WO2019008826A1 - Dispositif radiographique et procédé de détection d'image radiographique - Google Patents

Dispositif radiographique et procédé de détection d'image radiographique Download PDF

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Publication number
WO2019008826A1
WO2019008826A1 PCT/JP2018/008635 JP2018008635W WO2019008826A1 WO 2019008826 A1 WO2019008826 A1 WO 2019008826A1 JP 2018008635 W JP2018008635 W JP 2018008635W WO 2019008826 A1 WO2019008826 A1 WO 2019008826A1
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Prior art keywords
image
radiation
phase
specific
predetermined
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PCT/JP2018/008635
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English (en)
Japanese (ja)
Inventor
▲高▼橋　渉
森　慎一郎
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株式会社島津製作所
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy

Definitions

  • the present invention relates to a radiation imaging apparatus and a radiation image detection method.
  • radiation treatment is performed by irradiating radiation to a treatment site such as a tumor, and radiation treatment is performed by imaging a radiation image during treatment and detecting the treatment site as a specific site. It is disclosed to control the irradiation of therapeutic radiation by the radiotherapy device according to the detection position of the site.
  • the specific site moves along with the respiration of the subject. Therefore, in the above-mentioned WO 2010/055881, the movement of the body surface of the subject is detected by a laser distance meter provided outside the body, and the respiratory phase is acquired based on the movement of the body surface. Thereby, when the specific region is in the irradiation range of the therapeutic radiation set in advance and the respiratory phase is a predetermined irradiation timing, the therapeutic radiation is irradiated.
  • the device configuration becomes complicated.
  • the acquired respiratory phase does not necessarily match the state of the specific part, such as temporal movement between the movement of the body surface and the change of the state of the specific part there is a possibility. Therefore, it is desirable to be able to accurately detect a specific site in a predetermined breathing phase without complicating the device configuration.
  • the present invention has been made to solve the problems as described above, and one object of the present invention is to accurately detect a specific region in a predetermined breathing phase without complicating the device configuration. It is an object of the present invention to provide a radiation imaging apparatus and a radiation image detection method capable of
  • a radiation imaging apparatus includes an irradiation unit that irradiates radiation to a subject, a radiation detection unit that detects radiation transmitted through the subject, and a radiation detection unit. And an image generation unit that generates a radiation image based on the detection signal; and a position detection unit that detects the position of a specific part of the subject from the radiation image and tracks the movement of the specific part.
  • Image recognition based on an image of a specific site in a respiratory phase is configured to detect a specific site in a predetermined respiratory phase from the radiation image.
  • the specific region in the predetermined respiratory phase is detected from the radiation image by image recognition based on the image of the specific region in the predetermined respiratory phase.
  • the position detection unit is configured. Thereby, if an image of a specific site at a predetermined respiratory phase is acquired in advance, the specific site at the predetermined respiratory phase can be directly detected from the radiation image based on the image. Therefore, as compared with the case of detecting the respiration phase from the movement of the body surface, it is possible to accurately detect the specific region in the predetermined respiration phase. Further, since the respiration phase can be grasped from the radiation image, it is not necessary to separately provide a sensor for detecting the respiration phase outside the subject. As a result, it is possible to accurately detect a specific site in a predetermined breathing phase without complicating the device configuration.
  • a first template image of a specific site generated at a predetermined breathing phase and a second template image of a specific site generated at a breathing phase other than the predetermined breathing phase is configured to specify a predetermined breathing phase by matching the radiation image generated by the image generation unit with each of the first template image and the second template image. It is configured to detect a site.
  • the matching result (similarity) with the first template image is higher than the matching result with the second template image, it is possible to detect a specific region of a predetermined breathing phase.
  • the first template image and the second template image are images in which at least one of the shape, the size, or the background portion superimposed and superimposed on the specific portion in the image is different.
  • the first template image and the second template image are different due to the difference in the respiratory phase, it is possible to specify a predetermined respiratory phase only by comparing the matching result with the first template image and the second template image. Whether it is an image of a part can be identified with high accuracy.
  • the storage unit includes N types of respiratory phases that are template images of specific regions in respective respiratory phases obtained by dividing one cycle of respiration into N (N is a natural number of 2 or more)
  • N is a natural number of 2 or more
  • the image is stored, and the first template image is a respiration phase image at one or more respiration phases selected from among the N divided respiration phases, and the second template image is a signal other than the first template image.
  • a respiratory phase image in a respiratory phase is used, and the position detection unit is configured to detect a specific region by performing matching with a radiographic image using each of N types of respiratory phase images.
  • each respiratory phase image more accurately reflects the state of the specific region in each respiratory phase, as compared to the case where a template image is generated from images of specific regions in various (unspecific) respiratory phases.
  • the matching accuracy of the specific part for each breathing phase can be improved. As a result, it is possible to improve the detection accuracy of the specific site in each breathing phase including the predetermined breathing phase.
  • a control unit connected to the radiation treatment apparatus for irradiating a treatment beam to a specific site of the subject is further provided, and the control unit
  • the trigger signal for irradiating the treatment beam is configured to be output to the radiation treatment apparatus only when the specific region of the respiratory phase is detected and the detection position of the specific region is within the predetermined beam irradiation range.
  • the treatment beam irradiation can be performed only at a predetermined breathing phase under the condition that the specific site exists in the beam irradiation range, so the irradiation dose further along the treatment plan It is possible to treat by distribution.
  • a radiation image detection method is a radiation image detection method for detecting a specific region in a radiation image of a subject, wherein radiation irradiated to the subject and transmitted through the subject Detecting the position of the specific region of the subject from the radiation image, and tracking the movement of the specific region, and tracking the movement of the specific region comprises the steps of:
  • the image recognition based on the image of the specific region in the predetermined respiratory phase includes the step of detecting the specific region in the predetermined respiratory phase from the radiation image.
  • FIG. 1 is a schematic view showing an entire configuration of a radiation imaging apparatus according to an embodiment of the present invention. It is a schematic diagram which showed the imaging
  • the radiation imaging apparatus 100 is an apparatus for capturing a radiation image obtained by imaging the inside of a subject T by irradiating radiation from the outside of the subject T such as a human body. .
  • the radiation image is an image of the subject T captured using radiation passing through the subject T.
  • the radiation imaging apparatus 100 is an X-ray imaging apparatus that captures an X-ray image using an X-ray that is an example of radiation.
  • the X-ray image is an example of a radiation image.
  • the radiation imaging apparatus 100 is combined with the radiation treatment apparatus 110 to configure a radiation treatment system for performing radiation treatment.
  • the radiation treatment apparatus 110 can irradiate a radiation beam (treatment beam) to a subject T that is a patient.
  • the radiation imaging apparatus 100 detects the position of the specific site 50 from the X-ray image of the subject T.
  • the specific site 50 is a tumor or the like to be treated, and is a site in the body of the subject T.
  • the radiation imaging apparatus 100 of the present embodiment can particularly preferably detect the specific region 50 in the vicinity of an organ involved in respiration, such as the lung and the diaphragm. Such a specific site 50 moves periodically with the passage of time as the subject T breathes.
  • the radiography apparatus 100 is a markerless (does not use a marker member with low X-ray transparency), directly detects the position of the specific region 50 from the X-ray image by image recognition, and tracks the movement of the specific region 50 Do tracking.
  • the treatment of the specific site 50 (tumor) is performed by irradiating the treatment beam from the radiation treatment apparatus 110 at the timing when the specific site 50 moves to the irradiation position of the radiation treatment apparatus 110 by the movement tracking.
  • the radiation treatment apparatus 110 can irradiate the subject T on the top 3 with a radiation beam such as an X-ray, a proton beam or a heavy particle beam.
  • the radiation treatment apparatus 110 includes a base 111, a gantry 112 pivotally installed with respect to the base 111, and a head 113 provided on the gantry 112 for emitting a treatment beam.
  • the radiation treatment apparatus 110 can change the irradiation direction of the treatment beam emitted from the head 113 by swinging the gantry 112 relative to the base 111.
  • the radiation treatment apparatus 110 can irradiate a treatment beam to a specific site 50 such as a tumor of the subject T from various directions.
  • the radiation imaging apparatus 100 includes an irradiation unit 1 that irradiates a subject T with radiation (X-rays), and an X-ray detection unit 2 that detects radiation (X-rays) that has passed through the subject T.
  • the irradiation unit 1 and the X-ray detection unit 2 are arranged in pairs so as to face each other across the top plate (examination table) 3 on which the subject T is placed.
  • the radiation imaging apparatus 100 includes a control unit 4 that controls the irradiation unit 1 and the top 3.
  • the X-ray detection unit 2 is an example of the “radiation detection unit” in the claims.
  • a plurality of pairs of the irradiation unit 1 and the X-ray detection unit 2 are provided.
  • two pairs of the irradiation unit 1a and the X-ray detection unit 2a and the pair of the irradiation unit 1b and the X-ray detection unit 2b are provided.
  • Each pair constitutes a first imaging system and a second imaging system that image the subject T from different directions.
  • the three-dimensional position of the specific site 50 (tumor) can be identified based on the X-ray image generated from each imaging system.
  • the top 3 is movable in, for example, three orthogonal axes (X axis, Y axis, Z axis), is rotatable around each axis, and can move in six axial directions.
  • the pair of the irradiation unit 1 and the X-ray detection unit 2 may be movable around the top 3 in a horizontal plane.
  • the irradiation unit 1 has an X-ray tube that generates X-rays by applying a high voltage.
  • the irradiation unit 1 is connected to the control unit 4.
  • the control unit 4 controls the irradiation unit 1 according to preset imaging conditions such as the tube voltage, the tube current, and the time interval of X-ray irradiation, and causes the irradiation unit 1 to generate X-rays.
  • the X-ray detection unit 2 detects an X-ray irradiated from the irradiation unit 1 and transmitted through the subject T, and outputs a detection signal according to the detected X-ray intensity.
  • the X-ray detection unit 2 is configured of, for example, an FPD (Flat Panel Detector).
  • the radiation imaging apparatus 100 further includes an image processing unit 5 that acquires an X-ray detection signal from the X-ray detection unit 2 and generates an X-ray image 30 (see FIG. 4).
  • the X-ray detection unit 2 outputs a detection signal of a predetermined resolution to the image processing unit 5.
  • the control unit 4 is a computer including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like.
  • the control unit 4 functions as a control unit that controls each unit of the radiation imaging apparatus 100 by the CPU executing a predetermined control program.
  • the control unit 4 controls the irradiation unit 1 and the image processing unit 5 and controls the movement of the top 3.
  • the radiation imaging apparatus 100 includes a display unit 6.
  • Display unit 6 is a monitor such as a liquid crystal display, for example.
  • the control unit 4 is configured to control the display unit 6 to display an image generated by the image processing unit 5.
  • the control unit 4 is connected to a radiation treatment apparatus 110 for irradiating a specific region 50 of the subject T with a treatment beam.
  • the control unit 4 is configured to output a trigger signal to the radiation treatment apparatus 110 when the specific site 50 detected by the image processing unit 5 reaches the irradiation position of the radiation treatment apparatus 110. Thereby, the irradiation of the treatment beam to the specific site 50 is performed with high accuracy.
  • the image processing unit 5 is a computer configured to include, for example, a processor 5a such as a CPU or a graphics processing unit (GPU), and a storage unit 5b such as a ROM and a RAM. That is, the image processing unit 5 is configured by causing the processor 5a to execute the image processing program 21 (see FIG. 3) stored in the storage unit 5b.
  • the image processing unit 5 may be configured integrally with the control unit 4 by causing the same hardware (CPU) as the control unit 4 to execute an image processing program.
  • the image processing unit 5 includes an image generation unit 11 and a position detection unit 12 as functions by the processor 5 a executing the image processing program 21.
  • the image generation unit 11 and the position detection unit 12 may be individually configured by dedicated processors.
  • the image generation unit 11 is configured to generate an X-ray image 30 (see FIG. 4) based on the detection signal of the X-ray detection unit 2.
  • the X-ray image 30 is an X-ray fluoroscopic image generated in the form of a moving image. That is, X-rays are intermittently emitted from the irradiation unit 1 to the subject T at predetermined time intervals, and the X-ray detection unit 2 sequentially detects X-rays transmitted through the subject T.
  • the image generation unit 11 generates an X-ray image 30 at a predetermined frame rate by imaging the detection signals sequentially output from the X-ray detection unit 2.
  • the frame rate is, for example, about 15 FPS to 30 FPS.
  • the image generation unit 11 outputs the generated X-ray image 30 to the control unit 4.
  • the X-ray image 30 is displayed on the display unit 6 by the control unit 4.
  • the position detection unit 12 is configured to detect the position of the specific region 50 of the subject T from the X-ray image 30 generated by the image generation unit 11 and to track the movement of the specific region 50.
  • the position detection unit 12 detects the specific portion 50 by image recognition using template matching.
  • the position information of the detected specific part 50 is output to the control unit 4.
  • the storage unit 5 b stores a program 21 (image processing program) for causing a computer to function as the image processing unit 5.
  • the storage unit 5 b also stores the X-ray image 30 generated by the image generation unit 11.
  • the storage unit 5 b stores template data 40 for detecting the specific part 50 and treatment plan data 22.
  • Template data 40 and treatment plan data 22 are prepared in advance prior to radiation treatment.
  • the treatment plan data 22 includes four-dimensional CT data created by continuously performing three-dimensional CT imaging of the subject T with time progress by CT (Computed Tomography) imaging. From the treatment plan data 22, the position, size, shape, movement range and the like of the specific site 50 in the subject T are grasped.
  • the template data 40 is acquired by imaging the specific region 50 of the subject T in advance by the radiation imaging apparatus 100 in accordance with a treatment plan created based on the treatment plan data 22.
  • the template data 40 is a set of template images (respiratory phase image 43) described later.
  • the template image is an image acquired by cutting out an image portion including the specific region 50 from the X-ray image 30 acquired in advance.
  • the relative positional relationship between the irradiation unit 1, the X-ray detection unit 2 and the top 3 is adjusted so that the specific region 50 of the subject T appears in the X-ray image 30.
  • a background portion 31 constituted by an image (not shown) of a structural portion 60 such as a bone of the subject T or other organs.
  • the specific portion 50 is captured in the overlapping state.
  • the specific site 50 moves with the respiration of the subject T. Since the respiration of the subject T is a repetition of an inspiratory movement for breathing and an exhalation movement for exhaling the breath, movement of the specific part 50 associated with breathing becomes periodic movement. Since the movement path of the specific part 50 is three-dimensional, it varies depending on the imaging direction of the X-ray image 30.
  • the irradiation position of the treatment beam is set in accordance with the treatment plan data 22 and is set as a beam irradiation range 32 having a predetermined area in the X-ray image 30.
  • the beam irradiation range 32 is set as an area having a shape close to the shape of the specific part 50 as much as possible in order to reduce the irradiation to areas other than the specific part 50, and slightly larger than the specific part 50 in consideration of the margin due to various error factors. It is set.
  • the specific portion 50 Since the specific portion 50 does not move in the same manner as the background portion 31, when the specific portion 50 moves with respiration, the position of the specific portion 50 with respect to the background portion 31 changes in the X-ray image 30. .
  • the movement of internal organs by respiration occurs along with the change in shape of organs, such as the expansion and contraction of the lungs.
  • the specific portion 50 in the X-ray image 30 changes in shape due to breathing. Therefore, even if the state of the specific region 50 falls within the beam irradiation range 32, it will differ depending on which breathing phase it is in.
  • the respiratory phase means timing (time position) within a cycle of the respiratory cycle.
  • the position detection unit 12 is configured to detect the specific region 50 at the predetermined breathing phase from the X-ray image 30 by image recognition based on the image of the specific region 50 at the predetermined breathing phase. It is done. Then, the control unit 4 irradiates the treatment beam only when the specific part 50 of the predetermined respiratory phase is detected by the position detection part 12 and the detection position of the specific part 50 is within the predetermined beam irradiation range 32. And a trigger signal to output to the radiation treatment apparatus 110. As a result, the treatment beam can be irradiated by the radiation treatment apparatus 110 in a state in which both the respiratory phase and the position of the specific region 50 are specified.
  • the detection of the specific portion 50 by image recognition is performed by template matching with the X-ray image 30 using the template image stored in the storage unit 5 b.
  • the storage unit 5b in order to identify the specific region 50 of the predetermined respiratory phase, includes the first template image 41 of the specific region 50 generated at the predetermined respiratory phase, and the predetermined region.
  • the second template image 42 of the specific region 50 generated at a breathing phase other than the breathing phase is stored.
  • the first template image 41 and the second template image 42 are images obtained by cutting out a portion of the specific region 50 from the X-ray image 30 captured at different breathing phases. Therefore, the first template image 41 and the second template image 42 are at least the shape (see FIG. 5) of the specific portion 50 in the image, the size, or at least the background portion 31 shown in FIG. One is an image that is different.
  • N is a natural number of 2 or more
  • a respiratory phase image 43 is stored.
  • one cycle of breathing can be roughly divided into an inspiratory phase that inhales a breath and an expiratory phase that exhales.
  • the inspiratory phase is divided into five respiratory phases In1 to In5
  • the expiratory phase is divided into five respiratory phases Ex1 to Ex5.
  • a plurality of respiratory phase images 43 are stored for each of these respiratory phases.
  • template matching one average image (template) is created from a plurality of respiratory phase images 43 in the same respiratory phase, and matching is performed using the average image.
  • the first template image 41 is a respiration phase image 43 at one or more respiration phases selected from among N divided respiration phases
  • the second template image 42 is other than the first template image 41. It is a respiration phase image 43 in a respiration phase.
  • the respiratory phase images 43 of the respiratory phase Ex5 at the end of the expiratory phase and the initial respiratory phase In1 of the inspiratory phase are the first template image 41. It is set as.
  • the position movement (displacement of the lung etc.) is the smallest between the end of exhalation (breathing phase Ex5) and the beginning of breathing (breathing phase In1) in one cycle of breathing motion, and the position of the specific region 50 is stable
  • the beam irradiation range 32 (see FIG. 4) is set in accordance with the position of the specific region 50 in the respiration phase Ex5 and the respiration phase In1.
  • respiratory phase images 43 of the ten types (ten phases) of respiratory phase images 43 are set as the second template image 42.
  • the position detection unit 12 detects the specific region 50 at a predetermined respiratory phase by matching the X-ray image 30 generated by the image generation unit 11 with each of the first template image 41 and the second template image 42. Is configured.
  • the position detection unit 12 detects the matching result (score value) between the X-ray image 30 and the first template image 41 and the matching result (score value) between the X-ray image 30 and the second template image 42. And) respectively.
  • the position detection unit 12 detects the specific region 50 in a predetermined breathing phase by comparing the score values.
  • the position detection unit 12 detects an image portion in the detection window 30 a set in the X-ray image 30 generated by the image generation unit 11 and each template image (respiratory phase image 43 Calculate the score value with).
  • the score value represents the similarity between the image portion in the detection window 30a and the template image, and is defined by, for example, a sum of squares of differences in pixel values between corresponding pixels in each image.
  • the position detection unit 12 moves the detection window 30 a and sequentially calculates score values.
  • the movement range of the detection window 30 a is limited to a part of the X-ray image 30.
  • the movement range of the detection window 30a is set, for example, as a range obtained by adding a predetermined margin to an estimated range in which the specific portion 50 moves.
  • the position detection unit 12 outputs, for example, the position having the maximum value among the score values calculated within the movement range of the detection window 30a as the detection position of the specific part 50.
  • the score value for each template image is detected.
  • the score value of the first template image 41 is larger than the score value of the second template image 42 (the score maximum value of the first template image 41 is the largest among the score values of all template images).
  • the position at which the maximum score value of the first template image 41 is calculated is output as the detection position of the specific region 50 in the predetermined breathing phase.
  • the position detection unit 12 is configured to detect the specific part 50 by performing matching with the X-ray image 30 using each of the N types of respiratory phase images 43. . Therefore, in the case of FIG. 7, the position detection unit 12 calculates ten types of score values by matching with the ten types of respiratory phase images 43 for the image portion of the detection window 30a. As a result, when the search of the detection window 30a is completed, the maximum score values Sm (In1) to Sm (In5) and Sm (Ex1) to Sm are obtained for the respiratory phase images 43 of the respiratory phases In1 to In5 and Ex1 to Ex5, respectively. (Ex5) is obtained.
  • the position detection unit 12 adopts the largest value (maxSm) of the 10 types of maximum score values Sm, determines the respiration phase of the respiration phase image 43 as the respiration phase of the X-ray image 30, and The position of the detection window 30a at which the position .alpha.
  • the position detection unit 12 sets the position of the detection window 30a when the maximum score value Sm (Ex5) of the respiration phase image 43 of the respiration phase (Ex5) is calculated to the position of the specific portion 50 in the X-ray image 30. Determined as the detection position. Further, the position detection unit 12 determines the respiration phase (Ex5) for which the maximum score value Sm (Ex5) is calculated to be the respiration phase when the X-ray image 30 (specific part 50) is acquired.
  • the position detection unit 12 not only detects the predetermined respiration phase (Ex 5 or In 1) or the predetermined respiration phase for the X-ray image 30 acquired this time, but also determines which respiration It is configured to detect an X-ray image 30 (in which state is In1 to In5, or Ex1 to Ex5 state X-ray image) in the phase.
  • the detection position of the specific part 50 is output to the control unit 4 (see FIG. 1).
  • the position detection unit 12 performs a matching process on each of the X-ray images 30 generated at a predetermined frame rate during radiation treatment.
  • the control unit 4 superimposes the identification display representing the detection position of the specific part 50 on the acquired X-ray image 30 and displays the superimposed indication on the display unit 6.
  • the identification display is, for example, a line indicating the outline of the specific portion 50 as shown in FIG. Every time the control unit 4 acquires a new X-ray image 30 and a new detection position from the image processing unit 5, the display unit 6 is updated and displayed, and the X-ray image 30 and detection position are displayed in real time moving image format.
  • processing operation of the radiation imaging apparatus 100 is basically performed by the cooperation of the image processing unit 5 (the image generation unit 11 and the position detection unit 12) and the control unit 4.
  • steps S1 and S2 for creating a template image (respiratory phase image 43) for each respiratory phase, tracking processing of a specific region 50 during treatment, and trigger signal output It shows the processing (steps S3 ⁇ S8).
  • step S1 the image processing unit 5 acquires an X-ray image 30. That is, the X-ray image 30 is imaged in advance as preparation before treatment. A plurality of X-ray images 30 are captured over a predetermined period of one or more cycles so that an image of the specific region 50 for each respiratory phase of the subject T can be obtained.
  • step S2 a region including the specific region 50 is cut out of the X-ray image 30, whereby a respiratory phase image 43 is obtained. That is, the plurality of X-ray images 30 acquired in step S1 are classified into ten types for each respiratory phase and trimmed, whereby ten types of respiratory phase images 43 having different respiratory phases are created.
  • the respiratory phase image 43 may be created by the image processing unit 5 being cut out, or the respiratory phase image 43 created separately may be read out from a network or recording medium (not shown).
  • the created 10-phase respiratory phase image 43 is stored in the storage unit 5b.
  • predetermined respiration phases (Ex5 and In1) are the first template image 41
  • phases (In2 to In5, Ex1 to Ex4) other than the predetermined respiration phases are the second template image 42.
  • step S3 the image processing unit 5 acquires the X-ray image 30. That is, the irradiation unit 1 irradiates the subject T with radiation, and the X-ray detection unit 2 detects the radiation transmitted through the subject T, and based on the detection signal from the X-ray detection unit 2, the image generation unit 11 Generates an X-ray image 30.
  • the X-ray image 30 is output to the position detection unit 12 and the control unit 4.
  • step S4 the image processing unit 5 performs a matching process. That is, the position detection unit 12 performs matching using each template image (respiratory phase image 43) and the X-ray image 30 generated by the image generation unit 11. The position detection unit 12 moves the detection window 30 a to calculate each score value of the respiration phase image 43 at each position in the X-ray image 30. Then, the position detection unit 12 detects the position of the detection window 30 a at which the maximum score value (maxSm) is calculated among the 10 types of respiratory phase images 43 as the position of the specific part 50. Further, the respiration phase of the respiration phase image 43 showing the largest score value (maxSm) is determined as the respiration phase of the X-ray image 30. Since two pairs of the irradiation unit 1 and the X-ray detection unit 2 are provided, the detection of the specific portion 50 is performed for each X-ray image 30.
  • step S5 the image processing unit 5 outputs the respiratory phase detected in each X-ray image 30 and the detection position of the specific region 50 to the control unit 4.
  • the control unit 4 acquires the three-dimensional position of the specific part 50 based on the detection position of the specific part 50 in each X-ray image 30.
  • the control unit 4 superimposes an identification display indicating the detection position of the specific part 50 on the X-ray image 30 acquired this time, and displays (update display) on the display unit 6.
  • step S6 the control unit 4 determines whether it is the irradiation timing of the treatment beam by the radiation treatment apparatus 110 or not. That is, the control unit 4 determines whether the three-dimensional position of the specific part 50 acquired this time is included in the beam irradiation range 32 set in advance by the treatment plan. Further, the control unit 4 determines whether the currently detected respiratory phase corresponds to a predetermined respiratory phase (Ex5 or In1).
  • the control unit 4 When the specific region 50 of the predetermined respiratory phase is detected and the detection position of the specific region 50 is within the predetermined beam irradiation range 32, the control unit 4 outputs a trigger signal to the radiation treatment apparatus 110 in step S7. Do. When the specific part 50 is deviated from the beam irradiation range 32, or when it is not the predetermined breathing phase (Ex5 or In1), the control unit 4 advances the process to step S8 without outputting the trigger signal.
  • step S8 the control unit 4 determines whether to end the radiation treatment.
  • tracking of the specific region 50 is performed by repeatedly executing each process of steps S3 to S8.
  • control over detection processing and radiation treatment ends.
  • the position detection unit 12 detects the detection position of the specific portion 50 and the respiration phase with the passage of time.
  • FIG. 9 shows time variation on the horizontal axis and the detection position of the specific region 50 on the vertical axis, and shows the positional variation of the specific region 50 with the passage of time (respiration).
  • suction phase the detection position moves toward the lower side of FIG. 9
  • expiration phase the detection position moves toward the upper side of FIG.
  • a band-like region hatched in FIG. 9 is a beam irradiation range 32.
  • the radiation treatment is generally divided into a plurality of times every predetermined period (such as one week). For example, in the first radiation therapy, even when the detection position changes as shown by the solid line in FIG. 9, in the Kth (the 12th etc.) radiation therapy, the first time as shown by the alternate long and short dash line in FIG.
  • the specific site 50 is detected at a position different from When beam irradiation is performed based on only the detection position of the specific part 50 without considering the respiratory phase, in the first radiation therapy, beam irradiation is performed from the end of the expiratory phase to the initial inspiratory phase (Ex3 to In3) On the other hand, in the Kth treatment (the alternate long and short dash line portion), the treatment is performed from the end of the inspiratory phase to the initial expiratory phase (In4 to Ex2).
  • the respiratory phase at the time of beam irradiation is different, the dose distribution of the radiation at the specific region 50 changes due to the difference in the range of the radiation beam, etc. Therefore, the beam irradiation is based only on the detection position of the specific region 50 If you do, you may not get the dose distribution as planned.
  • the respiratory phase is predetermined. Beam irradiation is not performed because it differs from the respiratory phase (Ex5 or In1) of Therefore, in radiotherapy, appropriate alignment will be performed so that radiotherapy may be performed in the same situation as the first radiotherapy. If alignment is performed by a doctor or the like, radiation treatment can be performed with the dose distribution according to the treatment plan.
  • the position detection unit 12 is configured to detect 50. Thereby, if the image of the specific region 50 in the predetermined respiratory phase (Ex5 and In1) is obtained in advance, the specific region 50 in the predetermined respiratory phase is directly detected from the X-ray image 30 based on the image. be able to. Therefore, as compared with the case of detecting the respiratory phase from the movement of the body surface, the specific region 50 in the predetermined respiratory phase can be detected accurately.
  • the respiration phase can be grasped from the X-ray image 30, it is not necessary to separately provide a sensor for detecting the respiration phase outside the subject. As a result, it is possible to accurately detect the specific region 50 in a predetermined breathing phase without complicating the device configuration.
  • the 50 second template images 42 are stored in the storage unit 5b.
  • the position detection unit 12 matches the X-ray image 30 generated by the image generation unit 11 with each of the first template image 41 and the second template image 42 to obtain a predetermined respiratory phase (Ex5 or In1). It is configured to detect the specific site 50.
  • the score value in the first template image 41 is higher than the score value in the second template image 42, it is possible to detect the specific region 50 of the predetermined breathing phase (Ex5 or In1).
  • the first template image 41 and the second template image 42 are at least at least part of the background portion 31 that is superimposed on the shape, size or specific portion 50 of the specific portion 50 in the image.
  • One is an image that is different.
  • the first template image 41 and the second template image 42 are different due to the difference in the respiration phase, it is necessary to compare the matching result with the first template image 41 and the second template image 42. Whether it is an image of the specific part 50 of the respiratory phase (Ex5 or In1) can be identified with high accuracy.
  • the N types of respiratory phase images 43 which are images are stored.
  • the first template image 41 is a respiratory phase image 43 in one or a plurality of respiratory phases (Ex5 or In1) selected from N divided respiratory phases, and the second template image 42 is other than the first template image 41.
  • the respiratory phase image 43 in the respiratory phase of The position detection unit 12 is configured to detect the specific region 50 by performing matching with the X-ray image 30 using each of the N types of respiratory phase images 43.
  • a template image (respiratory phase image 43) can be prepared separately for each respiratory phase that divides one cycle of respiration.
  • each respiratory phase image 43 more accurately reflects the state of the specific region 50 in each respiratory phase, as compared with the case of creating a template image from images of the specific region 50 in various respiratory phases, the respiratory phase The matching accuracy of each specific portion 50 can be improved. As a result, it is possible to improve the detection accuracy of the specific region 50 in each breathing phase including the predetermined breathing phase (Ex5 and In1).
  • the control unit 4 causes the position detection unit 12 to detect the specific part 50 of the predetermined respiratory phase (Ex5 or In1), and the detection position of the specific part 50 is predetermined.
  • the trigger signal for irradiating the treatment beam is configured to be output to the radiation treatment apparatus 110 only when it is within the beam irradiation range 32.
  • the treatment beam irradiation can be performed only at a predetermined respiratory phase (Ex5 or In1) under the condition that the specific region 50 exists in the beam irradiation range 32, and therefore, the irradiation dose distribution along the treatment plan. Treatment is possible.
  • the position detection unit 12 detects the specific part 50 for each frame in the X-ray image 30 in the form of a moving image
  • the present invention is not limited thereto.
  • a specific part may be detected once in a plurality of frames instead of each frame.
  • the present invention is applied to an X-ray imaging apparatus that captures an X-ray image 30 using X-rays as an example of a radiation imaging apparatus, but the present invention is not limited to this. .
  • the present invention may be applied to an apparatus that performs imaging using radiation other than X-rays.
  • the respiration phase image 43 for each respiration phase may not be used. That is, it is only necessary to be able to detect at least whether it corresponds to the predetermined respiration phase (Ex5 or In1) or not to the predetermined respiration phase. For that purpose, it is only necessary to compare the first template image 41 consisting of the image of the specific part 50 of the predetermined respiratory phase with the second template image 42 consisting of the image of the specific part 50 other than the predetermined respiratory phase.
  • the respiratory phase image 43 of a predetermined respiratory phase (Ex5 or In1) is put together to create one average image, and is used as the first template image 41, and the remaining eight phases (In2 to In5, Ex1 to Ex4) of the respective breaths
  • the phase image 43 may be collected to create one average image as the second template image 42.
  • the example which set N to 10 as an example which divided N cycles into one cycle of respiration was shown in the said embodiment, this invention is not limited to this.
  • the number N of breathing phases may be other than ten. Different numbers of respiratory phases may be set for the expiratory phase and the inspiratory phase. In that case, the breathing phase does not have to be set by equally dividing one cycle.
  • the respiration phases In2 to In5 and Ex1 to Ex4 assigned to the second template image 42 only two or three respiration phases may be set instead of eight respiration phases.
  • the respiratory phases in the vicinity of the irradiation timing (Ex4, Ex5, In1, In2) may be further subdivided to set five or more respiratory phases.
  • the position detection unit 12 detects the specific portion 50 by template matching using template images (the first template image 41, the second template image 42, and the respiratory phase image 43).
  • the position detection unit 12 may distinguish between the specific region 50 of a predetermined respiratory phase and the specific region 50 other than the predetermined respiratory phase using a machine learning classifier.
  • a machine learning classifier For example, in FIG. 7, instead of the template consisting of the respiratory phase images 43, classifiers are created by machine learning using the respiratory phase images 43 as teacher images, and the position detection unit 12 uses the classifiers. The image recognition of the image of the detection window 30a is performed.
  • the score value of whether or not it is the specific region 50 corresponding to the respiratory phase image 43 can be acquired for each classifier. Therefore, the detection position by the discriminator showing the largest score value in the X-ray image 30 is adopted, and the respiration phase of the respiration phase image 43 learned by the discriminator is determined by the respiration of the X-ray image 30 (specific part 50). It can be determined to be the phase.
  • the classifier may be configured by any method such as SVM (support vector machine), neural network, AdaBoost using Haar-Like feature value, and the like.
  • the storage unit 5 b stores data of each learned classifier as learning result data of machine learning.
  • the processing of the image processing unit has been described using a flow-driven flow in which processing is sequentially performed along the processing flow, but the present invention is not limited to this.
  • the processing of the image processing unit may be performed by event-driven (event-driven) processing that executes processing in units of events.
  • the operation may be completely event driven, or the combination of event driving and flow driving may be performed.
  • irradiation unit 2 X-ray detector (radiation detector) 4 control unit 5b storage unit 11 image generation unit 12 position detection unit 30 X-ray image (radiographic image) 32 beam irradiation range 41 first template image 42 second template image 43 respiratory phase image 50 specific region 100 radiography apparatus 110 radiotherapy apparatus In1 to In5, Ex1 to Ex5 respiratory phase T subject

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Abstract

Ce dispositif radiographique (100) selon l'invention comporte : une unité d'émission (1) pour émettre un rayonnement ; une unité de détection de rayonnement (2) ; une unité de génération d'image (11), et une unité de détection de position (12). L'unité de détection de position est configurée pour détecter une partie spécifique (50) d'une phase respiratoire prédéterminée à partir d'une image radiographique (30) au moyen d'une reconnaissance d'image.
PCT/JP2018/008635 2017-07-06 2018-03-06 Dispositif radiographique et procédé de détection d'image radiographique WO2019008826A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120278055A1 (en) * 2009-11-18 2012-11-01 Koninklijke Philips Electronics N.V. Motion correction in radiation therapy
JP2012210232A (ja) * 2009-08-19 2012-11-01 Mitsubishi Electric Corp 放射線治療システム
WO2015125600A1 (fr) * 2014-02-24 2015-08-27 独立行政法人放射線医学総合研究所 Dispositif de suivi de corps mobile pour la radiothérapie, dispositif de détermination de région d'irradiation pour radiothérapie, et dispositif de radiothérapie

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012210232A (ja) * 2009-08-19 2012-11-01 Mitsubishi Electric Corp 放射線治療システム
US20120278055A1 (en) * 2009-11-18 2012-11-01 Koninklijke Philips Electronics N.V. Motion correction in radiation therapy
WO2015125600A1 (fr) * 2014-02-24 2015-08-27 独立行政法人放射線医学総合研究所 Dispositif de suivi de corps mobile pour la radiothérapie, dispositif de détermination de région d'irradiation pour radiothérapie, et dispositif de radiothérapie

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