject (35) was arrange | positioned at the 1st time when the 1st image (51) (91) was image | photographed. It is easy to see how the subject (35) is displaced at the second time. For this reason, the user can align the subject (35) more easily by aligning the subject (35) using such a display image (61).

  The first image (51) (91) preferably has less noise than the second image. That is, the radiotherapy apparatus control device (10) is based on an image with less noise of a planning time image taken at the time of planning and a positioning time image taken at the time of alignment different from the planning time. It is preferable to extract a plurality of display portions (56-1 to 56-n).

  The alignment display area calculation unit (45) calculates a plurality of evaluation function values corresponding to a plurality of combinations for selecting a plurality of display area candidate luminance gradients from the plurality of luminance gradients, and based on the plurality of evaluation function values. A plurality of display parts (56-1 to 56-n) are extracted. At this time, an evaluation function value corresponding to an arbitrary combination of the plurality of evaluation function values is an arbitrary value selected from a plurality of selected luminance gradients selected by the arbitrary combination of the plurality of luminance gradients. The larger the sum of the distances between the two positions where the two luminance gradients are respectively arranged, the larger the sum of the respective selected luminance gradients is. The greater the angle between the two gradient directions shown, the greater is the right angle.

  The plurality of display portions (56-1 to 56-n) are configured such that the sum of the intervals between any two display portions selected from the plurality of display portions (56-1 to 56-n) is larger, and Two luminance gradients corresponding to two arbitrary display portions so that the sum of a plurality of degrees indicated by the plurality of luminance gradients corresponding to the plurality of display portions (56-1 to 56-n) is larger. Are preferably extracted so that the angle formed by the two gradient directions respectively becomes closer to a right angle. The radiotherapy apparatus control device (10) is preferable because it can calculate such a plurality of display portions (56-1 to 56-n) based on the plurality of evaluation function values.

  The luminance gradient calculation unit (44) divides the first image (91) into a plurality of image portions (92-1 to 92-m), and corresponds to the plurality of image portions (92-1 to 92-m). A plurality of average brightness gradients are calculated. At this time, the average luminance gradient corresponding to an arbitrary image portion of the plurality of average luminance gradients is an average of the gradient directions in which the plurality of first luminances change in the arbitrary image portion, and the plurality of first luminances. It shows the degree to which the luminance changes to the average in the arbitrary image portion. The alignment display area calculation unit (45) extracts a plurality of display portions (56-1 to 56-n) from the first image (91) based on the plurality of average luminance gradients. Such a radiation therapy apparatus control device (10) has a plurality of display portions (56-1 to 56-n) based on a plurality of luminance gradients corresponding to a plurality of pixels constituting the first images (51) (91). ) Is extracted, the amount of calculation for extracting the plurality of display portions (56-1 to 56-n) can be reduced, and the plurality of display portions (56-1 to 56-n) can be reduced. Can be extracted at a higher speed. As a result, such a radiation therapy apparatus control device (10) can align the subject (35) at a higher speed.

  The plurality of display element positions indicate a plurality of positions at which a plurality of pixels arranged on a plane are respectively arranged. That is, the first image (51) (91), the second image, and the display image (61) are preferably images displayed on a plane.

  The outline of an arbitrary display portion among the plurality of display portions (56-1 to 56-n) is an edge (72) parallel to the average of the gradient directions in which the plurality of first luminances change in the arbitrary display portion. ) Is preferably included. As for such a display image (61), the 2nd image was image | photographed with respect to the position where the subject (35) was arrange | positioned at the 1st time when the 1st image (51) (91) was image | photographed. It is easy to see how much the subject (35) is arranged at the second time. For this reason, the user can align the subject (35) more easily by aligning the subject (35) using such a display image (61).

  The radiotherapy device control apparatus (10) according to the present invention includes a position where the subject (35) is arranged at the first time when the first images (51) (91) are taken and the second image where the second image is taken. A deviation amount calculation unit (47) for calculating a deviation amount from the position where the subject (35) is arranged at two times is further provided. At this time, the radiotherapy apparatus control device (10) can calculate the shift amount with higher accuracy by calculating the shift amount using the display image (61).

  The radiotherapy apparatus control apparatus (10) according to the present invention moves the couch (33) supporting the subject (35) based on the amount of deviation so that the subject (35) is arranged at a predetermined position. It is preferable to further include an alignment portion (48) for controlling the drive devices (21, 34).

  The radiotherapy apparatus control apparatus (10) according to the present invention exposes the therapeutic radiation (24) to a predetermined part of the subject (35) after the subject (35) is placed at the predetermined position. It is preferable to further include an irradiation unit (49) for controlling the irradiation device (6, 21, 23, 34).

  The radiotherapy apparatus control method according to the present invention includes a step of collecting first images (51) and (91) obtained by imaging a subject (35), and a plurality of gradient calculations based on the first images (51) and (91). Calculating a plurality of luminance gradients corresponding to the position to be used, and a plurality of displays respectively displayed in a plurality of different display areas of the first images (51) (91) based on the plurality of luminance gradients A step of extracting the portions (56-1 to 56-n) and a second image in which the subject (35) is imaged at a second time different from the first time at which the first images (51) and (91) are imaged. And a step of creating a display image (61) based on the second image and the plurality of display areas. The first images (51) (91) show a plurality of first luminances corresponding to a plurality of display element positions. The second image shows a plurality of second luminances corresponding to the plurality of display element positions. The luminance gradient corresponding to an arbitrary position among the plurality of luminance gradients is a gradient direction in which the plurality of first luminances change most at the arbitrary position, and the plurality of first luminances at the arbitrary position. The degree of change in the gradient direction is shown. In the display image (61), a plurality of display portions (56-1 to 56-n) are respectively displayed in the plurality of display areas of the display image (61), and the plurality of display images (61) are displayed. The second image is displayed in a region other than the display region.

  As for such a display image (61), the 2nd image was image | photographed with respect to the position where the subject (35) was arrange | positioned at the 1st time when the 1st image (51) (91) was image | photographed. It is easy to see how the subject (35) is displaced at the second time. For this reason, the user can align the subject (35) more easily by aligning the subject (35) using such a display image (61).

  The first image (51) (91) has less noise than the second image. That is, in such a radiotherapy apparatus control method, based on the image with less noise of the image at the time of planning taken at the time of planning and the image at the time of alignment taken at the time of alignment different from the time of planning. It is preferable to extract a plurality of display portions (56-1 to 56-n).

  The radiotherapy apparatus control method according to the present invention further includes a step of calculating a plurality of evaluation function values corresponding to a plurality of combinations for selecting a plurality of display area candidate luminance gradients from the plurality of luminance gradients. At this time, the plurality of display portions (56-1 to 56-n) are extracted based on the plurality of evaluation function values. The evaluation function value corresponding to an arbitrary combination of the plurality of evaluation function values is any two luminances selected from the plurality of selected luminance gradients selected by the arbitrary combination of the plurality of luminance gradients. The larger the sum of the distances between the two positions where the gradients are respectively arranged, the larger the sum of the levels indicated by the plurality of selected brightness gradients, and the greater the sum of the two selected brightness gradients. The closer the angle formed by the two gradient directions is, the larger the angle.

  The plurality of display portions (56-1 to 56-n) are configured such that the sum of the intervals between any two display portions selected from the plurality of display portions (56-1 to 56-n) is larger, and Two luminance gradients corresponding to two arbitrary display portions so that the sum of a plurality of degrees indicated by the plurality of luminance gradients corresponding to the plurality of display portions (56-1 to 56-n) is larger. Are preferably extracted so that the angle formed by the two gradient directions respectively becomes closer to a right angle. In such a radiotherapy apparatus control method, such a plurality of display portions (56-1 to 56-n) can be calculated based on the plurality of evaluation function values, which is preferable.

  The radiotherapy apparatus control method according to the present invention includes a step of dividing the first image (91) into a plurality of image portions (92-1 to 92-m), and the plurality of image portions (92-1 to 92-m). And calculating a plurality of average luminance gradients corresponding to. The average luminance gradient corresponding to an arbitrary image portion of the plurality of average luminance gradients is an average of gradient directions in which the plurality of first luminance changes in the arbitrary image portion, and the plurality of first luminances is It shows the degree of change to the average in an arbitrary image portion. At this time, the plurality of display portions (56-1 to 56-n) are extracted from the first image (91) based on the plurality of average luminance gradients. In such a radiotherapy apparatus control method, a plurality of display portions (56-1 to 56-n) are extracted based on a plurality of luminance gradients corresponding to a plurality of pixels constituting the first image (91). In comparison, the amount of calculation for extracting the plurality of display portions (56-1 to 56-n) can be reduced, and the plurality of display portions (56-1 to 56-n) can be extracted at higher speed. be able to. As a result, such a radiotherapy apparatus control method allows the subject (35) to move faster when the subject (35) is aligned based on the plurality of display portions (56-1 to 56-n). Can be aligned.

  In the radiotherapy apparatus control method according to the present invention, the plurality of display element positions indicate a plurality of positions at which a plurality of pixels arranged on a plane are respectively arranged. That is, the first image (51) (91), the second image, and the display image (61) are preferably images displayed on a plane.

  The outline of an arbitrary display portion among the plurality of display portions (56-1 to 56-n) is an edge (72) parallel to the average of the gradient directions in which the plurality of first luminances change in the arbitrary display portion. ) Is preferably included. As for such a display image (61), the 2nd image was image | photographed with respect to the position where the subject (35) was arrange | positioned at the 1st time when the 1st image (51) (91) was image | photographed. It is easy to see how much the subject (35) is arranged at the second time. For this reason, the user can align the subject (35) more easily by aligning the subject (35) using such a display image (61).

  According to the radiotherapy apparatus control apparatus and the radiotherapy apparatus control method according to the present invention, such a display image makes it easier to see how the subject has shifted between the two times when the two images were respectively captured. The user can easily align the subject by using such a display image.

FIG. 1 is a block diagram showing a radiation therapy system. FIG. 2 is a perspective view showing the radiation therapy apparatus. FIG. 3 is a block diagram illustrating the radiotherapy apparatus control apparatus. FIG. 4 is a diagram illustrating the first image. FIG. 5 is a diagram showing a plurality of display portions. FIG. 6 is a diagram showing a display image. FIG. 7 is a diagram showing one display portion. FIG. 8 is a diagram illustrating a comparative example of the display portion. FIG. 9 is a flowchart showing an operation for aligning a patient. FIG. 10 is a flowchart showing an operation of extracting a display portion. FIG. 11 is a diagram illustrating a plurality of divided images divided from the first image.

  Embodiments of a radiotherapy apparatus control apparatus according to the present invention will be described with reference to the drawings. The radiotherapy apparatus controller 10 is applied to a radiotherapy system as shown in FIG. The radiotherapy system includes a radiotherapy apparatus 1, a radiotherapy apparatus control apparatus 10, and a CT (Computed Tomography) apparatus 20. The radiotherapy apparatus control apparatus 10 is connected to the radiotherapy apparatus 1 and the CT apparatus 20 so that information can be transmitted bidirectionally.

  As shown in FIG. 2, the radiotherapy device 1 includes an O-ring 2, a traveling gantry 3, and a therapeutic radiation irradiation device 6. The O-ring 2 is formed in a ring shape, and is supported by a base so as to be rotatable around the rotation shaft 11. The rotating shaft 11 is parallel to the vertical direction. The traveling gantry 3 is formed in a ring shape. The traveling gantry 3 is disposed inside the ring of the O-ring 2 and is supported by the O-ring 2 so as to be rotatable about the rotation shaft 12. The rotating shaft 12 is perpendicular to the vertical direction and intersects the rotating shaft 11 at the isocenter 14. The rotating shaft 12 is fixed with respect to the O-ring 2, that is, rotates around the rotating shaft 11 together with the O-ring 2.

  The therapeutic radiation irradiation device 6 is arranged inside the ring of the traveling gantry 3. The therapeutic radiation irradiation device 6 is supported by the traveling gantry 3 so as to be rotatable about the tilt shaft 16 and rotatable about the pan shaft 17. The tilt axis 16 is orthogonal to the pan axis 17. The intersection of the tilt axis 16 and the pan axis 17 is 1 m away from the isocenter 14. The therapeutic radiation irradiation apparatus 6 emits the therapeutic radiation 24 whose irradiation field is controlled by being controlled by the radiotherapy apparatus control apparatus 10. The therapeutic radiation 24 is a cone beam whose apex is the intersection of the tilt axis 16 and the pan axis 17.

  The radiotherapy apparatus 1 further includes a turning drive device 21 and a gimbal device 23, and a travel drive device (not shown). The turning drive device 21 is controlled by the radiotherapy device control device 10 to rotate the O-ring 2 around the rotation shaft 11. The turning drive device 21 further measures the turning angle at which the O-ring 2 is disposed with respect to the foundation, and outputs the turning angle to the radiation therapy device control device 10. The traveling drive device rotates the traveling gantry 3 around the rotation shaft 12 by being controlled by the radiotherapy device control device 10. The traveling drive apparatus further measures a gantry angle at which the traveling gantry 3 is disposed with respect to the O-ring 2 and outputs the gantry angle to the radiation therapy apparatus control apparatus 10.

  The gimbal device 23 is controlled by the radiotherapy device control device 10 to rotate the therapeutic radiation irradiation device 6 around the tilt axis 16 and rotate the therapeutic radiation irradiation device 6 around the pan axis 17. The gimbal device 23 further measures the tilt angle at which the therapeutic radiation irradiation device 6 rotates with respect to the traveling gantry 3 around the tilt axis 16 and outputs the tilt angle to the radiotherapy device control device 10. The gimbal device 23 further measures the pan angle at which the therapeutic radiation irradiation device 6 rotates with respect to the traveling gantry 3 around the pan axis 17 and outputs the pan angle to the radiotherapy device control device 10.

  The therapeutic radiation 24 is swung once once fixed on the traveling gantry 3 so that the therapeutic radiation irradiating device 6 faces the isocenter 14 by the therapeutic radiation irradiating device 6 being supported on the traveling gantry 3 in this way. Even if the O-ring 2 is rotated by the driving device 21 or the traveling gantry 3 is rotated by the traveling driving device, the light is always emitted to the isocenter 14 at all times. That is, the radiation therapy apparatus 1 can irradiate the therapeutic radiation 24 from any direction toward the isocenter 14 by running and turning.

  The radiotherapy apparatus 1 further includes a plurality of imager systems. That is, the radiotherapy apparatus 1 includes a first diagnostic X-ray source 25, a second diagnostic X-ray source 26, a first sensor array 27, and a second sensor array 28. The first diagnostic X-ray source 25 is supported by the traveling gantry 3, and an angle formed by a line segment connecting the first diagnostic X-ray source 25 from the isocenter 14 and a line segment connecting the therapeutic radiation irradiation device 6 from the isocenter 14. Is arranged inside the ring of the traveling gantry 3 so as to have an acute angle. The second diagnostic X-ray source 26 is supported by the traveling gantry 3, and an angle formed by a line segment connecting the second diagnostic X-ray source 26 from the isocenter 14 and a line segment connecting the therapeutic radiation irradiation device 6 from the isocenter 14. Is arranged inside the ring of the traveling gantry 3 so as to have an acute angle. In the second diagnostic X-ray source 26, the angle formed by the line connecting the isocenter 14 and the first diagnostic X-ray source 25 and the line connecting the isocenter 14 and the second diagnostic X-ray source 26 is a right angle ( (90 degrees). The first sensor array 27 is supported by the traveling gantry 3 and is disposed so as to face the first diagnostic X-ray source 25 via the isocenter 14. The second sensor array 28 is supported by the traveling gantry 3 and is disposed so as to face the second diagnostic X-ray source 26 via the isocenter 14.

  The first diagnostic X-ray source 25 is controlled by the radiation therapy apparatus control apparatus 10 to emit the first diagnostic X-ray 31 toward the isocenter 14 at a predetermined timing. The first diagnostic X-ray 31 is a conical cone beam that is emitted from one point of the first diagnostic X-ray source 25 and has the one point as a vertex. The second diagnostic X-ray source 26 is controlled by the radiotherapy apparatus controller 10 to emit the second diagnostic X-ray 32 toward the isocenter 14 at a predetermined timing. The second diagnostic X-ray 32 is a conical cone beam that is emitted from one point of the second diagnostic X-ray source 26 and has one point as a vertex.

  The first sensor array 27 includes a light receiving unit. The first sensor array 27 is controlled by the radiation therapy apparatus control device 10 to generate a first fluoroscopic image based on X-rays received by the light receiving unit. The second sensor array 28 includes a light receiving unit. The second sensor array 28 is controlled by the radiation therapy apparatus control apparatus 10 to generate a second fluoroscopic image based on the X-rays received by the light receiving unit. The perspective image is formed of a plurality of pixels. The plurality of pixels are arranged in a matrix on the perspective image, and are associated with luminance. The fluoroscopic image projects a subject by the luminance corresponding to each of the plurality of pixels being colored to each of the plurality of pixels. Examples of the first sensor array 27 and the second sensor array 28 include an FPD (Flat Panel Detector) and an X-ray II (Image Intensifier).

  According to such an imager system, a fluoroscopic image centered on the isocenter 14 can be generated based on the image signals obtained by the first sensor array 27 and the second sensor array 28.

  The radiation therapy apparatus 1 further includes a couch 33 and a couch driving device 34. The couch 33 is supported by a base so as to be able to rotate about the x-axis, y-axis and z-axis, and to be able to translate in parallel to the x-axis, y-axis and z-axis. The x-axis, y-axis, and z-axis are orthogonal to each other. The couch 33 is used when the patient 35 to be treated by the radiation treatment system lies down. The couch 33 includes a fixture (not shown). The fixture fixes the patient 35 to the couch 33 so that the patient 35 does not move. The couch driving device 34 is controlled by the radiotherapy device control device 10 to rotate the couch 33 and translate the couch 33.

  FIG. 3 shows the radiotherapy apparatus control apparatus 10. The radiotherapy device control device 10 is a computer, and includes a CPU, a storage device, a removable memory drive, a communication device, an input device, an output device, and an interface (not shown). The CPU executes a computer program installed in the radiation therapy apparatus control apparatus 10 to control the storage device, the removable memory drive, the communication device, the input device, the output device, and the interface. The storage device records the computer program. The storage device records information used by the CPU and records information generated by the CPU. The removable memory drive is used to read data recorded on the recording medium when the recording medium is inserted. The removable memory drive is used particularly when the computer program is installed in the radiation therapy apparatus control apparatus 10 when a recording medium in which the computer program is recorded is inserted. The communication apparatus downloads information distributed from another computer connected via the communication line network to the radiotherapy apparatus control apparatus 10. The communication device is particularly used when a computer program is downloaded from another computer to the radiation therapy apparatus control apparatus 10 and the computer program is installed in the radiation therapy apparatus control apparatus 10. The input device outputs information generated by being operated by the user to the CPU. Examples of the input device include a keyboard and a mouse. The output device outputs the information generated by the CPU so that the user can recognize it. Examples of the output device include a display that displays an image generated by the CPU.

  The interface outputs information generated by an external device connected to the radiotherapy apparatus control apparatus 10 to the CPU, and outputs information generated by the CPU to the external device. The external devices include a CT apparatus 20, a therapeutic radiation irradiation apparatus 6, a turning drive apparatus 21, a traveling drive apparatus, a gimbal apparatus 23, a first diagnostic X-ray source 25, a second diagnostic X-ray source 26, and a first sensor. An array 27, a second sensor array 28, and a couch drive 34 are included.

  The computer program installed in the radiation therapy apparatus control apparatus 10 is formed of a plurality of computer programs for causing the radiation therapy apparatus control apparatus 10 to realize a plurality of functions. The plurality of functions are a treatment plan collection unit 41, a planned image collection unit 42, an alignment image photographing unit 43, a luminance gradient calculation unit 44, an alignment display area calculation unit 45, a display image creation unit 46, and a deviation amount calculation. A unit 47, a patient positioning unit 48, and an irradiation unit 49 are included.

  The treatment plan collection unit 41 collects a treatment plan from the input device. The treatment plan shows a combination of irradiation angle and dose. The irradiation angle indicates the direction in which the therapeutic radiation 24 is irradiated to the affected area of the patient 35, and indicates the couch position, the O-ring rotation angle, and the gantry rotation angle. The couch position indicates the position of the couch 33 relative to the foundation. The O-ring rotation angle indicates the position of the O-ring 2 with respect to the foundation. The gantry rotation angle indicates the position of the traveling gantry 3 with respect to the O-ring 2. The dose indicates the dose of the therapeutic radiation 24 irradiated to the patient 35 from the irradiation angle. The treatment plan is created based on the planned three-dimensional data photographed by the CT apparatus 20.

  The planned image collection unit 42 collects the planned three-dimensional data from the CT apparatus 20. The planned three-dimensional data indicates the three-dimensional data of the patient 35, and a plurality of CT values are associated with a plurality of voxels. Each of the plurality of voxels corresponds to a plurality of regions that are filled with no space in the space in which the patient 35 is disposed. For example, the plurality of regions are each formed in a rectangular parallelepiped. One CT value corresponding to an arbitrary voxel among the plurality of CT values corresponds to a transmittance at which X-rays pass through a region corresponding to the arbitrary voxel among the plurality of regions. The planned image collection unit 42 further reconstructs a planned tomographic image based on the planned three-dimensional data.

  The alignment image capturing unit 43 captures the radiation therapy apparatus 1 so that a plurality of alignment first fluoroscopic images and a plurality of alignment second fluoroscopic images that reflect the patient 35 lying on the couch 33 are captured. Control. That is, the alignment image capturing unit 43 controls the turning drive device 21 so that the O-ring 2 is arranged at a predetermined turning angle with respect to the foundation. The alignment image photographing unit 43 further controls the traveling drive device so that the traveling gantry 3 rotates about the rotating shaft 12 at a constant angular velocity with respect to the O-ring 2. The image capturing unit 43 at the time of alignment is further configured so that the first diagnostic X-ray 31 is exposed when the traveling gantry 3 is arranged at a plurality of predetermined gantry angles with respect to the O-ring 2. 1 X-ray source 25 for diagnosis is controlled. The image capturing unit 43 at the time of alignment further exposes the second diagnostic X-ray 32 when the traveling gantry 3 is arranged at the predetermined plurality of gantry angles with respect to the O-ring 2. The second diagnostic X-ray source 26 is controlled. Further, when the traveling gantry 3 is disposed at the predetermined plurality of gantry angles with respect to the O-ring 2, the alignment-time image capturing unit 43 generates a plurality of alignment-time first perspective images. In addition, the first sensor array 27 is controlled. Further, when the traveling gantry 3 is disposed at the predetermined plurality of gantry angles with respect to the O-ring 2, the alignment-time image capturing unit 43 generates a plurality of alignment-time second perspective images. In addition, the second sensor array 28 is controlled.

  The alignment image capturing unit 43 further calculates alignment three-dimensional data based on the plurality of alignment first fluoroscopic images and the plurality of alignment second fluoroscopic images. The three-dimensional data at the time of alignment indicates the three-dimensional data of the patient 35, and a plurality of CT values are associated with a plurality of voxels in the same manner as the three-dimensional data at the time of planning. The three-dimensional data of the patient 35 is shown, and a plurality of CT values are associated with a plurality of voxels. One CT value corresponding to an arbitrary voxel among the plurality of CT values corresponds to a transmittance at which X-rays pass through a region corresponding to the arbitrary voxel among the plurality of regions. The alignment image capturing unit 43 further reconstructs the alignment tomographic image based on the alignment three-dimensional data.

  The luminance gradient calculating unit 44 calculates the planned image noise amount based on the planned tomographic image reconstructed by the planned image collecting unit 42. The planned image noise amount indicates the amount of noise included in the planned tomographic image. The luminance gradient calculation unit 44 calculates the image noise amount during alignment based on the tomographic image during alignment reconstructed by the image capturing unit 43 during alignment. The image noise amount at the time of alignment indicates the amount of noise included in the tomographic image at the time of alignment. The brightness gradient calculating unit 44 determines the first image and the second image from the planned tomographic image and the aligned tomographic image based on the planned image noise amount and the aligned image noise amount. Select. The first image shows an image with a smaller amount of noise between the planned tomographic image and the alignment tomographic image. The second image shows an image having a larger amount of noise among the planned tomographic image and the alignment tomographic image.

  The luminance gradient calculation unit 44 removes noise from the first image using a Gaussian filter. The luminance gradient calculation unit 44 may be applied with another noise removal method different from the Gaussian filter. Examples of the noise removal technique include a mean filter and a median filter. The luminance gradient calculation unit 44 reduces the noise-removed first image by the nearest neighbor method. Note that the luminance gradient calculation unit 44 may be applied with another reduction method different from the nearest neighbor method. Examples of the reduction method include a bilinear method, a bicubic method, and an average pixel method.

  The luminance gradient calculation unit 44 further calculates a plurality of luminance gradients corresponding to the plurality of pixels indicated by the first image. Each of the plurality of luminance gradients indicates a gradient direction and a gradient amount. A gradient direction indicated by one luminance gradient corresponding to an arbitrary pixel among the plurality of luminance gradients indicates a direction in which the plurality of luminances indicated by the first image changes most in the arbitrary pixel. The gradient amount indicated by the one luminance gradient indicates the degree to which the plurality of luminances indicated by the first image change in the gradient direction at the arbitrary pixel.

  According to such reduction, the amount of calculation for calculating the plurality of luminance gradients is reduced, and the luminance gradient calculating unit 44 can calculate the plurality of luminance gradients at higher speed.

  The alignment display area calculation unit 45 is arranged based on the plurality of luminance gradients calculated by the luminance gradient calculation unit 44 from the first image selected by the luminance gradient calculation unit 44 in a plurality of display table areas. Extract the display part.

  The display image creation unit 46 creates a display image based on the second image selected by the luminance gradient calculation unit 44 and the plurality of display portions extracted by the alignment display area calculation unit 45. The display image creation unit 46 further displays the display image on the display device.

  The deviation amount calculation unit 47 calculates the deviation amount based on the display image created by the display image creation unit 46.

  The patient positioning unit 48 calculates a correction amount based on the shift amount calculated by the shift amount calculation unit 47. The correction amount is formed of an x-axis rotation correction amount, a y-axis rotation correction amount, a z-axis rotation correction amount, an x-axis translation correction amount, a y-axis translation correction amount, and a z-axis translation correction amount. The x-axis rotation correction amount indicates a rotation angle for rotating the couch 33 around the x-axis. The y-axis rotation correction amount indicates a rotation angle for rotating the couch 33 around the y-axis. The z-axis rotation correction amount indicates a rotation angle for rotating the couch 33 around the z-axis. The x-axis translation correction amount indicates a distance for moving the couch 33 in parallel with the x-axis. The y-axis translation correction amount indicates the distance for moving the couch 33 in parallel with the y-axis. The z-axis translation correction amount indicates a distance for moving the couch 33 in parallel with the z-axis.

  The patient positioning unit 48 controls the couch driving device 34 based on the correction amount. In other words, the patient positioning unit 48 rotates the couch 33 by the x-axis rotation correction amount around the x-axis, and after the couch 33 rotates around the x-axis, by the y-axis rotation correction amount around the y-axis. The couch drive device 34 is controlled such that the couch 33 rotates and the couch 33 rotates about the y axis, and then the couch 33 rotates about the z axis by the z axis rotation correction amount. The patient positioning unit 48 further moves the couch 33 in parallel with the y axis by the y axis translation correction amount after the couch 33 rotates about the z axis, and the y axis translation correction in parallel with the y axis. The couch drive device 34 is controlled so that the couch 33 translates by the amount, and the couch 33 translates by the y-axis translation correction amount parallel to the y-axis.

  The irradiation unit 49 controls the radiotherapy device 1 so that the radiotherapy indicated by the treatment plan collected by the treatment plan collection unit 41 is executed. That is, the irradiation unit 49 controls the couch driving device 34, controls the turning driving device 21, and controls the radiation so that the therapeutic radiation irradiation device 6 is arranged with respect to the patient 35 at the irradiation angle indicated by the treatment plan. The traveling drive device of the treatment device 1 is controlled. The irradiation unit 49 further controls the first diagnostic X-ray source 25 and the first sensor array 27 so that a first fluoroscopic image at the time of treatment of the patient 35 is taken. The irradiation unit 49 further controls the second diagnostic X-ray source 26 and the second sensor array 28 so that a second fluoroscopic image at the time of treatment that captures the patient 35 is captured. The irradiation unit 49 further calculates the position of the affected part of the patient 35 based on the first fluoroscopic image during treatment and the second fluoroscopic image during treatment, and calculates the shape of the affected part. The irradiation unit 49 further controls the gimbal device 23 so that the therapeutic radiation irradiation device 6 faces the calculated position of the affected part. The irradiation unit 49 further controls the therapeutic radiation irradiation device 6 so that the irradiation field of the therapeutic radiation 24 matches the shape of the affected part, and the therapeutic radiation 24 is irradiated to the affected part. The radiation irradiating apparatus 6 is controlled. The irradiating unit 49 further takes the therapeutic radiation from the imaging of the first fluoroscopic image during treatment and the second fluoroscopic image during treatment until the affected part of the patient 35 is irradiated with the therapeutic radiation 24 of the dose indicated by the treatment plan. The operation up to 24 irradiation is repeated.

  FIG. 4 shows the first image selected by the luminance gradient calculation unit 44. The first image 51 is two-dimensional data, that is, a plurality of luminances are associated with a plurality of pixels arranged on one plane. The first image 51 displays an image 52 that reflects a portion of the patient 35 that intersects a predetermined plane. That is, the luminance corresponding to an arbitrary pixel of the plurality of luminances indicates a transmittance that allows X-rays to pass through a portion of the patient 35 corresponding to the arbitrary pixel.

  The second image selected by the luminance gradient calculating unit 44 is two-dimensional data in the same manner as the first image 51, that is, a plurality of luminances are associated with a plurality of pixels arranged on one plane. It has been. The second image displays an image showing a portion of the patient 35 that intersects a predetermined plane. The predetermined plane coincides with the plane on which the portion of the patient 35 indicated by the first image 51 is arranged. The luminance corresponding to an arbitrary pixel of the plurality of luminances indicates a transmittance that allows X-rays to pass through a portion of the patient 35 corresponding to the arbitrary pixel.

  FIG. 5 shows a plurality of display portions extracted by the alignment display area calculation unit 45. The plurality of display portions 55 are associated with a plurality of display areas 56-1 to 56-n (n = 2, 3, 4,...). The plurality of display portions 55 indicate a plurality of portions displayed in the plurality of display areas 56-1 to 56-n of the first image 51, respectively.

  At this time, the alignment display area calculation unit 45 selects a plurality of combinations of display point candidates from the plurality of pixels indicated by the first image 51 based on the plurality of luminance gradients calculated by the luminance gradient calculation unit 44. A plurality of evaluation functions corresponding to is calculated. The evaluation function corresponding to any combination of the plurality of evaluation functions is larger as the sum of the intervals between any two display point candidates selected from the plurality of display point candidates selected by the arbitrary combination is larger. And a plurality of displays selected by any combination thereof so that the angle formed by the gradient directions of the two luminance gradients corresponding to the two arbitrary display point candidates becomes larger as the angle is closer to the right angle. The calculation is performed such that the larger the sum of the gradient amounts of the plurality of luminance gradients corresponding to the point candidate, the larger.

That is, the evaluation function D _n corresponding to the combination of selecting n display point candidates from the plurality of pixels indicated by the first image 51 is _expressed by the following formula:
D _n = | ∇I (x _n ) | × (к · D _{xy, n} + (1−к) · D _{Δθ, n} )
It is represented by Here, the variable D _{xy, n} is _expressed by the following formula:
D _{xy, n} = Σ _{1 ≦ l ≦ n} [Σ _{l ≦ k ≦ n} || x ₁ −x _k ||]
It is expressed by The variable D _{Δθ, n} is given by
_{DΔθ, n} = Σ1 _{≦ l ≦ n} [Σl _{≦ k ≦} nf (Δθ1 _{, k} )]
It is expressed by The function f (x) has the following formula:
f (x) = {π / 2− | (| x | mod π) −π / 2 |}
It is expressed by The angle difference Δθ _{l, k} is given by
Δθ _{l, k} = cos ⁻¹ {∇I (x _k ) · ∇I (x _l ) / (| ∇I (x _k ) || ∇I (x _l ) |)}
It is expressed by The coordinate x _k indicates the position of the pixel selected as the k th (1 ≦ k ≦ n−1) of the n display point candidates. The luminance I (x _k ) indicates the luminance indicated by the kth (1 ≦ k ≦ n−1) selected pixel among the n display point candidates. The luminance gradient ∇I (x _k ) indicates the luminance gradient corresponding to the kth (1 ≦ k ≦ n−1) selected point among the n display point candidates. The enhancement coefficient к represents a number between 0 and 1, and when it is large _, the term of the variable D _{xy, n} is emphasized in the evaluation function D _n .

  FIG. 6 shows a display image created by the display image creation unit 46. In the display image 61, an image 62 and a plurality of display portions 63-1 to 63-n are displayed. An image 62 shows an image of the patient 35 displayed in the second image selected by the luminance gradient calculation unit 44. The plurality of display portions 63-1 to 63-n respectively indicate the plurality of display portions extracted by the alignment display area calculation unit 45. The plurality of display portions 63-1 to 63-n are displayed in the plurality of display areas 56-1 to 56-n in the display image 61, respectively.

  FIG. 7 shows one display portion among the plurality of display portions 63-1 to 63-n. The display portion 71 displays a feature line 73. The feature line 73 includes a point where the luminance gradient corresponding to the display portion 71 is calculated, and indicates a region in the display portion 71 where the change in luminance is relatively large. That is, the feature line 73 is substantially parallel to the gradient direction 75 indicated by the luminance gradient corresponding to the display portion 71. The display part 71 is formed in a rectangular shape. The plurality of sides forming the rectangle includes a side 72. The side 72 is formed such that the direction 74 of the side 72 is substantially perpendicular to the feature line 73, that is, the direction 74 is parallel to the gradient direction 75.

  FIG. 7 further shows a part of the image 62. The image 62 displays a feature line 76. A feature line 76 indicates an area of the image 62 where the luminance change is relatively large, and indicates the same subject as the subject indicated by the feature line 73. At this time, the shift amount calculation unit 47 calculates an image shift amount 77 based on the feature line 73 and the feature line 76. The image shift amount 77 indicates the distance from the feature line 73 to the feature line 76. The shift amount calculation unit 47 calculates a plurality of image shift amounts corresponding to the plurality of display portions 63-1 to 63-n in the same manner as calculating the image shift amount 77 from the display portion 71. The deviation amount calculation unit 47 calculates the deviation amount based on the plurality of image deviation amounts and the plurality of gradient directions respectively indicated by the plurality of luminance gradients corresponding to the plurality of display portions 63-1 to 63-n.

  The amount of deviation indicates an x-axis rotation deviation amount, a y-axis rotation deviation amount, a z-axis rotation deviation amount, an x-axis translation displacement amount, a y-axis translation displacement amount, and a z-axis translation displacement amount. Yes. The amount of rotational deviation around the x axis indicates an angle by which the patient 35 is rotated about a rotation axis parallel to the x axis. The amount of rotational deviation about the y axis indicates an angle by which the patient 35 is rotated about a rotation axis parallel to the y axis. The amount of rotational deviation about the z axis indicates an angle by which the patient 35 is rotated about a rotation axis parallel to the z axis. The x-axis translation shift amount indicates a distance by which the patient 35 is translated in parallel with the x-axis. The y-axis translation shift amount indicates a distance by which the patient 35 is translated in parallel with the y-axis. The z-axis translation shift amount indicates a distance by which the patient 35 is translated in parallel with the z-axis. The misalignment amount is a tomographic position reconstruction reconstructed from the three-dimensional data at the time of alignment imaged by the image capturing unit 43 at the time of alignment using the radiotherapy apparatus 1 when the patient 35 moves by the amount of deviation. The image is calculated so as to be similar to the planned tomographic image reconstructed by the planned image collection unit 42.

  FIG. 8 shows a comparative example of the display part. The display portion 81 displays a feature line 83. The feature line 83 includes a point where the luminance gradient corresponding to the display portion 81 is calculated, and indicates a region in the display portion 81 where the change in luminance is relatively large. That is, the feature line 83 is substantially parallel to the gradient direction 85 indicated by the luminance gradient corresponding to the display portion 81. The display part 81 is formed in a rectangular shape. The plurality of sides forming the rectangle include a side 82. The side 82 is formed such that the direction 84 of the side 82 is not perpendicular to the feature line 83, that is, the direction 84 is not parallel to the gradient direction 85.

  FIG. 8 further shows a part of an image displayed together with the display portion 81 on the display screen created by the display image creation unit 46. The image displays feature lines 86. A feature line 86 indicates a region of the image where the luminance change is relatively large, and indicates the same subject as the subject indicated by the feature line 83. At this time, in the display portion 81, the degree to which the luminance changes along the side 82 is smaller than the degree to which the luminance changes along the side 72. The boundary between two parts displayed in an image is generally less clear as the difference in luminance between the two parts is smaller, that is, the contrast between the two parts is smaller. For this reason, the user viewing the display screen may mistake the degree of the image shift amount 87 indicating the distance from the feature line 83 to the feature line 86. Further, the feature line 83 and the feature line 86 may appear as a part of one curve that is gently bent when the feature line 83 and the feature line 86 are not arranged in the same straight line. For this reason, the user viewing the display screen may mistake the degree of the image shift amount 87 indicating the distance from the feature line 83 to the feature line 86.

  That is, the display part 71 can reduce the possibility of misidentifying that the feature line 73 and the feature line 76 are not arranged in the same straight line as compared to the display part 81. Further, each of the plurality of display portions 63-1 to 63-n is created in the same manner as the display portion 71, so that the shift amount calculation unit 47 can correspond to the plurality of display portions 63-1 to 63-n. The image shift amount can be calculated with higher accuracy, and the shift amount of the patient 35 can be calculated with higher accuracy.

  In addition, the display part 71 can also be formed in the other shape different from a rectangle. The shape includes polygons (triangles, hexagons) having sides that are generally perpendicular to the feature line 73, that is, sides that are parallel to the gradient direction 75. The shape further includes a figure (for example, an ellipse) surrounded by a curve. At this time, the curve has a straight line perpendicular to the feature line 73 as a tangent, that is, a straight line parallel to the gradient direction 75 as a tangent. The curve intersects the characteristic line 73 at the contact point of the tangent line. The display portion formed in such a shape may misidentify whether the feature line 73 and the feature line 76 are arranged in the same straight line as the display portion 71 in the above-described embodiment. Can be reduced.

  The embodiment of the radiotherapy apparatus control method according to the present invention is executed by the radiotherapy apparatus control apparatus 10 and includes an operation of aligning a patient and an operation of radiotherapy.

  The operation of capturing the fluoroscopic image at the time of alignment is executed after the CT apparatus 20 captures the three-dimensional data of the patient 35 and creates a treatment plan for the patient 35 by the user. As shown in FIG. 9, after the patient 35 is fixed to the couch 33, the radiation therapy apparatus control apparatus 10 first performs a plurality of alignments for displaying the patient 35 and a plurality of first fluoroscopic images and a plurality of alignments. The radiotherapy apparatus 1 is controlled so that the second fluoroscopic image is captured. The radiotherapy apparatus controller 10 further calculates the three-dimensional data at the time of alignment based on the plurality of first fluoroscopic images at the time of alignment and the plurality of second fluoroscopic images at the time of alignment. The radiotherapy apparatus controller 10 further reconstructs a tomographic image at the time of alignment based on the three-dimensional data at the time of alignment.

  The radiotherapy apparatus controller 10 selects the first image and the second image from the planned tomographic image and the alignment tomographic image (step S1). The first image shows an image with a smaller amount of noise between the planned tomographic image and the alignment tomographic image. The second image shows an image having a larger amount of noise among the planned tomographic image and the alignment tomographic image. The radiation therapy apparatus control apparatus 10 removes noise from the first image using a Gaussian filter (step S2), and reduces the first image using the nearest neighbor method (step S3). The radiotherapy apparatus control apparatus 10 further calculates a plurality of luminance gradients corresponding to the plurality of pixels indicated by the first image 51 created in this way (step S4).

  The radiotherapy apparatus control apparatus 10 can reduce the amount of calculation for calculating the plurality of luminance gradients by such noise removal and reduction, and can calculate the plurality of luminance gradients at higher speed. The radiotherapy apparatus control device 10 is configured such that when the noise of the first image is sufficiently small, or when the radiotherapy apparatus control apparatus 10 can calculate a plurality of luminance gradients sufficiently quickly. Noise removal or reduction can be omitted.

  The radiotherapy apparatus control apparatus 10 extracts a plurality of display portions 55 arranged in the plurality of display areas 56-1 to 56-n from the first image 51 based on the plurality of luminance gradients (step S5). The radiation therapy apparatus control apparatus 10 creates a display image 61 based on the second image and the plurality of display portions 55 (step S6). The radiation therapy apparatus control device 10 further displays the display image 61 on the display device. By viewing the display image 61, the user can easily confirm how much the patient 35 is disposed in which direction.

  The radiation therapy apparatus control apparatus 10 calculates the amount of deviation based on the display image 61 (step S7). The radiation therapy apparatus control apparatus 10 calculates a correction amount based on the deviation amount. The correction amount is formed of an x-axis rotation correction amount, a y-axis rotation correction amount, a z-axis rotation correction amount, an x-axis translation correction amount, a y-axis translation correction amount, and a z-axis translation correction amount. The radiation therapy apparatus control apparatus 10 controls the couch driving apparatus 34 based on the correction amount (step S8). That is, the radiotherapy apparatus controller 10 rotates the couch 33 by the x-axis rotation correction amount around the x-axis, and after the couch 33 rotates around the x-axis, the y-axis rotation correction amount around the y-axis. The couch drive device 34 is controlled so that the couch 33 rotates only by the amount of the z-axis rotation correction amount after the couch 33 rotates about the y-axis and then the z-axis rotation correction amount. Further, after the couch 33 rotates about the z-axis, the radiotherapy device control apparatus 10 translates the couch 33 in parallel to the y-axis by the y-axis translation correction amount and translates the y-axis in parallel to the y-axis. The couch driving device 34 is controlled so that the couch 33 translates by the correction amount and the couch 33 translates by the y-axis translation correction amount in parallel with the y-axis.

FIG. 10 shows the extraction of the display area in step S5. The radiation therapy apparatus control apparatus 10 extracts the first display portion based on the plurality of luminance gradients calculated in step S4 (step S11). The first display portion is a region including the pixel x ₁ corresponding to the luminance gradient having the maximum gradient amount | ∇I (x) | of the plurality of luminance gradients. The radiation therapy apparatus control apparatus 10 substitutes 2 for the variable n (step S12). The radiation therapy apparatus control apparatus 10 calculates a plurality of evaluation functions D _n corresponding to a plurality of combinations for selecting n display point candidates from a plurality of pixels indicated by the first image 51. The n display point candidates include the first display portion extracted in step S11. The evaluation function D _n is given by the following formula:
D _n = | ∇I (x _n ) | × (к · D _{xy, n} + (1−к) · D _{Δθ, n} )
It is represented by Here, the variable D _{xy, n} is _expressed by the following formula:
D _{xy, n} = Σ _{1 ≦ l ≦ n} [Σ _{l ≦ k ≦ n} || x ₁ −x _k ||]
It is expressed by The variable D _{Δθ, n} is given by
_{DΔθ, n} = Σ1 _{≦ l ≦ n} [Σl _{≦ k ≦} nf (Δθ1 _{, k} )]
It is expressed by The function f (x) has the following formula:
f (x) = {π / 2− | (| x | mod π) −π / 2 |}
It is expressed by The angle difference Δθ _{l, k} is given by
Δθ _{l, k} = cos ⁻¹ {∇I (x _k ) · ∇I (x _l ) / (| ∇I (x _k ) || ∇I (x _l ) |)}
It is expressed by The coordinate x _k indicates the position of the pixel selected as the k th (1 ≦ k ≦ n−1) of the n display point candidates. The luminance I (x _k ) indicates the luminance indicated by the kth (1 ≦ k ≦ n−1) selected pixel among the n display point candidates. The luminance gradient ∇I (x _k ) indicates the luminance gradient corresponding to the kth (1 ≦ k ≦ n−1) selected point among the n display point candidates. The enhancement coefficient к indicates a constant set by the user, and indicates a number from 0 to 1.

The radiotherapy apparatus control apparatus 10 selects an evaluation function D _n that is the maximum of the plurality of evaluation functions D _n , and one pixel x out of the plurality of pixels based on the selected evaluation function D _{n. n} is selected, and a display area including the pixel _xn is added to a plurality of display areas to be obtained (step S13). Pixel x _n indicates the n-th display point candidate among the n display point candidates selected by the combination corresponding to the evaluation function D _n which is the selected one of the plurality of combinations.

The radiation therapy apparatus control apparatus 10 updates the variable n to a sum obtained by adding 1 to the value of the variable n (step S14). The radiotherapy apparatus control apparatus 10 determines whether or not the variable D _{xy, n} and the variable D _{Δθ, n} calculated when calculating the selected evaluation function D _n are within a predetermined range (step) S15). The radiotherapy apparatus control apparatus 10 has the following formula:
D _{xy, n} −D _{xy, n−1} > Th _xy
Or the following formula:
D _{Δθ, n} −D _{Δθ, n−1} > Th _Δθ
Is established (step S15, YES), the magnitude relationship between the variable n and the constant N is determined (step S16). The threshold value Th _xy and the threshold value Th _Δθ are constants set by the user. The constant N is a natural number set by the user and is a natural number of 2 or more.

When the variable n is smaller than the constant N (step S16, YES), the radiotherapy apparatus control apparatus 10 selects a plurality of combinations corresponding to a plurality of combinations for selecting n display point candidates from a plurality of pixels indicated by the first image 51. calculating the evaluation function _{D n} again (step S13).

The radiotherapy apparatus control apparatus 10 has the following formula:
D _{xy, n} −D _{xy, n−1} > Th _xy
Does not hold and the following formula:
D _{Δθ, n} −D _{Δθ, n−1} > Th _Δθ
Steps S13 to S14 are repeatedly executed until NO is satisfied (NO in Step S15) or until the variable n becomes a constant N (NO in Step S16).

  According to the plurality of display portions 55 extracted in this way, the radiotherapy apparatus control device 10 shifts the second image with respect to the first image in what direction and how much the first image and the second image are shifted. Whether or not they match can be calculated with higher accuracy. Therefore, the shift amount of the patient 35 can be calculated with higher accuracy, and the patient 35 can be aligned with higher accuracy. In step S15, the radiotherapy apparatus control apparatus 10 can prevent unnecessary display areas from being selected, and can calculate the shift amount of the patient 35 at a higher speed.

In addition, the radiation therapy apparatus control apparatus 10 is a following formula by step S13:
D _{xy, n} −D _{xy, n−1} > Th _xy
And the following formula:
D _{Δθ, n} −D _{Δθ, n−1} > Th _Δθ
When the above holds, the process can proceed to step S16 to determine the magnitude relationship between the variable n and the constant N. Also in this case, the radiotherapy apparatus control apparatus 10 calculates with higher accuracy how much the second image is shifted in which direction and how much the first image matches the first image. Therefore, the shift amount of the patient 35 can be calculated with higher accuracy, and the patient 35 can be aligned with higher accuracy. Also in this case, the radiation therapy apparatus control apparatus 10 can further prevent the unnecessary display area from being selected, and can calculate the shift amount of the patient 35 at a higher speed.

  In addition, the radiotherapy apparatus control apparatus 10 can also omit step S15. At this time, the radiation therapy apparatus control apparatus 10 repeatedly executes steps S13 to S14 until the variable n becomes a constant N. Also in this case, the radiotherapy apparatus control apparatus 10 calculates with higher accuracy how much the second image is shifted in which direction and how much the first image matches the first image. Can do. For this reason, the radiotherapy apparatus control apparatus 10 can calculate the shift amount of the patient 35 with higher accuracy, and can align the patient 35 with higher accuracy.

  Note that the user may manually control the couch driving device 34 so that the patient 35 moves by the deviation amount after the radiation therapy apparatus control device 10 calculates the deviation amount, with reference to the deviation amount. it can. Also in this case, the user can align the patient 35 with higher accuracy. Furthermore, after the patient 35 is aligned, the user can easily check whether the patient 35 is placed at a predetermined position by creating a display image again and viewing the display image. it can.

  In addition, after the user creates the display image 61 by the radiotherapy apparatus control device 10, the user 35 looks at the display image 61 to displace the patient 35 in which direction and how much without using the radiotherapy apparatus control apparatus 10. It can also be calculated. At this time, the radiotherapy apparatus control apparatus 10 can omit the deviation amount calculation unit 47. At this time, the radiotherapy device control apparatus 10 controls the couch driving device 34 based on the shift amount so that the patient 35 moves by the shift amount, or the user moves the patient 35 by the shift amount. The couch drive device 34 is manually controlled as described above. Such alignment can also align the patient 35 with higher accuracy in the same manner as the above-described embodiment.

  The radiation treatment operation is performed after the operation of aligning the patient is performed. The radiotherapy device control apparatus 10 controls the turning drive device 21 so that the O-ring 2 is arranged at the O-ring rotation angle indicated by the treatment plan. The radiotherapy device controller 10 further controls the travel drive device of the radiotherapy device 1 so that the travel gantry 3 is arranged at the gantry rotation angle indicated by the treatment plan.

  The radiotherapy apparatus control apparatus 10 first X-rays for diagnosis so that a first tracking fluoroscopic image of the patient 35 is taken after the therapeutic radiation irradiation apparatus 6 is placed at a predetermined position with respect to the patient 35. The source 25 and the first sensor array 27 are controlled, and the second diagnostic X-ray source 26 and the second sensor array 28 are controlled so that a second tracking fluoroscopic image of the patient 35 is taken.

  The radiotherapy apparatus controller 10 calculates the position and shape of the affected part of the patient 35 based on the first tracking fluoroscopic image and the second tracking fluoroscopic image. The radiation therapy apparatus control apparatus 10 controls the gimbal apparatus 23 so that the therapeutic radiation irradiation apparatus 6 faces the calculated position. The radiation therapy apparatus control apparatus 10 irradiates the therapeutic radiation so that the irradiation field of the therapeutic radiation 24 matches the shape of the affected part, and the therapeutic radiation 24 is irradiated to the affected part by a predetermined dose. The apparatus 6 is controlled. The radiotherapy apparatus control apparatus 10 further performs operations from taking a tracking fluoroscopic image to irradiating the therapeutic radiation 24 until the affected part of the patient 35 is irradiated with the therapeutic radiation 24 of the dose indicated by the treatment plan. Execute periodically and repeatedly.

  According to such a radiotherapy apparatus control method, the radiotherapy apparatus control apparatus 10 allows the patient 35 to be aligned with higher accuracy so that the bone of the patient 35 is positioned at a predetermined position. The therapeutic radiation 24 can be irradiated to the affected area 35 with higher accuracy, and the patient 35 can be subjected to radiotherapy with higher accuracy.

  In addition, the operation | movement which carries out a radiotherapy can also be substituted by the other operation | movement which carries out a radiotherapy. For example, the radiation therapy apparatus control device 10 treats treatment when the difference between the calculated position of the affected part and the position where the therapeutic radiation 24 is about to be exposed by the therapeutic radiation irradiation apparatus 6 is included in a predetermined range. The therapeutic radiation irradiation device 6 is controlled so that the therapeutic radiation 24 is emitted. When the difference between the calculated position of the affected part and the position where the therapeutic radiation 24 is about to be exposed by the therapeutic radiation irradiation device 6 is not included in the predetermined range, the radiation therapy device control device 10 performs treatment. The therapeutic radiation irradiation device 6 is controlled so that the therapeutic radiation 24 is not exposed. Also in this case, the radiotherapy device control apparatus 10 can perform radiotherapy of the patient 35 with higher accuracy in the same manner as in the above-described radiotherapy.

  The radiotherapy apparatus control apparatus 10 can also fix whether the planned tomographic image or the alignment tomographic image is the first image or the second image regardless of the amount of noise. Also in this case, the display image can more easily show how much the patient 35 is displaced in which direction, and the user can easily align the subject by using such a display image. be able to.

  Note that the image capturing unit 43 at the time of alignment can also capture only the first fluoroscopic image at the time of alignment and the second fluoroscopic image at the time of alignment without capturing the three-dimensional data at the time of alignment. The first fluoroscopic image at the time of alignment indicates an image photographed by the first diagnostic X-ray source 25 and the first sensor array 27. The second fluoroscopic image at the time of alignment indicates an image photographed by the second diagnostic X-ray source 26 and the second sensor array 28. At this time, the radiotherapy apparatus control apparatus 10 reconstructs the first DRR image and the second DRR image based on the planned three-dimensional data imaged by the CT apparatus 20. The first DRR image shows an image photographed by the first diagnostic X-ray source 25 and the first sensor array 27. The second DRR image shows an image photographed by the second diagnostic X-ray source 26 and the second sensor array 28. The radiotherapy apparatus control apparatus 10 creates a display image in the same manner as in the case of a tomographic image. The display image created in this way can show the direction and how much the patient 35 is displaced in the same manner as the display image created based on the tomographic image. By using the display image, the subject can be aligned more easily.

  In another embodiment of the radiotherapy apparatus control method according to the present invention, the processes in steps S4 and S5 are replaced with other processes. As shown in FIG. 11, the radiotherapy apparatus control apparatus 10 calculates a plurality of luminance gradients corresponding to a plurality of pixels indicated by the first image 91, and then converts the first image 91 into a plurality of divided images 92-. It is divided into 1 to 92-m (m = 2, 3, 4,...). The radiotherapy apparatus control apparatus 10 includes a plurality of pixels corresponding to a plurality of pixels included in each of the divided images 92-j (j = 1, 2, 3,..., M) of the plurality of divided images 92-1 to 92-m. A plurality of average luminance gradients corresponding to the plurality of divided images 92-1 to 92-m are calculated by averaging the luminance gradients. An average luminance gradient corresponding to an arbitrary divided image 92-j among the plurality of average luminance gradients indicates an average gradient direction and an average gradient amount. The average gradient direction indicates the direction in which the plurality of luminances corresponding to the plurality of pixels included in the divided image 92-j change most. The average gradient amount indicates the degree to which the plurality of luminances corresponding to the plurality of pixels included in the divided image 92-j change in the average gradient direction.

  The radiotherapy device control apparatus 10 selects a plurality of divided images from the plurality of divided images 92-1 to 92-m so that the evaluation function becomes larger. The radiotherapy device control apparatus 10 selects a plurality of display portions based on the selected plurality of divided images. The plurality of display areas in which the plurality of display portions are respectively arranged are extracted from the first image 91 so as to include the selected plurality of divided images. The radiotherapy apparatus control apparatus 10 creates a display image based on the second image and the selected plurality of display portions. The radiotherapy device control apparatus 10 further displays the display image on the display device.

  According to the display image created in this way, the user can easily confirm in which direction and how much the patient 35 is arranged in the same manner as the display image 61 in the above-described embodiment. Can do. The radiotherapy apparatus control device 10 is further based on the plurality of average luminance gradients compared to extracting the plurality of display portions based on the plurality of luminance gradients corresponding to the plurality of pixels indicated by the first image 91. The amount of calculation for extracting the plurality of display portions can be reduced, and the plurality of display portions can be extracted at higher speed. As a result, the radiation therapy apparatus control apparatus 10 can align the patient 35 at a higher speed.

  The display image can be replaced with three-dimensional data. That is, the radiotherapy apparatus control apparatus 10 extracts a plurality of three-dimensional parts displayed in a plurality of three-dimensional regions from one of the planning three-dimensional data and the alignment three-dimensional data, and the planning three A three-dimensional display image is created in which the other of the three-dimensional data and the three-dimensional data at the time of alignment and a plurality of extracted three-dimensional parts are displayed in an overlapping manner. According to such a three-dimensional display image, in the same way as the two-dimensional display image 61 in the above-described embodiment, the user can easily confirm in which direction and how much the patient 35 is arranged. can do. According to such a three-dimensional display image, compared to the two-dimensional display image 61 in the above-described embodiment, the user can determine in which three-dimensional direction and how much the patient 35 is arranged. It can be easily confirmed.

DESCRIPTION OF SYMBOLS 1: Radiation therapy apparatus 2: O-ring 3: Traveling gantry 6: Radiation irradiation apparatus for treatment 10: Radiation therapy apparatus control apparatus 11: Rotation axis 12: Rotation axis 14: Isocenter 16: Tilt axis 17: Pan axis 20: CT apparatus 21: Swiveling drive device 23: Gimbal device 24: Radiation for treatment 25: X-ray source for first diagnosis 26: X-ray source for second diagnosis 27: First sensor array 28: Second sensor array 31: For first diagnosis X-ray 32: X-ray for second diagnosis 33: Couch 34: Couch drive device 35: Patient 41: Treatment plan collection unit 42: Plan-time image collection unit 43: Registration-time image photographing unit 44: Brightness gradient calculation unit 45: Alignment display area calculation unit 46: Display image creation unit 47: Deviation amount calculation unit 48: Patient alignment unit 49: Irradiation unit 51: First image 52: Image 55: Display part 56-1 56-n: a plurality of display areas 61: a display image 62: an image 63-1 to 63-n: a plurality of display parts 71: a display part 72: a side 73: a characteristic line 74: a direction 75: a gradient direction 76: a characteristic line 77 : Image shift amount 91: First image 92-1 to 92-m: Multiple divided images

Claims (15)

A first image collection unit for collecting a first image obtained by imaging a subject;
A luminance gradient calculation unit that calculates a plurality of luminance gradients corresponding to a plurality of gradient calculation positions based on the first image;
An alignment display region calculation unit that extracts a plurality of display portions respectively displayed in a plurality of different display regions of the first image based on the plurality of luminance gradients;
A second image collection unit for collecting a second image obtained by photographing the subject at a second time different from the first time obtained by photographing the first image;
A display image creation unit that creates a display image based on the second image and the plurality of display areas;
The first image shows a plurality of first luminances corresponding to a plurality of display element positions,
The second image shows a plurality of second luminances corresponding to the plurality of display element positions;
A luminance gradient corresponding to an arbitrary position among the plurality of luminance gradients is:
A gradient direction in which the plurality of first luminance values change most at the arbitrary position;
The degree of the plurality of first luminances changing in the gradient direction at the arbitrary position;
The display image is
The plurality of display portions are respectively displayed in the plurality of display areas of the display image;
The radiotherapy apparatus control apparatus, wherein the second image is displayed in an area other than the plurality of display areas of the display image. In claim 1,
The first image has less noise than the second image. In any one of Claims 1-2.
The alignment display region calculation unit calculates a plurality of evaluation functions corresponding to a plurality of combinations for selecting a plurality of display region candidate luminance gradients from the plurality of luminance gradients, and based on the plurality of evaluation functions, the plurality of evaluation functions Extract the display part,
An evaluation function corresponding to any combination of the plurality of evaluation functions is:
The larger the sum of the distances between the two positions at which any two luminance gradients selected from the plurality of selected luminance gradients selected by the arbitrary combination of the plurality of luminance gradients are arranged,
The larger the total sum of the plurality of selected luminance gradients, the larger
The radiotherapy apparatus control apparatus is such that the angle formed by the two gradient directions indicated by each of the two arbitrary intensity gradients is greater as the angle is closer to a right angle. In any one of Claims 1-2.
The luminance gradient calculation unit divides the first image into a plurality of image portions, calculates a plurality of average luminance gradients corresponding to the plurality of image portions,
An average brightness gradient corresponding to an arbitrary image portion of the plurality of average brightness gradients is:
An average of gradient directions in which the plurality of first luminance values change in the arbitrary image portion;
The degree of the plurality of first luminances changing to the average in the arbitrary image portion;
The alignment display region calculation unit extracts the plurality of display portions from the first image based on the plurality of average luminance gradients. In any one of Claims 1-4,
The plurality of display element positions indicate a plurality of positions at which a plurality of pixels arranged on a plane are respectively arranged. In claim 5,
An outline of an arbitrary display portion among the plurality of display portions includes a side parallel to an average of gradient directions in which the plurality of first luminances change in the arbitrary display portion. In any one of Claims 1-6,
A deviation amount for calculating a deviation amount between a position where the subject is arranged at the first time when the first image is taken and a position where the subject is placed at the second time where the second image is taken. A radiotherapy apparatus control apparatus further comprising a calculation unit. In claim 7,
A radiotherapy apparatus control apparatus, further comprising: an alignment unit that controls a driving device that moves a couch that supports the subject based on the shift amount so that the subject is disposed at a predetermined position. In claim 8,
A radiotherapy apparatus control apparatus further comprising: an irradiation unit that controls an irradiation apparatus so that therapeutic radiation is exposed to a predetermined part of the subject after the subject is arranged at the predetermined position. Collecting a first image of a subject imaged;
Calculating a plurality of luminance gradients corresponding to a plurality of gradient calculation positions based on the first image;
Extracting a plurality of display portions respectively displayed in a plurality of different display areas of the first image based on the plurality of luminance gradients;
Collecting a second image in which the subject is imaged at a second time different from the first time at which the first image was imaged;
Creating a display image based on the second image and the plurality of display areas,
The first image shows a plurality of first luminances corresponding to a plurality of display element positions,
The second image shows a plurality of second luminances corresponding to the plurality of display element positions;
A luminance gradient corresponding to an arbitrary position among the plurality of luminance gradients is:
A gradient direction in which the plurality of first luminance values change most at the arbitrary position;
The degree of the plurality of first luminances changing in the gradient direction at the arbitrary position;
The display image is
The plurality of display portions are respectively displayed in the plurality of display areas of the display image;
The radiotherapy apparatus control method, wherein the second image is displayed in a region other than the plurality of display regions of the display image. In claim 10,
The radiotherapy apparatus control method, wherein the first image has less noise than the second image. In any one of Claims 10 to 11,
Calculating a plurality of evaluation functions corresponding to a plurality of combinations for selecting a plurality of display area candidate luminance gradients from the plurality of luminance gradients;
The plurality of display portions are extracted based on the plurality of evaluation functions,
An evaluation function corresponding to any combination of the plurality of evaluation functions is:
The larger the sum of the distances between the two positions at which any two luminance gradients selected from the plurality of selected luminance gradients selected by the arbitrary combination of the plurality of luminance gradients are arranged,
The larger the total sum of the plurality of selected luminance gradients, the larger
The radiotherapy apparatus control method, wherein the angle formed by the two gradient directions indicated by each of the two arbitrary luminance gradients is larger as the angle is closer to a right angle. In any one of Claims 10 to 11,
Dividing the first image into a plurality of image portions;
Calculating a plurality of average brightness gradients corresponding to the plurality of image portions,
An average brightness gradient corresponding to an arbitrary image portion of the plurality of average brightness gradients is:
An average of gradient directions in which the plurality of first luminance values change in the arbitrary image portion;
The degree of the plurality of first luminances changing to the average in the arbitrary image portion;
The plurality of display portions are extracted from the first image based on the plurality of average luminance gradients. In any one of Claims 10-13,
The plurality of display element positions indicate a plurality of positions at which a plurality of pixels arranged on a plane are respectively arranged. In claim 14,
The outline of an arbitrary display part among the plurality of display parts includes a side parallel to an average of gradient directions in which the plurality of first luminances change in the arbitrary display part.

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