JP5197026B2 - Radiotherapy system, radiotherapy support apparatus, and radiotherapy support program - Google Patents

Description

  The present invention relates to a radiotherapy system, a radiotherapy support apparatus, and a radiotherapy support program having a function of providing information for assisting treatment to an operator during radiotherapy.

  In radiation therapy represented by external X-ray irradiation treatment, an irradiation plan (from which direction and how much dose is irradiated to the treatment site) is planned on the patient image before treatment, and based on this The patient is irradiated. However, at present there is no means to confirm whether the patient is actually receiving the position and dose as planned, and even if there is under-irradiation to the treatment site or over-exposure to normal tissue, it will not be noticed. Is the current situation. It may be confirmed that irradiation can be performed as planned using a phantom and an X-ray detector before irradiation, but unlike a phantom that can be easily carried and adjusted freely, the patient can be placed on the bed. However, it is difficult to place them in the position as planned for irradiation, and these pre-irradiation confirmations do not completely guarantee the irradiation as planned for the patient.

In addition, as a well-known document relevant to this application, there exist the following, for example.
JP, 5-146426, A The art which this patent document discloses detects a scattered X-ray of an X-ray subject, and obtains a tomographic image of a subject. It is characterized by reconstructing and obtaining a three-dimensional scattered radiation image of a subject by scanning with a pencil beam. In other words, this technology assumes only a pencil-shaped beam, and does not obtain a scattered image (spatial distribution of the dose of the treatment beam) of the region through which the beam with a finite width used in X-ray therapy has passed. . In addition, since scattering of high-energy treatment beams (several MeV) within a subject is superior to forward scattering, it is difficult to distinguish scattered and transmitted rays if a detector is placed in the incident X-ray direction, and detection of scattered rays is difficult. Correction processing is essential.

  With increasing social interest in medical malpractice, over-irradiation of patients has also been reported in radiotherapy. It is expected that it will become more and more important in the future to record the “facts” of the medical practice performed, such as how much dose the patient has received. Recently, in the field of external X-ray irradiation therapy, a method of irradiating in sync with and following the movement of the tumor in the patient due to breathing, a method of collimating and irradiating a therapeutic X-ray beam according to the tumor shape, etc. Attempts have been made to irradiate the lesion more precisely. These precision irradiations are intended to concentrate the dose on the lesion. For this reason, in the unlikely event that the therapeutic X-ray beam deviates from the irradiation target, the normal tissue is seriously damaged. For this reason, it is important to confirm whether or not the irradiation is performed as planned as the irradiation becomes more precise.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to provide an operator with information for preventing under-irradiation of a treatment site and over-irradiation of a normal tissue in radiation irradiation treatment. Another object of the present invention is to provide a radiotherapy system, a radiotherapy support apparatus, and a radiotherapy support program that enable accurate and safe treatment.

  In order to achieve the above object, the present invention takes the following measures.

  A radiotherapy system according to the present invention includes an irradiation unit that irradiates a subject with a therapeutic radiation beam, a detection unit that detects scattered radiation generated based on the therapeutic radiation beam, and a radiotherapy system that performs irradiation of the therapeutic radiation beam. Acquisition means for acquiring the irradiated position and absorbed dose from the scattered radiation data, at least one of the acquired irradiated position and absorbed dose, and the reference dose for each position of the treatment site and normal site of the subject And generating means for generating information that contrasts.

  The radiation therapy support apparatus according to the present invention irradiates a subject with a therapeutic radiation beam, and detects treatment support information using scattered radiation data obtained by detecting scattered radiation generated based on the therapeutic radiation beam. A radiotherapy information providing device to generate, an acquisition means for acquiring an irradiated position and an absorbed dose from the scattered radiation data for each irradiation of the therapeutic radiation beam, and the acquired irradiated position and absorbed dose And generating means for generating information that compares at least one of the reference dose for each position of the treatment site and the normal site of the subject.

  The radiotherapy support program according to the present invention provides treatment support information using scattered radiation data obtained by irradiating a subject with a therapeutic radiation beam and detecting scattered radiation generated based on the therapeutic radiation beam. A program for controlling a radiotherapy information providing apparatus to be generated, the computer having an acquisition function for acquiring an irradiated position and an absorbed dose from the scattered radiation data for each irradiation of the therapeutic radiation beam, and the acquired A generation function for generating information that compares at least one of an irradiation position and an absorbed dose with a reference dose for each position of a treatment site and a normal site of the subject is executed.

  As described above, according to the present invention, in radiation treatment, radiation that enables an operator to provide information for preventing under-irradiation to a treatment site and over-irradiation to a normal tissue, and enables accurate and safe treatment. A treatment system, a radiation therapy support device, and a radiation therapy support program can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

[Principle and method]
The radiotherapy system according to the present embodiment measures the scattered radiation from the subject based on the radiation irradiated to the subject, and based on this, what part of the subject is irradiated with how much dose? The information which objectively shows is acquired. The principle and method are as follows.

  FIG. 1 is a diagram for explaining the principle and method of measuring scattered radiation from a subject based on therapeutic radiation of the present radiation treatment system.

  The therapeutic effect of external X-ray irradiation is mainly brought about by X-ray scattering that occurs in the patient. That is, when the therapeutic X-ray beam is scattered by electrons in the patient, the electrons that have received energy fly through the tissue and then stop. At this time, the electrons radicalize the molecules in the tissue until they stop, damaging the DNA in the cells. Cells that are damaged and cannot be repaired eventually die. This is the therapeutic effect of X-ray irradiation. The more recoiled electrons are generated, the higher the probability that the cells constituting the tissue will die, so the therapeutic effect is proportional to the number of times the scattering reaction occurs.

  From the above, knowing the number of scatterings that have occurred in the tissue, it is possible to know the therapeutic effect (= how much the tissue has been damaged). The number of scattering that has occurred can be determined by measuring the number of scattered rays. Since most of the scattered X-rays are transferred to the outside of the patient after the traveling direction is changed by electrons, they can be measured by an X-ray detector installed outside the patient.

  In the radiation therapy system according to the first example of the present embodiment, a detector having a collimator is installed at a position that makes a specific angle with respect to the treatment X-ray beam, and only scattered rays that come in that direction are selected. Detect. Since it is theoretically possible to know how much X-rays are scattered at which angle by Compton scattering, if the scattered radiation at one angle can be detected, the number of scattered rays at other angles can be estimated. Furthermore, in order to obtain a three-dimensional distribution of the locations where scattering occurs in the patient, the detector is rotated during irradiation, and the scattered radiation is measured from all directions (see, for example, FIG. 5). Thereafter, reconstruction processing is performed, and the generation distribution of scattered radiation inside the subject is imaged three-dimensionally.

  In addition, in the radiotherapy system according to the second example of the present embodiment, a detector having a collimator is installed at a position that forms a predetermined angle (scattering angle) with respect to the treatment X-ray beam and comes in that direction. The detection X-ray beam and the detection surface are detected while maintaining the angle formed by the axis of the therapeutic X-ray beam irradiated from the irradiation unit and the detection surface of the detector. By scanning while moving the 3D region in the subject. Using the obtained three-dimensional scattered radiation data for a given scattering angle, the scattered radiation volume data is reconstructed, and the scattered radiation volume data is converted into absorbed dose volume data indicating a three-dimensional distribution of absorbed radiation. Then, an absorbed dose image is generated.

[Constitution]
FIG. 2 shows a block configuration diagram of the radiation therapy system 1 according to the present embodiment. As shown in the figure, the radiation treatment system 1 includes a radiation irradiation system 2, a scattered radiation detection system 3, a data acquisition control unit 4, a data processing system 5, a display unit 6, a storage unit 7, an operation unit 8, and a network I. / F9. The radiation irradiation system 2 and the scattered radiation detection system 3 are installed on a gantry, and can be arranged at arbitrary positions with respect to the subject by moving and rotating the gantry. Moreover, the data acquisition control part 4, the data processing system 5, the display part 6, the memory | storage part 7, the operation part 8, and network I / F9 are installed in the main body (housing | casing) of the radiotherapy system 1, for example.

[Radiation irradiation system]
The radiation irradiation system 2 includes a power supply unit 201, an irradiation unit 203, a timing control unit 205, and a gantry control unit 207.

  The power supply unit 201 supplies power to the irradiation unit 203 according to the control from the data acquisition control unit 4.

  The irradiation unit 203 is a radiation irradiation apparatus having a mechanism such as a linear accelerator (linac). In the irradiation unit 203, thermoelectrons emitted from the cathode are accelerated to several hundred keV by an electron gun provided at one end of the accelerating tube. Next, the microwave generated by the klystron is guided to the accelerating tube using a waveguide, where the thermoelectrons are accelerated until they reach several MeV energy. The accelerated thermoelectrons are changed in direction by the magnet and collide with the transmission target. At this time, X-rays with energy of several MeV are generated by bremsstrahlung. The irradiation unit 203 shapes the X-rays into a predetermined shape (for example, a conical shape or a thin planar shape) using a collimator, and irradiates the three-dimensional region of the subject placed on the bed.

  The timing control unit 205 controls the power supply unit 201 so that power is supplied to the irradiation unit 203 at a predetermined timing according to the control from the data acquisition control unit 4.

  The gantry control unit 207 controls the movement position / rotation position of the gantry in accordance with, for example, a control instruction from the operation unit 8 or the data acquisition control unit 4.

[Scattered radiation detection system]
The scattered radiation detection system 3 includes a detector 301, a collimator 303, a movement mechanism unit 305, and a position detection unit 307.

  The detector 301 is a semiconductor detector capable of detecting X-rays of several hundred keV, an imaging plate, or the like, and detects scattered rays from the subject based on radiation irradiated to the subject. A preferable size of the detector, an arrangement angle with respect to the irradiation beam axis, the number of pixels, and the like will be described later.

  The collimator 303 is a diaphragm device for selectively detecting only scattered rays coming in a specific direction.

  The moving mechanism unit 305 has an angle of the detection surface of the detector 301 with respect to the irradiation beam axis of the irradiation unit 203 (that is, an angle between the irradiation beam axis and the normal of the detection surface of the detector 301), and a radiation beam axis as a center. It is a moving mechanism unit for moving the position and angle of the detector 301 in order to control the rotation angle of the detector 301, the distance between the subject and the detection surface of the detector 301, and the like.

  The position detection unit 307 is an encoder for detecting the position of the detector 301.

[Data acquisition control unit]
The data acquisition control unit 4 performs comprehensive control relating to scattered radiation measurement during radiation therapy. For example, the data acquisition control unit 4 obtains a signal from the timing control unit 205 of the radiation irradiation system 2 and transmits a scattered radiation measurement start trigger or a detection data transmission trigger to the scattered radiation detection system 3. The radiation therapy system 1 is controlled statically or dynamically for irradiation, scattered radiation measurement, data processing, image display, network communication, and the like. In addition, the data acquisition control unit 4 optimizes the scan time according to the irradiation time of each irradiation based on the treatment plan received from the radiation treatment planning apparatus via the network as necessary.

[Data processing system]
FIG. 3 is a functional block diagram showing the configuration of the data processing system 5.

  The data processing system 5 includes a correction processing unit 501, a reconstruction processing unit 503, a conversion processing unit 505, and a data processing unit 507.

  The correction processing unit 501 performs data calibration processing, correction processing for removing noise, and the like as necessary. The details of the correction processing executed by the correction processing unit 501 will be described in detail later.

  The reconstruction processing unit 503 executes image reconstruction processing using the scattered radiation image data detected in the scattered radiation detection system 3 and position information indicating the position where each scattered radiation image data is detected, and the number of scattering events ( Scattered ray volume data showing a three-dimensional distribution of the number of scattering occurrences) is acquired. As the reconstruction method, for example, a CT reconstruction method is used if the direction of the collimator is orthogonal to the scan axis, and a tomographic reconstruction method is used if the direction is not orthogonal.

  The conversion processing unit 505 converts the three-dimensional image data obtained by the image reconstruction process into absorbed dose volume data indicating a three-dimensional distribution of absorbed radiation dose (absorbed dose).

  The data processing unit 507 includes a fusion model module 511, a plan evaluation module 513, and a plan update module 515.

  The fusion model module 511 creates a three-dimensional model based on morphological image data acquired by an X-ray imaging apparatus or other modality of CT, and uses the absorbed dose volume data to fuse the absorbed dose image into the three-dimensional model. Create (Fusion) fusion model data.

  The plan evaluation module 513 compares and displays the radiation irradiation plan and the actual irradiation result, and performs a simulation for predicting the influence of the subsequent irradiation.

  The plan update module 515 determines the suitability of the irradiation plan based on the absorbed dose data based on a predetermined evaluation standard, and provides an optimal treatment plan. Details of each module will be described later.

[Display unit, storage unit, operation unit, network I / F]
The display unit 6 includes a display such as an LCD. Based on the data output by the various modules of the data processing unit 507, the display unit 6 displays, for example, an absorbed dose image by fusion with a plan image or an image obtained immediately before or during irradiation.

  As shown in FIG. 4, the storage unit 7 performs a predetermined scan sequence 701 for acquiring (scanning) scattered radiation data while rotating the detector 301 around the axis of the radiation beam to be irradiated, correction processing, image reconstruction, Execution of configuration processing, conversion processing, display processing, and the like, and a control program 702 for displaying and editing a treatment plan on the system, scattered radiation volume data 703 and absorbed dose volume data 704 acquired by the radiation treatment system 1 The morphological image data 705 and the like acquired by other modalities such as an X-ray computed tomography apparatus are stored. These data stored in the storage unit 7 can also be transferred to an external device via the network I / F 90.

  The storage unit 7 also stores an allowable dose table 706, treatment plan data 707, and treatment history data 708 taken from an external treatment plan apparatus or the like via the network I / F 90. Further, the storage unit 7 stores fusion model data 709 created by the fusion model module 511.

  The operation unit 8 includes various switches, buttons, a trackball 13s, a mouse 13c, and a keyboard for incorporating various instructions, conditions, a region of interest (ROI) setting instruction, various image quality condition setting instructions, and the like from the operator into the apparatus main body 11. 13d and the like.

  The network I / F 9 transfers the absorbed dose image data obtained by the radiotherapy system 1 to another apparatus via the network, and acquires, for example, the treatment plan created in the radiotherapy planning apparatus via the network. To do.

(Method of generating absorbed dose image data)
(First embodiment)
Next, a method for generating absorbed dose image data using the radiotherapy system 1 according to the first embodiment will be described. In the radiotherapy system according to the present embodiment, a detector having a collimator is installed at a position that forms a specific angle with respect to the therapeutic X-ray beam, and only scattered rays that come in that direction are selectively detected. Further, in order to obtain a three-dimensional distribution of locations where scattering occurs in the patient, the detector is rotated during irradiation, and the scattered radiation is measured from all directions (see, for example, FIG. 6). Thereafter, reconstruction processing is performed, and the generation distribution of scattered radiation inside the subject is imaged three-dimensionally.

  FIG. 5 is a flowchart showing a flow of processing at the time of radiation therapy including processing for generating absorbed dose image data according to the present embodiment. Hereinafter, the processing content of each step will be described.

[Subject placement, etc .: Step S1a]
First, the data acquisition control unit 4 acquires treatment plan information related to the subject via a network, for example, and displays it on the display unit 6. The surgeon places the subject on the bed according to the displayed treatment plan, sets the radiation irradiation time via the operation unit 8, and sets the number of times of performing scattered radiation measurement and the angle to be measured in one rotation. For example, a scan sequence is selected (step S1a). Note that the setting of the radiation irradiation time and the like may be automatically performed based on the acquired treatment plan information.

[Radiation irradiation / Acquisition of scattered radiation image data in multiple directions: Step S2a]
FIG. 6 is a diagram showing a measurement form of scattered radiation of the present radiation therapy system 1. As shown in the figure, the radiation irradiation system 2 generates therapeutic radiation for irradiating a subject with a three-dimensional region at a predetermined timing. Further, the scattered radiation detection system 3 detects the scattered radiation coming out of the subject based on the irradiation radiation at a plurality of rotation angles around the axis of the radiation beam irradiated (step S2a). For example, when irradiation can be performed for 3 minutes from one direction, data in 18 directions is collected for 10 seconds per direction. At this time, the 18 directions are preferably equiangular intervals with the beam axis as the center. The count number of scattered rays detected by the detector 301 in each direction and the position information of the detector 301 at the time of detecting scattered rays measured by the position detector 307 are transmitted to the data processing system 5.

  In the present embodiment, the detector 301 is arranged such that the backscattered rays having a scattering angle θ within a range of 120 ° ≦ θ ≦ 165 ° (for example, 155 °) are detected. It is assumed that an arrangement angle 301 is set.

In the above example, for example, when 2 Gy irradiation is performed from three directions, the number of counts per direction is 1.24 × 10 ⁵ × 1 / 3≈4 × 10 ⁴ [counts / cm ² ]. If it is irradiated for 180 seconds per direction and measured for 10 seconds, 4 × 10 ⁴ × 10/180 = 2 × 10 ³ [counts / cm ² ] is obtained, but there is no problem in the S / N ratio.

  In addition, the detection of scattered radiation requires at least two directions, but it is preferable to detect in as many directions as possible in practice. Moreover, it is preferable that the detection positions are arranged at equiangular intervals around the axis of the irradiation beam.

[Preprocessing (correction processing, etc.): Step S3a]
In the collected data, only X-rays scattered in the detector installation angle direction are counted. In reality, however, X-rays are scattered in all directions. The correction processing unit 501 of the data processing system 5 corrects the count value of the detector, and acquires the number of scattering in all directions according to a predetermined calculation threshold (step S3a).

[Image reconstruction processing: Step S4a]
Next, the reconstruction processing unit 503 of the data processing system 5 executes image reconstruction processing using multidirectional projection data, and acquires scattered radiation volume data (step S4a). At this time, when the rotation axis of the detector 301 and the direction of the collimator are orthogonal and an image is captured in an angle range of 180 degrees (+ α) or more, a CT reconstruction method may be used. A tomographic reconstruction method is used. As a tomographic technique, for example, a filtered backprojection method in which a back projection process is performed after a filter process is applied to a projection image is used. As a filter configuration method, a classic Shepp-Logan filter or a filter disclosed in Japanese Patent Application Nos. 2006-284325 and 2007-269447 is used. In particular, if a method described in Japanese Patent Application Nos. 2006-284325 and 2007-269447 is used, a scatter source distribution image with a clear physical meaning can be generated.

  An image obtained by subjecting the detector image to filter processing and performing back projection has a scattered radiation generation density per unit volume (the number of scatterings per unit volume). Three-dimensional distribution of scattered radiation generation density in the vicinity where therapeutic radiation passes through the subject through all steps of the reconstruction process (various correction processes, filter processes, and back projection processes) (scattered radiation volume data) Can be obtained.

[Conversion processing: Step S5a]
Next, the conversion processing unit 505 of the data processing system 5 converts the number n of scattering per unit volume calculated for each voxel into an absorbed dose, thereby absorbing the radiation dose absorbed by the scattered radiation volume data. It is converted into absorbed dose volume data indicating a three-dimensional distribution of (absorbed dose) (step S5a).

[Generation of Absorbed Dose Image Data / Display of Image Data: Steps S6a, S7a]
Next, the data processing unit 507 generates absorbed dose image data indicating the distribution of absorbed radiation dose (absorbed dose) regarding a predetermined part of the subject CT image, and synthesizes it with, for example, a CT image (step S6a). The display unit 6 displays the absorbed dose image in a predetermined form (step S7a).

(Second embodiment)
Next, a method for generating absorbed dose image data using the radiation therapy system 1 according to the second embodiment will be described. In the radiotherapy system according to the present embodiment, a detector equipped with a collimator is installed at a position that forms a predetermined angle (scattering angle) with respect to the therapeutic X-ray beam, and only scattered rays that come in that direction are selectively selected. By detecting and performing this detection while moving the therapeutic X-ray beam and the detection surface while maintaining the angle formed by the axis of the therapeutic X-ray beam irradiated from the irradiation unit and the detection surface of the detector Scan a 3D area within the subject. Using the obtained three-dimensional scattered radiation data for a given scattering angle, the scattered radiation volume data is reconstructed, and the scattered radiation volume data is converted into absorbed dose volume data indicating a three-dimensional distribution of absorbed radiation. Then, an absorbed dose image is generated.

  FIG. 7 is a flowchart showing the flow of processing at the time of radiation therapy including generation processing of absorbed dose image data according to the present embodiment. Hereinafter, the processing content of each step will be described.

[Subject placement, etc .: Step S1b]
First, similar to the first embodiment, the placement of the subject is executed (step S1b).

[Radiation irradiation (acquisition of scattered radiation data): Step S2]
FIG. 8 is a diagram showing an example of a measurement form of scattered radiation of the radiation therapy system 1. As shown in the figure, the radiation irradiation system 2 irradiates a subject with an X-ray beam B2 shaped into a thin flat surface at a predetermined timing, and the scattered radiation detection system 3 is based on the irradiation radiation. Scattered rays having a predetermined scattering angle coming out of the subject are detected. In addition, the data acquisition control unit 4 moves the excitation cross section of the X-ray beam B2 while maintaining the angle formed by the axis of the therapeutic X-ray beam B2 irradiated from the irradiation unit 203 and the line-of-sight direction of the detector 301. The gantry control unit 207 or the movement mechanism unit 305 is controlled so as to scan the three-dimensional region in the subject (step S2). By scanning the three-dimensional region using the therapeutic X-ray beam B2, three-dimensional scattered radiation data including a plurality of two-dimensional scattered radiation data corresponding to the plane of the X-ray beam B2 is acquired.

  FIG. 8 is an example of a measurement form of scattered radiation. Therefore, the scattered radiation measurement mode according to the present embodiment is not limited to this example. For example, as shown in FIG. 9, the axis of the therapeutic radiation beam is maintained while maintaining the detection surface of the detector 301 (and the opening surface of the collimator 303) at a constant angle between the detection surface and the irradiation direction of the therapeutic radiation beam. The three-dimensional scattered radiation data consisting of a plurality of two-dimensional scattered radiation data can also be acquired by moving the movement in conjunction with the movement of the position.

[Preprocessing (correction processing, etc.): Step S3b]
Next, the correction processing unit 501 of the data processing system 5 executes preprocessing including attenuation correction, and acquires projection data (step S3). Here, the attenuation correction is a correction process related to signal attenuation caused by propagation of therapeutic radiation or scattered radiation in the subject.

[Image reconstruction processing: Step S4b]
Next, the reconstruction processing unit 503 of the data processing system 5 executes image reconstruction processing using the acquired projection data, and acquires scattered radiation volume data (step S4).

[Conversion processing: Step S5b]
Next, the conversion processing unit 505 of the data processing system 5 converts the scattered radiation volume data into absorbed dose volume data indicating a three-dimensional distribution of absorbed radiation dose (absorbed dose), as in the first embodiment. (Step S5).

[Generation of Absorbed Dose Image Data / Display of Image Data: Steps S6b, S7b]
Next, the data processing unit 507 uses the absorbed dose volume data or the like to generate absorbed dose image data indicating the distribution of absorbed radiation dose (absorbed dose) related to a predetermined part of the subject, for example, for fusion display. Are combined with the CT image (step S6b). The display unit 6 displays the absorbed dose image in a predetermined form (step S7b).

  Next, the operation of each module of the data processing system will be described in detail.

(Fusion model module)
Processing of the fusion model module 511 will be described.
[Construction of fusion model data]
FIG. 10 shows the positional relationship between the radiation irradiation system 2, the scattered radiation detection system 3, and the X-ray imaging systems 101 and 102.
The X-ray imaging systems 101 and 102 are means for measuring morphological images from a plurality of directions. In this embodiment, the X-ray imaging systems 101 and 102 are shown as X-ray biplanes, but may be CT, MRI apparatuses, ultrasonic apparatuses, or the like. Images captured by these imaging devices are stored as morphological image data 705 in the storage unit 7.

FIG. 11 is a flowchart showing the processing procedure of the fusion model module 511.
In FIG. 11, the fusion model module 511 includes a three-dimensional image (for example, a morphological image, a metabolic image, or a functional image) such as CT or PET acquired before radiation therapy among the morphological image data 705 stored in the storage unit 7. Is used to create a three-dimensional model image as a base of the fusion model (step S1c). On the other hand, a two-dimensional / three-dimensional real-time image of the treatment site is acquired from a CT, an X-ray imaging apparatus, an MRI apparatus, or the like during radiotherapy (step S2c).

  The fusion model module 511 performs feature point extraction and tumor shape surface tracing for each of the above images, and synthesizes the three-dimensional model and the real-time image by fitting the extracted feature points and the trace image (steps). S3c). As feature points, bones or markers embedded in advance are used. Then, the fusion model module 511 divides the three-dimensional model combined with the real-time image into a plurality of segments (step S4c). The fusion model data 709 that stores the absorbed dose volume data 704 is constructed in association with each of the divided segments (step S5c). This association is, for example, the result of fitting by a feature point of a three-dimensional model and a real-time image, and the mechanical properties of the X-ray imaging device that captured the real-time image and the scattered radiation detection device that is the basis for generating absorbed dose volume data. Perform according to the positional relationship. As a result, absorbed doses corresponding to a plurality of segments are stored as fusion model data. In addition, fitting parameters for associating segments and mechanical positional relationships are also stored as part of the fusion model data.

  Further, for the fusion model data 709, parameters (attribute information) such as “X-ray absorption”, “functional information”, and “radiation sensitivity” are stored in association with each segment using the same method as described above. deep. The X-ray absorption can be obtained from a CT value acquired from another modality, an X-ray absorption coefficient, or the like. In addition, function (MI) information and metabolic information are obtained from PET, MRS images, and the like, and in particular, the degree of cancer activity and hypoxia can be grasped from molecular imaging images using PET or the like. In addition, if the tissue site and the target site to be treated can be specified, the radiation sensitivity can be grasped from the database information (table information on the tissue and radiation sensitivity) held in advance.

[Display of absorbed dose using fusion model data]
By using the fusion model data 709, an image representing an absorbed dose of an arbitrary cross section can be displayed on the display unit 6. Using the “position information in the radiation irradiation direction” and the “position information in the image acquisition direction”, for example, an image of a cross section perpendicular to the radiation irradiation direction and an image of a cross section horizontal to the irradiation direction are created. In addition, regarding the accumulated information of radiation absorbed dose, the target site and tissue site can be obtained by accumulating the reconstruction result of the absorbed dose once and once on the fusion model by performing fusion processing for each measurement. The accumulated radiation information can be displayed. For specifying the display region, tissue recognition is performed on the fusion model image for the tissue specified by the operator. There is a method of performing tissue recognition by specifying by an operator, or a method of performing tissue recognition by automatically performing segmentation and selecting a tissue site or a target site.

  A display example of the created fusion model is shown below.

[Display Example 1]
FIG. 12 is an example of an absorbed dose image displayed by the fusion model. The upper part of FIG. 12 is an image of a cross section perpendicular to the irradiation direction of the therapeutic radiation beam, and the lower part of FIG. 12 is an image of a cross section horizontal to the irradiation direction of the therapeutic radiation beam. FIG. 12A is a display example in which a tumor (target region for treatment) is included and a region irradiated with radiation and a cumulative absorbed dose are superimposed and displayed. FIG. 12C shows a tissue (risk organ: dangerous region) that is present in the vicinity of the therapeutic radiation beam passage region and is relatively weak against radiation irradiation. By displaying the irradiation history and cumulative value of radiation, it is possible to check on the spot whether the exposure limit has been exceeded. FIG. 12B is a display example in which the images of FIGS. 12A and 12B are superimposed and displayed.

  Although FIG. 12 shows an example in which one cross section including a tumor and a risk organ is displayed, a thick image including a tumor and a risk organ may be displayed. In this case, as shown in FIG. 12B and FIG. 12C, the cumulative dose is a numerical value calculated by the Minimum Intensity Projection for tumors and the Maximum Intensity Projection for risk organs. Moreover, you may display with a certain slice pitch. In addition, the cumulative absorbed dose may be displayed as a numerical value, or may be expressed as a color or luminance.

[Display Example 2]
FIG. 13 shows a display example of the absorbed dose image with respect to the radiation sensitivity threshold display. Similarly to FIG. 12, the upper stage is a cross section perpendicular to the irradiation direction of the radiation beam, and the lower stage is a cross section horizontal to the irradiation direction of the therapeutic radiation beam.

  For a site to be treated (cancer target site), a warning is displayed if the prescribed therapeutic radiation dose is not exceeded. For example, when the threshold value is not exceeded, the color is changed and displayed. On the other hand, a warning is displayed when the threshold value is reached for a tissue site that is outside the treatment target range, particularly for a highly sensitive tissue site. For example, when the threshold value is exceeded, the color is changed and displayed.

[Display Example 3]
FIG. 14 shows a display example of an absorbed dose image when molecular level activity information is added. Similarly to FIG. 12, the upper stage is a cross section perpendicular to the irradiation direction of the radiation beam, and the lower stage is a cross section horizontal to the irradiation direction of the therapeutic radiation beam.
Utilizing molecular imaging technology using molecular diagnostics typified by FDG, hypoxia and cancer activity are displayed in a superimposed manner.

  As described above, by using the fusion model data in which the absorbed dose is associated with the three-dimensional model, it is possible to display the absorbed dose image at an angle orthogonal to the radiation irradiation or an arbitrary angle in real time during the treatment. . Further, it is possible to create a cumulative absorbed dose image obtained by superimposing absorbed doses for each irradiation of a therapeutic radiation beam, and to superimpose and display a radiation sensitivity threshold value, molecular level activity information, and the like. In particular, the target area and the dangerous area are displayed on an image at an angle orthogonal to the radiation exposure, and the absorbed dose or accumulated absorbed dose is displayed superimposed on the Maximum Intensity Projection or Minimum Intensity Projection, so that the absorbed dose ( It is possible to provide an image that can be judged by a two-dimensional image whether the accumulated absorbed dose) exceeds a threshold value. Since the absorbed dose that originally has three-dimensional information can be provided to the operator on the two-dimensional image, there is an effect that the operator's judgment becomes easy.

(Plan Evaluation Module)
Next, the process of the plan evaluation module 513 will be described.
(First embodiment)
FIG. 15 is an example of a radiotherapy workflow in the radiotherapy system 1 according to the present invention. A first embodiment of the plan evaluation module 513 will be described according to this workflow.

[Obtaining Treatment Plan: Step S1d]
In FIG. 15, first, a treatment plan such as a radiation irradiation method (irradiation position and number of times) for a patient is determined in advance by a surgeon or the like on the treatment planning apparatus before treatment, and the treatment plan is stored in the storage unit 7 via the network interface 9. It is stored as data 707. Details of the treatment plan will be described later.

[Radiation irradiation: Step S3d]
As shown in FIG. 6, at the start of treatment, the patient is fixed on the bed of the radiation irradiation system 2 so as to be in the same position as the treatment plan. When the surgeon presses a treatment start button (not shown), a treatment start signal is transmitted to the data acquisition control unit 4, and the data acquisition control unit 4 reads out the treatment plan data 707 from the storage unit 7 and performs radiation according to the treatment plan. The irradiation system 2 is controlled. As a result, radiation is irradiated from the radiation irradiation system 2 to a predetermined position of the patient.

[Recording of irradiation position and absorbed dose: Step S4d]
At the time of radiation irradiation from the radiation irradiation system 2, the data acquisition control unit 4 controls the scattered radiation detection system 3, and measures the irradiation position of the radiation irradiated to the patient from the radiation irradiation system 2 and the scattered dose generated by this irradiation. The data processing system 5 obtains an irradiation position and an absorbed dose from the measured scattered dose by the conversion processing unit 505. The obtained irradiation position (hereinafter, actually measured irradiation position) and absorbed dose (hereinafter, actually measured absorbed dose) are stored in the storage unit 7 in time series.

[Comparison of Irradiation Plan and Actual Value: Step S5d]
The plan evaluation module 513 calls the treatment plan data 707, the actually measured irradiation position and the actually measured absorbed dose stored in the storage unit 7 manually or automatically at the time when the irradiation is once finished, and displays it on the screen of the display unit 6. . For example, as shown in FIG. 16 (a), the actual measurement values are superimposed and displayed on the plan image (for example, a CT image taken before surgery). FIG. 16 (a) is a superposition display of the planned irradiation position and the actually measured irradiation position, and the deviation of the irradiation position can be grasped at a glance.

  Further, the planned irradiation dose and the actually measured absorbed dose are compared by the plan evaluation module 513 so that the operator can know the presence / absence of the difference, the difference value when there is a difference, the determination of whether the difference value is acceptable, and the like. Shown in For example, it can be expressed in a table format as shown in FIG. 16B or a graph format as shown in FIG. Further, as shown in FIG. 16 (b), it is preferable to highlight a dangerous organ sensitive to radiation such as the heart so as to call attention. In addition, as shown in FIG. 17, the absorbed dose for each irradiation can be overlapped, and the absorbed dose with respect to the tumor target can be represented by contour lines, and can be synthesized and displayed on the morphological image of the treatment site.

[Determining whether or not they match: Step S6d]
As a result of the comparison between the treatment plan and the actual measurement value, the plan evaluation module 513 indicates that the data acquisition control unit 4 manually outputs a signal for starting the next irradiation when the two match completely or the difference is within the allowable range. It transmits to the radiation irradiation system 2 automatically. The radiation irradiation system 2 irradiates a position based on the treatment plan with an amount of radiation based on the treatment plan. While the treatment plan and the actually measured value match or are within the allowable range, the steps S1d to 6d in FIG. 15 are completed at the end of the plan ([End of workflow: step S8d]) unless a special change occurs. Repeat until it reaches.

  The storage unit 7 stores the measured irradiation position and the measured absorbed dose for each irradiation, the difference between the measured value and the planned value in time series, and the operator can perform the treatment at any time or any position during the treatment as necessary. The integrated value of the absorbed dose can be calculated and displayed.

[Warning: Step S7d]
On the other hand, if there is an unacceptable difference between the treatment plan and the actual measurement value, as shown in step S7d of FIG. 15, a warning is output by the plan evaluation module 513, and the treatment is (temporarily) stopped. When the entire treatment is completed according to the treatment plan, change of treatment plan, or treatment stop, the plan evaluation module 513 displays a series of treatment data (measured irradiation position and measured absorbed dose for each irradiation, measured dose) The difference between the value and the plan value) is stored in the storage unit 7 as a set. These data sets can be used, for example, for confirmation of treatment effects, reflected in the next treatment plan, or used for examination of delayed effects of radiation.

(Second embodiment)
FIG. 18 is another example of a radiotherapy workflow in the radiotherapy system 1 according to the present invention. A second embodiment of the plan evaluation module 513 will be described according to this workflow.

[Treatment plan: Step S1e]
First, a treatment plan such as a radiation irradiation method for a patient is determined in advance by an operator or the like with a treatment plan apparatus (not shown) on a network before treatment, and stored in the storage unit 7 (details of the treatment plan will be described later). ).

[Previous image shooting: Step S3e]
At the start of treatment, the patient is fixed on the bed of the radiation irradiation system 2 so as to be in the same position as the treatment plan. The surgeon operates the image capturing devices 101 and 102 arranged as shown in FIG. 10 to capture a pre-treatment image of the radiation irradiation region of the patient. As the image capturing apparatuses 101 and 102, for example, an X-ray imaging apparatus, an X-ray CT apparatus, a 3D ultrasonic diagnostic apparatus, or the like can be used. Here, the coordinates of the treatment planning apparatus, the image capturing apparatuses 101 and 102, and the radiation irradiation system 2 need to be aligned. As described above, the coordinate alignment is performed in the fusion model of the data processing system. It is also possible to use the coordinates of a point on the bed at the time of treatment, a marker placed on a part of the patient, or a feature that becomes a landmark inside or outside the patient as a base point. It is assumed that the positions of all the images are aligned with the irradiation center 2.

[Comparison of Irradiation Plan and Previous Image: Step S4e]
FIG. 19A is a plan image showing an irradiation position based on the treatment plan, and the plan evaluation module 513 superimposes the treatment plan image and the image just before the treatment on the display of the display unit 6 as shown in FIG. To display.

[Determining whether or not they match: Step S5e]
By this display, the presence or absence of a positional shift that affects the treatment is confirmed by the operator's visual observation. For example, important positional deviations such as the position of a treatment target such as a tumor deviating from the radiation irradiation position, and a critical organ vulnerable to radiation entering the radiation passing region are given top priority.

[Alignment: Step S7e]
If these significant misalignments occur, the surgeon moves the patient or bed and adjusts it to match the position on the treatment plan.

  Here, it is also possible to automatically detect a positional shift from a predetermined marker position on the image, an outline of an organ, a feature amount, or the like without depending on an operator's visual observation. FIG. 20 is a flowchart showing the procedure of the alignment process in this case. The plan evaluation module 513 automatically detects the positional deviation from a predetermined marker position on the image, organ contour, feature amount, and the like (step S1f). If the positional deviation is within the allowable range, the irradiation is continued (step S3f). On the other hand, when a positional deviation is detected exceeding the allowable range, the plan evaluation module 513 displays a warning message for prompting alignment on the display unit 6 (step S2f). When the positional deviation exceeding these allowable ranges has occurred (step S2f: YES), the treatment is temporarily stopped (step S4f), and the operator moves the patient or the bed to match the position on the treatment plan. (Step S5f). Here, the data acquisition control unit 4 warns the operator in order to prevent a medical accident when an important misalignment is detected regardless of visual detection or automatic detection by the operator. It is desirable to lock the radiotherapy system 1 so that it does not operate.

[Radiation irradiation: Step S6e]
When the surgeon confirms that the patient's positional deviation is within an allowable range with respect to the treatment plan, the data acquisition control unit 4 drives the radiation irradiation system 2 based on the treatment plan by an operation such as the operator pressing a button. Then, the patient is irradiated with radiation as shown in FIG.

[Recording of Actual Irradiation Position and Actual Absorbed Dose: Step S8e]
At the time of radiation irradiation from the radiation irradiation system 2, the data acquisition control unit 4 controls the scattered radiation detection system 3, and measures the irradiation position of the radiation irradiated to the patient from the radiation irradiation system 2 and the scattered dose generated by this irradiation. In the data processing system 5, the conversion processing unit 505 obtains an actually measured irradiation position and an actually measured absorbed dose from the measured scattered dose. The actually measured irradiation position and the actually measured absorbed dose are stored in the storage unit 7 in time series.

[Previous Image Capture 2: Step S9e]
Once the irradiation is finished, the plan evaluation module 513 again captures an image immediately before treatment of the patient. In addition to patient movement due to insufficient fixation, organs may be deformed during treatment, resulting in misalignment, so it is possible to check the periphery of the treatment target in near real time for accurate treatment. desirable. When it is determined that the treatment target is displaced beyond the allowable range, it is necessary to stop the treatment once and move the patient or the bed to correct the position.

[Confirmation of influence of next irradiation: step S10e]
Next, the treatment result (measured irradiation position and measured absorbed dose) stored in the storage unit 7 is superimposed on the photographed image immediately before treatment and displayed on the display of the display unit 6 (FIG. 21A).
Here, a simulation of the effect of the next irradiation on the treatment target and surrounding organs will be described with reference to FIG. FIG. 21A is an image in which the image immediately before treatment and the treatment result are displayed in an overlapping manner. The measured irradiation position is shown as a line, and the measured absorbed dose is shown as a number. FIG. 21B is a diagram in which the next treatment plan is called from the storage unit 7 and superimposed on the image obtained by superimposing the immediately preceding treatment image and the treatment result.

  First of all, it is possible to display the radiation irradiation position and irradiation dose to be irradiated next on the treatment plan as they are, and confirm whether the treatment target has been missed or whether the dangerous organ will be irradiated more than allowable. It is done. It is further desirable to simulate how the next treatment will affect the current treatment results, especially to see if there is an excess or deficiency of radiation dose. A method is used in which the radiation dose planned to be irradiated next to the actually measured absorbed dose up to the present time is aligned using a fusion model and then added. Using the Monte Carlo method or the like, the radiation dose of the next irradiation plan is calculated in consideration of the absorption and scattering of the radiation, and the accumulated value of the actually measured absorbed dose and the predicted value totaled are displayed. It is also possible to show the simulation result in a diagram as shown in FIG. 21C, or to display the current state and the simulation result in a table format as shown in FIG.

  As shown in FIG. 21 (c), when the predicted value exceeds a predetermined irradiation capacity, the plan evaluation module warns with warning means such as sound, light, and letters. For example, based on the flowchart of FIG. 23, the plan evaluation module 513 suspends treatment (step S3g) when it determines that the next irradiation plan is inappropriate in the simulation (step S1g: YES). Then, the surgeon selects whether to continue the treatment as it is or to cancel the treatment plan (step S4g). For safety, it is desirable that the irradiation system 2 is locked so as not to operate automatically or manually.

[Confirmation of influence of next irradiation: step S11e]
Although the method for predicting the influence of the next radiation irradiation on the treatment target and surrounding organs by simulation has been described above, pre-irradiation may be performed in order to judge more accurately. This is because weak radiation that does not affect treatment is irradiated from the radiation irradiation system 2 to a position as planned for the next irradiation of the patient, the irradiation position is measured by the scattered radiation detection system 3, and the position of the plan and the actual measurement is obtained. Whether there is a shift is determined by comparing the treatment plan image and the actually measured absorption line image. Deviations may be automatically determined from values on the image such as CT values, or a scaler may be displayed on the image as shown in FIG. 24 so that the amount of deviation can be visually confirmed. .

(About treatment plan)
Here, an example of the treatment plan will be described with reference to FIGS.
Since the allowable dose of normal cells varies from organ to organ, the treatment plan is designed to irradiate therapeutic radiation from the direction of the organ where a relatively large amount of radiation can be applied and minimize the irradiation to the organ that should be avoided as much as possible. One of the purposes. Therefore, first, segmentation is performed for each organ as shown in FIG. Specifically, voxels belonging to the same organ (actually about 1 to 5 mm are assumed, but are shown as large voxels for convenience of explanation. Registered as the same group. Here, a liver malignant tumor group a, a normal liver tissue group c, a normal stomach tissue group e, a normal intestinal tissue group f, a normal spinal cell group g,. Segmentation may be performed automatically from information such as CT values on the image or manually using a touch pen or the like.

  When the voxels at the boundary of the organ belong to a plurality of organs, if all of them are normal tissues, the risk of side effects is reduced by registering them as belonging to the organ having the smallest allowable dose. However, if there is a tumor area that must be irradiated with a predetermined amount of radiation, it must be registered as a tumor area. Further, since the radiation has a skirt as shown in FIG. 26, a normal tissue that is sacrificed when a radiation beam is applied to the tumor is generated. The range of the sacrificed normal tissue is registered as “margin area b”.

  The acceptable dose for normal tissues is indicated in the “Radiation Treatment Planning Guidelines 2004” of the Japanese Radiological Association and Medical Association.

In the present embodiment, as shown in FIG. 4, the storage unit 7 has an allowable dose table in which the allowable dose for each organ is stored. Therefore, each voxel is given an area name arbitrarily assigned to the organ name and an address in the area as shown in the table of FIG. 27, for example. Here, assuming that the region name of the normal liver tissue is region c and there are n voxels in region c, the addresses are c1 to cn, respectively.
Furthermore, information on the allowable dose is given for each voxel. As with normal tissues of the stomach, intestine, and spinal cord, when the allowable dose for each point (per cell) is determined, 1/3, 2/3 of the organ volume from the viewpoint of reserve capacity, There is a case where each allowable dose up to 3/3 is determined (see FIG. 27). For this reason, in the normal tissue region of the stomach, intestine, and spinal cord, a warning is issued when it is determined that the radiation dose to at least one voxel exceeds or is likely to exceed the allowable amount. It is determined whether or not the radiation dose exceeds the allowable value based on two pieces of information, that is, what percentage of voxels are irradiated with respect to the whole liver and the average value of the radiation dose that has been applied to each voxel (Fig. 27).

  On the other hand, information on the minimum value of the radiation necessary for the treatment is given to the voxel belonging to the region a of the malignant tumor to be treated, and whether or not the radiation can finally be irradiated exceeding the minimum value is a criterion for determination. .

  Each cell is known to have a survival curve against radiation as shown in FIG. By actually measuring the absorbed dose, it is possible to know how much radiation has been applied to the cell of a certain voxel, so the survival rate of the cell is predicted by the survival curve of the cell of the organ to which that voxel belongs. Can be used to determine whether or not irradiation can be performed as planned. A survival curve table can be obtained from a treatment planning apparatus on the network, and the cell survival rate for each voxel can be calculated. In addition, if genetic information shows different radiation sensitivities for each individual, the information can be reflected in the setting of the allowable dose, so if you try to obtain a table of patient genetic information from the treatment planning device Good.

  At the time of planning, as shown in FIG. 29, for example, a minimum value of the ratio of the remaining tissue to the normal liver tissue is set. When the survival rate of each voxel is calculated based on the accumulated value of the actually measured absorbed dose, the survival rate for all the voxels of the normal liver tissue is calculated, collated with the minimum value set at the time of planning, and a warning is given.

  The error value obtained from the accuracy of the apparatus is also set for each voxel or voxel group as shown in FIG. 30, and is reflected on the threshold value of the allowable amount.

(Third embodiment)
A third embodiment of the plan evaluation module 513 will be described using the workflow shown in FIG.

[Treatment plan: Step S1e]
First, as shown in the table of FIG. 31, a treatment plan such as a radiation irradiation method for a patient is determined in advance by an operator or the like on the treatment planning apparatus before the treatment and is stored in the storage unit 7. Here, it is assumed that divided irradiation is performed for three days by irradiation from three directions per day. The irradiation plan for six times can be seen as a table or figure on the display of the display unit 6.

[Previous image shooting: Step S3e]
At the start of treatment, the patient is fixed on the bed of the radiation irradiation system 2 so as to be in the same position as the treatment plan. The surgeon operates the image capturing devices 101 and 102 arranged as shown in FIG. 10, and captures a pre-treatment image (FIG. 32) of the radiation irradiation region of the patient. As the image capturing apparatuses 101 and 102, for example, an X-ray imaging apparatus, an X-ray CT apparatus, a 3D ultrasonic diagnostic apparatus, or the like can be used. Here, a kv image using an X-ray fluoroscope integrated with the radiation irradiation system 2 is used. Here, the coordinates of the treatment planning apparatus, the image capturing apparatuses 101 and 102, and the radiation irradiation system 2 need to match. As a method of matching the coordinates, it is also possible to consider using the coordinates of a point on the bed at the time of treatment, a marker placed on a part of the patient, or a part having a feature that is a landmark inside or outside the patient as a base point However, here, it is assumed that the positions of all the images are aligned with the irradiation center of the radiation irradiation system 2.

[Comparison of Irradiation Plan and Previous Image: Step S4e]
The plan evaluation module 513 displays the treatment plan image and the immediately preceding treatment image superimposed on the display of the display unit 6 as shown in FIG.

[Determining whether or not they match: Step S5e]
By the above display, the presence or absence of a positional shift that affects the treatment is confirmed by the operator's visual observation. For example, important positional deviations such as the position of a treatment target such as a tumor deviating from the radiation irradiation position, and a critical organ vulnerable to radiation entering the radiation passing region are given top priority.

[Alignment: Step S7e]
If these important misalignments have occurred, the surgeon moves the patient or bed 9 and adjusts it to match the position on the treatment plan.

  Here, the shift can be automatically detected from the marker position on the image, the outline of the organ, the feature amount, and the like without depending on the visual observation of the operator. In both cases of visual detection and automatic detection, if an important misalignment is detected, the control device warns the operator to prevent a medical accident, or the radiotherapy device is locked to prevent it from operating. It is desirable to do.

[Radiation irradiation: Step S6e]
When the position of the patient coincides with the treatment plan, the data acquisition control unit 4 drives the radiation irradiation system 2 to irradiate the patient with radiation based on the treatment plan by an operator's operation such as pressing a button.

[Recording of Actual Irradiation Position and Actual Absorbed Dose: Step S8e]
At the time of radiation irradiation from the radiation irradiation system 2, the data acquisition control unit 4 controls the scattered radiation detection system 3, and measures the irradiation position of the radiation irradiated to the patient from the radiation irradiation system 2 and the scattered dose generated by this irradiation. In the data processing system 5, the conversion processing unit 505 obtains the actually measured irradiation position and the actually measured absorbed dose from the measured scattered dose. The actually measured irradiation position and the actually measured absorbed dose are stored in time series in the storage unit 7 as shown in FIG. Moreover, as shown in FIG. 35, it can also represent with the distribution map of absorbed dose.

  Further, an image obtained by superimposing the treatment result (measured irradiation position and measured absorbed dose) and the treatment plan image stored in the storage unit 7 on the photographed image immediately before treatment is displayed on the display of the display unit 6 (FIG. 36). 37). The plan evaluation module 513 determines whether there is a difference from the planned dose set for each voxel, whether the allowable dose is exceeded, or the like. As an example, the determination procedure example in the case of the liver region is shown in the table of FIG. If an abnormality such as the actually measured absorbed dose exceeding the allowable range is found by the above determination, a warning is given by light, sound, or character display as shown in FIG. 39 to alert the operator.

[Previous Image Capture 2: Step S9e]
Once the irradiation is finished, the plan evaluation module 513 again captures an image immediately before treatment of the patient. In addition to patient movement due to insufficient fixation, organs may be deformed during treatment, resulting in misalignment, so it is possible to check the periphery of the treatment target in near real time for accurate treatment. desirable. When it is determined that the treatment target is displaced beyond the allowable range, it is necessary to stop the treatment once and move the patient or the bed to correct the position.

[Confirmation of influence of next irradiation: step S10e]
FIG. 40 is a second treatment plan image. The numerical value indicates the distribution of radiation to be irradiated next. By displaying the second immediately preceding image (kv image) on top of this, the displacement can be confirmed. Next, weak radiation that does not affect treatment is irradiated from the radiation irradiation system 2 to a position as planned for the next irradiation of the patient (pre-irradiation), and the irradiation position is measured by the scattered radiation detection system 3, and the plan and actual measurement are performed. It is determined by comparing the treatment plan image with the actually measured absorption line image (FIG. 41).

  Deviations may be automatically determined by the plan evaluation module from values on the image such as CT values, or a scaler may be displayed on the image so that the amount of deviation can be visually confirmed. When it is determined that the next irradiation plan is inappropriate due to a deviation that cannot be corrected, the operator selects whether to continue the treatment as it is, to suspend the treatment, or to change the treatment plan.

  Thus, it is possible to perform accurate and safe radiotherapy by confirming the actual irradiation status during the treatment and performing irradiation while collating with the irradiation plan. In addition, it is possible to reduce irradiation leakage to the treatment site and excessive irradiation to the normal site.

(Planned update module)
Next, the process of the plan update module 515 will be described.
(First embodiment)
The first embodiment of the plan update module 515 evaluates the irradiation plan in consideration of the actually measured absorbed dose, and determines the optimal irradiation conditions (position and output dose) of the irradiation unit 203 of the radiation irradiation system 2 to the operator. It is to be presented.

  In the following, it is assumed that the irradiation dose is the dose irradiated from the irradiation head, the absorbed dose is the dose absorbed by the human tissue, and the accumulated dose is the total of the absorbed dose of a certain tissue.

In FIG. 42, variables are defined as follows.
A: Output of radiotherapy apparatus (value at the k-th irradiation)
r _exposure : irradiation head position of radiotherapy apparatus (value at the k-th irradiation)
u: Direction of irradiation head of radiotherapy apparatus (value at the k-th irradiation)
r: vector to an arbitrary voxel in the coordinate system
f _j (r _i ): absorbed dose (measured value) in an arbitrary voxel
w: Mass of each voxel
R: Vector to the center of gravity of the element
μ: Absorption coefficient distribution of irradiation area (vector in which values of all voxels are arranged)
For example, μ is obtained from the pixel value of the planned CT.

(Method of grasping actual absorbed dose)
[Definition of absorbed dose]
The main organs and tissues are extracted and segmented from medical images such as CT and MRI taken in real time, and the target tumor (treatment site) and risk organ (risk site) are defined.

The segmented target tumor and risk organ are meshed into M elements. At this time, the division is performed so that each element is regarded as homogeneous. Since there are seven variables (A, r _exposure and u described later), the number of element divisions is set to seven or more.

For absorbed dose of voxels in r _i is defined as _f j _{(r i),} the center of gravity position _{R i} is,

The average absorbed dose of the i-th element is defined as a weighted average value obtained by multiplying the absorbed dose of each voxel included in this element by the mass of each voxel as follows.

[Identification of structure]
When determining the irradiation dose in the irradiation plan, it is necessary to consider the dose (absorbed dose) absorbed by each structure (main tissue, risk organ, etc.) up to the previous time. In order to determine the past absorbed dose of each structure, the position of the structure must be tracked. For example, as shown in FIG. 43, when the structure moves (rotates and translates) and deforms, the previous structure area is divided into elements. The contour of the previous structure is adjusted by movement and deformation, and is superimposed on the contour of the current structure (nodes on the contour of the previous structure are superimposed on the current structure). Compare the volume of the previous structure with the current structure, and determine the position of the node inside the current structure so that the variation in the volume expansion / reduction ratio of each element is minimized. Thereby, the absorbed dose of each element can be traced.

(Generation method of multi-gate irradiation plan)
[Various evaluation criteria]
The total number of irradiations for today is K times. The actually measured absorbed dose irradiated up to the n-th time is F _i , and the target dose in the tumor area for today's K-time total irradiation is d _tumor .

[Condition 1: Dose evaluation of tumor tissue]
The absorbed dose must exceed d _tumor in all areas of the _tumor .

In order for each absorbed dose distribution scheduled for irradiation from the (n + 1) th to Kth times to be E ^k _i (A, r _exposure , u, μ), and for the absorbed dose of the tumor tissue to be greater than or equal to the target dose d _tumor , r _i ∈Ω _tumor The following formula needs to be satisfied for all the regions i (Ω _tumor represents a tumor region), that is, for all segments belonging to the tumor region.

[Condition 2: Evaluation of exposure dose to risk organ]
The absorbed dose to the risk organ is evaluated in the same way as the dose to the main tissue.

N + 1 th from K th each absorbed dose distribution ^E _k i of the irradiation plan _{(A, r exposure, u,} μ) When, in order to suppress the absorption dose risk organ below the allowable dose _d ^j riskOrgan, each risk Each element included in the organ segment needs to satisfy the following expression for all regions i where r _i ∈Ω ^j _riskOrgan .

Here, Ω ^j _riskOrgan represents a region of the jth risk organ among a plurality of risk _organs .

[Condition 3: Evaluation of radiation dose to risk organ (2)]
Just because a small limited area of a risk organ exceeds the allowable accumulated dose does not mean that all functions are lost. As another method for the standard of radiation dose to the risk organ, a standard of “making the survival rate of the cell of the risk organ at a certain value or more” is also conceivable. The residual function (function residual ratio) of the risk organ is evaluated by the following formula.

Here, V _i is the volume of the region i, and p _{riskOrgan A} (F) is the probability that the cells of the tissue will survive when the absorbed dose F is irradiated to the risk organ j. Here, Volume (r _i ∈Ω ^j _riskOrgan ) represents the total volume of the corresponding region.

Furthermore, the residual functional factor of risk organ j required for the maintenance of biological Defining the rate ^j _survive on whether satisfies the following equation, it can be determined whether the irradiation method is appropriate. If the inequality is satisfied, irradiation using A, r _exposure and u at that time is possible. rate ^j _survive is a value to be set at the time of plan.

(Determination method of irradiation method)
An irradiation method is determined based on the following policy using the above evaluation criteria (conditional expressions 1 to 3).
Condition 1-3 satisfy _{A, r exposure,} among combinations of u, functional residual ratio ^{_{S j riskOrgan (A, r exposure}} , u, μ) to maximize _{A, r exposure,} seek u. However, A, r _exposure and u must satisfy the conditions according to the design of the apparatus, the geometrical constraints (arm length) of the radiation irradiation system 2 and the maximum output. A, r _exposure and u are irradiation conditions for the k-th irradiation, and it is necessary to determine all the irradiation conditions for the kn times from the (n + 1) th time to the Kth time.

First, using conditional expressions 1 to 3 and the design conditions of the apparatus as constraints, L examples of combinations of A, r _exposure , and u that can be irradiated are obtained, and these are obtained as C _l (l = 1,. L). As a specific method, a method of testing the irradiation conditions A, r _exposure , u generated with random numbers with the conditional expressions 1 to 3 and the design conditions, and setting the test condition as C ₁ is performed. is there.

Next, the following equation is calculated using these L conditions.

C _l having the maximum value among these S _l is presented to the user as the optimum protocol of the irradiation plan. min _j (..) represents obtaining the minimum value among the values in parentheses for a plurality of j.

(Irradiation plan update)
[Step 1: First irradiation plan]
Using a large number (for example) of about 100,000 as L, the irradiation plan is created using the multi-gate irradiation plan generation method described in the previous section. At this time, it is necessary to calculate K E ^k _i (A, r _exposure , u, μ) for all 100,000 kinds of irradiation conditions C _l , and this can be achieved by using a known computer simulation method. It is feasible. In this step, all irradiation conditions K times are once determined. K is set to a relatively small value such as 10 times. Since the number of completed irradiations is zero in the first irradiation plan, n = 0.

[Step 2]
Each irradiation of K irradiation conditions is performed and an absorbed dose distribution is measured (pre-irradiation). However, in order to reduce the exposure dose, the output A must be one-hundredth of the actual value, and the measured absorbed dose must be multiplied by its reciprocal.

[Step 3]
Under the first irradiation conditions (k = 1), the predicted dose E ¹ _i (A, r _exposure , u, μ) when the irradiation is executed is displayed on the screen. The E ¹ _i (A, r _exposure , u, μ) displayed at this time is obtained in step 2.

[Step 4]
Irradiation is performed under the first irradiation condition.

[Step 5]
The actual absorbed dose in the first irradiation is measured (n = 1).

[Step 6]
Use the first actual absorbed dose to regenerate the second and subsequent irradiation plans. At this time, a value of several times K is used as L. Since a value significantly smaller than the 100,000 types used in the first time is used, it can be executed at high speed and can be executed in a short time during irradiation. When the irradiation condition determined by the first set to C ^1, C _l is better to choose from a value close to C ¹ used for the second irradiation plan. If such a selection method is used, the irradiation plan updated after one irradiation becomes a fine correction from the first irradiation plan. The first ^E _k i in irradiation planning _{(A, r exposure, u,} μ) was determined by simulation, in the second and subsequent, ^E using measurements of simulation and pre-irradiation _{k i (A, r exposure,} u , Μ). That is, a change in the absorbed dose distribution with respect to the fine correction is obtained by simulation, and a similar modification is applied to the absorbed dose measured in Step 2 to change k = n + 1 to k = K for each of the L irradiation plan candidates C ₁ . K−n predicted doses E ^k _i (A, r _exposure , u, μ) are obtained. Here, since irradiation has been completed once, n = 1.

[Step 7]
The second irradiation condition (k = 2) and the predicted dose when the irradiation is executed are displayed on the screen.

[Step 8]
Irradiation is performed under the second irradiation condition.

[Step 9]
The actual absorbed dose in the second irradiation is measured, and the accumulated dose obtained by summing the first and second actual absorbed doses is obtained (n = 2). In order to obtain the accumulated dose, the aforementioned fusion model is used.

[Step 10]
Similarly to step 6, the third and subsequent irradiation plans are regenerated.

[Step 11]
Similarly, the process is executed up to the Kth irradiation.

  During the irradiation treatment described above, the screen display described below is performed. The doctor looks at this screen to determine whether the irradiation process is proceeding as planned. If the planned X-ray absorption coefficient error or the patient moves greatly during the irradiation process and there is a significant deviation from the plan, for example, as shown in Fig. 49, the estimated accumulated dose to the risk organ exceeds the allowable dose. It can happen. In such a case, the irradiation plan is re-created by the same method as in Step 1 instead of Step 6. In this way, the irradiation condition is not a fine correction from the initial plan, but the irradiation plan can be changed significantly after taking into account the accumulated dose so far. It is possible to find an irradiation plan that will result in an acceptable dose or less.

(Irradiation plan update flow)
FIG. 44 is a flowchart showing a procedure of irradiation plan update processing in the plan update module 515.

  The surgeon inputs patient information through the operation unit 8 (step S1h), and requests acquisition of past radiation treatment history (step S2h). Upon receiving this request, the plan update module 515 reads the past radiation treatment history of the corresponding patient from the storage unit 7 and outputs it to the display unit 6 (step S3h).

  The operator inputs setting information such as the number of irradiation divisions and irradiation dose (step S4h), and requests creation of a treatment plan (step S5h). The plan update module 515 segments a structure such as a tumor / risk organ from a medical image (step S6h). Then, the structure such as the segmented tumor / risk organ is registered with the past image (step S7h).

  The plan update module 515 superimposes the past absorbed dose and the planned irradiation dose for each structure such as a tumor / risk organ (step S8h). It is determined whether the absorbed dose reaches the target absorbed dose for each structure such as a tumor / risk organ and falls within the allowable absorbed dose (step S9h). If the condition is not satisfied in the above determination, the fact is presented on the display unit 6, and the surgeon adds a condition permitting, for example, a risk organ functional loss (step S10h). The determination in step S9h is performed again, and if the condition is satisfied, a protocol is presented (step S11h).

  The determination result as to whether the irradiation plan satisfies the condition and the protocol satisfying the condition are presented as follows. If the plan is not modified, if the plan is finely modified using the method described in Step 6, or if the plan is modified using the method described in Step 1, the total accumulated dose and the predicted dose are calculated for each of the three cases. indicate. On the screen, the judgment result of whether or not the condition is satisfied for each of the three cases is presented. The surgeon refers to the displayed image and the determination result, determines which of the three protocols is to be adopted, and selects the protocol to be adopted on the operation screen. The image display and the presentation of the determination result for the method described in step 1 may be configured to be displayed in response to a user operation instead of being initially displayed.

  When the presentation protocol is adopted by the surgeon (step S12h), the plan update module 515 transfers the presentation protocol to the data acquisition control unit 4 (step S13h). The plan update module 515 acquires the reconstructed absorbed dose distribution (step S14h) and determines whether the absorbed dose reaches the target absorbed dose and falls within the allowable absorbed dose for each structure such as a tumor / risk organ. (Step S15h). If this determination condition is not satisfied, the surgeon again adds a condition allowing the risk organ functional loss (step S16h).

When the above judgment condition is satisfied, the plan update module 515 evaluates whether the absorbed dose reaches the target absorbed dose or falls within the allowable absorbed dose for each structure such as a tumor / risk organ, and the optimal irradiation protocol. Is derived (step S17h). Then, it is presented to the surgeon as an optimal protocol (step S18h).

(Display GUI image)
45 and 46 are screen configuration examples of the GUI image displayed on the display unit 6.
Before starting treatment, the surgeon enters the patient ID and patient name and requests past radiation treatment data. At this time, the absorbed dose for each element of the risk organ and the absorbed dose for each element of the tumor tissue are requested as radiotherapy data.

[Past treatment history]
At the time of display, the absorbed dose obtained by multiplying the absorbed dose of each element included in the risk organ by the weight of the element and weighted average is displayed as the absorbed dose of the risk organ. Similarly, the weighted average absorbed dose is displayed as the absorbed dose of the tumor tissue.

  Set the risk organ tolerance limit manually or automatically (such as pulling a numerical value from the reference value DB defined in the guidelines, etc.), set the number of gates to be irradiated this time, the irradiation dose, and request the creation of a plan To do.

[Setting risk organ tolerance limits]
In the case of automatic, a predetermined allowable accumulated dose and function remaining rate are displayed.

Acceptable functional residual ratio is utilized as the allowable limit when risk organ is exposed at any of the illumination beam path _{(rate survive).} The residual function rate is expressed as the proportion of all elements included in the risk organ that do not exceed the allowable accumulated dose.

[Setting of irradiation division number and dose]
Enter the conditions for creating a treatment plan.

[Presentation of multi-gate irradiation plan]
The above-mentioned conditions are satisfied, and the optimum protocol is displayed by the evaluation of the planned dose. (After irradiation, an update request is made to obtain the absorbed dose up to one gate, and an optimal protocol is generated and displayed using the above-described multi-gate irradiation plan generation processing.)
In order to visually confirm the expected effect of the specified gate (or the actual result after irradiation) and the protocol, “irradiation optimal position”, “measured / predicted absorbed dose”, and absorbed dose history are displayed.

[Display of irradiation range]
FIG. 47 is a diagram illustrating a method of presenting an irradiation position. The irradiation position / area that satisfies the above-mentioned evaluation of the planned dose is displayed in a color-coded manner in an area that damages the risk organ and an area that can irradiate the tumor tissue with a sufficient dose. When the therapeutic device in the figure is dragged and rotated, “actually measured / predicted absorbed dose” and “absorbed dose history” corresponding to the irradiation position are displayed. Thereby, the surgeon can confirm the effect. When irradiation is performed from the position where the surgeon drags the treatment device in the figure, the “submit” button is pushed to reflect in the “multiple plan” (→ the surgeon can also decide manually). By updating the “multi-gate plan”, the subsequent plans are updated based on the irradiation position designated by the surgeon.

[Absorbed dose and remaining function of each structure]
FIG. 48 is a diagram showing the relationship between the absorbed dose and the number of elements in tumors and risk organs. Alternatively, the survival rate may be displayed. A scheduled value for each irradiation may be indicated, or a scheduled value after completion of all the irradiations scheduled for today may be indicated. Naturally, when actually irradiated, the actual measurement value is displayed. You may display the measured value of already completed irradiation, and the scheduled value of the remaining irradiation. As a result, it will become clear on the way whether it can achieve the goal that was finally planned.

[Display of past absorbed dose history]
Accumulated dose to tumor and risk organ (both expected and measured) is displayed. For example, as shown in FIG. 49, the predicted values from 1 to 5 (final) gates are plotted immediately before the irradiation, and the dose to the risk organ is less than the allowable value at the same time as the tumor is sufficiently irradiated with the dose. ing.

FIG. 50 shows a case where the first gate is irradiated and a deviation occurs. The actual measured values of the first gate and the predicted values up to the final 2-5 gates are plotted, and it can be seen that the target cannot be achieved if irradiation is continued as it is. In such a case, the plan is corrected by returning to step (6) or step (1).

The ratio of tumor tissue (treatment achievement rate)

And this may be used on the vertical axis. Here, Volume (..) represents the total volume of the corresponding area.

  As described above, in the first embodiment, the evaluation function of the irradiation plan is created in consideration of the past absorbed dose, and the position and output dose of the irradiation unit 203 of the radiation irradiation system 2 that satisfies the evaluation function are presented to the operator. To do.

(Second embodiment)
The second embodiment of the plan update module 515 assesses the risk that a risk organ (dangerous site) will be exposed to a radiation beam. The irradiation plan is evaluated in consideration of the actually measured absorbed dose, and the optimal irradiation conditions (position and output dose) of the irradiation unit 203 of the radiation irradiation system 2 are presented to the operator.

  The risk that the risk gun will be exposed to the radiation beam depends on the beam path and the placement of the risk organ. Therefore, the distance from the center of the radiation beam to the risk organ is considered as an evaluation index. The beam path that maximizes the sum of the distance from each element included in the risk organ to the radiation beam is proposed to the operator as the optimal beam path with the lowest risk that the risk organ will be exposed to the radiation beam.

When there are a plurality of risk organs, a beam path that maximizes the sum of the distances from the elements included in all risk organs to the radiation beam path is proposed to the surgeon as an optimal beam path. For example, the distance from the j-th element included in the i-th risk organ shown in FIG. 51 to the beam path is expressed by the following equation.

The distance from all elements of all risk organs is ΣΣ | h _ij |, and the plan update module 515 presents the beam path (r _exposure and u) maximizing this distance to the operator. A route that maximizes min _{i, j} (h _ij ) may be obtained and presented.

  In the second embodiment, the risk that the risk organ is exposed to the radiation beam is evaluated by the distance between the risk organ and the beam path. Thus, by introducing the prevention area numerically, it becomes possible to present a beam path that reduces the risk that the risk organ is exposed to the radiation beam.

  As described above, according to the above embodiment, the radiation absorbed dose is superimposed and displayed on the morphological image of an arbitrary cross section in real time, so that the position and absorbed dose irradiated with radiation can be visually confirmed quickly and easily. Can do. Furthermore, based on the acquired absorbed dose, it is possible to obtain information for evaluating a treatment plan in advance and treatment support information such as an optimal treatment plan. Thereby, it can be grasped during the treatment whether or not the radiation treatment is performed according to the treatment plan, and it is possible to prevent under-irradiation of the radiation treatment site, over-irradiation to the surrounding normal site, and the like. As a result, it is possible to improve the effect of radiation therapy, reduce the amount of extra exposure to the subject, and contribute to improving the quality of radiation therapy.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Specific examples of modifications are as follows.

  Each function according to the present embodiment can also be realized by installing a program for executing the processing in a computer such as a workstation and developing the program on a memory. At this time, a program capable of causing the computer to execute the technique is stored in a recording medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. It can also be distributed.

  In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  As described above, according to the present invention, in radiation treatment, it is actually measured which part of a patient is irradiated with how much dose, and the result is provided in a predetermined form. A radiotherapy system, a radiotherapy support device, and a radiotherapy support program that can prevent excessive irradiation and excessive irradiation of normal tissues can be realized.

FIG. 1 is a diagram for explaining the principle and method of measuring scattered radiation from a subject based on therapeutic radiation of the present radiation treatment system. FIG. 2 shows a block configuration diagram of the radiation therapy system according to the present embodiment. FIG. 3 is a functional block diagram showing the configuration of the data processing system. FIG. 4 is a diagram illustrating a data configuration stored in the storage unit. FIG. 5 is a flowchart showing the flow of processing during radiotherapy including the operation of the present radiotherapy system. FIG. 6 is a diagram showing an example of a measurement form of scattered radiation of the present radiation treatment system. FIG. 7 is a flowchart showing the flow of processing during radiotherapy including the operation of the present radiotherapy system. FIG. 8 is a diagram showing an example of a measurement form of scattered radiation of the present radiation treatment system. FIG. 9 is a diagram showing another example of the measurement form of scattered radiation of the present radiotherapy system. FIG. 10 is a diagram showing the positional relationship of each system. FIG. 11 is a flowchart showing the processing procedure of the fusion model module. FIG. 12 is a display example of an absorbed dose image displayed by the fusion model data. FIG. 13 is a display example of an absorbed dose image with respect to the radiation sensitivity threshold display. FIG. 14 is a display example of an absorbed dose image when molecular level activity information is added. FIG. 15 is a diagram showing an example of a radiotherapy workflow of the present radiotherapy system. FIG. 16 is a diagram illustrating an example of a display image generated by the plan evaluation module. FIG. 17 is a diagram illustrating an example of a display image generated by the plan evaluation module. FIG. 18 is a diagram showing another example of a radiotherapy workflow of the present radiotherapy system. FIG. 19 is a diagram illustrating an example of a display image generated by the plan evaluation module. FIG. 20 is a flowchart illustrating the procedure of the alignment process. FIG. 21 is a diagram illustrating an example of a display image generated by the plan evaluation module. FIG. 22 is a diagram illustrating an example in which the current state and simulation results are represented in a table format. FIG. 23 is a flowchart showing a procedure of warning processing when the irradiation capacity is exceeded. FIG. 24 is a diagram illustrating an example in which a scaler is displayed in order to determine the positional deviation between the plan image and the measured absorption line image. FIG. 25 is a diagram in which the plan image is segmented. FIG. 26 is a diagram showing an irradiation range of a radiation beam. FIG. 27 is a diagram illustrating an example of the configuration of the allowable dose table. FIG. 28 is a diagram showing an example of a cell survival curve with respect to radiation. FIG. 29 is a diagram showing an example of a treatment plan expressed in a table format. FIG. 30 is a diagram in which an allowable error is reflected in the plan value. FIG. 31 is a diagram showing an example of a treatment plan expressed in a table format. FIG. 32 is a diagram illustrating an example of an image immediately before treatment in a radiation irradiation region. FIG. 33 is a diagram illustrating an example of a plan image and an image immediately before treatment. FIG. 34 is a diagram showing the actually measured irradiation position and the actually measured absorbed dose stored in the storage unit 7. FIG. 35 is a distribution diagram showing the actually measured irradiation position and the actually measured absorbed dose. FIG. 36 is a diagram illustrating an example of an image in which a treatment result and a treatment plan image are superimposed on an image immediately before treatment. FIG. 37 is a diagram illustrating an example of an image in which a treatment result and a treatment plan image are superimposed on an image immediately before treatment. FIG. 38 is a diagram illustrating an example of a determination procedure in the case of a liver region. FIG. 39 is a diagram illustrating an example of a warning display when the actually measured absorbed dose exceeds the allowable range. FIG. 40 is a diagram illustrating the influence of the treatment plan image of the next irradiation. FIG. 41 is a diagram illustrating an example of an image in which a treatment plan image and an actually measured absorption line image are superimposed. FIG. 42 is a diagram for explaining the definition of variables. FIG. 43 is a diagram for explaining segment division. FIG. 44 is a flowchart showing the procedure of the irradiation plan update process. FIG. 45 is a diagram illustrating an example of a screen image displayed on the display unit. FIG. 46 is a diagram illustrating an example of a screen image displayed on the display unit. FIG. 47 is a diagram illustrating a method of presenting an irradiation position. FIG. 48 is a diagram showing the relationship between the absorbed dose and the number of elements in tumors and risk organs. FIG. 49 is a diagram displaying accumulated doses to tumors and risk organs. FIG. 50 is a diagram displaying accumulated doses to tumors and risk organs. FIG. 51 is a diagram showing the arrangement of the risk organ and the radiation beam.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Radiation treatment system, 2 ... Radiation irradiation system, 3 ... Scattered ray detection system, 4 ... Data acquisition control part, 5 ... Data processing system, 6 ... Display part, 7 ... Memory | storage part, 8 ... Operation part, 9 ... Network I / F, 201 ... power supply unit, 203 ... irradiation unit, 205 ... timing control unit, 207 ... gantry control unit, 301 ... detector, 303 ... collimator, 305 ... moving mechanism unit, 307 ... position detection unit, 501 ... Correction processing unit 503 ... Reconstruction processing unit 505 ... Conversion processing unit 507 ... Data processing unit 511 ... Fusion model module 513 ... Plan evaluation module 515 ... Plan update module 701 ... Scan sequence 702 ... Control program 703 ... Scattered ray volume data, 704 ... Absorbed dose volume data, 705 ... Morphological image data, 706 ... Tolerance line Table, 707 ... treatment planning data, 708 ... treatment history data, 709 ... fusion model data.

Claims (12)

An irradiation means for irradiating the subject with a therapeutic radiation beam;
Detection means having a detection surface arranged to form a predetermined angle with respect to the axis of the therapeutic radiation beam, and detecting scattered rays having a predetermined scattering angle based on the therapeutic radiation beam at a plurality of rotational positions. When,
Acquisition for acquiring an irradiation dose and an absorbed dose indicating a three-dimensional distribution based on data obtained by reconstructing the detected two-dimensional scattered radiation data in a plurality of directions for each irradiation of the therapeutic radiation beam Means,
And generating means for generating information by comparing at least one of the acquired irradiated position and absorbed dose with a reference dose for each position of the treatment site and normal site of the subject. Radiation therapy system. Scattering with a predetermined scattering angle generated on the basis of the therapeutic radiation beam by irradiating the subject with a therapeutic radiation beam , the detection surface being arranged at a predetermined angle with respect to the axis of the therapeutic radiation beam A radiotherapy information providing apparatus that generates treatment support information using two-dimensional scattered radiation data in a plurality of directions obtained by detecting a line at a plurality of rotational positions ,
Based on the data obtained by reconstructing the two-dimensional scattered radiation data in the plurality of directions for each irradiation of the therapeutic radiation beam, an acquisition unit for acquiring an irradiated position and an absorbed dose indicating a three-dimensional distribution ;
And generating means for generating information by comparing at least one of the acquired irradiated position and absorbed dose with a reference dose for each position of the treatment site and normal site of the subject. Radiation therapy support device. Collation means for collating the reference dose for each position of the treatment site and normal site of the subject with the irradiated position and absorbed dose,
The radiotherapy apparatus according to claim 2, further comprising a presenting unit that presents the generated contrasted information and the collation result.   The radiotherapy support apparatus according to claim 2, wherein the generation unit generates an image obtained by superimposing the acquired irradiation position and an irradiation position planned based on the reference dose.   The radiotherapy support apparatus according to claim 2, wherein the generation unit generates information by comparing an accumulated absorbed dose obtained by accumulating an absorbed dose for each irradiation of the therapeutic radiation beam and the reference dose.   The radiotherapy support apparatus according to claim 5, wherein the generation unit further displays the accumulated absorbed dose in a contour line.   The radiotherapy support apparatus according to claim 5, wherein the presenting unit presents warning information when the cumulative absorbed dose of each part exceeds the reference dose of the part.   The radiotherapy support apparatus according to claim 5, wherein the presenting unit presents warning information when the cumulative absorbed dose of each part is less than a reference dose of the part.   6. The radiotherapy support apparatus according to claim 5, wherein the presenting means further presents warning information when the survival rate of each segment of the normal region is lower than the reference value of the segment.   When the reference dose differs according to the volume of the normal part, the verification unit obtains the volume irradiated to the normal part based on the absorbed dose in the normal part of the subject, The radiation therapy support apparatus according to claim 3, further comprising using a dose.   The apparatus further includes pre-irradiation means for performing irradiation with a dose smaller than that of the therapeutic radiation beam, and the generation means compares at least one of the irradiated position and absorbed dose acquired by the pre-irradiation with the reference dose. The radiotherapy support apparatus according to claim 2, wherein information is generated. Scattering with a predetermined scattering angle generated on the basis of the therapeutic radiation beam by irradiating the subject with a therapeutic radiation beam , the detection surface being arranged at a predetermined angle with respect to the axis of the therapeutic radiation beam A program for controlling a radiotherapy information providing apparatus that generates treatment support information using two-dimensional scattered radiation data in a plurality of directions obtained by detecting a line at a plurality of rotational positions ,
On the computer,
Based on the data obtained by reconstructing the two-dimensional scattered radiation data in the plurality of directions for each irradiation of the therapeutic radiation beam, an acquisition function for acquiring the irradiated position and the absorbed dose indicating the three-dimensional distribution ;
A generation function for generating information that compares at least one of the acquired irradiated position and absorbed dose with a reference dose for each position of the treatment site and normal site of the subject is executed. Radiation therapy support program.

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