JP6274481B2 - Radiotherapy system, radiotherapy apparatus, and medical image processing apparatus - Google Patents

Description

  Embodiments described herein relate generally to a radiation therapy system, a radiation therapy apparatus, and a medical image processing apparatus.

  Systems for radiation therapy have been developed. In radiation therapy, a treatment plan is performed at a stage prior to radiation treatment, and radiation treatment is performed according to the treatment plan on the day of treatment. A captured image for position confirmation is collected immediately before the radiation treatment, and the subject is positioned by aligning the captured image for position confirmation with the captured image collected at the time of treatment planning.

JP-A-10-192427

  The image alignment is performed by using the density information of the pixel area in the captured image. For this reason, when a captured image includes a clear portion of shading such as a bone region, the unsharp portion of shading is strongly influenced by the clear portion, and the unsharp portion of shading cannot be accurately aligned. In addition, it is possible to grasp the degree of coincidence between the captured image for position confirmation and the captured image at the time of treatment planning by image alignment, but it is possible to directly grasp the positional relationship between the treatment plan result and the subject. I can't. Therefore, it is difficult to perform an accurate treatment in which the subject is strictly positioned with respect to the treatment plan result.

  An object of the embodiment is to provide a radiotherapy system, a radiotherapy apparatus, and a medical image processing apparatus that enable a subject to perform an accurate treatment in which the subject is strictly positioned with respect to a treatment plan result.

The radiation therapy system according to the present embodiment includes a first radiation source that generates radiation for treatment during radiation therapy, a first support mechanism that rotatably supports the first radiation source, and radiation. A second radiation source that generates radiation for imaging at the time of position confirmation before treatment; a radiation detector that detects radiation generated from the second radiation source and transmitted through the subject; and A plurality of cross-sections related to a plurality of cross-sections having different orientations with respect to the subject at the time of position confirmation based on a second support mechanism that supports the radiation source and the radiation detector, and an output from the radiation detector; a generator for generating an image, treatment planning a storage unit for storing the determined irradiation conditions at the time of radiation treatment at the time, the position of the first radiation source in the irradiation condition and the position confirmation time Based on the positions of the plurality of cross-sectional, and calculation unit for calculating an irradiation path and radiation field shape in the plurality of cross-section of the radiation from the first radiation source, at the time the radiation treatment was the calculated A display unit configured to display the irradiation path and the calculated irradiation field shape on the plurality of cross-sectional images.

The figure which shows schematic structure of the radiotherapy system which concerns on this embodiment. The figure which shows the detailed structure of the radiotherapy system which concerns on this embodiment. The figure which shows the typical flow of the image display process performed under control of the system control part of FIG. The figure which shows typically three orthogonal cross sections set by the image generation part of FIG. The figure which shows typically three orthogonal cross sections in real space set by the image generation part of FIG. The figure for demonstrating the calculation process of the irradiation field shape by the calculation part of FIG. The figure for demonstrating the calculation process of the irradiation path by the calculation part of FIG. The other figure for demonstrating the calculation process of the irradiation path | pass by the calculation part of FIG. The figure which shows the example of a display screen of the irradiation path | pass and irradiation field shape by the display part of FIG.

  Hereinafter, a radiotherapy system, a radiotherapy apparatus, and a medical image processing apparatus according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a radiation therapy system according to the present embodiment. As shown in FIG. 1, the radiotherapy system according to the present embodiment includes a treatment frame 1, a bed 3, an imaging frame 5, and a console 7. The treatment stand 1, the bed 3, and the imaging stand 5 are installed in a radiation therapy treatment room. The console 7 is installed in a radiotherapy control room.

  The treatment stand 1 irradiates a subject with radiation for treatment. Specifically, the radiation is an X-ray, an electron beam, a neutron beam, a proton beam, a heavy particle beam, or the like. In this embodiment, the radiation is MV class high energy X-rays. The imaging gantry 5 images the subject in order to generate captured image data for positioning the subject. Imaging for positioning is mainly performed immediately before radiation therapy. The imaging gantry 5 may be a gantry of an X-ray diagnostic apparatus that images a subject using X-rays or a gantry of an X-ray computed tomography apparatus. However, in the following, for the sake of specific description, it is assumed that the imaging gantry 5 is a gantry for an X-ray computed tomography apparatus. The bed 3 movably supports a top plate on which the subject is placed. The bed 3 is shared by the treatment frame 1 and the imaging frame 5. Note that the bed 3 is not necessarily shared by the treatment frame 1 and the imaging frame 5. A bed for the treatment frame 1 and a bed for the imaging frame 5 may be provided separately. The console 7 controls the treatment frame 1, the bed 3, and the imaging frame 5. The console 7 is also communicably connected to another device such as a treatment planning device not shown in FIG. 1 via a network.

  Here, a treatment plan performed by the treatment planning apparatus will be described. The treatment planning device is a computer that determines a plurality of treatment parameters related to a treatment plan. Treatment planning is performed prior to the date of radiation therapy. Examples of the treatment parameters related to the treatment plan include a tumor region, a dose distribution, and irradiation conditions. Examples of irradiation conditions include the quality of therapeutic radiation, the range of possible irradiation angles, and the shape of the irradiation field. Various treatment parameters regarding these treatment plans are supplied from the treatment planning apparatus to the console via a network or the like.

  FIG. 2 is a diagram showing a detailed configuration of the radiation therapy system according to the present embodiment. As shown in FIG. 2, the treatment base 1 includes a rotation support mechanism 11. The rotation support mechanism 11 supports the support 13 so as to be rotatable around the rotation axis AR. The rotation drive unit 15 generates power according to a control signal from the treatment control unit 17. The rotation support mechanism 11 that has received the generated power rotates the support 13 about the rotation axis AR.

  The support 13 is equipped with a radiation source 19 and a diaphragm mechanism 21. The radiation source 19 generates radiation (X-rays) in response to application of a high voltage from the high voltage generator 23. The high voltage generator 23 applies a high voltage to the radiation source 19 in accordance with a control signal from the treatment controller 17. A diaphragm mechanism 21 is attached to the irradiation port portion of the radiation source 19. The aperture mechanism 21 has a plurality of collimators for reproducing the dose distribution and irradiation field calculated in the treatment plan. The diaphragm mechanism 21 receives power from the diaphragm mechanism drive unit 23 and moves the collimator. The diaphragm mechanism drive unit 25 generates power according to the control signal from the treatment control unit 17. Thus, the aperture mechanism 21 has a multi-segment aperture (multi-leaf collimator) structure. A line passing through the execution center (focal point) of the radiation source 19 and the center of the irradiation field is called a beam axis AB. The intersection of the beam axis AB and the rotation axis AR is called an isocenter IC. The rotation angle of the beam axis AB around the isocenter IC is also called an irradiation angle. The irradiation angle is synonymous with the position of the radiation source 19.

  The treatment control unit 17 receives a control signal from the console 7 via the communication unit 27. The treatment control unit 17 controls the rotation drive unit 15, the high voltage generation unit 23, and the aperture drive unit 25 in accordance with the control signal from the console 7. For example, the treatment control unit 17 controls the rotation drive unit 15, the high voltage generation unit 23, and the aperture drive unit 25 according to the treatment parameter related to the treatment plan. Specifically, the treatment control unit 17 controls the rotation driving unit 15 so as to rotate the support 13 according to the irradiation possible angle range of the treatment parameters. The treatment control unit 17 controls the high voltage generation unit 23 so that radiation is generated from the radiation source 19 in accordance with the quality of the treatment parameters. The treatment control unit 17 controls the diaphragm drive unit 25 according to the radiation dose distribution and the irradiation field shape among the treatment parameters.

  Next, the imaging stand 5 will be described.

  As shown in FIG. 2, the imaging stand 5 mounts a ring-shaped or disk-shaped rotating frame 51. The rotating frame 51 supports the X-ray tube 53 and the X-ray detector 55 so as to be rotatable about the rotation axis Z. The X-ray tube 53 and the X-ray detector 55 are attached to the rotating frame 51 so as to face each other with the rotation axis Z interposed therebetween. The rotating frame 51 is electrically connected to the rotation driving unit 57. The rotation drive unit 57 generates power in response to a control signal from the imaging control unit 59. The rotating frame 51 rotates around the rotation axis Z in response to the generated power. The imaging gantry 5 and the treatment gantry 1 are arranged so that the rotation axis Z of the rotation frame 51 and the rotation axis AR of the rotation support mechanism 11 coincide.

  As described above, the Z axis is defined as the rotation axis of the rotating frame 51. The Y axis is defined as an axis connecting the X-ray focal point of the X-ray tube 53 and the center of the X-ray detection surface of the X-ray detector 55. The Y axis is orthogonal to the Z axis. The X axis is defined as an axis orthogonal to the Y axis and the Z axis. Thus, the XYZ orthogonal coordinate system constitutes a rotating coordinate system that rotates with the rotation of the X-ray tube 53.

  The X-ray tube 53 is electrically connected to the high voltage generator 61. The X-ray tube 53 receives an application of a high voltage from the high voltage generator 61 and generates X-rays having keV class energy. The high voltage generator 61 applies a high voltage to the X-ray tube 72 in accordance with a control signal from the imaging controller 59.

  The X-ray detector 55 detects X-rays generated from the X-ray tube 53. The X-ray detector 55 has a plurality of X-ray detection elements arranged in a two-dimensional manner. Each X-ray detection element detects X-rays generated from the X-ray tube 53 and generates an electrical signal (current signal) corresponding to the detected X-ray intensity. The generated electrical signal is supplied to a data acquisition unit (DAS: data acquisition system) 63.

  The data collection unit 63 collects electrical signals from the X-ray detector 55 for each view in accordance with control signals from the imaging control unit 59. The data collection unit 63 converts the collected analog electrical signals into digital data. Digital data is called raw data. The raw data is transmitted to the console 7 by the communication unit 65.

  The imaging control unit 59 receives a control signal from the console 7 via the communication unit 65. The imaging control unit 59 controls the rotation drive unit 57, the high voltage generation unit 61, and the data collection unit 63 according to the control signal from the console 7. Specifically, the imaging control unit 59 controls the rotation driving unit 57 so that the rotating frame 51 rotates at a constant angular velocity during CT imaging. Further, the imaging control unit 59 controls the high voltage generation unit 61 so that X-rays are generated from the X-ray tube 53. Further, the imaging control unit 59 controls the data collection unit 63 so as to collect raw data for each view.

  Next, the bed 3 will be described.

  As shown in FIG. 2, the bed 3 has a top plate 31. The top plate 31 is configured so that the subject P can be placed thereon. The top plate 31 is supported by a top plate support mechanism 33 so as to be movable in a three-dimensional space. The top plate support mechanism 33 is connected to the bed driving unit 35. The bed driving unit 35 generates power in response to a control signal from the bed control unit 37. The top plate support mechanism 33 that has received the generated power moves the top plate 31 according to the control signal. The bed control unit 37 receives a control signal from the console 7 via the communication unit 39. The bed control unit 37 controls the bed driving unit 35 according to this control signal.

  Next, the console 7 will be described.

  The console 7 includes a communication unit 71, a reconstruction unit 73, an image generation unit 75, a calculation unit 77, an analysis unit 79, a display unit 81, an operation unit 83, an image storage unit 85, a main storage unit 87, and a system control unit 89. Prepare.

  The communication unit 71 transmits / receives various data to / from the treatment frame 1, the bed 3, and the imaging frame 5 via the network. Moreover, the communication part 71 can also transmit / receive data between other apparatuses, such as the treatment plan apparatus which is not shown in FIG.1 and FIG.2. Specifically, the communication unit 71 receives various treatment parameters related to the treatment plan from the treatment planning apparatus via the network. The treatment parameters are stored in the main storage unit 87. Further, the communication unit 71 may receive data of a CT image (hereinafter referred to as a treatment plan image) generated at the time of a treatment plan by an X-ray computed tomography apparatus (not shown) via a network. good. The data of the treatment plan image is stored in the image storage unit 85. In addition, the communication unit 71 transmits a control signal to the treatment frame 1, the bed 3, and the imaging frame 5.

  The reconstruction unit 73 reconstructs volume data related to the imaging region of the subject P based on raw data from the imaging platform 5. The volume data is stored in the image storage unit 85.

  The image generation unit 75 performs two-dimensional image processing on the volume data to generate two-dimensional image data. Examples of the three-dimensional image processing include MPR processing (Multiple planar reconstruction), volume rendering, pixel value projection processing, and the like. For example, the image generation unit 75 performs MPR processing on the volume data to generate data of a plurality of cross-sectional images related to a plurality of cross-sections having different directions. Hereinafter, the generated cross-sectional image is referred to as a position confirmation image, and the cross section of the position confirmation image is referred to as a position confirmation cross section. Data of a plurality of position confirmation images is stored in the image storage unit 85.

  The calculation unit 77 sets the current radiation source position based on the irradiation conditions stored in the main storage unit 87 to be described later, the cross-sectional positions of the plurality of position confirmation cross sections, and the current radiation source position of the radiation source 19. A planned passage path and an irradiation field shape in a plurality of cross-sections for position confirmation of radiation from the arranged radiation source 19 are calculated. Hereinafter, the planned passage route in the cross section for confirming the position of the radiation from the radiation source 19 scheduled at the time of treatment planning will be referred to as an irradiation path. Further, hereinafter, the irradiation field shape determined in the treatment plan is referred to as an irradiation field shape at the time of the treatment plan.

  The analysis unit 79 determines whether the angle around the isocenter IC of the beam axis AB connecting the isocenter IC of the treatment frame 1 and the execution center (focal point) of the radiation source 19 is within the irradiation possible angle range determined at the time of treatment planning. Determine whether or not. Hereinafter, the irradiation possible angle range determined at the time of treatment planning will be referred to as the irradiation possible angle range at the time of treatment planning. In addition, the analysis unit 79 calculates a spatial displacement amount between the position confirmation image and the treatment planning image in order to align the position of the subject at the time of treatment with the position of the subject at the time of treatment planning. Also good.

  The display unit 81 displays various data on a display device. For example, the display unit 81 displays a treatment plan image, a position confirmation image, a treatment parameter, and the like. Further, the display unit 81 displays the irradiation path and the irradiation field cross-sectional shape calculated by the calculation unit 77 in a superimposed manner on a plurality of position confirmation images. As the display device, for example, a CRT display, a liquid crystal display, an organic EL display, a plasma display, or the like can be used as appropriate.

  The operation unit 83 accepts various commands and information input from the user via the input device. As an input device, a keyboard, a mouse, a switch, or the like can be used.

  The image storage unit 85 stores various image data. For example, the image storage unit 85 is generated at the time of treatment planning by the volume data reconstructed by the reconstruction unit 73, the image data for position confirmation generated by the image generation unit 75, and another X-ray computed tomography apparatus. The data of the treatment planning image is stored. Further, the image storage unit 85 may store the raw data transmitted from the imaging gantry 5.

  The main storage unit 87 stores various treatment parameters determined at the time of treatment planning. Specifically, the main storage unit 87 stores the above-described tumor region, dose distribution, irradiation conditions, and the like as treatment parameters. As described above, irradiation conditions include the quality of therapeutic radiation, the range of possible irradiation angles, the shape of the irradiation field, and the like. The irradiation possible angle range is a range of an angle (irradiation angle) around the rotation axis AR of the radiation source 19 that is allowed at the time of performing radiotherapy. The irradiation field shape is an irradiation field range on the reference plane of the radiation emitted from the radiation source 19. The reference plane is typically defined as a plane (isocenter plane) orthogonal to the beam axis AB and passing through the isocenter IC, as will be described later. The reference plane is not limited to the isocenter plane, and may be another plane orthogonal to the beam axis AB. Further, the main storage unit 87 stores an operation program for the radiation therapy system according to the present embodiment.

  The system control unit 89 functions as the center of the radiation therapy system. The system control unit 89 controls each unit according to the operation program stored in the main storage unit 87 and executes the image display process according to the present embodiment.

  Hereinafter, an operation example of the radiation therapy system according to the present embodiment will be described. FIG. 3 is a diagram showing a typical flow of image display processing performed under the control of the system control unit. The image display process shown in FIG. 3 is typically performed when the subject is positioned on the day of radiation therapy.

  First, the user places the subject P on the top plate 31 of the bed 3 for position confirmation. When preparation for imaging of the subject P is completed, the user inputs an instruction to start CT imaging via the operation unit 83 or the like. In response to the input of the CT imaging start instruction, the system control unit 89 controls the imaging control unit 59 to execute CT imaging of the subject P (step S1). Specifically, the imaging control unit 59 controls the rotation driving unit 57 to rotate the rotating frame 51 around the rotation axis Z at a constant angular velocity. After the rotation frame 51 rotates, the imaging control unit 59 controls the high voltage generation unit 61 to generate a predetermined dose of X-rays from the X-ray tube 53. The imaging control unit 59 controls the data collection unit 63 in synchronization with the exposure cycle of the X-ray tube 53 and collects raw data for each view. The collected raw data is supplied to the communication unit 65.

  If step S1 is performed, the communication part 65 will transmit raw data to the console 7 for every predetermined | prescribed view (step S2). The raw data is stored in the image storage unit 85 for each view.

  When step S2 is performed, the system control unit 89 causes the reconfiguration unit 73 to perform reconfiguration processing (step S3). In step S <b> 3, the reconstruction unit 73 reconstructs volume data regarding the imaging region of the subject P based on raw data regarding a plurality of views. The volume data is stored in the image storage unit 85.

  When the volume data reconstruction is performed, the user retreats the imaging platform 5 from the subject P. Then, the user starts positioning the subject P according to the treatment plan.

  When step S3 is performed, the system control unit 89 causes the image generation unit 75 to perform generation processing (step S4). In step S4, the image generation unit 75 performs MPR processing on the volume data to generate a plurality of position confirmation image data relating to a plurality of position confirmation sections. For example, the plurality of position confirmation cross sections may be defined as three cross sections orthogonal to each other, that is, three orthogonal cross sections.

  FIG. 4 is a diagram schematically showing three orthogonal cross sections. As shown in FIG. 4, the three orthogonal cross sections have one orthogonal cross section SO and two parallel cross sections SP1 and SP2. The orthogonal section SO is set to be orthogonal to the beam axis AB connecting the execution center of the radiation source 19 and the isocenter IC of the treatment frame 1. The two parallel sections SP1 and SP2 are set to be parallel to the beam axis AB. The first parallel section SP1 and the second parallel section SP2 are set to be orthogonal to each other.

  FIG. 5 is a diagram schematically showing three orthogonal cross sections in real space. FIG. 5 shows the geometry related to the treatment base 1 when the radiation source 19 is in the front direction of the patient P. The patient P is placed on the top board 31. Initially, the first parallel section SP1 is set to be parallel to the beam axis AB and parallel to the body axis of the patient P. The second parallel cross section SP2 is set to be parallel to the beam axis AB and orthogonal to the body axis of the patient P. As shown in FIG. 5, the orthogonal cross-section SO, the first parallel cross-section SP1, and the second parallel cross-section SP2 initially intersect at the three-dimensional coordinates of the isocenter IC of the treatment gantry 1 when performing radiotherapy. Is set as follows. The cross-sectional positions of the orthogonal cross-section SO, the first parallel cross-section SP1, and the second parallel cross-section SP2 can be arbitrarily set by the user via the operation unit 83.

  In step S <b> 4, the image generation unit 75 generates MPR processing on the volume data for the data of the three position confirmation images regarding the set three orthogonal cross sections. In addition, the cross section for position confirmation such as the three orthogonal cross sections may have no thickness or may have a thickness. When there is a thickness, the image generation unit generates three position confirmation image data regarding three orthogonal cross sections by performing a pixel value projection process with thickness on the volume data. As the pixel value projecting process, for example, a minimum value projecting process, a maximum value projecting process, an average value projecting process, an intermediate value projecting process, or the like may be used as appropriate. The data for the position confirmation image is stored in the image storage unit 85.

  When step S5 is performed, the system control unit 89 causes the calculation unit 77 to perform calculation processing (step S5). In step S <b> 5, the calculation unit 77 sets the current position based on the irradiation conditions at the time of the treatment plan stored in the main storage unit 87, the positions of the plurality of position confirmation cross sections, and the current position of the radiation source 19. An irradiation path in a plurality of position confirmation cross sections of radiation from the arranged radiation source 19 and an irradiation field shape in the plurality of position confirmation cross sections are calculated. More specifically, the calculation unit 77 calculates the irradiation field shape in the orthogonal cross section based on the irradiation field shape at the time of treatment planning and the cross-sectional position of the orthogonal cross section. Further, the calculation unit 77 calculates an irradiation path in the parallel section based on the irradiation field shape at the time of treatment planning and the cross-sectional position of the parallel section. Hereinafter, a method for calculating the irradiation field shape and the irradiation path will be described in detail.

  FIG. 6 is a diagram for explaining the calculation process of the irradiation path and the irradiation field shape by the calculation unit 77. As shown in FIG. 6, the irradiation field shape at the time of treatment planning is a cross section passing through the isocenter IC and orthogonal to the beam axis AB, that is, a range occupied by the geometric irradiation field RI in the isocenter plane SC. The range occupied by the geometric irradiation field RI is specifically defined by the irradiation aperture. The irradiation aperture is defined by the positions of a plurality of collimators mounted on the aperture mechanism 21.

  When the orthogonal section SO coincides with the isocenter plane SC, the calculation unit 77 sets the irradiation field shape at the time of treatment planning to the irradiation field shape RIO in the orthogonal section SO. When the orthogonal section SO does not coincide with the isocenter plane SC, the calculation unit 77 calculates the irradiation field in the orthogonal section SO based on the irradiation field shape RI at the time of treatment planning and the distance LS from the isocenter plane SC to the orthogonal section SO. Calculate the shape RIO. Specifically, the irradiation field shape RIO in the orthogonal cross section SO is calculated by enlarging or reducing the irradiation field shape RI in the isocenter plane SC according to the distance LS. When the orthogonal section SO is far from the current radiation source position of the radiation source 19 compared to the isocenter plane SC, the irradiation field shape RI is enlarged according to the distance LS, and the expanded irradiation field shape is changed to the orthogonal section SO. Is set to the irradiation field shape RIO. When the orthogonal cross section SO is closer to the current radiation source position of the radiation source 19 than the isocenter plane SC, the irradiation field shape RI is reduced according to the distance LS, and the reduced irradiation field shape is changed to the orthogonal cross section SO. Is set to the irradiation field shape RIO. The current radiation source position means the radiation source position of the radiation source 19 at the time of calculating the irradiation field shape RIO.

  When the irradiation field shape in the orthogonal section is calculated, the calculation unit 77 calculates the irradiation path in the parallel section based on the irradiation field shape at the time of treatment planning, the sectional position of the parallel section, and the current radiation source position of the radiation source 19. calculate. 7 and 8 are diagrams for explaining the calculation process of the irradiation path in the parallel section SP. First, the calculation unit 77 calculates a three-dimensional irradiation path BP3 as shown in FIG. Specifically, the calculation unit 77 calculates a virtual plane connecting the edge RR of the irradiation field shape RI and the current radiation source position of the radiation source 19 at the time of treatment planning in the isocenter plane SC. The calculated plane composed of a plurality of lines represents a three-dimensional path (irradiation path) BP3 of radiation emitted from the radiation source 19 arranged at the current radiation source position. When the three-dimensional irradiation path BP3 is calculated, the calculation unit 77 sets a parallel section BP in the three-dimensional image space in which the three-dimensional irradiation path BP3 is defined as shown in FIG. The calculation unit 77 calculates a line where the three-dimensional irradiation path BP3 and the parallel section BP intersect as the irradiation path BPP in the parallel section BP. In FIG. 8, the parallel cross section BP includes the isocenter IC, but may be set to a cross sectional position not including the isocenter IC.

  In FIG. 8, for the sake of simplicity, a single parallel section of two parallel sections constituting the three orthogonal sections is shown, but in reality, two parallel sections constituting the three orthogonal sections are shown. BP1 and BP2 are set in the three-dimensional image space. The calculation unit 77 calculates the irradiation path in each of the parallel cross sections BP1 and BP2 for each of the two parallel cross sections BP1 and BP2 by executing the above processing.

  When step S5 is performed, the system control unit 89 causes the display unit 81 to perform display processing (step S6). In step S <b> 6, the display unit 81 displays the irradiation path and the irradiation field shape superimposed on the three position confirmation images regarding the three orthogonal cross sections.

  FIG. 9 is a diagram illustrating a display screen example of the irradiation path and the irradiation field shape by the display unit 81. As illustrated in FIG. 9, the display unit 81 displays a position confirmation image IO regarding the orthogonal cross section, a position confirmation image IP1 regarding the first parallel section, and a position confirmation image IP2 regarding the second parallel section. In FIG. 9, for example, the position confirmation image IO is an axial cross-sectional image, the position confirmation image IP1 is a sagittal cross-sectional image, and the position confirmation image IP2 is a coronal cross-sectional image. The tumor region RT is highlighted in the position confirmation image IO, the position confirmation image IP1, and the position confirmation image IP2. The display unit 81 displays the mark MR indicating the shape of the irradiation field in the orthogonal cross section superimposed on the position confirmation image IO. The display unit 81 superimposes and displays a mark MP indicating an irradiation path on each of the position confirmation image IP1 related to the first parallel section and the position confirmation image IP2 related to the second parallel section. Thus, by displaying the mark MR indicating the irradiation field mark and the mark MP indicating the irradiation path superimposed on each position confirmation image IO, IP1, IP2, the user can confirm the irradiation field shape and the irradiation path for position confirmation. It can be intuitively associated with an image.

  The display unit 81 may display other information as necessary. For example, the display unit 81 may display a dose distribution determined in the treatment plan. In this case, the display unit 81 aligns and displays the dose distribution on the superimposed image of the irradiation path, the irradiation field shape, and the position confirmation image. Thus, the user can grasp the irradiation path, the irradiation field, and the dose distribution in association with each other on the position confirmation image. The display unit 81 may display a treatment planning image in addition to the position confirmation image. In this case, the display unit 81 may display the treatment plan image superimposed on the position confirmation image, or display the treatment plan image and the position confirmation image side by side. Note that the position confirmation image to be displayed may be all of the three position confirmation images, or any one or two of the three position confirmation images. Thereby, the user can easily grasp the degree of coincidence between the treatment plan image and the position confirmation image.

  The user determines whether or not the subject is correctly positioned by observing the irradiation field shape and the irradiation path displayed on the display unit 81 in step S6. For example, when the mark indicating the irradiation path or the mark indicating the irradiation field shape is deviated from the tumor region, or when the user determines that the current position of the patient is not appropriate, the bed 3 or the treatment stand 1 via the operation unit 83. Instruct to move. At this time, the analysis unit 79 may calculate an amount of positional deviation between the treatment planning image and the position confirmation image in response to an instruction from the user via the operation unit 83. The displacement amount is displayed on the display unit 81. The amount of positional deviation between the treatment planning image and the position confirmation image is provided as a material for determining the degree of positioning of the subject P by the user.

  If it is determined that the position of the treatment base 1 is not appropriate, the user changes the radiation source position of the radiation source 19 to change the radiation source position. In other words, the rotation instruction of the support 13 is changed via the operation unit 83 or the like. Enter instructions. The treatment control unit 17 controls the rotation driving unit 15 according to the rotation instruction to rotate the support 13 around the rotation axis AR. In conjunction with the rotation of the support 13, the image generation unit 75 updates the position confirmation image. Specifically, the image generation unit 75 recalculates the cross-sectional positions of the three orthogonal cross sections by the above method according to the radiation source position of the radiation source 19 after the rotation, and 3 regarding the three orthogonal cross-sections after the recalculation. One position confirmation image data is generated. As a result, the position confirmation image is updated. The calculation unit 77 recalculates the irradiation path and the irradiation field shape in the updated position confirmation image according to the radiation source position of the rotated radiation source 19 by the above method. The display unit 81 displays the recalculated irradiation path and irradiation field shape on the three position confirmation images related to the updated three orthogonal cross sections. Accordingly, the user can intuitively grasp the irradiation field shape and the irradiation path in association with the position confirmation image after the change of the cross-sectional position.

  The change of the cross-sectional position of the position confirmation cross-section is not limited to the method of rotating the support 13. That is, the position of the cross section for position confirmation may be changed by software without actually rotating the support 13. In this case, the user inputs a virtual irradiation angle change instruction. The image generation unit 75 recalculates the positions of the three orthogonal cross sections in accordance with a virtual irradiation angle change instruction. That is, the image generation unit 75 recalculates the three orthogonal cross sections by the above method according to the radiation source position corresponding to the irradiation angle designated by the user. The image generation unit 75 generates data of three position confirmation images regarding three orthogonal cross sections after recalculation. As a result, the position confirmation image is updated. The calculation unit 77 recalculates the irradiation path and the irradiation field shape in the updated position confirmation image according to the radiation source position corresponding to the irradiation angle designated by the user by the above method. The display unit 81 superimposes and displays the updated irradiation path and irradiation field shape on the three position confirmation images regarding the three orthogonal cross sections after the update. Thereby, the irradiation path and the irradiation field shape at an arbitrary irradiation angle can be confirmed on software without actually rotating the support 13.

  When changing the irradiation angle, it is convenient if it is possible to grasp whether or not the irradiation angle is within the irradiation possible angle range determined in the treatment plan. During the display of the position confirmation image, the analysis unit 79 determines whether or not the irradiation angle of the radiation source 19 is within the irradiation possible angle range. The irradiation angle to be determined may be the rotation angle of the radiation source 19 around the actual rotation axis AR, or may be a virtual irradiation angle. The display unit 81 changes the display mode of the mark indicating the irradiation path and the mark indicating the irradiation field shape according to the determination result by the analysis unit 79. Specifically, in the display unit 81, when the analysis unit 79 determines that the irradiation angle to be determined is within the irradiable angle range, and when the analysis unit 79 determines that the irradiation angle is not within the irradiable angle range. The display mode of the mark indicating the irradiation path and the mark indicating the irradiation field shape is changed. For example, when the analysis unit 79 determines that the irradiation angle to be determined is not within the irradiation possible angle range, the display unit 81 erases the mark indicating the irradiation path and the mark indicating the irradiation field shape from the screen, or blinks. Or display a message to that effect. Further, the display unit 81 has a case where the analysis unit 79 determines that the irradiation angle of the determination target is within the irradiable angle range and a case where the analysis unit 79 determines that the irradiation angle of the determination target is not within the irradiable angle range. The mark indicating the irradiation path and the mark indicating the irradiation field shape may be displayed in different colors, or the background color and the position confirmation image may be displayed in different colors. As a result, the user can easily determine whether or not it is during radiation irradiation only by observing the screen.

  When the patient is correctly positioned, the user inputs a treatment start instruction. When a treatment start instruction is input, the treatment control unit 17 emits radiation according to the treatment parameter. As a result, tumor areas such as cancer and tumor can be eliminated or reduced.

  Above, description is complete | finished to the operation example of the image display process which concerns on this embodiment.

  In the above description, it is assumed that the treatment frame 1 and the imaging frame 5 are separate devices. However, the treatment gantry 1 and the imaging gantry 5 may be an integrated device (treatment / imaging gantry) having the configuration of both gantry. As is well known, a treatment / imaging stand includes a radiation source for treatment, a radiation source for position confirmation, and a radiation detector for detecting radiation from the radiation source for position confirmation in one rotating frame. It is a mounting base.

  In the above description, the imaging stand 5 is assumed to be a stand for an X-ray computed tomography apparatus. That is, the position confirmation image is generated based on the raw data collected by the X-ray computed tomography apparatus. However, this embodiment is not limited to this. The imaging gantry according to the present embodiment may be a gantry for an X-ray diagnostic apparatus. In this case, the gantry of the X-ray diagnostic apparatus according to the present embodiment generates a plurality of X-ray image data regarding the plurality of irradiation angles by performing X-ray imaging of the subject P at a plurality of imaging angles. The imaging angle is an angle formed by an axis connecting the focal point of the X-ray tube equipped in the X-ray diagnostic apparatus and the center of the detection surface of the X-ray detector with respect to the rotation axis of the X-ray diagnostic apparatus. The X-ray detector detects X-rays generated from the X-ray tube and generates X-ray image data relating to the subject. The generated X-ray image data is used as the position confirmation image according to the present embodiment. For example, X-ray imaging of the subject is performed at three imaging angles corresponding to the three orthogonal sections by the gantry of the X-ray diagnostic apparatus, thereby generating three position confirmation image data regarding the three orthogonal sections. These position confirmation image data are transmitted to the console 7 and stored in the image storage unit 85. The imaging angle is defined as the angle formed by the axis connecting the focal point of the X-ray tube equipped in the X-ray diagnostic apparatus and the center of the detection surface of the X-ray detector with respect to the rotation axis of the X-ray diagnostic apparatus. .

  In the present embodiment, the treatment frame 1 and the imaging frame are controlled by a single console 7. However, this embodiment is not limited to this. That is, the console for the treatment frame 1 and the console for the imaging frame 5 may be provided independently so as to communicate with each other. In this case, for example, the reconstruction unit 73 and the image processing generation unit 75 are provided in a console for the imaging gantry 5 and include a calculation unit 77, an analysis unit 79, a display unit 81, an operation unit 83, an image storage unit 85, The main storage unit 87 may be provided on a console for the treatment stand 1.

  As described above, the radiation therapy system according to this embodiment includes the first radiation source 19, the first support mechanism 11, the second radiation source 53, the radiation detector 55, the second support mechanism 51, and the image. A generation unit 75, a main storage unit 87, a calculation unit 77, and a display unit 81 are included. The first radiation source 19 generates radiation for treatment. The 1st support mechanism 11 supports the radiation source 19 rotatably. The second radiation source 53 generates radiation for imaging. The radiation detector 55 detects radiation generated from the radiation source 53 and transmitted through the subject. The second support mechanism 51 supports the radiation source 53 and the radiation detector 55. The image generation unit 75 generates a plurality of cross-sectional images related to a plurality of cross-sections whose directions are different from each other based on the output from the radiation detector 55. The main storage unit 87 stores irradiation conditions at the time of radiation therapy determined at the time of treatment planning. Based on the irradiation conditions, the current radiation source position of the radiation source 19 and the positions of the plurality of cross sections, the calculation unit 77 calculates the radiation from the radiation source 19 arranged at the current radiation source position in the plurality of cross sections. Calculate irradiation path and field shape. The display unit 81 displays the calculated irradiation path and the calculated irradiation field shape superimposed on the plurality of cross-sectional images.

  With the above configuration, the user can intuitively grasp the treatment plan result such as the irradiation field shape immediately before the radiation treatment. Therefore, the user can strictly position the subject with respect to the treatment plan result as compared with the conventional method of positioning the subject by image alignment. Thus, according to the present embodiment, it is possible to perform an accurate treatment in which the subject is strictly positioned with respect to the treatment plan result.

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

  DESCRIPTION OF SYMBOLS 1 ... Treatment stand, 3 ... Bed, 5 ... Imaging stand, 7 ... Console, 11 ... Support, 13 ... Rotation support mechanism, 15 ... Rotation drive part, 17 ... Treatment control part, 19 ... Radiation source, 21 ... Diaphragm mechanism , 23 ... High voltage generating unit, 25 ... Diaphragm driving unit, 27 ... Communication unit, 31 ... Top plate, 33 ... Top plate support mechanism, 35 ... Bed driving unit, 37 ... Bed control unit, 39 ... Communication unit, 51 ... Rotating frame, 53 ... X-ray tube, 55 ... X-ray detector, 57 ... Rotation driving unit, 59 ... Imaging control unit, 61 ... High voltage generating unit, 63 ... Data collecting unit, 65 ... Communication unit, 71 ... Communication unit 73 ... Reconstruction unit, 75 ... Image generation unit, 77 ... Calculation unit, 79 ... Analysis unit, 81 ... Display unit, 83 ... Operation unit, 85 ... Image storage unit, 87 ... Main storage unit, 89 ... System control unit

Claims (12)

During radiation therapy, a first radiation source that generates radiation for treatment;
A first support mechanism for rotatably supporting the first radiation source;
A second radiation source for generating radiation for imaging at the time of position confirmation before radiation treatment ;
A radiation detector for detecting radiation generated from the second radiation source and transmitted through the subject;
A second support mechanism for supporting the second radiation source and the radiation detector;
Based on an output from the radiation detector, a generating unit that generates a plurality of cross-sectional images related to a plurality of cross-sections having different directions with respect to the subject at the time of the position confirmation ,
A storage unit for storing irradiation conditions at the time of radiation therapy determined at the time of treatment planning;
Based on the irradiation conditions, the position of the first radiation source at the time of the position confirmation, and the positions of the plurality of cross sections, irradiation paths and irradiation field shapes in the plurality of cross sections of the radiation from the first radiation source A calculation unit for calculating
At the time of the radiation therapy, a display unit that displays the calculated irradiation path and the calculated irradiation field shape superimposed on the plurality of cross-sectional images;
A radiation therapy system comprising: The radiotherapy system according to claim 1, wherein the display unit displays a CT image generated by an X-ray computed tomography apparatus at the time of treatment planning and at least one cross-sectional image of the plurality of cross-sectional images superimposed or side by side.   The radiation treatment according to claim 1, wherein the irradiation condition is an irradiation field shape in a cross section orthogonal to an axis connecting a focal point of the first radiation source and an isocenter in the first support mechanism and passing through the isocenter. system.   The plurality of cross sections are an orthogonal cross section orthogonal to an axis connecting a focal point of the first radiation source and an isocenter in the first support mechanism, a first parallel cross section parallel to the axis, and parallel to the axis. The radiation therapy system according to claim 3, wherein the radiation therapy system is a second parallel section orthogonal to the first parallel section.   The radiotherapy system according to claim 4, wherein the calculation unit calculates the irradiation field shape in the orthogonal cross section based on the irradiation condition and the position of the orthogonal cross section.   The calculation unit calculates the irradiation path in the first parallel cross section based on the irradiation condition and the position of the first parallel cross section, and based on the irradiation condition and the position of the second parallel cross section. The radiotherapy system according to claim 4, wherein the irradiation path in the second parallel section is calculated. Said computing unit, said first radiation source position at the time the position check, position of the isocenter in the at the position check first support mechanism, and calculates the irradiation path based on the irradiation aperture size The radiation therapy system according to claim 1.   The calculation unit updates the irradiation path and the irradiation field shape in the plurality of cross sections according to a change in an angle around an axis connecting a focal point of the first radiation source and an isocenter in the first support mechanism. The radiation therapy system according to claim 1. 2. The calculation unit according to claim 1, wherein when the positions of the plurality of cross sections are designated by a user, the calculation unit updates the irradiation path and the irradiation field shape in the plurality of cross sections corresponding to the designated positions . Radiation therapy system. A determination unit for determining whether an angle around the isocenter of an axis connecting the focal point of the first radiation source and the isocenter in the first support mechanism is within a predetermined angle range;
The display unit changes a display mode of the irradiation path and the irradiation field shape according to a determination result by the determination unit.
The radiation therapy system according to claim 1. During radiation therapy, a radiation source that generates radiation for treatment,
A support mechanism for rotatably supporting the radiation source;
An irradiation condition storage unit that stores the irradiation condition during the radiation treatment as determined during treatment planning,
An image storage unit for storing a plurality of cross-sectional images related to a plurality of different cross-sections generated at the time of position confirmation before radiotherapy by an X-ray diagnostic apparatus or an X-ray computed tomography apparatus ;
Based on the irradiation condition, the position of the radiation source, and the position of the plurality of cross sections, a calculation unit that calculates an irradiation path and an irradiation field shape in the plurality of cross sections of the radiation from the radiation source;
At the time of the radiation therapy, a display unit that displays the calculated irradiation path and the calculated irradiation field shape superimposed on the plurality of cross-sectional images;
A radiotherapy apparatus comprising: A medical image processing apparatus connected to a radiotherapy apparatus,
An irradiation condition storage unit for storing irradiation conditions at the time of radiation therapy determined at the time of treatment planning;
An image storage unit for storing a plurality of cross-sectional images related to a plurality of different cross-sections generated at the time of position confirmation before radiotherapy by an X-ray diagnostic apparatus or an X-ray computed tomography apparatus ;
Based on the irradiation conditions and the position of the radiation source of the X-ray diagnostic apparatus or the X-ray computed tomography apparatus at the time of the position confirmation and the position of the plurality of sections, the radiation from the radiation source in the plurality of sections A calculation unit for calculating an irradiation path and an irradiation field shape;
At the time of the radiation therapy, a display unit that displays the calculated irradiation path and the calculated irradiation field shape superimposed on the plurality of cross-sectional images;
A medical image processing apparatus comprising:

Images