WO2021003925A1 - 一种放射治疗cbct的成像方法及系统 - Google Patents

一种放射治疗cbct的成像方法及系统 Download PDF

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Publication number
WO2021003925A1
WO2021003925A1 PCT/CN2019/117305 CN2019117305W WO2021003925A1 WO 2021003925 A1 WO2021003925 A1 WO 2021003925A1 CN 2019117305 W CN2019117305 W CN 2019117305W WO 2021003925 A1 WO2021003925 A1 WO 2021003925A1
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level
kilovolt
imaging subsystem
megavolt
image data
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PCT/CN2019/117305
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English (en)
French (fr)
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文虎儿
费旋珈
姚毅
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苏州雷泰智能科技有限公司
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computerised tomographs
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/40—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4064—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis specially adapted for producing a particular type of beam
    • A61B6/4085—Cone-beams
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4417—Constructional features of apparatus for radiation diagnosis related to combined acquisition of different diagnostic modalities
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/48—Diagnostic techniques
    • A61B6/482—Diagnostic techniques involving multiple energy imaging
    • 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
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam

Definitions

  • the present invention relates to the field of medical technology, in particular to an imaging method and system for radiotherapy CBCT.
  • CBCT Computed Tomography
  • CT Computed Tomography
  • the existing technology can be divided into kilovolt-level cone-beam electronic tomography (KiloVolt-CBCT, KVCBCT) and mega-volt-level cone-beam electronic tomography (MegaVolt- CBCT and MVCBCT), in which KVCBCT highlights soft tissue information, and MVCBCT highlights bone structure information.
  • KVCBCT kilovolt-level cone-beam electronic tomography
  • MegaVolt- CBCT and MVCBCT mega-volt-level cone-beam electronic tomography
  • KVCBCT highlights soft tissue information
  • MVCBCT highlights bone structure information.
  • Varian Company of the United States and Elekta of Sweden adopt KVCBCT technology
  • Siemens of Germany adopts MVCBCT.
  • the X-ray beam source of MVCBCT directly adopts the treatment source of the linear accelerator, and the plane of the image acquisition board is perpendicular to the X-ray beam axis; the realization of KVCBCT technology requires an additional board on the traditional megavolt linear accelerator system.
  • On-Board Imager the system consists of a kilovolt X-ray source and a kilovolt image detector installed on two independent robotic arms. The two robotic arms and the linear accelerator's ray beam The central axis is perpendicular.
  • the maximum rotation speed of the large linear accelerator frame cannot exceed one minute per revolution.
  • the IEC regulations directly limit the shortest image acquisition time of KVCBCT and MVCBCT.
  • the CBCT half-scan Half-scan (Half-scan) that requires the image acquisition angle range not less than 180°
  • the Scan mode requires at least 30 seconds to capture images
  • the CBCT full-scan (Full-Scan) mode which requires the image capture angle range not less than 360°, requires at least one minute to capture images.
  • the image acquisition time of the existing CBCT technology is limited by the rotation speed of the large gantry of the linear accelerator and is difficult to reduce, which affects the treatment time of patients and the efficiency of medical treatment.
  • the existing CBCT system can only implement KVCBCT or MVCBCT, and the final three-dimensional volume image cannot simultaneously highlight the soft tissue and bone structure, which affects the user's subjective analysis and evaluation.
  • the purpose of the present invention is to provide a CBCT imaging method and system for radiotherapy in order to solve the problem of difficulty in reducing the image acquisition time in radiotherapy and/or that conventional three-dimensional volume imaging cannot simultaneously highlight soft tissue and bone.
  • the present invention provides an imaging method for radiotherapy CBCT, which is applied to a radiotherapy device having both a megavolt-level imaging subsystem and a kilovolt-level imaging subsystem, wherein the megavolt-level imaging subsystem is set in On the large frame of the radiotherapy equipment, the kilovolt imaging subsystem is set on the independent slip ring of the radiotherapy equipment; the rotation center of the independent slip ring is the same as the rotation center of the large frame, and the megavolt imaging subsystem is the same as the kilovolt
  • the first-level imaging subsystem can perform relatively independent rotation;
  • the method includes the following steps:
  • the kilovolt-level imaging subsystem and the megavolt-level imaging subsystem are used to separately collect the kilovolt-level two-dimensional images and the megavolt-level two-dimensional images in the scanning coverage area.
  • the megavolt-level imaging subsystem scans the 90° area. The scanning coverage of the kilovolt imaging subsystem and the scanning coverage area of the megavolt imaging subsystem do not overlap another 90° area;
  • the association relationship is a predetermined conversion relationship between kilovolt-level two-dimensional image data and megavolt-level two-dimensional image data;
  • the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem can perform relatively independent rotations through one of the following:
  • the independent slip ring can rotate relative to the large gantry, thereby driving the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment, so as to realize the relatively independent rotation of the megavolt imaging subsystem and the kilovolt imaging subsystem ;
  • the independent slip ring is fixed relative to the large frame, and the kilovolt imaging subsystem can slide reciprocally along the independent slip ring to rotate around the isocenter of the radiotherapy equipment to realize the megavolt imaging subsystem and kilovolt imaging
  • the subsystem rotates relatively independently;
  • the independent slip ring can rotate relative to the large gantry to drive the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment.
  • the kilovolt imaging subsystem can slide back and forth along the independent slip ring to move around the radiotherapy equipment. Isocentric rotation to achieve relatively independent rotation of the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem.
  • step a specifically includes:
  • the central controller of the radiotherapy equipment controls the start of the large gantry, and rotates 90° at a predetermined speed of 1 minute per revolution.
  • the central controller controls the independent slip ring to drive the kilovolt imaging subsystem to start simultaneously with the large gantry. It rotates in the same direction, and the speed of the independent slip ring is faster than that of the large frame.
  • the megavolt imaging subsystem synchronously scans the 90° area it passes, and the independent slip ring also stops. Rotate, and the kilovolt imaging subsystem has just scanned another 90° area that the megavolt imaging subsystem has not scanned.
  • step b the method further includes:
  • the preset reconstruction algorithm is an FDK reconstruction algorithm.
  • the two subsystems in the imaging method provided by the present invention can perform relatively independent rotations, thereby obtaining kilovolt-level images and megavolt-level images in different scanning coverage areas.
  • the relationship between the megavolt level image is converted into a kilovolt level image, and then the CBCT three-dimensional volume image reconstruction is performed using the kilovolt level image obtained by scanning and the kilovolt level image obtained by the conversion.
  • the finally obtained CBCT three-dimensional volume image can simultaneously highlight the soft tissue and bone tissue information, and because each subsystem only needs to scan a small coverage area (For example, 90° area), compared with the prior art, the image acquisition time is shortened, the time of the plan confirmation stage is reduced, the waiting time for the patient is reduced, and the treatment efficiency of the medical staff is improved.
  • a small coverage area For example, 90° area
  • the present invention provides a radiotherapy CBCT imaging system, which includes a radiotherapy equipment having both a megavolt imaging subsystem and a kilovolt imaging subsystem, and a deep learning subsystem, wherein the megavolt imaging The subsystem is set on the large frame of the radiotherapy equipment, and the kV-level imaging subsystem is set on the independent slip ring of the radiotherapy equipment; the rotation center of the independent slip ring is the same as the rotation center of the large frame, and the megavolt image sub-system
  • the system and the kilovolt imaging subsystem can rotate relatively independently, and the deep learning subsystem is used to correlate the megavolt imaging data obtained by the megavolt imaging subsystem with the kilovolt imaging data obtained by the kilovolt imaging subsystem To obtain the correlation between the kilovolt-level image data and the mega-volt-level image data.
  • the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem can perform relatively independent rotations through one of the following:
  • the independent slip ring can rotate relative to the large gantry, thereby driving the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment, so as to realize the relatively independent rotation of the megavolt imaging subsystem and the kilovolt imaging subsystem ;
  • the independent slip ring is fixed relative to the large frame, and the kilovolt imaging subsystem can slide reciprocally along the independent slip ring to rotate around the isocenter of the radiotherapy equipment to realize the megavolt imaging subsystem and kilovolt imaging
  • the subsystem rotates relatively independently;
  • the independent slip ring can rotate relative to the large gantry to drive the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment.
  • the kilovolt imaging subsystem can slide back and forth along the independent slip ring to move around the radiotherapy equipment. Isocentric rotation to achieve relatively independent rotation of the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem.
  • the central controller of the radiotherapy equipment controls the rotation speeds of the independent slip ring and the large gantry respectively, and the large gantry drives the megavolt imaging subsystem to rotate 90° and scan Cover the 90° area, obtain the megavolt image data in the 90° area, and convert the megavolt image data into the kilovolt image data through the correlation obtained by the deep learning subsystem; independent slip ring drives the kilovolt image sub
  • the system rotates 90° independently with respect to the large rack, and scans another 90° area that does not overlap the scan coverage area of the megavolt imaging subsystem, so as to obtain a total of kV image data in a 180° non-repetitive area, and use it
  • the preset reconstruction algorithm completes CBCT three-dimensional volume reconstruction.
  • the deep learning subsystem includes a data acquisition module and a data pairing learning module.
  • the data acquisition module is used to acquire kilovolt-level image data and megavolt-level image data
  • the data pairing learning module is used to image images based on the same target at the same angle.
  • the kilovolt-level image data and the megavolt-level image data are paired and learned to obtain the association relationship between the kilovolt-level image data and the megavolt-level image data.
  • the preset reconstruction algorithm is an FDK reconstruction algorithm.
  • the imaging system provided by the present invention is provided with a kilovolt-level imaging subsystem and a mega-volt-level imaging subsystem on an independent slip ring and a large frame respectively, thereby enabling simultaneous acquisition of kilovolt-level image data and mega-volt-level image data.
  • the deep learning subsystem can obtain the correlation between the kilovolt-level image data and the megavolt-level image data.
  • the megavolt imaging subsystem and the kilovolt imaging subsystem in this system can rotate relatively independently, so that image data with different scanning coverage areas can be obtained, thereby reducing the scanning range of each subsystem and reducing The imaging time in radiotherapy is determined.
  • Fig. 1 shows a schematic flow chart of an imaging method for radiotherapy CBCT provided by an embodiment of the present invention
  • FIG. 2 shows a schematic diagram of the conversion between megavolt-level images and kilovolt-level images provided by an embodiment of the present invention
  • Fig. 3 shows a schematic structural diagram of a radiotherapy equipment provided by an embodiment of the present invention.
  • the present invention provides a radiotherapy CBCT imaging method and system, which is expected to improve or even solve this problem in the radiotherapy process and improve the treatment efficiency.
  • Fig. 1 shows a schematic flow chart of a radiotherapy CBCT imaging method provided by an embodiment of the present invention.
  • the method can be applied to radiotherapy equipment that has both a megavolt-level imaging subsystem and a kilovolt-level imaging subsystem.
  • the megavolt-level imaging subsystem is set on the large rack of the radiotherapy equipment, and the kilovolt-level imaging subsystem is set up On the independent slip ring of the radiotherapy equipment; the rotation center of the independent slip ring is the same as the rotation center of the large frame, and the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem can rotate relatively independently;
  • the method includes the following steps: a. Simultaneously use the kilovolt imaging subsystem and the megavolt imaging subsystem to separately collect the kilovolt two-dimensional images and the megavolt two-dimensional images in the scanning coverage area, and the megavolt imaging sub-systems The system scans a 90° area, and the kilovolt imaging subsystem scans and covers another 90° area that does not overlap with the megavolt imaging subsystem’s scan coverage area; b.
  • the correlation between the images is to convert the megavolt-level two-dimensional image in the 90° area into a kilovolt-level two-dimensional image, so as to obtain a total of kilovolt-level two-dimensional images with a collection angle coverage of 180°.
  • the correlation is The pre-determined conversion relationship between kilovolt-level two-dimensional image data and megavolt-level two-dimensional image data; c.
  • the preset reconstruction algorithm is used CBCT three-dimensional volume imaging.
  • the two subsystems in the imaging method provided by the embodiment of the present invention can perform relatively independent rotations, so that kilovolt-level images and megavolt-level images in different scanning coverage areas can be obtained.
  • the correlation relationship between the megavolt-level images is converted into a kilovolt-level image, and then the CBCT three-dimensional volume image reconstruction is performed using the kilovolt-level image obtained by scanning and the kilovolt-level image obtained by the conversion. Since the kilovolt level image and the megavolt level image can be acquired at the same time and used for the reconstruction of the CBCT three-dimensional volume image, the finally obtained CBCT three-dimensional volume image can simultaneously highlight the soft tissue and bone tissue information.
  • the traditional CBCT reconstruction algorithm requires the large gantry to rotate one circle (360°), and it takes at least one minute to obtain the three-dimensional volume image, while this method only needs to rotate the large gantry 90° to reconstruct the three-dimensional image, which only takes 15 seconds.
  • it greatly shortens the image acquisition time, reduces the time in the plan confirmation phase, reduces the patient's waiting time for treatment, and improves the treatment efficiency of medical staff.
  • the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem can rotate relatively independently through one of the following: 1) The independent slip ring can rotate relative to the large frame, thereby driving The kilovolt imaging subsystem rotates around the isocenter of the radiotherapy equipment to achieve relatively independent rotation between the megavolt imaging subsystem and the kilovolt imaging subsystem; 2) the independent slip ring is fixed relative to the large frame, The kilovolt imaging subsystem can slide back and forth along the independent slip ring to rotate around the isocenter of the radiotherapy equipment, so as to realize relatively independent rotation of the megavolt imaging subsystem and the kilovolt imaging subsystem; 3) the independent slip ring can Relative to the large gantry, it drives the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment. At the same time, the kilovolt imaging subsystem can slide back and forth along the independent slip ring to rotate around the isocenter of the radiotherapy equipment to achieve The megavolt
  • step a specifically includes: the central controller of the radiotherapy equipment controls the large gantry Start, and rotate 90° according to the predetermined speed of 1 minute per revolution.
  • the central controller controls the independent slip ring to drive the kV imaging subsystem and the large frame to start and rotate in the same direction at the same time, and the independent slip ring rotates fast
  • the mega-volt imaging subsystem will synchronously scan the 90° area it has passed through, the independent slip ring also stops rotating, and the kilovolt imaging subsystem just scans the mega-volt The other 90° area not scanned by the V-level imaging subsystem.
  • the preset reconstruction algorithm is an FDK reconstruction algorithm.
  • the method further includes: acquiring a plurality of kilovolt-level two-dimensional image data at different angles; acquiring megavolt-level two-dimensional images shot at an angle one-to-one corresponding to the kilovolt-level two-dimensional image data Data; One-to-one correspondence between the kilovolt-level two-dimensional image data and the megavolt-level two-dimensional image data at the same angle, and obtain the correlation between the kilovolt-level two-dimensional image data and the megavolt-level two-dimensional image data according to the deep learning algorithm relationship.
  • the correlation between the kilovolt-level two-dimensional image data and the megavolt-level two-dimensional image data may be a correlation function between the kilovolt-level two-dimensional image data and the megavolt-level two-dimensional image data.
  • the embodiment of the present invention also provides a radiotherapy CBCT imaging system, which includes a radiotherapy equipment having both a megavolt-level imaging subsystem and a kilovolt-level imaging subsystem, and a deep learning subsystem.
  • the system is installed on the large frame of the radiotherapy equipment, and the kilovolt imaging subsystem is installed on the independent slip ring of the radiotherapy equipment; the rotation center of the independent slip ring is the same as that of the large frame, and the megavolt imaging subsystem It can rotate relatively independently with the kilovolt imaging subsystem, and the deep learning subsystem is used to correlate the megavolt imaging data obtained by the megavolt imaging subsystem with the kilovolt imaging data obtained by the kilovolt imaging subsystem , To obtain the correlation between the kilovolt-level image data and the mega-volt-level image data.
  • the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem can rotate relatively independently through one of the following: 1) The independent slip ring can rotate relative to the large frame, Thereby driving the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment to achieve relatively independent rotation of the megavolt imaging subsystem and the kilovolt imaging subsystem; 2) the independent slip ring is not fixed relative to the large frame
  • the kV-level imaging subsystem can slide back and forth along the independent slip ring to rotate around the isocenter of the radiotherapy equipment to achieve relatively independent rotation between the mega-level imaging subsystem and the kV-level imaging subsystem; 3) Independent sliding
  • the ring can rotate relative to the large gantry to drive the kilovolt imaging subsystem to rotate around the isocenter of the radiotherapy equipment, while the kilovolt imaging subsystem can slide back and forth along the independent slip ring to rotate around the isocenter of the radiotherapy equipment.
  • the central controller of the radiotherapy equipment controls the rotation speeds of the independent slip ring and the large gantry respectively.
  • the large gantry drives the megavolt imaging subsystem to rotate 90°, and the scan covers a 90° area.
  • the rack rotates independently by 90°, and the scanning covers another 90° area that does not overlap the scanning coverage area of the megavolt imaging subsystem, so as to obtain a total of kV-level image data in the 180° non-repetitive area, and use the preset reconstruction algorithm (For example, FDK reconstruction algorithm) Complete CBCT three-dimensional volume reconstruction.
  • FDK reconstruction algorithm Complete CBCT three-dimensional volume reconstruction.
  • the imaging system provided by the embodiment of the present invention provides a kilovolt-level imaging subsystem and a megavolt-level imaging subsystem on an independent slip ring and a large frame respectively, thereby enabling simultaneous acquisition of kilovolt-level image data and mega-volt-level image data .
  • the deep learning subsystem can obtain the correlation between the kV-level image data and the mega-level image data.
  • the CBCT 3D volume image reconstructed based on this can be At the same time highlight the soft tissue and bone structure.
  • the megavolt-level imaging subsystem and the kilovolt-level imaging subsystem in this system can rotate relatively independently.
  • the large gantry only needs to rotate 90° to achieve CBCT reconstruction, which requires a full rotation (360° ) Can be reconstructed to save three-quarters of the acquisition time, thereby reducing the imaging time in radiotherapy.
  • the deep learning subsystem includes a data acquisition module and a data pairing learning module.
  • the data acquisition module is used to acquire kilovolt-level image data and megavolt-level image data
  • the data pairing learning module is used to image images based on the same target at the same angle.
  • the kilovolt-level image data and the megavolt-level image data are paired and learned to obtain the association relationship between the kilovolt-level image data and the megavolt-level image data.
  • the data acquisition module is a data interface device that performs data communication with a megavolt-level digital image panel and a kilovolt-level digital image panel, and is used to capture imaging data from the two and mark their imaging angles.
  • the data pairing learning module is used for pairing learning of imaging data of the same angle, and outputting the association relationship between the kilovolt-level imaging data and the megavolt-level imaging data.
  • the megavolt-level images acquired in use can be converted into kilovolt-level images through correlation.
  • Fig. 2 shows a schematic diagram for realizing conversion between megavolt-level images and kilovolt-level images provided by an embodiment of the present invention.
  • the correlation between the two-dimensional image of the kilovolt level and the two-dimensional image of the megavolt level can be obtained through the deep learning subsystem.
  • the details are as follows: obtain multiple kilovolt-level two-dimensional image data from different angles; One-to-one correspondence between two-dimensional image data of megavolt level two-dimensional image data shot at an angle; one-to-one correspondence between two-dimensional image data of kilovolt level and two-dimensional image data of megavolt level at the same angle, according to the deep learning algorithm, obtain the two-dimensional The relationship between the two-dimensional image data and the megavolt-level two-dimensional image data. Then, the association relationship obtained by the deep learning subsystem can be used to convert the megavolt image into a kilovolt image.
  • the embodiment of the present invention also provides a radiotherapy device, which can be used to implement the imaging method provided in the foregoing embodiment of the present invention, and the radiotherapy device can also be used as the foregoing implementation of the present invention.
  • the radiotherapy equipment includes a fixed frame 101, a large frame 102, an independent slip ring 103, a kilovolt (KV) level imaging subsystem and a megavolt (MV) level imaging subsystem.
  • KV kilovolt
  • MV megavolt
  • the large frame 102 is rotatably installed in a fixed On the frame 101, the megavolt-level imaging subsystem is fixedly arranged on the large frame 102, and the kilovolt-level imaging subsystem is fixedly arranged on the independent slip ring 103.
  • the megavolt imaging subsystem is used to collect megavolt two-dimensional images and includes megavolt X-rays A source 104 and a megavolt-level image detector 105.
  • the kilovolt-level imaging subsystem is used to collect a kilovolt-level two-dimensional image and includes a kilovolt-level X-ray source 106 and a kilovolt-level image detector 107.
  • the central controller of the radiotherapy equipment controls the rotation speeds of the independent slip ring 103 and the large gantry 102 respectively.
  • the large gantry 102 drives the MV-level imaging subsystem to rotate 90°, and the scanning coverage is In the 90° area
  • the independent slip ring 103 drives the KV-level imaging subsystem to independently rotate 90° relative to the large gantry 102, and scans an additional 90° area that does not overlap with the MV-level imaging subsystem's scanning coverage area.
  • the central controller of the radiotherapy equipment controls the start of the large gantry 102, and rotates it by 90° at a prescribed rotation speed of 1 minute per revolution, and controls the independent slip ring 103 to drive the KV-level imaging subsystem and the large gantry 102 to start and merge at the same time. It rotates in the same direction, but its speed is faster than that of the large frame 102.
  • the large frame 102 completes the 90° rotation and stops
  • the MV-level imaging subsystem synchronously scans the 90° area it passes, and the independent slip ring 103 also stops rotating.
  • the KV-level imaging subsystem has just scanned another 90° area that the MV-level imaging subsystem has not scanned. Therefore, it only takes the large rack 102 to rotate 90°.
  • the MV-level imaging subsystem and the KV-level imaging subsystem share the same Finished 180° area scanning, saving 50% of scanning time.
  • the independent slip ring 103 has an important role. It allows the MV-level imaging subsystem and the KV-level imaging subsystem to move relatively independently, which can greatly improve the CT image data and MV imaging data required for pair learning described below. Collection efficiency, and the efficiency of collaborative work between the two subsystems. For example, when the MV-level imaging subsystem completes a certain angle of irradiation (including treatment and MV imaging), it leaves this angle to work in other positions. At this time, the KV-level imaging subsystem can be moved to the This angle completes the KV imaging. Compared with the solution in the prior art where the relative positions of the KV-level ray device and the MV-level accelerator are fixed, the technical solution of the present invention has significant advantages.
  • the independent slip ring 103 can rotate relatively independently of the large frame 102, and the independent slip ring 103 can also rotate together with the large frame 102 as required.
  • a ring guide rail is fixedly installed on the large rack 102, the ring rail and the large rack 102 are co-circular, and two or more sliders are installed on the ring rail, and the sliders can freely rotate around the center of the circle along the ring rail.
  • the independent slip ring 103 is installed on the slider (in Figure 1, the independent slip ring 103 and the KV-level imaging subsystem are separated for ease of understanding), so that the independent slip ring 103 can be relative to the large machine along the circular guide rail.
  • the rotation axis of the independent slip ring 103 is the same as the rotation axis of the large frame 102.
  • a rack or gear is provided on the outer edge of the independent slip ring 103, and an independent slip ring drive motor 108 is also installed on the large frame 102.
  • the independent slip ring drive motor 108 and the rack or gear on the outer edge of the independent slip ring 103 pass through gears.
  • the group or timing belt is connected in transmission, so that the independent slip ring drive motor 108 can drive the independent slip ring 103 to rotate relative to the large frame 102.
  • the independent slip ring drive motor 108 and the rack or gear on the outer edge of the independent slip ring 103 are connected by a synchronous belt transmission
  • two rings of synchronous teeth are provided on the edge of the independent slip ring 103 ,
  • the two rings of synchronous teeth are separated by grooves or flanges.
  • the synchronous belt includes two synchronous belts.
  • the two synchronous belts are matched and connected to the two synchronous teeth respectively, and the two synchronous belts are connected to the On the two independent slip ring drive motors 108 on both sides of the large frame 102, one of them is used as a backup transmission device and rotates together.
  • the backup timing belt works immediately.
  • two independent slip ring drive motors 108 are arranged on both sides of the large frame 102 along the diameter of the large frame 102.
  • the radiotherapy equipment also includes a safety sensor and a video monitoring device.
  • the safety sensor and the video monitoring device are respectively used to sense and monitor the use of the radiotherapy equipment, and evaluate the risk of the radiotherapy process to decide whether to stop immediately or continue to complete Treatment plan.
  • the independent slip ring drive motor 108 is electrically connected to the encoder, and the encoder is used to control the independent slip ring drive motor 108 and thereby control the rotation angle of the independent slip ring 103.
  • a holding brake is arranged on the ring guide rail. When the synchronous belt fails, the holding brake is used to stop the rotation of the synchronous slip ring.
  • a plurality of light-emitting elements are uniformly arranged on the annular guide rail, and the independent slip ring 103 is provided with a detection element at the starting position of the imaging subsystem corresponding to the kilovolt level.
  • the detection element detects the light emitted by the light-emitting element to obtain the relevant kilovolt level.
  • the light-emitting elements are uniformly arranged according to the preset angle unit, and the wavelength of the light emitted by each light-emitting element is different.
  • the detection element obtains the rotation speed and angle of the imaging subsystem on the kilovolt level by detecting the wavelength information of the light emitted by the light-emitting element Information on at least one of position and rotation direction.

Abstract

一种放射治疗CBCT的成像方法及系统，涉及医疗技术领域。成像方法应用于同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备，两个子系统能够进行相对独立的旋转，从而可以获得不同扫描覆盖区域内的千伏级影像和兆伏级影像，通过根据千伏级影像与兆伏级影像之间的关联关系将兆伏级影像转换为千伏级影像，然后利用扫描获得的千伏级影像和转换获得的千伏级影像进行CBCT三维容积影像重建。通过同时采集千伏级影像和兆伏级影像并用于CBCT三维容积影像重建，使最终获得的三维影像同时突显软组织和骨组织信息，由于兆伏级与千伏级影像子系统分别仅扫描较小的覆盖区域，因此缩短了影像采集时间。

Description

一种放射治疗CBCT的成像方法及系统 技术领域
本发明涉及医疗技术领域，具体涉及一种放射治疗CBCT的成像方法及系统。
背景技术
为满足医护人员在放疗患者临床摆位验证方面的需求，可采用锥形束电子计算机断层扫描(Cone Beam Computed Tomography，CBCT)技术获取治疗室内患者的三维容积影像，然后与计划电子计算机断层扫描(Computed Tomography，CT)影像进行三维配准确定患者摆位偏差，从而医护人员可以根据该摆位偏差修正患者的摆位。
根据用于成像的X射线能级的不同，可将现有技术分为千伏级锥形束电子计算机断层扫描(KiloVolt-CBCT，KVCBCT)和兆伏级锥形束电子计算机断层扫描(MegaVolt-CBCT，MVCBCT)两种，其中KVCBCT突显软组织信息，而MVCBCT突显骨性结构信息。其中美国瓦里安公司和瑞典医科达公司采用KVCBCT技术，德国西门子公司则采用MVCBCT。在机械与电气方面，MVCBCT的X射线出束源直接采用直线加速器的治疗源，影像采集板平面垂直于X射线束轴线；KVCBCT技术的实现需要在传统兆伏级直线加速器系统上额外增加一个板载影像系统(On-BoardImager，OBI)，该系统由分别安装在两个独立机械臂上的千伏级X射线源和千伏级影像探测器组成，两个机械臂与直线加速器的射线束的中心轴相垂直。
根据国际电工委员会(International Electrotechnical Commission，IEC)的规定，直线加速器大机架的旋转速度最快不能超过每圈一分钟。由于现有CBCT的影像采集系统均固定在大机架上，导致IEC的规定直接限定了KVCBCT与MVCBCT的最短影像采集时间，例如要 求影像采集角度范围不低于180°的CBCT半扫描(Half-Scan)模式至少需要三十秒的时间用于采集影像，而要求影像采集角度范围不低于360°的CBCT全扫描(Full-Scan)模式至少需要一分钟的时间用于采集影像。
现有CBCT技术的影像采集时间受限于直线加速器大机架旋转速度而难以降低，影响患者治疗时间，影响医用的治疗效率。同时现有CBCT系统仅能单纯实现KVCBCT或者MVCBCT，最终获取的三维容积影像无法同时突显软组织和骨性结构，影响用户的主观分析评价。
发明内容
本发明的目的在于，针对上述现有技术中的不足，提供一种放射治疗CBCT的成像方法及系统，以解决放射治疗中影像采集时间难以降低和/或常规三维容积影像无法同时突显软组织和骨性结构的问题。
为实现上述目的，本发明采用的技术方案如下：
第一方面，本发明提供了一种放射治疗CBCT的成像方法，该方法应用于同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备，其中兆伏级影像子系统设置在放射治疗设备的大机架上，千伏级影像子系统设置在放射治疗设备的独立滑环上；独立滑环的旋转中心与大机架的旋转中心相同，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转；
所述方法包括以下步骤：
a、同时利用千伏级影像子系统和兆伏级影像子系统分别采集扫描覆盖区域内的千伏级二维影像和兆伏级二维影像，兆伏级影像子系统扫描覆盖90°区域，千伏级影像子系统扫描覆盖与兆伏级影像子系 统的扫描覆盖区域不交叠的另外90°区域；
b、根据千伏级二维影像与兆伏级二维影像之间的关联关系，将90°区域的兆伏级二维影像转换成千伏级二维影像，从而共获得采集角度覆盖范围为180°的千伏级二维影像，所述关联关系为预先确定的千伏级二维影像数据与兆伏级二维影像数据之间的转换关系；
c、基于所获得的角度覆盖范围为180°的千伏级二维影像，使用预设重建算法获取CBCT三维容积影像。
可选地，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：
1)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；
2)独立滑环相对于大机架固定不动，千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；
3)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，同时千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转。
可选地，在通过1)来实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转的情况下，a步骤具体包括：
放射治疗设备的中央控制器控制所述大机架启动，并按照预定的1分钟每圈的转速旋转90°，同时中央控制器控制独立滑环带动千伏级影像子系统与大机架同时启动并同向旋转，并且独立滑环的转速要快于大机架，当大机架完成90°旋转停止时，兆伏级影像子系统同步 扫描完其经过的90°区域，独立滑环也停止旋转，并且千伏级影像子系统刚好扫描完兆伏级影像子系统未曾扫描到的另外90°区域。
可选地，在b步骤之前，所述方法还包括：
获取多个不同角度的千伏级二维影像数据；
获取与千伏级二维影像数据一一对应角度拍摄的兆伏级二维影像数据；
将同一角度的千伏级二维影像数据和兆伏级二维影像数据一一对应，根据深度学习算法，获得千伏级二维影像数据与兆伏级二维影像数据之间的关联关系。
可选地，预设重建算法为FDK重建算法。
本发明提供的成像方法中的两个子系统能够进行相对独立的旋转，从而可以获得不同扫描覆盖区域内的千伏级影像和兆伏级影像，通过根据千伏级影像与兆伏级影像之间的关联关系将兆伏级影像转换为千伏级影像，然后利用扫描获得的千伏级影像和转换获得的千伏级影像进行CBCT三维容积影像重建。由于可以同时采集千伏级影像和兆伏级影像并用于CBCT三维容积影像的重建，使最终获得的CBCT三维容积影像同时突显软组织和骨组织信息，而且由于每个子系统仅需要扫描较小覆盖区域(例如，90°区域)，相比于现有技术缩短了影像采集时间，减少计划确认阶段时间，降低患者等待治疗时间，提高医护人员治疗效率。
第二方面，本发明提供了一种放射治疗CBCT的成像系统，该系统包括同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备以及深度学习子系统，其中兆伏级影像子系统设置在放射治疗设备的大机架上，千伏级影像子系统设置在放射治疗设备的独立滑环上；独立滑环的旋转中心与大机架的旋转中心相同，兆伏级影像子系 统与千伏级影像子系统能够进行相对独立的旋转，深度学习子系统用于将兆伏级影像子系统获得的兆伏级影像数据与千伏级影像子系统获得的千伏级影像数据相关联，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。
可选地，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：
1)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；
2)独立滑环相对于大机架固定不动，千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；
3)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，同时千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转。
可选地，在利用所述系统进行成像时，通过放射治疗设备的中央控制器对独立滑环和大机架的转速进行分别控制，大机架带动兆伏级影像子系统旋转90°，扫描覆盖90°区域，获取90°区域内的兆伏级影像数据，通过深度学习子系统所获得的关联关系将兆伏级影像数据转换成千伏级影像数据；独立滑环带动千伏级影像子系统相对于大机架独立旋转90°，扫描覆盖与兆伏级影像子系统扫描覆盖区域不交叠的另外90°区域，从而共获得180°不重复区域内的千伏级影像数据，并使用预设重建算法完成CBCT三维容积重建。
可选地，深度学习子系统包括数据采集模块和数据配对学习模 块，数据采集模块用于获取千伏级影像数据和兆伏级影像数据，数据配对学习模块用于对基于同一目标同一角度成像的千伏级影像数据和兆伏级影像数据进行配对学习，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。
可选地，预设重建算法为FDK重建算法。
本发明提供的成像系统通过分别在独立滑环和大机架上设置千伏级影像子系统和兆伏级影像子系统，从而使得能够同时获取千伏级影像数据和兆伏级影像数据，由深度学习子系统可以获得千伏级影像数据与兆伏级影像数据之间的关联关系，通过将兆伏级影像数据转换为千伏级影像数据，并基于此重建的CBCT三维容积影像能够同时突显软组织和骨性结构。另外，本系统中的兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转，从而可以获得扫描覆盖范围不同的影像数据，从而可以减小每一子系统的扫描范围，减少了放射治疗中的影像成像时间。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本发明的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1示出了本发明实施例提供的放射治疗CBCT的成像方法的流程示意图；
图2示出了本发明实施例提供的实现兆伏级影像与千伏级影像转换的原理图；
图3示出了本发明实施例提供的放射治疗设备的结构示意图。
附图标记：101-固定机架；102-大机架；103-独立滑环；104-兆伏级X射线源；105-兆伏级影像探测器；106-千伏级X射线源；107-千伏级影像探测器；108-独立滑环驱动电机。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
放疗用CBCT在重建图像时，受到加速器机架旋转速度的限制，重建时间基本要超过一分钟，延长了病人的治疗时间。为此，本发明提供了一种放射治疗CBCT的成像方法及系统，有望改善乃至解决放疗过程中的这一问题，提高治疗效率。
图1示出了本发明实施例提供的放射治疗CBCT的成像方法的流程示意图。该方法可以应用于同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备，其中兆伏级影像子系统设置在放射治疗设备的大机架上，千伏级影像子系统设置在放射治疗设备的独立滑环上；独立滑环的旋转中心与大机架的旋转中心相同，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转；
所述方法包括以下步骤：a、同时利用千伏级影像子系统和兆伏级影像子系统分别采集扫描覆盖区域内的千伏级二维影像和兆伏级二维影像，兆伏级影像子系统扫描覆盖90°区域，千伏级影像子系统扫描覆盖与兆伏级影像子系统的扫描覆盖区域不交叠的另外90°区 域；b、根据千伏级二维影像与兆伏级二维影像之间的关联关系，将90°区域的兆伏级二维影像转换成千伏级二维影像，从而共获得采集角度覆盖范围为180°的千伏级二维影像，所述关联关系为预先确定的千伏级二维影像数据与兆伏级二维影像数据之间的转换关系；c、基于所获得的角度覆盖范围为180°的千伏级二维影像，使用预设重建算法获取CBCT三维容积影像。
本发明实施例提供的成像方法中的两个子系统能够进行相对独立的旋转，从而可以获得不同扫描覆盖区域内的千伏级影像和兆伏级影像，通过根据千伏级影像与兆伏级影像之间的关联关系将兆伏级影像转换为千伏级影像，然后利用扫描获得的千伏级影像和转换获得的千伏级影像进行CBCT三维容积影像重建。由于可以同时采集千伏级影像和兆伏级影像并用于CBCT三维容积影像的重建，使最终获得的CBCT三维容积影像同时突显软组织和骨组织信息。传统CBCT重建算法需要大机架旋转一周(360°)，至少耗时一分钟才能获得三维容积影像，而本方法只需大机架旋转90°即可以重建三维影像，仅耗时15秒。与传统CBCT重建算法相比，大大缩短了影像采集时间，减少计划确认阶段时间，降低患者等待治疗时间，提高医护人员治疗效率。
在本发明实施例中，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：1)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；2)独立滑环相对于大机架固定不动，千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；3)独立滑 环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，同时千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转。
可选地，在通过1)来实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转的情况下，a步骤具体包括：放射治疗设备的中央控制器控制所述大机架启动，并按照预定的1分钟每圈的转速旋转90°，同时中央控制器控制独立滑环带动千伏级影像子系统与大机架同时启动并同向旋转，并且独立滑环的转速要快于大机架，当大机架完成90°旋转停止时，兆伏级影像子系统同步扫描完其经过的90°区域，独立滑环也停止旋转，并且千伏级影像子系统刚好扫描完兆伏级影像子系统未曾扫描到的另外90°区域。可选地，预设重建算法为FDK重建算法。
可选地，在b步骤之前，所述方法还包括：获取多个不同角度的千伏级二维影像数据；获取与千伏级二维影像数据一一对应角度拍摄的兆伏级二维影像数据；将同一角度的千伏级二维影像数据和兆伏级二维影像数据一一对应，根据深度学习算法，获得千伏级二维影像数据与兆伏级二维影像数据之间的关联关系。在本发明实施例中，千伏级二维影像数据与兆伏级二维影像数据之间的关联关系可以为千伏级二维影像数据与兆伏级二维影像数据之间的关联函数。
本发明实施例还提供了一种放射治疗CBCT的成像系统，该系统包括同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备以及深度学习子系统，其中兆伏级影像子系统设置在放射治疗设备的大机架上，千伏级影像子系统设置在放射治疗设备的独立滑环上；独立滑环的旋转中心与大机架的旋转中心相同，兆伏级影像子系统与 千伏级影像子系统能够进行相对独立的旋转，深度学习子系统用于将兆伏级影像子系统获得的兆伏级影像数据与千伏级影像子系统获得的千伏级影像数据相关联，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。
在本发明实施例的系统中，兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：1)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；2)独立滑环相对于大机架固定不动，千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转；3)独立滑环能够相对于大机架旋转，从而带动千伏级影像子系统绕放射治疗设备的等中心旋转，同时千伏级影像子系统能够沿独立滑环往复滑动以绕放射治疗设备的等中心旋转，以实现兆伏级影像子系统与千伏级影像子系统进行相对独立的旋转。
在利用所述系统进行成像时，通过放射治疗设备的中央控制器对独立滑环和大机架的转速进行分别控制，大机架带动兆伏级影像子系统旋转90°，扫描覆盖90°区域，获取90°区域内的兆伏级影像数据，通过深度学习子系统所获得的关联关系将兆伏级影像数据转换成千伏级影像数据；独立滑环带动千伏级影像子系统相对于大机架独立旋转90°，扫描覆盖与兆伏级影像子系统扫描覆盖区域不交叠的另外90°区域，从而共获得180°不重复区域内的千伏级影像数据，并使用预设重建算法(例如，FDK重建算法)完成CBCT三维容积重建。
本发明实施例提供的成像系统通过分别在独立滑环和大机架上设置千伏级影像子系统和兆伏级影像子系统，从而使得能够同时获取 千伏级影像数据和兆伏级影像数据，由深度学习子系统可以获得千伏级影像数据与兆伏级影像数据之间的关联关系，通过将兆伏级影像数据转换为千伏级影像数据，并基于此重建的CBCT三维容积影像能够同时突显软组织和骨性结构。另外，本系统中的兆伏级影像子系统与千伏级影像子系统能够进行相对独立的旋转，大机架仅需旋转90°就可以实现CBCT重建，相比常规技术需要旋转一周(360°)才能重建节约了四分之三的采集时间，从而减少了放射治疗中的影像成像时间。
可选地，深度学习子系统包括数据采集模块和数据配对学习模块，数据采集模块用于获取千伏级影像数据和兆伏级影像数据，数据配对学习模块用于对基于同一目标同一角度成像的千伏级影像数据和兆伏级影像数据进行配对学习，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。具体地，数据采集模块为与兆伏级数字图像平板、千伏级数字图像平板进行数据通讯的数据接口装置，用于将来自二者的成像数据抓取出来，并标记其成像角度。数据配对学习模块用于对相同角度的成像数据进行配对学习，并输出千伏级成像数据与兆伏级成像数据之间的关联关系。使用中获取的兆伏级影像可通过关联关系转换成千伏级影像。
图2示出了本发明实施例提供的实现兆伏级影像与千伏级影像转换的原理图。千伏级二维影像与兆伏级二维影像之间的关联关系可以通过深度学习子系统来获得，具体如下：获取多个不同角度的千伏级二维影像数据；获取与千伏级二维影像数据一一对应角度拍摄的兆伏级二维影像数据；将同一角度的千伏级二维影像数据和兆伏级二维影像数据一一对应，根据深度学习算法，获得千伏级二维影像数据与兆伏级二维影像数据之间的关联关系。然后，可以利用深度学习子系统 所获得的关联关系将兆伏级影像转换为千伏级影像。
如图3所示，本发明实施例还提供了一种放射治疗设备，该放射治疗设备可以用于实施本发明前述实施例所提供的成像方法，并且该放射治疗设备也可以作为本发明前述实施例所提供的成像系统中的放射治疗设备。该放射治疗设备包括固定机架101、大机架102、独立滑环103、千伏(KV)级影像子系统和兆伏(MV)级影像子系统，大机架102可旋转地安装在固定机架101上，兆伏级影像子系统固定设置在大机架102上，千伏级影像子系统固定设置在独立滑环103上，独立滑环103的旋转轴心与大机架102的旋转轴心相同，独立滑环103可跟随大机架102一起旋转或做与大机架102相对独立的旋转，兆伏级影像子系统用于采集兆伏级二维影像并且包括兆伏级X射线源104和兆伏级影像探测器105，千伏级影像子系统用于采集千伏级二维影像并且包括千伏级X射线源106和千伏级影像探测器107。
在利用上述放射治疗设备进行治疗时，通过放射治疗设备的中央控制器对独立滑环103和大机架102的转速进行分别控制，大机架102带动MV级影像子系统旋转90°，扫描覆盖90°区域，独立滑环103带动KV级影像子系统相对于大机架102独立旋转90°，扫描覆盖与MV级影像子系统扫描覆盖区域不交叠的另外90°区域。其中，放射治疗设备的中央控制器控制大机架102启动，并按照规定的1分钟每圈的转速旋转90°，同时控制独立滑环103带动KV级影像子系统与大机架102同时启动并同向旋转，但是其转速要快于大机架102，当大机架102完成90°旋转停止时，MV级影像子系统同步扫描完其经过的90°区域，独立滑环103也停止旋转，并且KV级影像子系统刚好扫描完MV级影像子系统未曾扫描到的另外90°区域，因此，仅用了大机架102旋转90°的时间，MV级影像子系统和KV级影像子系 统共同完成了180°的区域扫描，节约了50％的扫描时间。
设置的独立滑环103具有重要作用，它使得MV级影像子系统和KV级影像子系统可相对独立运动，从而可以大大提高下文中将描述的配对学习所需的CT图像数据及MV成像数据的采集效率，及两套子系统的协同工作效率。例如，当MV级影像子系统完成某一角度的照射(包括治疗及MV成像)后，离开这一角度去其他位置工作，此时，通过独立滑环103就可以将KV级影像子系统移动到该角度完成KV成像，与现有技术中KV级射线装置与MV级加速器相对位置固定不变的方案而言，本发明的技术方案具有显著优势。
应当理解，在本发明提供的放射治疗设备中，可以根据需要，独立滑环103能够与大机架102相对独立地旋转，独立滑环103也可以跟随大机架102一起旋转。
可选地，大机架102上还固定安装有环形导轨，环形导轨与大机架102共圆心，环形导轨上安装有两个或更多个滑块，滑块能够沿环形导轨绕圆心自由旋转，独立滑环103安装在滑块上(在图1中，为了便于理解，将独立滑环103及KV级影像子系统脱离出来)，从而使得独立滑环103能够沿环形导轨进行相对于大机架102的独立旋转，独立滑环103的旋转轴心与大机架102的旋转轴心相同。
独立滑环103的外沿上设置有齿条或齿轮，大机架102上还安装有独立滑环驱动电机108，独立滑环驱动电机108与独立滑环103外沿的齿条或齿轮通过齿轮组或同步带传动连接，从而使得独立滑环驱动电机108能够驱动独立滑环103相对于大机架102进行旋转。
在独立滑环驱动电机108与独立滑环103外沿的齿条或齿轮通过同步带传动连接的情况下，为了防止同步带失效带来的风险，独立滑环103边沿上设置有两圈同步齿，两圈同步齿相互之间设置有沟槽或 法兰隔离，同步带包括两条同步带，两条同步带分别匹配连接在两圈同步齿上，并且两条同步带分别连接于分别设置在大机架102两侧的两个独立滑环驱动电机108上，其中一组作为备用传动装置，跟随一起转动，当工作的同步带失效时，备用同步带立即工作。优选地，两个独立滑环驱动电机108沿大机架102的直径设置大机架102两侧。
可选地，该放射治疗设备还包括安全传感器和视频监控装置，安全传感器和视频监控装置分别用于感测和监控放射治疗设备的使用，对放疗过程进行评估风险，以决定立即停止还是继续完成治疗计划。独立滑环驱动电机108与编码器电连接，编码器用于控制独立滑环驱动电机108，进而控制独立滑环103的旋转角度。环形导轨上设置有抱闸，当同步带失效时，抱闸用于停止同步滑环的旋转。环形导轨上均匀设置有多个发光元件，独立滑环103上对应于千伏级影像子系统的起始位置处设置有检测元件，检测元件通过检测发光元件所发出的光来获得关于千伏级影像子系统的旋转速度、角度位置、旋转方向中的至少一者的信息。发光元件根据预设角度单位均匀设置，每个发光元件所发出的光的波长不相同，检测元件通过检测发光元件所发出的光的波长信息来获得关于千伏级影像子系统的旋转速度、角度位置、旋转方向中的至少一者的信息。
上述实施例只为说明本发明的技术构思及特点，其目的在于让本领域普通技术人员能够了解本发明的内容并加以实施，并不能以此限制本发明的保护范围，凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围内。

Claims (10)

  1. 一种放射治疗CBCT的成像方法，其特征在于，应用于同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备，其中所述兆伏级影像子系统设置在所述放射治疗设备的大机架上，所述千伏级影像子系统设置在所述放射治疗设备的独立滑环上；所述独立滑环的旋转中心与所述大机架的旋转中心相同，所述兆伏级影像子系统与所述千伏级影像子系统能够进行相对独立的旋转；
    所述方法包括以下步骤：
    a、同时利用所述千伏级影像子系统和所述兆伏级影像子系统分别采集扫描覆盖区域内的千伏级二维影像和兆伏级二维影像，所述兆伏级影像子系统扫描覆盖90°区域，所述千伏级影像子系统扫描覆盖与所述兆伏级影像子系统的扫描覆盖区域不交叠的另外90°区域；
    b、根据千伏级二维影像与兆伏级二维影像之间的关联关系，将90°区域的兆伏级二维影像转换成千伏级二维影像，从而共获得采集角度覆盖范围为180°的千伏级二维影像，所述关联关系为预先确定的千伏级二维影像数据与兆伏级二维影像数据之间的转换关系；
    c、基于所获得的角度覆盖范围为180°的千伏级二维影像，使用预设重建算法获取CBCT三维容积影像。
  2. 根据权利要求1所述的方法，其特征在于，所述兆伏级影像子系统与所述千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：
    1)所述独立滑环能够相对于所述大机架旋转，从而带动所述千伏级影像子系统绕所述放射治疗设备的等中心旋转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转；
    2)所述独立滑环相对于所述大机架固定不动，所述千伏级影像子系 统能够沿所述独立滑环往复滑动以绕所述放射治疗设备的等中心旋转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转；
    3)所述独立滑环能够相对于所述大机架旋转，从而带动所述千伏级影像子系统绕所述放射治疗设备的等中心旋转，同时所述千伏级影像子系统能够沿所述独立滑环往复滑动以绕所述放射治疗设备的等中心旋转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转。
  3. 根据权利要求2所述的方法，其特征在于，在通过1)来实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转的情况下，所述a步骤具体包括：
    所述放射治疗设备的中央控制器控制所述大机架启动，并按照预定的1分钟每圈的转速旋转90°，同时所述中央控制器控制所述独立滑环带动所述千伏级影像子系统与所述大机架同时启动并同向旋转，并且所述独立滑环的转速要快于所述大机架，当所述大机架完成90°旋转停止时，所述兆伏级影像子系统同步扫描完其经过的90°区域，所述独立滑环也停止旋转，并且所述千伏级影像子系统刚好扫描完所述兆伏级影像子系统未曾扫描到的另外90°区域。
  4. 根据权利要求1所述的方法，其特征在于，在所述b步骤之前，还包括：
    获取多个不同角度的千伏级二维影像数据；
    获取与千伏级二维影像数据一一对应角度拍摄的兆伏级二维影像数据；
    将同一角度的千伏级二维影像数据和兆伏级二维影像数据一一对应，根据深度学习算法，获得千伏级二维影像数据与兆伏级二维影像数 据之间的关联关系。
  5. 根据权利要求1所述的方法，其特征在于，所述预设重建算法为FDK重建算法。
  6. 一种放射治疗CBCT的成像系统，其特征在于，包括同时具备兆伏级影像子系统和千伏级影像子系统的放射治疗设备以及深度学习子系统，其中所述兆伏级影像子系统设置在所述放射治疗设备的大机架上，所述千伏级影像子系统设置在所述放射治疗设备的独立滑环上；所述独立滑环的旋转中心与所述大机架的旋转中心相同，所述兆伏级影像子系统与所述千伏级影像子系统能够进行相对独立的旋转，所述深度学习子系统用于将所述兆伏级影像子系统获得的兆伏级影像数据与所述千伏级影像子系统获得的千伏级影像数据相关联，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。
  7. 根据权利要求6所述的系统，其特征在于，所述兆伏级影像子系统与所述千伏级影像子系统能够进行相对独立的旋转通过如下中的一者来实现：
    1)所述独立滑环能够相对于所述大机架旋转，从而带动所述千伏级影像子系统绕所述放射治疗设备的等中心旋转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转；
    2)所述独立滑环相对于所述大机架固定不动，所述千伏级影像子系统能够沿所述独立滑环往复滑动以绕所述放射治疗设备的等中心旋转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转；
    3)所述独立滑环能够相对于所述大机架旋转，从而带动所述千伏级影像子系统绕所述放射治疗设备的等中心旋转，同时所述千伏级影像子系统能够沿所述独立滑环往复滑动以绕所述放射治疗设备的等中心旋 转，以实现所述兆伏级影像子系统与所述千伏级影像子系统进行相对独立的旋转。
  8. 根据权利要求6所述的系统，其特征在于，在利用所述系统进行成像时，通过所述放射治疗设备的中央控制器对所述独立滑环和所述大机架的转速进行分别控制，所述大机架带动所述兆伏级影像子系统旋转90°，扫描覆盖90°区域，获取90°区域内的兆伏级影像数据，通过所述深度学习子系统所获得的关联关系将兆伏级影像数据转换成千伏级影像数据；所述独立滑环带动所述千伏级影像子系统相对于所述大机架独立旋转90°，扫描覆盖与所述兆伏级影像子系统扫描覆盖区域不交叠的另外90°区域，从而共获得180°不重复区域内的千伏级影像数据，并使用预设重建算法完成CBCT三维容积重建。
  9. 根据权利要求6所述的系统，其特征在于，所述深度学习子系统包括数据采集模块和数据配对学习模块，所述数据采集模块用于获取千伏级影像数据和兆伏级影像数据，所述数据配对学习模块用于对基于同一目标同一角度成像的千伏级影像数据和兆伏级影像数据进行配对学习，以获得千伏级影像数据与兆伏级影像数据之间的关联关系。
  10. 根据权利要求8所述的系统，其特征在于，所述预设重建算法为FDK重建算法。
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