Proton imaging method and apparatus

Abstract

The present disclosure provides a proton imaging method and device, which comprises: generating a proton beam by a proton accelerator and emitting the proton beam to a scintillator; adjusting the beam spot size and the number of protons of the proton beam by a collimator to obtain an adjusted proton beam during the process of the proton beam reaching the scintillator; controlling a camera device to take a range photo of the proton beam in the scintillator by a proton imaging equipment when the adjusted proton beam does not pass through an imaging object to obtain an initial range photo; controlling the camera device to take a residual range of the adjusted proton beam in the scintillator by the proton imaging equipment when the adjusted proton beam passes through the imaging object, and adjusting the angle and position of a displacement table by the proton imaging equipment to obtain a plurality of residual range image data; and processing the initial range image and the plurality of residual range image data by the proton imaging equipment and performing image reconstruction to obtain a relative stopping power distribution image of the imaging object.

Description

Technical Field

[0001] This disclosure relates to the field of particle radiation imaging, and more specifically to a proton imaging method and apparatus. Background Technology

[0002] Current proton imaging systems are mainly divided into two categories: single-proton tracking systems based on individual proton detection and proton-integrating systems based on proton beam detection. Single-proton tracking systems typically include four position-sensitive detectors and one residual energy detector. They reconstruct images using the position and energy of individual protons. Their disadvantages include complex structure and the need for a high-speed data acquisition system to obtain the position and energy of individual protons. Proton-integrating systems contain only one residual energy detector (such as multi-layer ionization chamber detectors or flat-panel detectors). Their disadvantages include the spatial resolution of the reconstructed image being affected by the size of the proton beam spot, making it difficult to improve, and the high imaging dose. Summary of the Invention

[0003] In view of the above problems, this disclosure provides a proton imaging method and apparatus.

[0004] According to a first aspect of this disclosure, a proton imaging method includes:

[0005] A proton beam is generated using a proton accelerator and then emitted toward a scintillator.

[0006] During the process of the proton beam reaching the scintillator, the size of the proton beam spot and the number of protons are adjusted using a collimator to obtain the adjusted proton beam.

[0007] Before the adjusted proton beam passes through the imaging object, the camera device is controlled by the proton imaging equipment to capture the initial range of the adjusted proton beam in the scintillator, and the initial range image data is obtained.

[0008] When the adjusted proton beam passes through the imaging object, it is incident on the scintillator after passing through the imaging object. The camera device is controlled by the proton imaging equipment to capture the remaining range of the adjusted proton beam in the scintillator. The angle and position of the displacement stage are adjusted by the proton imaging equipment to obtain multiple images of the remaining range when the adjusted proton beam passes through the imaging object at different positions and angles. The imaging object is placed on the displacement stage.

[0009] The range image data is processed using a proton imaging device to obtain the water equivalent range. The range image data includes initial range image data and multiple remaining range image data, and the water equivalent range includes initial water equivalent range and multiple remaining water equivalent ranges.

[0010] Based on the water equivalent range, including the initial water equivalent range and multiple remaining water equivalent ranges, multiple water equivalent lengths of the imaged object are obtained.

[0011] Image reconstruction is performed based on multiple water equivalent lengths to obtain a distribution image of the relative stopping power of the imaged object.

[0012] According to embodiments of this disclosure, before obtaining the initial range image, the method further includes:

[0013] Under shaded conditions, a camera device is used to photograph the scintillator to obtain background image data.

[0014] According to embodiments of this disclosure, a proton imaging device is used to control a camera device to capture the remaining range of the adjusted proton beam in the scintillator, and the angle and position of the displacement stage are adjusted using the proton imaging device to obtain multiple remaining range image data of the adjusted proton beam passing through different positions and angles of the imaging object, including:

[0015] The proton imaging equipment controls the displacement stage to translate or rotate after a single image is captured on the camera device.

[0016] The proton imaging device controls the camera to capture the remaining range of the adjusted proton beam as it passes through the imaging object in the scintillator, obtaining multiple image data of the remaining range when the adjusted proton beam passes through different positions and angles of the imaging object.

[0017] According to embodiments of this disclosure, the range image data is processed using a proton imaging device to obtain the water equivalent range. The range image data includes initial range image data and multiple remaining range image data. The water equivalent range includes an initial water equivalent range and multiple remaining water equivalent ranges, including:

[0018] Based on the background image data, multiple image processing steps are performed on the initial range image data and multiple remaining range image data to obtain multiple optical ranges;

[0019] Multiple optical ranges were calibrated to obtain multiple water equivalent ranges.

[0020] According to embodiments of this disclosure, multiple image processing steps are performed on initial range image data and multiple remaining range image data based on background image data to obtain multiple optical ranges, including:

[0021] Based on the background image data, the initial range image data and multiple remaining range image data are respectively processed to remove the background, resulting in multiple first image data;

[0022] Distortion correction processing is performed on multiple first image data to obtain multiple second image data;

[0023] Denoising is performed on multiple second image data to obtain multiple third image data;

[0024] Multiple depth light intensity distribution curves were obtained based on the light intensity signals from multiple third image data.

[0025] Multiple light ranges were obtained based on the light intensity distribution curves at various depths.

[0026] According to embodiments of this disclosure, multiple optical ranges are calibrated to obtain multiple water equivalent ranges, including:

[0027] Multiple optical ranges were linearly calibrated to obtain multiple calibrated optical ranges.

[0028] Multiple calibrated optical ranges are multiplied by the relative stopping power of the scintillator to obtain multiple water equivalent ranges. The relative stopping power of the scintillator is calculated using the Bragg additivity rule based on the elemental composition of the scintillator, the mass fraction of each element, and the average ionization energy of each element.

[0029] According to embodiments of this disclosure, based on the water equivalent range, including an initial water equivalent range and multiple remaining water equivalent ranges, multiple water equivalent lengths of the imaged object are obtained, including:

[0030] The equivalent length of water is determined by the following formula:

[0031] WEPL=R W0 -R W1 ;

[0032] Where WEPL represents the water equivalent length of the imaged object, R W0 R represents the initial water equivalent range. W1 This indicates the equivalent range of the remaining water.

[0033] According to embodiments of this disclosure, image reconstruction based on multiple water equivalent lengths to obtain a relative stopping power distribution image of the imaging object includes:

[0034] Along the path of the proton beam, image reconstruction is performed using the relationship between the equivalent length of water and the relative stopping power of the imaging object, resulting in an image of the relative stopping power distribution of the imaging object. The relationship between the equivalent length of water and the relative stopping power of the imaging object is determined by the following formula:

[0035] WEPL=∫RSP(x,y)dl;

[0036] Where WEPL represents the water equivalent length of the imaged object, RSP(x,y) represents the relative stopping power value at position (x,y) on the relative stopping power distribution image, and dl represents the unit length increment along the proton beam path.

[0037] According to embodiments of this disclosure, adjusting the displacement stage using a proton imaging device includes:

[0038] In response to the proton accelerator being turned on and off, the proton imaging device collects the on and off signals emitted by the proton accelerator and controls the camera device to take pictures between the on and off states of the proton accelerator using an external trigger mode.

[0039] After the camera takes a picture, the proton imaging device adjusts the angle and position of the displacement stage.

[0040] A second aspect of this disclosure provides a proton imaging apparatus, comprising:

[0041] A proton accelerator is used to generate a proton beam and to emit the proton beam into a scintillator.

[0042] Collimator, used to adjust the beam spot size and the number of protons in the proton beam;

[0043] A displacement stage is used to place imaging objects and has rotation and translation functions;

[0044] Scintillators are used to deposit the energy of a proton beam and generate visible light along the proton path;

[0045] A camera device for acquiring range image data of a proton beam incident on a scintillator;

[0046] The proton imaging device is used to control the camera device to acquire range image data and adjust the angle and position of the displacement stage. It also processes the range image data to obtain multiple water equivalent ranges, and performs image reconstruction based on the water equivalent ranges to obtain the relative stopping power distribution image of the imaged object.

[0047] According to embodiments of this disclosure, a proton beam is generated by a proton accelerator and emitted towards a scintillator. During the journey of the proton beam to the scintillator, a collimator is used to adjust the beam size and number of protons, improving the spatial resolution of the imaging and reducing the proton imaging dose. The collimated proton beam passes through the imaging object and then enters the scintillator. A proton imaging device controls a camera to capture images of the scintillator, thus obtaining the adjusted range of the proton beam within the scintillator. This eliminates the need for a high-speed data acquisition system to collect the position and energy information of each proton, and also avoids the development of complex data processing algorithms, thereby reducing the R&D cost of the proton imaging system. By depositing the proton beam in the scintillator and converting its energy into visible light, the range of the proton beam within the scintillator is obtained, improving the detection efficiency and sensitivity of the proton beam energy. Multiple remaining range image data are obtained by capturing images of the scintillator using a camera device, and these images are processed using a proton imaging device to obtain a relative stopping power distribution image of the imaging object. Attached Figure Description

[0048] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0049] Figure 1 A flowchart illustrating a proton imaging method according to an embodiment of the present disclosure is shown schematically.

[0050] Figure 2 A flowchart illustrating the process of obtaining multiple optical ranges according to embodiments of the present disclosure is shown schematically;

[0051] Figure 3 A flowchart illustrating the adjustment of a displacement stage using a proton imaging apparatus according to an embodiment of the present disclosure is shown schematically.

[0052] Figure 4 A schematic diagram of a proton imaging apparatus according to an embodiment of the present disclosure is shown.

[0053] Figure 5(a) , 5(b) Figures 5(c) and 5(c) respectively schematically illustrate range image data without a collimator, range image data with a collimator, and range image data through an imaging object according to embodiments of the present disclosure; and

[0054] Figure 6(a) , 6(b) The diagrams illustrate, respectively, an imaging object according to an embodiment of the present disclosure and a schematic diagram of the relative blocking ability distribution of the imaging object. Detailed Implementation

[0055] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0056] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0057] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0058] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0059] In the technical solution of this invention, the user information (including but not limited to user personal information, user image information, user device information, such as location information) and data (including but not limited to data used for analysis, stored data, and displayed data) involved are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of related data all comply with the relevant laws, regulations, and standards of the relevant countries and regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entry points for users to choose to authorize or refuse.

[0060] Embodiments of this disclosure provide a proton imaging method, which utilizes a proton accelerator to generate a proton beam and emits the proton beam towards a scintillator; during the process of the proton beam reaching the scintillator, a collimator is used to adjust the number of protons in the proton beam to obtain an adjusted proton beam; the adjusted proton beam is passed through an imaging object and incident on the scintillator, wherein the imaging object is placed on a displacement stage; a proton imaging device is used to control a camera device to capture the range of the adjusted proton beam in the scintillator, and the angle and position of the displacement stage are adjusted using the proton imaging device to obtain multiple remaining range image data; the multiple remaining range image data are processed by the proton imaging device to obtain multiple water equivalent ranges; image reconstruction is performed based on the multiple water equivalent ranges to obtain a relative stopping power distribution image of the imaging object.

[0061] Figure 1 A flowchart illustrating a proton imaging method according to an embodiment of the present disclosure is shown schematically.

[0062] like Figure 1 As shown, proton imaging in this embodiment includes operations S101 to S107.

[0063] In operation S101, a proton beam is generated using a proton accelerator and emitted towards the scintillator.

[0064] According to embodiments of this disclosure, a proton beam refers to a proton beam having a predetermined energy and a predetermined intensity.

[0065] According to embodiments of this disclosure, a proton accelerator is a device that accelerates protons to a predetermined energy to generate a proton beam. The proton accelerator can be a linear accelerator or a cyclotron accelerator.

[0066] According to an embodiment of this disclosure, a proton accelerator is turned on and its parameters are adjusted so that the proton beam generated by the proton accelerator is directed onto the scintillator.

[0067] In operation S102, during the process of the proton beam reaching the scintillator, the size of the proton beam spot and the number of protons are adjusted using a collimator to obtain the adjusted proton beam.

[0068] According to embodiments of this disclosure, a scintillator is used to deposit the energy of a proton beam and emit visible light along the path of the proton beam. The distribution of the visible light emitted by the scintillator is related to the dose distribution of the proton beam within the scintillator. The scintillator can be a plastic scintillator with advantages such as easy processing, stable performance, short emission decay time, small light attenuation coefficient, and low cost.

[0069] According to embodiments of this disclosure, a collimator is a device made of metal with a through-hole of a specific geometry, used to reduce the flux of a proton beam and adjust the magnitude of the proton beam to a predetermined value. The metal can be brass, and the geometry can be a circle with a predetermined diameter.

[0070] According to embodiments of this disclosure, when a proton beam passes through a collimator, the collimator blocks and absorbs proton beams that deviate from the incident direction, and adjusts the shape of the proton beam to the same geometry as the collimator, thus obtaining an adjusted proton beam.

[0071] In operation S103, before the adjusted proton beam passes through the imaging object, the camera device is controlled by the proton imaging equipment to capture the initial range of the adjusted proton beam in the scintillator, and the initial range image data is obtained.

[0072] According to embodiments of this disclosure, the imaging object is an object defined as required.

[0073] According to embodiments of this disclosure, the adjusted proton beam is directly incident on the scintillator without passing through the imaging object, and the scintillator generates visible light along the incident path of the proton beam.

[0074] According to embodiments of this disclosure, a proton imaging device is connected to a camera device via a connection cable to receive range image data captured by the camera device. The camera device can be a research-grade scientific complementary metal-oxide-semiconductor (sCMOS) camera, which can be externally triggered and controlled by voltage pulse signals emitted by the proton accelerator. For example, voltage pulse signals emitted by the proton accelerator when it is turned on and off can be acquired and transmitted to the camera via the connection cable to externally trigger and control the camera, causing the sCMOS camera to continuously expose between the on and off signals.

[0075] According to an embodiment of this disclosure, a proton imaging device controls a camera device to capture the initial range of the adjusted proton beam in a scintillator, thereby obtaining initial range image data, wherein the initial range image data only needs to be captured once.

[0076] In operation S104, when the adjusted proton beam passes through the imaging object, the adjusted proton beam is incident on the scintillator after passing through the imaging object. The camera device is controlled by the proton imaging equipment to capture the remaining range of the adjusted proton beam in the scintillator. The angle and position of the displacement stage are adjusted by the proton imaging equipment to obtain multiple remaining range image data when the adjusted proton beam passes through different positions and angles of the imaging object.

[0077] According to embodiments of this disclosure, a displacement stage is a device for placing an imaging object and is capable of positional translation and angular rotation.

[0078] According to embodiments of this disclosure, the proton imaging device moves the displacement stage from its current position to a predetermined position along a predetermined route, based on the stage's predetermined position and current position. The proton imaging device also rotates the displacement stage from its current angle to a predetermined angle along a predetermined rotation route, based on the stage's predetermined angle and current angle. The proton imaging device can adjust the angle and position of the displacement stage in ways including, but not limited to, adjusting the stage's angle first and then its position, or adjusting the stage's position first and then its angle.

[0079] According to embodiments of this disclosure, the remaining range is less than the initial range because the energy of the proton beam is partially absorbed by the imaging object.

[0080] According to embodiments of this disclosure, range image data is used to record image data of the range of a proton beam in a scintillator. Multiple remaining range image data are range image data obtained at different angles and positions of the displacement stage. The displacement stage may have multiple predetermined angles, each position may have multiple predetermined positions, and the range image data may include the capture time and capture number.

[0081] According to embodiments of this disclosure, each proton beam corresponds to a position and an angle of the displacement stage, and when the camera device takes a picture once, a range image data is obtained.

[0082] According to embodiments of this disclosure, each time the angle or position of the displacement stage is adjusted, the proton accelerator generates the same proton beam. After being adjusted by the collimator, the proton beam passes through the imaging material on the displacement stage and is incident on the scintillator. The proton imaging device controls the camera device to capture the scintillator, thereby obtaining multiple remaining range image data.

[0083] In operation S105, the range image data is processed using a proton imaging device to obtain the water equivalent range. The range image data includes initial range image data and multiple remaining range image data, and the water equivalent range includes initial water equivalent range and multiple remaining water equivalent ranges.

[0084] According to embodiments of this disclosure, a proton imaging device can perform preprocessing, image correction, and image denoising on the range image data to obtain multiple corresponding depth light intensity distribution curves. Predetermined values ​​of light intensity changes in these curves are taken as corresponding optical ranges. The multiple optical ranges are then calibrated to obtain multiple target optical ranges. These target optical ranges are then multiplied by the relative stopping power value of the scintillator to obtain multiple water-equivalent ranges. The preprocessing can include background removal, image correction can include geometric correction and distortion correction, image denoising can include Gaussian filtering and median filtering, and calibration can be linear calibration.

[0085] In operation S106, based on the water equivalent range, including the initial water equivalent range and multiple remaining water equivalent ranges, multiple water equivalent lengths of the imaged object are obtained.

[0086] According to embodiments of this disclosure, the water equivalent length of the imaged object is the difference between the initial water equivalent range and the water equivalent range.

[0087] According to embodiments of this disclosure, the difference between the initial water equivalent range and multiple remaining water equivalent ranges is calculated to obtain multiple water equivalent lengths of the imaging object.

[0088] In operation S107, image reconstruction is performed based on multiple water equivalent lengths to obtain a relative stopping power distribution image of the imaging object.

[0089] According to embodiments of this disclosure, each pixel in the relative stopping power distribution map represents the relative stopping power value of the imaging object. The relative stopping power is the ratio of the energy loss per unit length of the proton beam in the imaging object to the energy loss per unit length of the proton beam in water.

[0090] According to embodiments of this disclosure, a proton beam is generated by a proton accelerator and emitted towards a scintillator. During the journey of the proton beam to the scintillator, a collimator is used to adjust the beam size and number of protons, improving the spatial resolution of the imaging and reducing the proton imaging dose. The collimated proton beam passes through the imaging object and then enters the scintillator. A proton imaging device controls a camera to capture images of the scintillator, thus obtaining the range of the adjusted proton beam within the scintillator. This eliminates the need for a high-speed data acquisition system to collect the position and energy information of each proton, and also avoids the development of complex data processing algorithms, thereby reducing the R&D cost of the proton imaging system. By depositing the proton beam in the scintillator and converting its energy into visible light, the range of the proton beam within the scintillator is obtained, improving the detection efficiency and sensitivity of the proton beam energy. The range image data is obtained by capturing images of the scintillator using a camera device, and the range image data is processed using a proton imaging device to obtain an image of the relative stopping power distribution of the imaging object.

[0091] According to embodiments of this disclosure, under shading conditions, a camera device is used to photograph a scintillator to obtain background image data.

[0092] According to embodiments of this disclosure, the background image data is image data of the scintillator captured during the proton accelerator shutdown period. The background image data only needs to be acquired once.

[0093] According to embodiments of this disclosure, a proton imaging device is used to control a camera device to capture the remaining range of an adjusted proton beam in a scintillator, and the proton imaging device is used to adjust the angle and position of a displacement stage to obtain multiple remaining range image data of the adjusted proton beam passing through different positions and angles of the imaging object. This can include the following operations: the proton imaging device controls the displacement stage to translate or rotate after a single capture on the camera device; the proton imaging device controls the camera device to capture the remaining range of the adjusted proton beam passing through the imaging object in the scintillator, thereby obtaining multiple remaining range image data of the adjusted proton beam passing through different positions and angles of the imaging object.

[0094] According to embodiments of this disclosure, the proton imaging device adjusts the displacement stage such that the displacement stage translates from an initial position to a predetermined position in predetermined steps, or rotates from an initial angle to a predetermined angle at predetermined angular intervals.

[0095] According to embodiments of this disclosure, when the displacement stage is at a specific position and angle, the proton imaging device controls the camera device to capture a single image of the range of the adjusted proton beam passing through the imaging object in the displacement stage and the scintillator, thus obtaining one range image data. Each time the position or angle of the displacement stage changes, the proton imaging device controls the camera device to capture a single image of the scintillator, obtaining multiple range image data.

[0096] According to embodiments of this disclosure, processing range image data using a proton imaging device to obtain a water equivalent range may include the following operations: performing multiple image processing operations on initial range image data and multiple remaining range image data based on background image data to obtain multiple optical ranges; and performing calibration processing on the multiple optical ranges to obtain multiple water equivalent ranges.

[0097] According to embodiments of this disclosure, the optical range is the range of the proton beam in the scintillator determined based on the distribution of scintillating photons.

[0098] According to embodiments of this disclosure, the initial range image data and multiple remaining range image data are subjected to the same multiple image processing, which may include image preprocessing, image correction processing, etc. The light intensity in the multiple processed images is superimposed along the direction perpendicular to the proton beam to obtain multiple depth light intensity distribution (PDL) curves. A predetermined change value of light intensity on the PDL curve is taken as the optical range, thereby obtaining multiple optical ranges, wherein the multiple optical ranges include the initial optical range and the remaining optical range.

[0099] According to embodiments of this disclosure, the calibration process is a process of calibrating the optical range based on a reference range.

[0100] According to embodiments of this disclosure, multiple optical ranges are calibrated based on the reference range of each optical range to obtain multiple target optical ranges. The multiple target optical ranges are then multiplied by the relative stopping power value of the scintillator to obtain multiple water equivalent ranges.

[0101] Figure 2 A flowchart illustrating the process of obtaining multiple optical ranges according to embodiments of the present disclosure is shown.

[0102] like Figure 2 As shown, multiple optical ranges are obtained by operating S251 to S255.

[0103] In operation S251, background removal processing is performed on the initial range image data and multiple remaining range image data based on the background image data to obtain multiple first image data.

[0104] According to embodiments of this disclosure, background removal processing involves subtracting the pixel values ​​at corresponding positions in the range image data from those in the background image data.

[0105] According to embodiments of this disclosure, multiple first image data can be obtained by subtracting the pixel values ​​of the corresponding positions of the initial range image data and the multiple remaining range image data from the corresponding positions of the background image data for the corresponding shooting duration, based on the shooting duration of the initial range image data and the multiple remaining range image data.

[0106] In operation S252, distortion correction processing is performed on multiple first image data to obtain multiple second image data.

[0107] According to embodiments of this disclosure, distortion correction processing is a process of correcting distortion in the first image data caused by the camera lens. Distortion correction processing can be implemented as follows: based on image data of multiple checkerboard calibration plates captured by the camera device, distortion parameters of the camera device are extracted using the MATLAB Camera Calibration Toolbox, and these distortion parameters are applied to the first image data.

[0108] According to embodiments of this disclosure, distortions in multiple first image data are corrected to obtain multiple second image data.

[0109] In operation S253, noise reduction processing is performed on multiple second image data to obtain multiple third image data.

[0110] According to embodiments of this disclosure, noise reduction is a process of removing noisy pixels from the second image data using a filtering function, wherein the filtering function may be Gaussian filtering or median filtering.

[0111] In operation S254, multiple depth light intensity distribution curves are obtained based on the light intensity signals in multiple third image data.

[0112] According to embodiments of this disclosure, the light intensity signals in multiple third image data are superimposed along the direction perpendicular to the proton beam. After superposition of each third image data, multiple light intensity signal points are obtained. Each light intensity signal point is connected to its adjacent light intensity signal points to obtain the PDL curve of each third image data.

[0113] By operating S255, multiple light ranges are obtained based on multiple depth light intensity distribution curves.

[0114] According to an embodiment of this disclosure, the position on the PDL curve where the light intensity drops to 80% of the maximum light intensity is taken as the light range.

[0115] According to embodiments of this disclosure, positions where the light intensity on multiple PDL curves drops to 80% of the maximum light intensity on the corresponding PDL curve are obtained to obtain multiple corresponding light ranges.

[0116] According to embodiments of this disclosure, after performing background removal processing, distortion correction processing, and noise reduction processing on the initial range image data and multiple remaining range image data respectively, multiple relatively accurate range image data are obtained. The light intensity signals in the multiple relatively accurate range image data are superimposed along the direction perpendicular to the proton beam to obtain multiple depth light intensity distribution curves. The light range of the proton beam is calculated by using the determined depth light intensity distribution curves.

[0117] According to embodiments of this disclosure, calibrating multiple optical ranges to obtain multiple water equivalent ranges may include the following operations: performing linear calibration on multiple optical ranges to obtain multiple calibrated optical ranges; multiplying the multiple calibrated optical ranges by the relative stopping power value of the scintillator to obtain multiple water equivalent ranges, wherein the relative stopping power value of the scintillator is calculated using the Bragg additivity rule based on the elemental composition of the scintillator, the mass fraction of each element, and the average ionization energy of each element.

[0118] According to embodiments of this disclosure, a one-dimensional linear correction coefficient is obtained by linearly fitting multiple measured optical ranges with corresponding reference ranges. The multiple optical ranges are then linearly corrected to obtain multiple calibrated optical ranges. The measured optical ranges are the ranges of proton beams of different energies in a scintillator obtained by the proton imaging method according to this invention. The reference ranges are the ranges of proton beams with the same energies as the measured optical ranges obtained from Monte Carlo simulations in a scintillator. The proton beams can be proton beams with energies between 110 MeV and 150 MeV.

[0119] According to embodiments of this disclosure, the water equivalent range is the equivalent range of the proton beam in water, which can be obtained from the optical range of the proton beam in the scintillator. For example, a proton beam can pass through 5 cm of water, but only through a 4 cm scintillator. Therefore, the relative stopping power of the scintillator is 1.25. When the optical range of the proton beam in the scintillator is 4 cm, then the equivalent range in water is 5 cm, i.e., the water equivalent range is 5 cm.

[0120] According to embodiments of this disclosure, multiple calibrated optical ranges are multiplied by the relative stopping power of the scintillator to obtain multiple water equivalent ranges.

[0121] According to embodiments of this disclosure, based on the water equivalent range, including an initial water equivalent range and multiple remaining water equivalent ranges, multiple water equivalent lengths of the imaged object are obtained, which may include the following operations:

[0122] The water equivalent length of the imaged object is determined using the following formula:

[0123] WEPL=R W0 -R W1 (1)

[0124] Where WEPL represents the water equivalent length of the imaged object, R W0 R represents the initial water equivalent range. W1 This indicates the equivalent range of the remaining water.

[0125] According to embodiments of this disclosure, the initial water equivalent range is the water equivalent range of the proton beam directly incident on the scintillator.

[0126] According to embodiments of this disclosure, multiple water equivalent ranges are subtracted from the initial water equivalent range to obtain multiple water equivalent lengths of the imaged object.

[0127] According to embodiments of this disclosure, image reconstruction based on the plurality of water equivalent lengths to obtain a relative stopping power distribution image of the imaging object may include the following operations:

[0128] Along the path of the proton beam, image reconstruction is performed using the relationship between the equivalent length of water and the relative stopping power of the imaging object, resulting in an image of the relative stopping power distribution of the imaging object. The relationship between the equivalent length of water and the relative stopping power of the imaging object is determined by the following formula:

[0129] WEPL=∫RSP(x,y)dl (2)

[0130] Where WEPL represents the water equivalent length of the imaged object, RSP(x,y) represents the RSP value at position (x,y) on the relative stopping power distribution image, and dl represents the unit length increment along the proton beam path.

[0131] According to embodiments of this disclosure, image reconstruction involves reconstructing the equivalent length of water into a relative stopping power distribution image using an image reconstruction algorithm. The image reconstruction algorithm can be a filtered back-projection method, an iterative method, etc.

[0132] Figure 3 A flowchart illustrating the adjustment of a displacement stage using a proton imaging apparatus according to an embodiment of the present disclosure is shown.

[0133] like Figure 3 As shown, adjusting the displacement stage using a proton imaging device includes operations S361 to S362.

[0134] In operation of S361, in response to the opening and closing of the proton accelerator, the proton imaging device collects the opening and closing signals emitted by the proton accelerator and controls the camera device to take pictures between the opening and closing of the proton accelerator in an external trigger mode.

[0135] According to embodiments of this disclosure, when the proton accelerator is turned on, the proton imaging device collects an on signal; when the proton accelerator is turned off, the proton imaging device collects a off signal; when the proton imaging device detects that the signal from the proton accelerator is an on signal, the camera device is controlled to take pictures using an external trigger mode; when the proton imaging device detects that the signal from the proton accelerator is an off signal, the camera device is controlled to stop taking pictures using an external trigger mode.

[0136] After the camera takes a picture, the proton imaging device adjusts the angle and position of the displacement stage when operating the S362.

[0137] According to an embodiment of this disclosure, after each shooting session, the camera device emits a voltage pulse signal. Upon receiving the voltage pulse signal emitted by the camera device, the proton imaging device adjusts the position or angle of the displacement stage.

[0138] Figure 4 A schematic diagram of a proton imaging apparatus according to an embodiment of the present disclosure is shown.

[0139] like Figure 4 As shown, the proton imaging device includes a proton accelerator 410, a collimator 430, a displacement stage 460, a scintillator 470, a camera device 480, and a proton imaging equipment 490.

[0140] According to an embodiment of this disclosure, the collimator 430 is made of brass and has a central circular through-hole with a diameter of 1 mm, which is used to reduce the flux of the proton beam and collimate the width of the proton beam to 1 mm.

[0141] According to an embodiment of the present disclosure, the displacement stage 460 includes a turntable 440 and a horizontal guide rail 450. The displacement stage 460 has rotation and translation functions, and the translation direction is perpendicular to the direction of proton incidence. The displacement stage 460 is located at the rear end of the collimator 430 and is used to place the imaging object.

[0142] According to embodiments of this disclosure, the proton imaging device 490 is used to control the camera device 480 to take pictures and to adjust the displacement stage 460 to translate or rotate.

[0143] According to an embodiment of this disclosure, the scintillator 470 is a plastic scintillator.

[0144] According to embodiments of this disclosure, the proton accelerator 410 generates multiple proton beams 420 with predetermined energies as needed. After passing through the collimator 430, the proton beams 420 are adjusted to obtain multiple adjusted proton beams. These adjusted proton beams pass through an imaging object located on the displacement stage 460 and are incident on the scintillator 470. The proton imaging device 490 is connected to the camera device 480 and controls the camera device 480 to capture images of the scintillator 470, obtaining multiple images of the remaining range. Simultaneously, the proton imaging device 490 is connected to the displacement stage 460 to adjust the angle of the turntable 440 or the position of the horizontal guide rail 450.

[0145] According to an embodiment of this disclosure, when there is no imaging object on the displacement stage 460, the camera device 480 captures the scintillator 470 to obtain initial range image data.

[0146] According to embodiments of this disclosure, a proton imaging device processes initial range image data and multiple remaining range image data and performs image reconstruction to obtain a relative stopping power distribution map of the imaged object.

[0147] Figure 5 schematically illustrates a diagram of range image data according to an embodiment of the present disclosure.

[0148] As shown in Figure 5, Figure 5(a) shows the range image data of a 150 MeV proton beam in a scintillator without a collimator; Figure 5(b) shows the range image data of a proton beam of the same energy in a scintillator with a collimator; and Figure 5(c) shows the range image data of a proton beam of the same energy in a scintillator after passing through the imaging object. Based on the light intensity distribution in Figure 5(b) and Figure 5(a), it can be seen that the collimator can effectively reduce the width of the proton beam. Based on the light intensity distribution in Figure 5(b) and Figure 5(c), it can be seen that the range of the proton beam in the scintillator becomes shorter after passing through the imaging object.

[0149] Figure 6 schematically illustrates a distribution of the relative blocking power of an imaging object according to an embodiment of the present disclosure.

[0150] As shown in Figure 6, Figure 6(a) shows an imaging object 610 placed on a displacement stage 620. The imaging object is made of plexiglass, with a diameter of 30 mm and a height of 45 mm, and has four cylindrical through holes with a diameter of 5 mm in the center. Figure 6(b) is a distribution diagram of the relative stopping power of the imaging object obtained by the proton imaging method.

[0151] According to an embodiment of the present disclosure, the RSP value of the pixel within circle 630 in FIG6(b) is calculated to obtain a reconstructed RSP of 1.154 for the imaged object and a reference RSP of 1.158 for the imaged object. For the air hole 640, the reconstructed RSP of the air hole is 0.121 and the reference RSP of the air hole is 0.001.

[0152] According to embodiments of this disclosure, program code for executing the computer programs provided in embodiments of this disclosure can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can execute entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0153] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0154] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0155] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A proton imaging method, comprising: A proton beam is generated using a proton accelerator and then emitted toward a scintillator. During the process of the proton beam reaching the scintillator, the size of the proton beam spot and the number of protons are adjusted using a collimator to obtain an adjusted proton beam; When the adjusted proton beam does not pass through the imaging object, the camera device is controlled by the proton imaging equipment to capture the initial range of the adjusted proton beam in the scintillator, and the initial range image data is obtained. When the adjusted proton beam passes through the imaging object, the adjusted proton beam is incident on the scintillator after passing through the imaging object. The proton imaging device controls the camera device to capture the remaining range of the adjusted proton beam in the scintillator, and the proton imaging device adjusts the angle and position of the displacement stage to obtain multiple remaining range image data when the adjusted proton beam passes through the imaging object at different positions and angles. The imaging object is placed on the displacement stage. The range image data is processed using the proton imaging device to obtain the water equivalent range, wherein the range image data includes initial range image data and multiple remaining range image data, and the water equivalent range includes initial water equivalent range and multiple remaining water equivalent ranges. Based on the water equivalent range, including the initial water equivalent range and the multiple remaining water equivalent ranges, multiple water equivalent lengths of the imaged object are obtained. Image reconstruction is performed based on the multiple water equivalent lengths to obtain a relative stopping power distribution image of the imaging object.

2. The method according to claim 1, wherein, Before obtaining the initial range image, the following steps are also included: Under shaded conditions, the camera device is used to photograph the scintillator to obtain background image data.

3. The method according to claim 1, wherein, The proton imaging device is used to control the camera device to capture the remaining range of the adjusted proton beam in the scintillator, and the angle and position of the displacement stage are adjusted using the proton imaging device to obtain multiple remaining range image data of the adjusted proton beam passing through different positions and angles of the imaging object, including: The proton imaging device controls the displacement stage to translate or rotate after a single image is captured on the camera device; The proton imaging device controls the camera to capture the remaining range of the adjusted proton beam passing through the imaging object in the scintillator, thereby obtaining multiple remaining range image data when the adjusted proton beam passes through the imaging object at different positions and angles.

4. The method according to claim 2, wherein, The process of processing the range image data using the proton imaging device to obtain the water equivalent range, wherein the range image data includes the initial range image data and the plurality of remaining range image data, and the water equivalent range includes the initial water equivalent range and the plurality of remaining water equivalent ranges, including: Based on the background image data, the initial range image data and the multiple remaining range image data are processed multiple times to obtain multiple optical ranges; The multiple optical ranges are calibrated to obtain multiple water equivalent ranges.

5. The method according to claim 4, wherein, The process involves performing multiple image processing steps on the initial range image data and the multiple remaining range image data based on the background image data to obtain multiple optical ranges, including: Based on the background image data, the initial range image data and the multiple remaining range image data are respectively subjected to background removal processing to obtain multiple first image data; Distortion correction processing is performed on the plurality of first image data respectively to obtain a plurality of second image data; Denoising processing is performed on the multiple second image data to obtain multiple third image data; Multiple depth light intensity distribution curves are obtained based on the light intensity signals in the multiple third image data; Multiple light ranges are obtained based on the multiple depth light intensity distribution curves.

6. The method according to claim 4, wherein, The calibration process for the plurality of optical ranges, resulting in a plurality of water equivalent ranges, includes: The multiple optical ranges are linearly calibrated to obtain multiple calibrated optical ranges; The multiple calibrated optical ranges are multiplied by the relative stopping power of the scintillator to obtain multiple water equivalent ranges. The relative stopping power of the scintillator is calculated using the Bragg additivity rule based on the elemental composition of the scintillator, the mass fraction of each element, and the average ionization energy of each element.

7. The method according to claim 1, wherein, The method, based on the water equivalent range, including the initial water equivalent range and the multiple remaining water equivalent ranges, obtains multiple water equivalent lengths of the imaged object, including: The equivalent length of the water is determined by the following formula: ； in, This represents the water-equivalent length of the imaged object. This indicates the initial water-equivalent range. This indicates the equivalent range of the remaining water.

8. The method according to claim 1, wherein, The process of reconstructing the image based on the multiple water equivalent lengths to obtain the relative stopping power distribution image of the imaging object includes: Along the path of the proton beam, image reconstruction is performed using the relationship between the water equivalent length and the relative stopping power of the imaging object to obtain a relative stopping power distribution image of the imaging object. The relationship between the water equivalent length and the relative stopping power of the imaging object is determined by the following formula: ； in, This represents the water-equivalent length of the imaged object. The image representing the relative stopping power distribution. The relative stopping power at the location, dl represents the unit length increment along the proton beam path.

9. The method according to claim 1 or 3, wherein, The adjustment of the displacement stage using the proton imaging device includes: In response to the opening and closing of the proton accelerator, the proton imaging device collects the opening and closing signals emitted by the proton accelerator and controls the camera device to take pictures between the opening and closing of the proton accelerator using an external trigger mode; After the camera device takes a picture, the proton imaging device adjusts the angle and position of the displacement stage.

10. A proton imaging apparatus for performing the method as described in any one of claims 1-9, comprising: A proton accelerator is used to generate a proton beam and to emit the proton beam into a scintillator. A collimator is used to adjust the beam spot size and the number of protons in the proton beam. A displacement stage is used to place imaging objects and has rotation and translation functions; A scintillator is used to deposit the energy of the proton beam and generate visible light along the proton path; A camera device is used to acquire range image data of the proton beam incident on the scintillator; A proton imaging device is used to control the camera device to acquire range image data and adjust the angle and position of the displacement stage, and to process the range image data to obtain multiple water equivalent ranges. Based on the water equivalent ranges, image reconstruction is performed to obtain a relative stopping power distribution image of the imaging object.

Images