JP2023113398A - Radiotherapy treatment collation device and program - Google Patents

Abstract

To improve accuracy of collation of a treatment part in a radiotherapy treatment.SOLUTION: A radiotherapy treatment collation device includes a first acquisition unit, a second acquisition unit, a determination unit, and an output control unit. The first acquisition unit acquires a projection position of a patient's treatment part on the patient's first body surface data at the time of a radiotherapy treatment plan. The second acquisition unit acquires a radiation position of a light beam radiated for positioning at the time of radiotherapy treatment on the patient's second body surface data at the time of the radiotherapy treatment. The determination unit determines a positional deviation between the projection position and the radiation position. The output control unit outputs a determination result of the positional deviation.SELECTED DRAWING: Figure 2

Description

The embodiments disclosed in this specification and drawings relate to a radiotherapy matching device and program.

Prior to radiation irradiation for radiotherapy, an operation is performed to confirm that the treatment site, which is the treatment target set in the radiotherapy plan, is correctly positioned at the isocenter of the radiotherapy apparatus. Such an operation is called treatment site matching or simply matching. If a site other than the treatment site is placed at the isocenter, there is a risk that the other site will be irradiated with radiation. In order to avoid such a situation, collation is performed. One method of matching is to use the patient's body surface data obtained by an optical profilometer. Since the shape measuring instrument is installed on the ceiling of the radiotherapy room, it optically scans the patient obliquely from above. Along with this, there are cases where loss occurs in the peripheral portion of the isocenter of the radiotherapy apparatus in the body surface data. When body surface data obtained during radiation therapy and body surface data obtained during treatment planning are collated, if there is a defect in the body surface data, the accuracy of collation is degraded.

JP-A-7-255716

One of the problems to be solved by the embodiments disclosed in this specification and drawings is to improve the accuracy of matching of treatment sites in radiotherapy. However, the problems to be solved by the embodiments disclosed in this specification and drawings are not limited to the above problems. A problem corresponding to each effect of each configuration shown in the embodiments described later can be positioned as another problem.

A radiotherapy collation apparatus according to an embodiment has a first acquisition unit, a second acquisition unit, a determination unit, and an output control unit. The first acquisition unit acquires the projection position of the treatment site of the patient on the first body surface data of the patient at the time of radiotherapy planning. The second acquisition unit acquires the irradiation position of the light beam irradiated for positioning during the radiotherapy on the second body surface data of the patient during the radiotherapy. A determination unit determines positional deviation between the projection position and the irradiation position. The output control unit outputs a determination result of the positional deviation.

FIG. 1 is a diagram showing a configuration example of a radiotherapy system according to this embodiment. FIG. 2 is a diagram showing a configuration example of a radiotherapy collation apparatus. FIG. 3 is a diagram showing an example of collation processing at the time of radiotherapy planning. FIG. 4 is a diagram showing projection positions in the first patient body surface data. FIG. 5 is a diagram showing an example of verification processing during radiotherapy. FIG. 6 is a diagram showing an appearance example of a radiotherapy apparatus provided with a shape measuring device. FIG. 7 is a diagram showing light irradiation positions in the second patient body surface data. FIG. 8 is a diagram showing an example of a display screen of a collation determination result (with positional deviation). FIG. 9 is a diagram illustrating an example of a display screen of a bird's-eye view image. FIG. 10 is a diagram showing an example of a display screen of a two-sided display image. FIG. 11 is a diagram showing an example of a display screen of a collation determination result (no positional deviation). FIG. 12 is a diagram schematically showing the body surface shape of a patient. FIG. 13 is a diagram showing an example of a display screen for comparison results of shapes in the craniocaudal direction.

Hereinafter, embodiments of a radiation therapy matching apparatus and a program will be described in detail with reference to the drawings.

The radiotherapy verification apparatus according to this embodiment is a computer that verifies a treatment site, which is a radiotherapy target site. A radiotherapy collating apparatus according to this embodiment is assumed to be included in a radiotherapy system.

FIG. 1 is a diagram showing a configuration example of a radiotherapy system 1 according to this embodiment. As shown in FIG. 1, the radiation therapy system 1 is a computer network system having a medical imaging device 2, a radiation therapy planning device 3, a shape measuring device 5, a radiation therapy matching device 6 and a radiation therapy device 7. The medical imaging device 2, the radiotherapy planning device 3, the shape measuring device 5, the radiotherapy matching device 6, and the radiotherapy device 7 are communicably connected to each other via a network.

The medical imaging apparatus 2 generates medical images used for radiotherapy planning. The medical imaging apparatus 2 has a pedestal (hereinafter referred to as imaging pedestal), a bed (hereinafter referred to as imaging bed), and a console. The imaging gantry includes a medical imaging mechanism, performs medical imaging on a patient placed on the imaging bed, and collects raw data. Medical imaging is performed on an imaging region, including a treatment region of a patient. The console generates medical image data for the patient based on the collected raw data. A treatment site is drawn on the medical image. As the medical imaging device 2, for example, an X-ray computed tomography device, a cone beam CT device, a magnetic resonance imaging device, or the like is used.

The radiotherapy planning apparatus 3 includes processors such as a CPU (Central Processing Unit) and GPU (Graphics Processing Unit), memories such as ROM (Read Only Memory) and RAM (Random Access Memory), a display device, an input interface, and a communication interface. is a computer containing The radiotherapy planning apparatus 3 receives medical images directly from the medical imaging apparatus 2 or via a PACS system or the like. The radiotherapy planning apparatus 3 utilizes medical images to create a radiotherapy plan for the patient. A treatment plan image and radiotherapy conditions are set as a radiotherapy plan. A treatment planning image is an image in which a radiation dose distribution is superimposed on a medical image. Radiation therapy conditions include various conditions such as the treatment site, the number of radiation irradiation directions (irradiation gates), radiation irradiation angle, radiation intensity, collimator opening, wedge filter, and the like. The radiotherapy planning apparatus 3 also applies image processing to the medical image to generate image data (hereinafter referred to as first patient body surface data) relating to the data area of the patient's body surface. The first patient body surface data represents the patient's body surface at the time of radiotherapy planning.

The shape measuring instrument 5 is a measuring device (three-dimensional scanner) that optically scans the object to be measured to measure the shape of the object. A three-dimensional camera or a depth sensor is used as the shape measuring device 5 . The shape measuring device 5 is provided in the radiotherapy device 7 . The shape measuring device 5 transmits and receives light beams to and from the patient placed on the bed of the radiotherapy apparatus 7 (hereinafter referred to as the treatment bed), and outputs scan data that quantifies the unevenness of the patient's body surface in a non-contact manner. . The shape measuring device 5 generates a three-dimensional graphical model of the patient's body surface (hereinafter referred to as second patient body surface data) based on the scan data. The second patient body surface data represents the patient's body surface during radiotherapy, more specifically, before radiation exposure.

The radiotherapy apparatus 7 has a pedestal (hereinafter referred to as a pedestal for treatment), a treatment bed, and a console. The treatment platform supports the irradiation head rotatably around the rotation axis. The irradiation head is equipped with an acceleration tube that accelerates electrons generated by an electron gun or the like, and a metal target that collides with the electrons accelerated by the acceleration tube. X-rays, which are radiation, are generated by the collision of electrons with the metal target. The irradiation head irradiates radiation according to the radiotherapy conditions determined by the radiotherapy planning system 3 . The point where the beam axis of radiation from the irradiation head and the rotation axis of the treatment table intersect is spatially immovable and is called the isocenter. The treatment bed has a treatment table on which a patient is placed, and a base for movably supporting the treatment table. The treatment table has a planar shape like the imaging table. The treatment platform, treatment couch and patient are aligned such that the patient treatment site coincides with the isocenter.

FIG. 2 is a diagram showing a configuration example of the radiotherapy collation device 6. As shown in FIG. The radiotherapy verification device 6 is a computer that verifies the treatment site using the first patient body surface data and the second patient body surface data. As shown in FIG. 2 , the radiotherapy collation device 6 has a processing circuit 61 , a storage device 62 , a display device 63 , an input interface 64 and a communication interface 65 . The processing circuit 61, the storage device 62, the display device 63, the input interface 64, and the communication interface 65 are communicably connected to each other via a bus.

The processing circuit 61 has a processor such as a CPU and a GPU as hardware resources. The processing circuit 61 executes a program for matching (hereinafter referred to as a matching program), and implements a projection position acquisition function 611, a light irradiation position acquisition function 612, an alignment function 613, a matching determination function 614, and an output control function 615. .

By implementing the projection position acquisition function 611, the processing circuit 61 acquires the projection position of the treatment site of the patient onto the first patient body surface data at the time of radiotherapy planning. Specifically, the processing circuitry 61 determines the position of the treatment site projected along the reference line onto the first patient body surface data as the projection position. The projection position corresponds to the position where the treatment site defined in the radiotherapy plan is projected onto the patient's body surface. Since the treatment site is located at the isocenter, the projection position also corresponds to the projection of the isocenter onto the patient body surface. This projection position is hereinafter referred to as an isocenter projection position.

By realizing the beam irradiation position acquisition function 612, the processing circuit 61 acquires the irradiation position of the beam irradiated for positioning during the radiotherapy (hereinafter referred to as the positioning beam) on the second patient body surface data during the radiotherapy. to get Specifically, the processing circuit 61 extracts a data area corresponding to the positioning light beam included in the second patient body surface data, and determines the irradiation position based on the pixel values and/or shape of the extracted data area. do. The irradiation position substantially corresponds to the projection position on the body surface of the site aligned with the isocenter during radiotherapy. The irradiation position is hereinafter referred to as a light irradiation position.

By implementing registration function 613, processing circuitry 61 registers the first patient surface data and the second patient surface data.

By implementing the collation determination function 614, the processing circuit 61 determines the positional deviation between the isocenter projection position and the light irradiation position. It is presumed that the occurrence of positional deviation is due to the placement of a site other than the treatment site at the isocenter. It is presumed that the treatment site is arranged at the isocenter because there is no positional deviation. By determining the positional deviation between the isocenter projection position and the beam irradiation position, the treatment site is collated. Determining the positional deviation between the isocenter projection position and the light irradiation position is called matching determination.

By implementing the output control function 615 , the processing circuit 61 outputs various information from the processing circuit 61 . As an example, the processing circuit 61 outputs a collation determination result regarding the positional deviation between the isocenter projection position and the light irradiation position by the collation determination function 614 .

The storage device 62 is a storage device such as a RAM, a ROM, a HDD (Hard Disk Drive), an SSD (Solid State Drive), an integrated circuit storage device, or the like, which stores various information. For example, the storage circuit device stores a scan data set, an interference determination program, and the like. As hardware, the storage device 62 may be a drive device for reading and writing various information from/to a portable recording medium such as a CD-ROM drive, a DVD drive, and a flash memory.

The display device 63 displays various information. Display device 63 may be, for example, a CRT display, liquid crystal display, organic EL display, LED display, plasma display, or any other display known in the art as appropriate. Also, the display device 63 may be a projector.

The input interface 64 inputs various commands received from the operator via the input device. A keyboard, a mouse, various switches, and the like can be used as input devices. The input interface 64 supplies output signals from the input device to the processing circuit 61 via the bus.

The communication interface 65 performs data communication with the medical imaging device 2, the radiotherapy planning device 3, the shape measuring device 5, the radiotherapy device 7, and the like via a wire or radio (not shown). As an example, the communication interface 65 receives first patient body surface data from the medical imaging device 2 . As another example, communication interface 65 receives second patient surface data from profilometer 5 . As another example, the communication interface 65 receives position data of the treatment site from the radiotherapy planning system 3 .

A series of processing related to collation by the radiotherapy system 1 will be described below. Matching is divided into processing during radiotherapy planning and processing during radiotherapy.

FIG. 3 is a diagram showing an example of collation processing at the time of radiotherapy planning. As shown in FIG. 3, the medical imaging apparatus 2 first generates a medical image of a patient (step SA1). In step SA1, the medical imaging apparatus 2 performs medical imaging on an imaging region including a treatment region such as a tumor of a patient placed on an imaging bed to generate a medical image including the treatment region. The patient is placed on the top plate of the treatment bed in the same posture as during radiotherapy. Medical imaging is performed on an imaging region, including a treatment region of a patient. A treatment site is drawn on the medical image. Medical imaging is three-dimensional imaging. A medical image is therefore a three-dimensional image. The medical images are transmitted to the radiotherapy planning device 3 .

When step SA1 is performed, the radiotherapy planning apparatus 3 creates a radiotherapy plan based on the medical images generated in step SA1 (step SA2). Specifically, the radiotherapy planning apparatus 3 identifies the treatment site from the medical image. The treatment site may be specified by any method such as image processing or manual designation by the operator. The type of image processing is not particularly limited, and any method such as threshold processing or image recognition may be used. The position data of the treatment site in the medical image is transmitted to the radiotherapy matching device 6 . Also, in step SA2, the radiotherapy planning apparatus 3 generates first patient body surface data from the medical image. For example, the radiotherapy planning apparatus 3 performs body surface extraction processing to which threshold processing or the like is applied to the medical image to extract data regions related to the patient's body surface. The extracted data in the data area related to the body surface is output as first patient body surface data representing the body surface shape of the patient at the time of radiotherapy planning. Here, the time of radiotherapy planning specifically means the time when medical imaging of a patient is performed by the medical imaging apparatus 2 in order to generate medical images used for radiotherapy planning. The first patient body surface data is transmitted to the radiotherapy matching device 6 .

When step SA2 is performed, the processing circuit 61 of the radiotherapy collation device 6 processes the first patient body surface data generated in step SA2 by realizing the projection position acquisition function 611, and obtains the representative point of the treatment site. A projection position on the patient's body surface (isocenter projection position) is determined (step SA3). Specifically, the processing circuit 61 determines a position obtained by projecting a representative point of the treatment site that coincides with the isocenter along the reference line onto the first patient body surface data as the isocenter projection position.

FIG. 4 is a diagram showing isocenter projection positions D121, D122, and D123 in the first patient body surface data D1. As shown in FIG. 4, the processing circuit 61 identifies the position of the treatment site D12 in the first patient body surface data D1 based on the first patient body surface data D1 and the position data of the treatment site. Processing circuitry 61 then determines a representative point for treatment site D12. The representative point D11 is a point that coincides with the isocenter of the radiotherapy apparatus 7 during radiotherapy. The representative point D11 may be determined as the center point, the center of gravity, or the like of the treatment site D12, or may be designated by the operator via the input interface 64 or the like.

When the representative point 11 is determined, the processing circuit 61 sets reference lines D131, D132 and D133 passing through the representative point D11. As an example, the reference lines D131, D132 and D133 are defined as orthogonal three axes based on the rotation axis of the radiotherapy apparatus. As a convention, the rotation axis of the radiation therapy apparatus is defined as the Z axis, the axis that intersects the Z axis in parallel with the top plate surface of the treatment bed as the X axis, and the top plate surface of the treatment bed with respect to the Z axis. An orthogonal axis is defined as the Y-axis. The reference lines D131, D132, and D133 correspond to imaginary straight lines connecting the projector that projects the positioning light beam irradiated to the patient during radiotherapy and the isocenter or representative point D11.

The processing circuit 61 generates a reference line D131 passing through the representative point D11 along the X-axis, a reference line D132 passing along the Y-axis, a Z A reference line D133 passing along the axis is set. Then, the processing circuit 61 determines the intersection of the reference line D131 and the first patient body surface data D1 as isocenter projection positions D121 and D122, and the intersection of the reference line D132 and the first patient body surface data D1 as isocenter projection positions. In the example of FIG. 4, there is no point where the projection position D123, the reference line D133, and the first patient body surface data D1 intersect. The isocenter projection positions D121, D122 and D123 correspond to the positions where the representative point D11 is projected onto the body surface along the reference lines D131 and D132.

Note that the number of reference lines is not limited to three, and may be one or more. Also, the reference line need not be parallel to the XYZ axes, and may be arranged in any direction according to the positional relationship between the projector and the representative point.

When step SA3 is performed, the processing circuit 61 of the radiotherapy collating device 6 stores the isocenter projection position determined in step SA3 in the storage device 62 (step SA4).

With the above, the process of radiotherapy collation at the time of treatment planning is completed.

When there are a plurality of treatment sites to be treated by radiotherapy, radiotherapy conditions and isocenter projection positions are determined for each treatment site. A database (hereinafter referred to as a treatment condition database) in which radiotherapy conditions and isocenter projection positions are associated and registered for each treatment site is stored in the storage device 62 .

FIG. 5 is a diagram showing an example of verification processing during radiotherapy. The time of radiotherapy specifically means before irradiation and after positioning on the day of irradiation for radiotherapy. At the start of FIG. 5, a radiological technologist or other medical worker uses positioning light beams to align the patient and the treatment area so that the treatment site assumed by the medical worker coincides with the isocenter of the radiotherapy apparatus 7 . It is assumed that the positioning of the couch has been performed. Collation is performed to confirm that the treatment site to be irradiated with radiation this time is arranged at the isocenter.

As shown in FIG. 5, first, the processing circuit 61 of the radiotherapy collation apparatus 6 acquires the isocenter projection position of the treatment site by implementing the projection position acquisition function 611 (step SB1). In this embodiment, it is assumed that radiation irradiation is performed on a plurality of treatment sites on the day of implementation. In this case, the processing circuit 61 automatically selects a treatment site to be irradiated with radiation this time from among a plurality of treatment sites in accordance with an operator's instruction or a treatment order. Next, the processing circuit 61 reads the isocenter projection position and radiotherapy conditions for the selected treatment site from the treatment condition database in the storage device 62 . Radiotherapy conditions are set in the radiotherapy apparatus 7 .

When step SB1 is performed, the shape measuring instrument 5 generates second patient body surface data during radiotherapy (step SB2). The profilometer 5 optically scans the patient positioned on the treatment couch to generate second patient body surface data. The shape measuring device 5 is provided on the rotating portion of the gantry of the radiotherapy apparatus 7 .

FIG. 6 is a diagram showing an appearance example of the radiotherapy apparatus 7 provided with the shape measuring device 5. As shown in FIG. As shown in FIG. 6, a treatment platform 71 and a treatment bed 72 of the radiotherapy apparatus 7 are arranged on the floor of the radiotherapy room. A base 721 of the treatment bed 72 is installed on the floor. The base 721 movably supports a top board 722 on which a patient is placed. The treatment platform 71 has a rotating portion 711 rotatable around the rotation axis Z. As shown in FIG. The rotating portion 711 is provided with an irradiation head 712 , an X-ray tube 73 and an X-ray detector 74 . The irradiation head 712 irradiates MV grade radiation for radiotherapy. The X-ray tube 73 emits KV-class X-rays for imaging. The X-ray detector 74 detects X-rays emitted from the X-ray tube 73 and transmitted through the patient. The X-ray image of the patient detected by the X-ray detector 74 is used for confirmation of anatomic structures inside the patient's body and for image-guided radiotherapy. Note that the rotating portion 711 may be mounted outside the housing of the treatment platform 71, or may be mounted within the housing.

The shape measuring device 5 is installed on the rotating portion 711 of the treatment platform 71 or the irradiation head 712, the X-ray tube 73, and the X-ray detector 74 mounted on the rotating portion 711. FIG. The shape measuring device 5 in FIG. 6 is provided on the side surface of the irradiation head 712 . While the treatment gantry 71 is rotating around the rotation axis Z, the shape measuring device 5 performs an optical three-dimensional scan of the patient. The shape measuring instrument 5 collects output data (scan data) having position information and color information for each sample point on the patient's body surface by performing an optical three-dimensional scan on the patient's body surface. The shape measuring instrument 5 generates second patient body surface data based on the scan data. More specifically, the shape measuring instrument 5 arranges a plurality of sample points forming scan data in a three-dimensional data space according to position information. The sample points are assigned the measured color information. A graphical model of the patient's surface may be constructed by connecting adjacent sample points with polygons, and color information may be assigned to each polygon. This generates second patient body surface data. The second patient body surface data is transmitted to the radiotherapy referencing device 6 . During the optical scanning by the shape measuring device 5, the patient is irradiated with the positioning light beam from the projector. Therefore, the second patient body surface data depicts the positioning light beam that is irradiated onto the patient body surface. To improve the contrast of the positioning beam in the second patient surface data, the three-dimensional optical scan may be performed in a radiation treatment room with the lights off.

By installing the shape measuring instrument 5 on the rotating portion 711 or a device mounted on the rotating portion 711, it is possible to suppress data omission of the second patient body surface data. For example, when collecting patient body surface data using a shape measuring instrument installed on the ceiling, the patient is optically scanned obliquely from above. In this case, the patient's body surface data is missing for the top of the head, shoulders, and the like where the light from the shape measuring device does not reach. In this respect, by providing the shape measuring device 5 in the rotating portion 711 or a device mounted on the rotating portion 711, it becomes possible to collect the second patient body surface data without missing data for the corresponding portion.

When step SB2 is performed, the processing circuit 61 of the radiation therapy collating device 6 processes the second patient body surface data generated in step SB2 by realizing the light irradiation position acquisition function 612, and outputs the data to the patient body surface. A beam irradiation position of the positioning beam is determined (step SB3). Specifically, the processing circuit 61 extracts a data region corresponding to the positioning light beam included in the second patient body surface data, and determines the light irradiation position based on the pixel value and/or shape of the extracted data region. to decide.

FIG. 7 is a diagram showing light irradiation positions D211, D212, and D213 in the second patient body surface data D2. The data area of the patient's body surface (hereinafter referred to as the body surface portion) of the second patient body surface data D2 includes the data areas of the positioning beams (hereinafter referred to as beam areas) D221, D222 and D223. It is assumed that three beams (corresponding to D221, D222, and D223) parallel to the Z-axis and a beam (D224) parallel to the X-axis are emitted from the projector as positioning beams. The processing circuit 61 extracts light ray regions D221, D222, D223, and D224 from the second patient body surface data D2 by image processing such as threshold processing. Next, the processing circuit 61 identifies intersections D211, S212, S213 of the ray regions D221, D222, D223 parallel to the Z-axis and the ray region D224 parallel to the X-axis. Intersection points D211, S212, and S213 are output as light irradiation positions.

In addition, a mark for positioning is attached to the body surface of the patient. The landmarks correspond to isocenter ray positions. The mark is drawn on the patient's body surface with a marker or the like before the radiotherapy is performed. During positioning, the treatment couch and the patient are positioned such that the intersection of two positioning rays, for example, a positioning ray parallel to the Z-axis and a positioning ray parallel to the X-axis, coincides with the mark. That is, the beam irradiation position corresponds to the projection position of the isocenter after positioning onto the second patient body surface data.

When step SB3 is performed, the processing circuit 61 aligns the first patient body surface data and the second patient body surface data by implementing the alignment function 613 (step SB4). At step SB4, the processing circuit 61 arranges the first patient body surface data and the second patient body surface data in the three-dimensional data space so that the first patient body surface data and the second patient body surface data are Moving the first patient surface data and/or the second patient surface data to overlap and aligning the first patient surface data and the second patient surface data. Since the patient body surface data represents the shape of the patient body surface around the treatment site, the non-overlapping of the first patient body surface data and the second patient body surface data means that the position at the isocenter during radiotherapy is determined. This suggests that the area being treated is different from the area to be treated, which is the target of radiation irradiation this time, that is, the area to be treated is mistaken. Therefore, when the first patient body surface data and the second patient body surface data do not overlap, the operator confirms the treatment site again, and if there is an error in the treatment site, positions the patient again, Steps SB1 to SB4 are performed. If the first patient surface data and the second patient surface data overlap, the next step SB5 is performed.

When step SB4 is performed, the processing circuit 61 implements the collation determination function 614 to determine the positional deviation between the isocenter projection position obtained in step SB1 and the beam irradiation position determined in step SB3 (step SB5). Specifically, first, the processing circuit 61 identifies the isocenter projection position in the first patient body surface data and the light irradiation position in the second patient body surface data which were aligned in step SB4. Next, the processing circuit 61 calculates the difference between the isocenter projection position and the beam irradiation position, and compares the difference with a threshold value. When there are a plurality of isocenter projection positions and beam irradiation positions for one treatment site, the processing circuit 61 calculates a difference for each combination of anatomically corresponding isocenter projection positions and beam irradiation positions. Statistical values such as the average value, the maximum value, and the minimum value of the plurality of differences obtained are calculated. Processing circuitry 61 compares the calculated statistical value with a threshold.

The threshold may be set to a value that allows detection of the positional deviation between the isocenter projection position and the light irradiation position. There are various causes of misalignment, but in the present embodiment, it is assumed that the cause is misidentification of the treatment site. In this case, the threshold value is set to a value that allows detection of a mix-up of treatment sites. The threshold may be set to the same value regardless of the region to be treated, body size, etc., or may be set to different values depending on the region to be treated, body size, and the like. The processing circuit 61 determines that there is positional deviation when the difference is larger than the threshold, and determines that there is no positional deviation when the difference is smaller than the threshold.

As described above, the isocenter projection position is determined for each treatment site and managed in the treatment condition database in association with radiotherapy conditions and the like for each treatment site. Since the radiotherapy apparatus 7 irradiates radiation according to the radiotherapy conditions, the isocenter projection position means the projection position on the body surface of the part to be irradiated with radiation by the radiotherapy apparatus 7 from now on. On the other hand, the beam irradiation position corresponds to the projection position of the site recognized by the operator as the treatment site on the body surface when the site is aligned with the isocenter. Therefore, by comparing the difference between the isocenter projection position and the beam irradiation position against a threshold value, it is possible to find out the mix-up of treatment sites.

For example, consider the case where treatment for esophageal cancer and treatment for nasopharyngeal cancer are scheduled on the same day. The esophagus and nasopharynx are anatomically close. Therefore, it is difficult to detect that the treatment of esophageal cancer is mistaken for the treatment of pharyngeal cancer in the registration of the first patient body surface data and the second patient body surface data in step SB4. However, since the determination of the positional deviation between the isocenter projection position and the beam irradiation position is a point-to-point comparison, it is possible to distinguish between anatomically close parts such as the esophagus and the pharynx. Treatment mix-ups can be detected.

When step SB5 is performed, the processing circuit 61 outputs the determination result (collation determination result) of the positional deviation in step SB5 by realizing the output control function 615 (step SB6). The collation determination result is displayed on the display device 63 . At step SB6, the processing circuit 61 displays the first patient body surface data and the second patient body surface data on the display device 63 so that the isocenter projection position and the light irradiation position can be identified. Further, when there are a plurality of treatment sites, the processing circuit 61 displays the second patient body surface data on the display device 63 so that a plurality of isocenter projection positions respectively corresponding to the plurality of treatment sites can be identified. At this time, the processing circuitry 61 may selectively display or emphasize a selected isocenter projection position from among the plurality of isocenter projection positions.

FIG. 8 is a diagram showing an example of the display screen I1 of the collation determination result when there is positional deviation. As shown in FIG. 8, a display image I11 that displays the isocenter projection position and the light irradiation position so as to be identifiable is displayed on the display screen I1. As an example, as a display image I11, a mark indicating an isocenter projection position (hereinafter referred to as an isocenter projection position mark) M1 and a mark indicating a light irradiation position (hereinafter referred to as It is preferable that an image superimposed with the light irradiation position mark) M2 is displayed. By observing the display image I11, it is possible to directly visually confirm the positional deviation between the isocenter projection position and the light irradiation position.

When there are a plurality of isocenter projection positions and beam irradiation positions for one treatment site, not all the isocenter projection positions and beam irradiation positions may be displayed. Some selected isocenter projection positions and ray irradiation positions may be displayed. In this case, the combination of anatomically corresponding isocenter projection positions and ray irradiation positions should be displayed in order to properly assess misalignment. The combination of the isocenter projection position and the beam irradiation position may be sequentially switched for display.

As shown in FIG. 8, the display screen I1 is further provided with a display column I12 for the positional deviation (difference) between the isocenter projection position and the beam irradiation position and a display column I13 for comments. The display field I12 displays, as an example, a numerical value such as "10 cm" that represents the difference between the isocenter projection position and the light irradiation position. A warning indicating the collation determination result is displayed in the display field I13. As a warning, for example, a message such as "The difference is large. The treatment site may be different. Please confirm." should be.

As shown in FIG. 8, the display screen I1 further includes various GUIs (graphical user Interface) button is displayed. The therapy start button I14 is a button for instructing the radiation therapy apparatus 7 to start radiation irradiation. The treatment start button I14 is set so that it can be pressed only when there is no positional deviation between the isocenter projection position and the beam irradiation position. The re-collation button I15 is a button for instructing the re-execution of steps SB2 to SB7. The discontinuation button I16 is a button for instructing discontinuation of the treatment site comparison. The collation display screen I17 is a button for instructing the display of the misregistration display image I11. The treatment site display screen I18 is a button for instructing display of an image (hereinafter referred to as a bird's-eye view image) displaying a plurality of isocenter projection positions corresponding to a plurality of treatment sites when there are a plurality of treatment sites. The dual display screen I19 is a button for instructing display of an image (hereinafter referred to as a dual display image) displaying a plurality of isocenter projection positions and light irradiation positions corresponding to a plurality of treatment sites.

FIG. 9 is a diagram showing an example of the display screen I2 of the overhead image I20. As shown in FIG. 9, the display screen I2 includes, in addition to the overhead image I20, a display field I12, a display field I13, a treatment start button I14, a recheck button I15, an interrupt button I16, a check display screen I17, and a treatment site display screen. I18 and dual display screen I19 are displayed.

As the bird's-eye view image I20, an image is displayed in which marks M11 and M12 indicating a plurality of isocenter projection positions corresponding to a plurality of treatment sites are superimposed on the first patient body surface data or the second patient body surface data. An example of creating the bird's-eye view image I20 is as follows. First, processing circuitry 61 reads a plurality of isocenter projection positions for a plurality of treatment sites from the treatment condition database. Next, the processing circuit 61 superimposes the readout marks M11 and M12 indicating the isocenter projection positions on the first patient body surface data or the second patient body surface data. As a result, a bird's-eye view image I20 representing the first patient body surface data or the second patient body surface data in which a plurality of types of isocenter projection positions for different treatment sites are emphasized by marks M11 and M12 is generated. The isocenter projection position marks M11 and M12 may be displayed in different shapes or colors depending on the position of the treatment site to which they belong in order to visually grasp the relationship between the mark and the treatment site. Further, not all of the plurality of isocenter projection positions present in one treatment site may be displayed, and some isocenter projection positions selected by the operator or the like may be displayed.

FIG. 10 is a diagram showing an example of the display screen I3 of the two-sided display image I21. As shown in FIG. 10, the display screen I3 includes, in addition to the two-sided display image I21, a display column I12, a display column I13, a treatment start button I14, a recheck button I15, an interrupt button I16, a check display screen I17, and a treatment site display. A screen I18 and a dual display screen I19 are displayed.

As a two-sided display image I21, a beam irradiation position mark M2 and a plurality of isocenter projection position marks M11 and M12 corresponding to a plurality of treatment sites are superimposed on the first patient body surface data or the second patient body surface data. An image is displayed.

When step SB6 is performed, the processing circuit 61 confirms whether or not it is determined in step SB5 that there is positional deviation (step SB7). If there is misalignment (step SB7: YES), it is assumed that the treatment site is mistaken. The operator refers to the radiotherapy plan or the like to confirm the correct treatment site. If it is confirmed that there is a wrong treatment site, the radiotherapy apparatus 7 moves the treatment bed according to the operator's instruction in order to align the correct treatment site with the isocenter (step SB8). After moving the treatment bed, the operator presses the collation button I15 again. When the collation button I15 is pressed again, the processing circuit 61 repeats steps SB2 to SB7. Steps SB2 to SB7 are preferably repeated until it is determined in step SB5 that there is no misalignment.

FIG. 11 is a diagram showing an example of the display screen I4 of the determination result when there is no positional deviation. As shown in FIG. 11, the display screen I4 includes a display field I12, a display field I13, a treatment start button I14, a recheck button I15, an interrupt button I16, a check display screen I17, a treatment site image I23, and a display field I12. A display screen I18 and a dual display screen I19 are displayed.

In the positional deviation display image I23 when there is no positional deviation, the mark M3 indicating the light irradiation position and the mark M2 indicating the isocenter projection position are displayed at the same position. Even when there is no positional deviation, it is possible to display the treatment site display image by pressing the treatment site display screen I18, and to display the dual display image by displaying the dual display screen I19. The display field I12 displays the difference between the isocenter projection position and the light irradiation position, such as "0 cm", and the display field I13 displays the evaluation of the difference, such as "no positional deviation".

If there is no positional deviation (step SB7: NO), the operator presses the treatment start button I14. Triggered by the depression of the treatment start button I14, the radiotherapy apparatus 7 irradiates the treatment site with radiation (step SB9). In step SB9, the radiotherapy apparatus 7 irradiates radiation according to the irradiation conditions corresponding to the treatment site. Radiation therapy is thus performed on the treatment site.

With the above, the process of matching the treatment site at the time of radiotherapy is completed.

It should be noted that the treatment site collation processing shown in FIGS. 3 and 5 is an example, and the present invention is not limited to this.

Although the isocenter projection position is determined by the radiotherapy verification device 6 in the radiotherapy planning phase in the above embodiment, it may be determined by the radiotherapy verification device 6 in the radiotherapy phase. As another example, the isocenter projection positions may be determined during the radiotherapy planning phase or by other devices such as the medical imaging device 2 or the radiotherapy planning device 3 . In this case, the radiotherapy collating device 6 acquires the isocenter projection position from the other device.

Although the beam irradiation position is determined by the radiotherapy reference device 6 in the above embodiment, it may be determined by another device such as the shape measuring device 5 or the like. In this case, the radiotherapy collating device 6 acquires the light irradiation position from the other device.

In the above embodiment, the first patient body surface data, which is the reference source, is generated based on the medical image generated by the medical imaging apparatus 2, but may be generated by other equipment. For example, the first patient body surface data may be generated by MR (Mixed Reality) glasses or AR (Augmented Reality) glasses worn by a radiologist or the like. MR glasses and AR glasses are equipped with the three-dimensional camera and depth camera described above to recognize the surrounding environment. A radiologist wearing MR glasses or AR glasses optically scans a patient placed on a bed of a medical imaging device with the MR glasses or AR glasses. First patient surface data can be generated based on scan data acquired by MR glasses or AR glasses.

Similarly, the second patient body surface data to be matched may also be generated by MR glasses or AR glasses. In this case, the second patient body surface data, the isocenter projection position mark and/or the beam irradiation position mark may be displayed on the MR glasses or AR glasses in alignment with the actual patient body surface. Various other display information according to this embodiment may also be displayed on the MR glasses or the AR glasses.

In the above embodiment, the alignment of the first patient body surface data and the second patient body surface data in step SB4 and the determination of the positional deviation between the isocenter projection position and the beam irradiation position in step SB5 are performed. However, registration between the first and second patient surface data may be omitted if desired.

In the above embodiment, the positional deviation between the isocenter projection position and the beam irradiation position was assumed to be caused by mistaking the treatment site. However, the cause of positional deviation is not limited to this, and may be positional deviation caused by inaccuracy in patient positioning or the like. By setting a threshold according to the cause of positional deviation, it is possible to arbitrarily select the cause of positional deviation to be determined.

In the above embodiment, the treatment site is collated based on the isocenter projection position in the first patient body surface data and the light irradiation position in the second patient body surface data. However, patient matching may be performed based on data of the patient's first facial surface at the time of radiation therapy planning and data of the patient's second facial surface at the time of radiation therapy. Specifically, the processing circuit 61 calculates the difference between the first face surface data and the second face surface data, determines whether the calculated difference is greater than a threshold value, and outputs the determination result. Output. A determination result is displayed on the display device 63 . If the difference is smaller than the threshold, it is presumed that the set patient and the patient to be irradiated are the same, and if the difference is larger than the threshold, it is presumed that the set patient and the patient to be irradiated are different. . By checking the determination result, the operator can determine whether or not there is a mix-up of patients.

In the above embodiment, the alignment of the first patient body surface data and the second patient body surface data in step SB4 did not particularly consider the body surface shape around the treatment site.

FIG. 12 is a diagram schematically showing the body surface shape of the patient P. FIG. As shown in FIG. 12, the torso of the patient P may have substantially the same shape in the cranio-caudal direction. For example, the regions 121 and 122, which are partial regions of the patient's body surface, differ in position in the craniocaudal direction but have substantially the same shape. Therefore, positional deviation between the first patient body surface data corresponding to the region 121 and the second patient body surface data corresponding to the region 122 cannot be detected.

Therefore, when acquiring the second patient body surface data, the patient is optically scanned by the shape measuring device 5 while moving the bed in the craniocaudal direction. This allows a wide range of second patient surface data to be collected in the craniocaudal direction. Processing circuitry 61 compares the shape of the second patient surface data for different craniocaudal positions. Specifically, the shape of the second patient body surface data of the craniocaudal position where the treatment site is located and the second patient body surface data of the craniocaudal position within a predetermined distance from the craniocaudal position are compared. If the two pieces of second patient body surface data are different in shape, it is possible to detect the difference in the position of the patient body surface in the craniocaudal direction, so the processing after step SB4 is executed. If the shapes of the second patient body surface data are substantially the same, it is not possible to detect the difference in the position of the patient body surface in the craniocaudal direction, so the processing after step SB4 is interrupted. The result of shape comparison in the cranial-caudal direction is displayed on the display device 63 .

FIG. 13 is a diagram showing an example of a display screen I5 for comparison results of shapes in the head-to-tail direction. A display screen I5 shown in FIG. 13 shows the comparison result when it is determined that the shapes are substantially the same. As shown in FIG. 13, the display screen I5 includes an image display field I24, a display field I12, a display field I13, a treatment start button I14, a recheck button I15, an interrupt button I16, a check display screen I17, and a treatment site display. A screen I18 and a dual display screen I19 are displayed. If it is determined that the shapes are substantially the same, the processing after step SB5 is not performed, so the display field I12 does not display the difference between the isocenter projection position and the beam irradiation position. In the display field I13, a message such as "Unable to match" is displayed, which expresses the shape comparison result regarding the head-to-tail direction. The image display field I24 does not display images such as the images I11, I20, I21, and I22, which express the positional deviation between the isocenter projection position and the light irradiation position. In addition, the second patient body surface data may be displayed in the image display field I24 as a basis for the comparison result.

As described above, the radiotherapy collation device 6 according to this embodiment has the processing circuit 61 . The processing circuit 61 acquires the projection position (isocenter projection position) of the treatment site of the patient onto the first patient body surface data at the time of radiotherapy planning. The processing circuit 61 acquires the irradiation position (light irradiation position) of the beam irradiated for positioning during the radiotherapy to the second patient body surface data during the radiotherapy. A processing circuit 61 determines the positional deviation between the isocenter projection position and the beam irradiation position. The processing circuit 61 outputs the determination result of positional deviation.

The isocenter projection position means the projection position on the body surface of the treatment site determined at the time of radiation therapy planning, and the beam irradiation position means the projection position on the body surface of the site aligned with the isocenter at the time of radiation therapy. means By determining the positional deviation between the isocenter projection position and the light irradiation position, it is possible to prevent a region other than the treatment region from being placed at the isocenter and irradiating the region with radiation.

According to at least one embodiment described above, it is possible to improve the accuracy of collation of treatment sites in radiotherapy.

The term "processor" used in the above description includes, for example, CPU, GPU, or Application Specific Integrated Circuit (ASIC)), programmable logic device (for example, Simple Programmable Logic Device : SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). The processor realizes its functions by reading and executing the programs stored in the memory circuit. It should be noted that instead of storing the program in the memory circuit, the program may be directly installed in the circuit of the processor. In this case, the processor realizes its function by reading and executing the program embedded in the circuit. On the other hand, if the processor is for example an ASIC, then instead of the program being stored in a memory circuit, the functionality is directly embedded as a logic circuit within the circuitry of the processor. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, and may be configured as one processor by combining a plurality of independent circuits to realize its function. good. Furthermore, multiple components in FIGS. 1 and 2 may be integrated into a single processor to achieve their functions.

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

1 Radiation therapy system 2 Medical imaging device 3 Radiation therapy planning device 5 Shape measuring device 6 Radiation therapy verification device 7 Radiation therapy device 61 Processing circuit 62 Storage device 63 Display device 64 Input interface 65 Communication interface 71 Treatment rack 72 Treatment bed 73 X Ray tube 74 X-ray detector 121 Region 122 Region 611 Projection position acquisition function 612 Light beam irradiation position acquisition function 613 Alignment function 614 Verification determination function 615 Output control function 711 Rotating part 712 Irradiation head 721 Base 722 Top board

Claims (12)

a first acquisition unit that acquires a projection position of the treatment site of the patient onto the first body surface data of the patient at the time of radiotherapy planning;
a second acquisition unit that acquires an irradiation position of a light beam irradiated for positioning during the radiotherapy, on the second body surface data of the patient during the radiotherapy;
a determination unit that determines a positional deviation between the projection position and the irradiation position;
an output control unit that outputs the determination result of the positional deviation;
Radiation therapy matching device comprising. The determination unit calculates a difference between the projection position and the irradiation position, compares the difference with a threshold,
The output control unit outputs a warning as the determination result when the difference is greater than the threshold.
The radiotherapy matching device according to claim 1. further comprising an alignment unit that aligns the first body surface data and the second body surface data;
The determination unit compares the positional deviation between the projection position in the aligned first body surface data and the irradiation position in the second body surface data.
The radiotherapy matching device according to claim 1. The first acquisition unit determines, as the projection position, a position obtained by projecting a representative point of the treatment site that matches the isocenter of the radiotherapy apparatus onto the first body surface data along a reference line. The radiotherapy matching apparatus according to claim 1. The second acquisition unit extracts a data area corresponding to the light beam included in the second body surface data, and determines the irradiation position based on pixel values and/or shapes of the data area. 1. The radiotherapy reference device according to 1. 2. The radiotherapy reference apparatus according to claim 1, wherein said radiotherapy planning time is a time when medical imaging of said patient is performed by a medical imaging device for generating a medical image used for radiotherapy planning. . The first acquisition unit acquires, as the first body surface data, a medical image of the treatment site of the patient to be used for radiotherapy planning, and performs image processing on the medical image to obtain the first body surface data. 2. The radiotherapy collation apparatus according to claim 1, which extracts . The second acquisition unit acquires the second body surface data generated based on the output data of a shape measuring device that performs optical three-dimensional scanning, and determines the irradiation position from the second body surface data. death,
The shape measuring instrument is provided in a gantry of a radiotherapy apparatus,
The output data is obtained by optical three-dimensional scanning of the patient by the profilometer while the gantry is rotating about an axis of rotation.
The radiotherapy matching apparatus according to claim 1. 2. The radiation therapy collation according to claim 1, wherein said output control unit displays said first body surface data and said second body surface data on a display device such that said projection position and said irradiation position can be identified. Device. 2. When there are a plurality of treatment sites, the output control unit displays the second body surface data on a display device such that a plurality of projection positions respectively corresponding to the plurality of treatment sites are identifiable. A radiotherapy reference device as described. 11. The radiotherapy collation apparatus according to claim 10, wherein said output control unit selectively displays or emphasizes a selected projection position from among said plurality of projection positions. to the computer,
A function of obtaining a projection position of a treatment site of the patient on the first body surface data of the patient at the time of radiotherapy planning;
A function of acquiring the irradiation position of the light beam irradiated for positioning during the radiotherapy to the second body surface data of the patient during the radiotherapy;
a function of determining positional deviation between the projection position and the irradiation position;
a function of outputting the determination result of the positional deviation;
A radiotherapy matching program that realizes