A system and method for minimum energy layer set determination for proton arc scanning

Abstract

The application discloses a minimum energy layer set determination system and method for proton arc scanning, and the system comprises a density distribution model construction module, which is used for acquiring a CT image to be processed, and constructing an electron density distribution model according to the CT image to be processed; an envelope interval calculation module, which is used for calculating water equivalent path lengths of each target voxel in a target region from a body surface incident point to the target voxel along multiple incident angle directions according to the electron density distribution model, and obtaining envelope intervals; a minimum energy layer number determination module, which is used for determining an effective range spread of a single energy proton beam, and determining a minimum energy layer number covering the envelope intervals according to the effective range spread; and a minimum energy layer set determination module, which is used for determining a minimum energy layer set according to the minimum energy layer number. The application can reduce the number of times of energy switching of a gantry, improve the efficiency of equipment, and enhance the repeatability and stability of a plan, and can be widely applied to the technical field of data processing.

Description

Technical Field

[0001] This application relates to the field of data processing technology, and in particular to a system and method for determining the minimum energy layer set for proton arc scanning. Background Technology

[0002] Current proton arc therapy (PAT / SPArc) achieves dose coverage of the tumor volume by continuously changing the gantry angle and combining multi-energy layer scanning. To ensure that tumor voxels at different depths are covered by the Bragg peak, existing techniques typically pre-set a large number of energy layers and then reduce the actual number of energy layers used through optimization algorithms or energy switching penalties. However, this strategy is essentially a post-optimization approach, resulting in a large energy search space, frequent energy switching, and low equipment efficiency. Furthermore, the optimization results heavily rely on empirical settings such as objective function weights and optimization algorithm parameters, leading to insufficient repeatability and stability of the plan. Summary of the Invention

[0003] To address the aforementioned technical problems, the purpose of this application is to provide a system and method for determining the minimum energy layer set for proton arc scanning, which can reduce the number of rack energy switching operations, improve equipment efficiency, and enhance the repeatability and stability of the plan.

[0004] To achieve the above objectives, one aspect of this application proposes a minimum energy level set determination system for proton arc scanning, comprising: The density distribution model construction module is used to acquire the CT image to be processed and construct an electron density distribution model based on the CT image to be processed. The envelope interval calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions according to the electron density distribution model, so as to obtain the envelope interval. The minimum energy layer number determination module is used to determine the effective range broadening of a single-energy proton beam, and to determine the minimum energy layer number covering the envelope region based on the effective range broadening. The minimum energy layer set determination module is used to determine the minimum energy layer set based on the number of minimum energy layers.

[0005] In some embodiments, the density distribution model construction module includes: The image acquisition module is used to acquire the CT image to be processed and the CT values ​​corresponding to each voxel in the CT image to be processed. A calibration curve construction module is used to construct a calibration curve, which is used to characterize the relationship between the CT value and the relative electron density. The relative electron density calculation module is used to substitute the CT value into the calibration curve to obtain the relative electron density corresponding to each voxel. The relative electron density integration module is used to integrate the relative electron densities corresponding to each voxel to obtain the electron density distribution model.

[0006] In some embodiments, the incident angle direction includes multiple arc-shaped scanning angles obtained by uniform or non-uniform sampling along the rotation direction of the proton therapy gantry.

[0007] In some embodiments, the envelope interval calculation module includes: The water equivalent path length calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions according to the electron density distribution model, and obtain the minimum and maximum water equivalent path lengths. The envelope interval determination module is used to determine the envelope interval based on the minimum value of the water equivalent path length and the maximum value of the water equivalent path length.

[0008] In some embodiments, the water equivalent path length calculation module includes: An incident point determination module is used to determine multiple incident points on the body surface based on the direction of each incident angle. The path construction module is used to construct multiple pencil beam paths from each of the said incident points on the body surface to each of the said target voxels; The path discretization module is used to discretize each of the pencil beam paths into several line segments, and then obtain the relative electron density of each line segment according to the electron density distribution model. An integration module is used to integrate the relative electron density of each line segment along each of the pencil beam paths to obtain the water equivalent path length. The extreme value determination module is used to determine the minimum and maximum values ​​of the water equivalent path length corresponding to each target voxel based on the water equivalent path length.

[0009] In some embodiments, the minimum energy layer number determination module includes: The threshold determination module is used to determine the water equivalent path length threshold. An effective range broadening determination module is used to determine the effective range broadening of a single-energy proton beam; The minimum energy layer number calculation module is used to determine the minimum energy layer number based on the effective range broadening when the maximum value of the water equivalent path length in the envelope interval is less than or equal to the water equivalent path length threshold. The early warning module is used to generate an early warning signal when the maximum value of the water equivalent path length in the envelope interval is greater than the water equivalent path length threshold.

[0010] In some embodiments, the effective range extension determination module includes: The factor determination module is used to obtain the energy broadening component, the range fluctuation component, and the system range error safety boundary; The effective range broadening calculation module is used to perform square root or addition operations on the energy broadening component, the range fluctuation component, and the system range error safety boundary to obtain the effective range broadening.

[0011] In some embodiments, the minimum energy layer number calculation module includes: A width calculation module is used to calculate the width of the envelope interval; The quantity calculation module is used to perform a ratio calculation on the width and the effective range expansion and take the integer value to obtain the minimum number of energy layers.

[0012] In some embodiments, each energy layer in the minimum energy layer set corresponds to a continuous arc-shaped scanning angle range, thereby reducing the number of energy switching operations.

[0013] To achieve the above objectives, another aspect of this application proposes a method for determining the minimum energy layer set for proton arc scanning, comprising the following steps: Acquire the CT image to be processed, and construct an electron density distribution model based on the CT image to be processed; Based on the electron density distribution model, the water equivalent path length from the body surface to the target voxel in the target area is calculated along multiple incident angle directions to obtain the envelope interval; Determine the effective range broadening of a single-energy proton beam, and based on the effective range broadening, determine the minimum number of energy layers covering the envelope region; The set of minimum energy layers is determined based on the number of minimum energy layers.

[0014] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0015] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer program product, including a computer program that, when executed by a processor, implements the aforementioned method.

[0016] The beneficial effects of this application are as follows: The minimum energy layer set determination system and method for proton arc scanning includes a density distribution model construction module, an envelope interval calculation module, a minimum energy layer number determination module, and a minimum energy layer set determination module. This application uses the envelope interval calculation module to calculate the water equivalent path length from the incident point on the body surface to each target voxel within the target area along multiple incident angle directions, obtaining the envelope interval. Then, the minimum energy layer number determination module determines the minimum energy layer number covering the envelope interval based on the effective range broadening of a single-energy proton beam. Through geometric and physical analysis, the theoretical minimum energy layer number and its set required to cover the target area can be determined before treatment planning optimization. This significantly reduces the number of energy layers and energy switching times required during proton arc scanning, reduces the number of gantry energy switching times, improves equipment efficiency, and enhances the repeatability and stability of the plan, while ensuring tumor dose coverage and without compromising organ protection. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments of this application are described below. It should be understood that the drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions in this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a minimum energy layer set determination system for proton arc scanning provided in one embodiment of this application; Figure 2 This is a geometric abstraction of a single-energy proton passing through the body surface and organs to reach the tumor in the body during arc therapy, as provided in one embodiment of this application. Figure 3 This is a flowchart illustrating the steps of a method for determining the minimum energy layer set for proton arc scanning according to an embodiment of this application. Figure 4 This is a schematic diagram of the hardware structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0020] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0021] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0022] Water Equivalent Path Length (WEPL): The thickness of a substance relative to a proton is equivalent to the thickness of water that can produce the same result.

[0023] Current proton arc therapy (PAT / SPArc) achieves dose coverage of the tumor volume by continuously changing the gantry angle and combining multi-energy layer scanning. To ensure that tumor voxels at different depths are covered by the Bragg peak, a large number of energy layers are typically pre-set, and then the actual number of energy layers used is reduced through optimization algorithms or energy switching penalties. However, this strategy is essentially a post-optimization approach, with a large energy search space and frequent energy switching, leading to low equipment efficiency. Furthermore, current technology fails to provide a theoretical lower bound on the number of energy layers based on the relationship between proton range and target geometry.

[0024] Furthermore, existing technologies also include a class of energy layer determination methods based on optimization selection (e.g., by constructing objective functions including target area coverage and energy switching time for optimization). While these methods can achieve relatively good selection within a given set of candidate energies, they are essentially still post-optimization methods. This method has the following inherent drawbacks: (1) Its candidate energy set itself may contain a large number of redundant energy layers. The optimization process can only screen from them, but cannot answer the fundamental question of "how many energy layers are needed at the minimum level" from a physical perspective. (2) The optimization results rely heavily on empirical settings such as objective function weights and optimization algorithm parameters, resulting in insufficient repeatability and stability of the plan; (3) Failed to establish a direct connection between the energy layer and the continuous arc angle range based on the physical essence of multi-angle scanning, thus reducing the weak physical basis of energy switching.

[0025] In view of this, this application proposes a minimum energy layer set determination system for proton arc scanning, including a density distribution model construction module, an envelope interval calculation module, a minimum energy layer number determination module, and a minimum energy layer set determination module. This application uses the envelope interval calculation module to calculate the water equivalent path length from the surface incident point to each target voxel within the target region along multiple incident angle directions, obtaining the envelope interval. Then, the minimum energy layer number determination module determines the minimum energy layer number covering the envelope interval based on the effective range broadening of a single-energy proton beam. Through geometric and physical analysis, the theoretical minimum energy layer number and its set required to cover the target region can be determined before treatment planning optimization. This significantly reduces the number of energy layers and energy switching times required during proton arc scanning, reduces the number of gantry energy switching times, improves equipment efficiency, and enhances the repeatability and stability of the plan, while ensuring tumor dose coverage and without compromising organ protection.

[0026] Reference Figure 1 , Figure 1 This is a schematic diagram of a minimum energy level set determination system for proton arc scanning according to an embodiment of this application. The embodiment of this application proposes a minimum energy level set determination system for proton arc scanning, comprising: The density distribution model construction module is used to acquire the CT image to be processed and construct an electron density distribution model based on the CT image to be processed. The envelope interval calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions based on the electron density distribution model, and obtain the envelope interval. The minimum energy layer number determination module is used to determine the effective range broadening of a single-energy proton beam and, based on the effective range broadening, to determine the minimum energy layer number covering the envelope region. The minimum energy layer set determination module is used to determine the minimum energy layer set based on the number of minimum energy layers.

[0027] It should be noted that, before optimizing the treatment plan, this embodiment uses an envelope interval calculation module to comprehensively analyze the water equivalent path length (WEPL) distribution of the tumor target area under all arc angles, obtaining a holistic physical quantity characterizing target accessibility—the WEPL envelope interval (geometric analysis). Then, using a minimum energy layer number determination module, combined with the effective range broadening of the monoenergetic proton beam (physical property), the minimum number of energy layers required to cover this interval is calculated, achieving the trimming and determination of energy layers. The final set of minimum energy layers is used as an immutable constraint for subsequent dose optimization. Determining the minimum energy layer set through the above geometric and physical analysis can significantly reduce the number of energy layers and energy switching times required during proton arc scanning, reduce the number of gantry energy switching times, and improve equipment efficiency; it can also reduce dependence on energy switching penalties and empirical parameters, improving the stability and repeatability of the plan.

[0028] Specifically, firstly, the density distribution model construction module acquires the user's CT images and calculates the relative electron density of each voxel to obtain an electron density distribution model. Next, the envelope interval calculation module calculates the water equivalent path length (WEPL) from the surface incident point to each voxel within the tumor target area along multiple incident angle directions, statistically obtaining the overall WEPL envelope interval of the tumor. Then, the minimum energy layer number determination module calculates the minimum energy layer number required to cover this envelope interval based on the effective range broadening of a single-energy proton beam. Finally, the minimum energy layer set determination module constructs the corresponding minimum energy layer set, on which proton arc scanning dose optimization is subsequently performed. This approach prunes the energy space from a physical and geometric perspective before optimization, avoiding the use of numerous redundant energy layers.

[0029] As an optional implementation, the density distribution model construction module includes: The image acquisition module is used to acquire the CT image to be processed and the CT values ​​corresponding to each voxel in the CT image to be processed. The calibration curve construction module is used to construct calibration curves, which characterize the relationship between CT value and relative electron density. The relative electron density calculation module is used to substitute the CT value into the calibration curve to obtain the relative electron density corresponding to each voxel; The relative electron density integration module is used to integrate the relative electron densities of each voxel to obtain an electron density distribution model.

[0030] Specifically, the user's CT image dataset is first acquired, where each voxel value represents a CT number (Hounsfield Unit, HU). Next, a set of standard phantoms with known electron densities (such as CT calibration phantoms with different density inserts) is used for scanning to establish a "CT number - relative electron density" calibration curve for this CT device under this scanning protocol. This curve represents a piecewise linear or polynomial function relationship, as shown in the following equation:

[0031] in, Relative electron density, This is the CT value.

[0032] Next, the calibration curve described above is applied to the user's entire CT image dataset. For each voxel in the CT images, based on its CT value... By querying or calculating the calibration curve The relative electron density corresponding to this voxel is obtained. This process transforms the entire CT volume data into a three-dimensional relative electron density distribution matrix with the same grid and resolution as the CT image, thus completing the establishment of the relative electron density model. Mathematically, this model can be represented as spatial coordinates. function .

[0033] As a further optional implementation, the incident angle direction includes multiple arc-shaped scanning angles obtained by uniform or non-uniform sampling along the rotation direction of the proton therapy gantry.

[0034] As a further optional implementation, the envelope interval calculation module includes: The water equivalent path length calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions based on the electron density distribution model, and to obtain the minimum and maximum water equivalent path lengths. The envelope interval determination module is used to determine the envelope interval based on the minimum and maximum equivalent path lengths of water.

[0035] It is understandable that, such as Figure 2 The diagram illustrates the geometric abstraction of a single-energy proton passing through the body surface and organs to reach the tumor within the body during arc therapy. Mathematically, a proton beam of one energy covering as many points within the tumor as possible can be abstracted as follows: two arbitrarily shaped closed contours, with the inner contour completely enclosed by the outer contour. A length is found such that the line connecting all points within the inner contour to some point on the outer contour has the same length. The proton energy, or the position of the Bragg peak, can be represented using the water equivalent path length (WEPL).

[0036] Specifically, the water equivalent path length is calculated by integrating the relative electron density of each target voxel along the propagation path of the proton beam within the user's body. This embodiment calculates the minimum and maximum WEPL values ​​of tumor voxels under multi-angle incident conditions to establish the overall WEPL envelope of the tumor, thereby geometrically quantifying the physical heterogeneity within the tumor and providing a basis for subsequently determining the minimum energy layer set.

[0037] As a further optional implementation, the water equivalent path length calculation module includes: The incident point determination module is used to determine multiple incident points on the body surface based on the direction of each incident angle. The path construction module is used to construct multiple pencil beam paths from each incident point on the body surface to each target voxel. The path discretization module is used to discretize each pencil beam path into several line segments, and then obtain the relative electron density of each line segment according to the electron density distribution model. The integration module is used to integrate the relative electron density of each line segment along each pencil beam path to obtain the water equivalent path length. The extreme value determination module is used to determine the minimum and maximum water equivalent path lengths for each target voxel based on the water equivalent path length.

[0038] Specifically, for any target voxel within the tumor target area and the direction of the incident angle (unit vector) (from the point of incidence on the body surface) To the target voxel Connect a straight line to form the hypothetical pencil beam path of a proton. Next, this path is discretized into several small line segments. For the first... A small line segment, the physical length of which is And located somewhere in the relative electron density model, thus obtained from the model through three-dimensional interpolation (such as trilinear interpolation). Obtain the relative electron density at that location Then the water equivalent path length of this path The following can be obtained by line integration along the path (discretized into summation): ; This calculation is the physical realization of integrating the relative electron density of each voxel in the proton beam along the pencil beam path.

[0039] For each target voxel within the target area , ... Repeat the above steps to calculate the direction for each incident angle. , ...... The equivalent water path length is used to determine the minimum equivalent water path length for each target voxel. Maximum equivalent path length of water Through the above process, this embodiment of the application converts anatomical information from clinical CT images into a key physical quantity (relative electron density) for proton range calculation, providing accurate input data for subsequent WEPL envelope analysis. This physical calibration-based conversion process is a crucial foundation for this embodiment of the application, distinguishing it from purely mathematical optimization and ensuring its robust clinical feasibility.

[0040] The overall envelope of the tumor is then: .

[0041] As a further optional implementation, the minimum energy layer number determination module includes: The threshold determination module is used to determine the water equivalent path length threshold. Effective range broadening determination module, used to determine the effective range broadening of a single-energy proton beam; The minimum energy layer number calculation module is used to determine the minimum energy layer number when the maximum value of the water equivalent path length in the envelope interval is less than or equal to the water equivalent path length threshold, based on the effective range widening. The early warning module is used to generate an early warning signal when the maximum value of the water equivalent path length in the envelope interval is greater than the water equivalent path length threshold.

[0042] It should be noted that the embodiments of this application aim to determine the minimum energy layer set when the entire tumor target area can be covered with only a very small number of energy layers (e.g., 2-3 layers). When the tumor envelope width W is too large, the minimum number of energy layers required... This will significantly increase the difficulty of determining the minimum energy layer set, making the system described in this application no longer applicable.

[0043] Therefore, this embodiment of the application quantitatively compares the water equivalent path length envelope interval with a preset water equivalent path length threshold. When the maximum value of the water equivalent path length in the envelope interval exceeds the water equivalent path length threshold, it is determined that the current tumor target area is not suitable for the minimum energy layer set determination system of this embodiment. At this time, an early warning signal is generated, such as "The envelope width exceeds the recommended range for low-energy optimization. It is recommended to use the standard multi-energy layer optimization process" to prompt the operator. When the maximum value of the water equivalent path length in the envelope interval does not exceed the water equivalent path length threshold, it is determined that the current tumor target area is suitable for the minimum energy layer set determination system of this embodiment, and then the minimum energy layer set is further calculated. This effectively avoids the technical limitations of short range and limited penetration ability of low-energy protons, avoids problems such as target area omission and uneven dose distribution, and reduces the cost of ineffective planning design.

[0044] The water equivalent path length threshold can be set based on the broad applicability of the actual application, the complexity of implementation, and the additional margin required to ensure dose coverage. For example, for target areas with an envelope width of less than 20 mm, there is a high probability that high-quality dose coverage can be achieved through 2-3 energy layers, so the water equivalent path length threshold can be set to 20 mm.

[0045] As a further optional implementation, the effective range extension determination module includes: The factor determination module is used to obtain the energy broadening component, the range fluctuation component, and the system range error safety boundary; The effective range broadening calculation module is used to perform square root or addition operations on the energy broadening component, the range fluctuation component, and the system range error safety boundary to obtain the effective range broadening.

[0046] Specifically, the effective range of a single-energy proton beam is broadened. This is a preset physical parameter, and in this embodiment, its value is determined by comprehensively considering the following factors: a) Energy broadening component: derived from the performance parameters of the proton therapy accelerator and beam delivery system, provided by the equipment manufacturer; b) Range fluctuation component: estimated based on the recognized theoretical model of range fluctuation in proton therapy physics (such as statistical calculation based on the Bethe-Bloch formula), its magnitude is related to proton energy and tissue density; c) System range error safety boundary: set according to the clinical quality control procedures and experience data of each institution, used to cover CT calibration error, positioning error, dose calculation error, etc. The common form is to add a fixed value (such as X mm) or percentage (such as Y%) to the calculated range.

[0047] Effective range extended The above factors can be synthesized using methods such as square root sums or direct addition, and preset to a fixed value in the planning system (e.g., 5.0 mm to 7.0 mm of water equivalent thickness). This preset value ensures that the subsequent plans derived from the minimum energy layer set remain robust even in the presence of various uncertainties.

[0048] As a further optional implementation, the minimum energy layer number calculation module includes: The width calculation module is used to calculate the width of the envelope interval; The quantity calculation module is used to perform ratio calculations on the width and effective range expansion and take the integer value to obtain the minimum number of energy layers.

[0049] Specifically, the width of the envelope interval is calculated using the following formula: ; Then, the ratio of the width to the effective range is calculated and the integer value is taken to obtain the theoretical minimum number of energy layers required to cover the entire envelope. : ; Ultimately, this determines the corresponding set of minimum energy layers, and the number of energy values ​​in the set of minimum energy layers is equal to the number of theoretical minimum energy layers.

[0050] As an optional implementation, each energy layer in the minimum energy layer set corresponds to a continuous arc-shaped scanning angle range, thereby reducing the number of energy switching operations.

[0051] It should be noted that, based on the minimum energy layer set determined in the embodiments of this application, each energy layer covers a continuous angle throughout the entire arc process, and the number of energy switching times is extremely small (1–2 times). Compared with traditional proton arc scanning therapy systems, this can significantly reduce the number of energy switching times during proton arc scanning and significantly improve equipment efficiency.

[0052] The minimum energy layer set determination system for proton arc scanning according to the embodiments of this application has been described above. The embodiments of this application will be further described below with reference to specific examples.

[0053] Taking head tumors as an example, the water equivalent path length distribution of tumor voxels under 360° arc scanning was calculated based on patient CT data. The results showed that the width of the overall WEPL envelope of the tumor was less than 10 mm (the water equivalent path length threshold). Based on this envelope, only 2 to 3 energy layers are needed to achieve target coverage. Compared with the traditional multi-energy layer PBS approach, the number of energy layers is reduced by more than 70% while ensuring D95 and OAR dose constraints, and the number of energy switching times is significantly reduced.

[0054] The minimum energy layer set determination system for proton arc scanning according to embodiments of this application has been described above. It can be understood that the embodiments of this application, including a density distribution model construction module, an envelope interval calculation module, a minimum energy layer number determination module, and a minimum energy layer set determination module, have the following advantages: First, before optimizing the treatment plan, determining the minimum energy layer set through geometric (WEPL envelope interval) and physical (effective range broadening) analysis can significantly reduce the number of energy layers and energy switching times required during proton arc scanning, reduce the number of gantry energy switching times, and significantly improve equipment efficiency; it can also reduce the dependence on energy switching penalty terms and empirical parameters, and improve the stability and repeatability of the treatment plan.

[0055] Second, the water equivalent path length envelope interval is quantitatively compared with the preset water equivalent path length threshold to determine whether the current CT image to be processed is applicable to the minimum energy layer set determination system of this application embodiment, thereby effectively avoiding the technical limitations of short range and limited penetration ability of low-energy protons, avoiding problems such as target area omission and uneven dose distribution, and reducing the cost of ineffective plan design.

[0056] Reference Figure 3 This application also provides a method for determining the minimum energy level set for proton arc scanning, including the following steps S101 to S104: Step S101: Obtain the CT image to be processed, and construct an electron density distribution model based on the CT image to be processed; Step S102: Based on the electron density distribution model, calculate the water equivalent path length from the surface of each target voxel in the target area along multiple incident angle directions to obtain the envelope interval; Step S103: Determine the effective range broadening of a single-energy proton beam, and based on the effective range broadening, determine the minimum number of energy layers covering the envelope region. Step S104: Determine the set of minimum energy layers based on the number of minimum energy layers.

[0057] It is understood that the content of the above system embodiments is applicable to this method embodiment. The specific functions implemented in this method embodiment are the same as those in the above system embodiments, and the beneficial effects achieved are also the same as those achieved in the above system embodiments.

[0058] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0059] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0060] Please see Figure 4 , Figure 4 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes: The processor 1001 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 1002 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1002 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 1002 and is called and executed by the processor 1001 using the methods described in the embodiments of this application. Input / output interface 1003 is used to implement information input and output; The communication interface 1004 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 1005 transmits information between various components of the device (e.g., processor 1001, memory 1002, input / output interface 1003, and communication interface 1004); The processor 1001, memory 1002, input / output interface 1003 and communication interface 1004 are connected to each other within the device via bus 1005.

[0061] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0062] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0063] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0064] It is understood that the content of the above method embodiments is applicable to the embodiments of this program product. The specific functions implemented by the embodiments of this program product are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0065] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0066] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the aforementioned blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0067] Furthermore, although this application is described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the aforementioned functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding this application. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the realm of conventional skill for an engineer. Therefore, those skilled in the art can implement the application set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of this application, which is determined by the full scope of the appended claims and their equivalents.

[0068] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0069] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0070] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0071] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0072] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A system for determining the minimum energy level set for proton arc scanning, characterized in that, include: The density distribution model construction module is used to acquire the CT image to be processed and construct an electron density distribution model based on the CT image to be processed. The envelope interval calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions according to the electron density distribution model, so as to obtain the envelope interval. The minimum energy layer number determination module is used to determine the effective range broadening of a single-energy proton beam, and to determine the minimum energy layer number covering the envelope region based on the effective range broadening. The minimum energy layer set determination module is used to determine the minimum energy layer set based on the number of minimum energy layers.

2. The system according to claim 1, characterized in that, The density distribution model construction module includes: An image acquisition module is used to acquire the CT image to be processed and the CT values ​​corresponding to each voxel in the CT image to be processed. A calibration curve construction module is used to construct a calibration curve, which is used to characterize the relationship between the CT value and the relative electron density. The relative electron density calculation module is used to substitute the CT value into the calibration curve to obtain the relative electron density corresponding to each voxel. The relative electron density integration module is used to integrate the relative electron densities corresponding to each voxel to obtain the electron density distribution model.

3. The system according to claim 1, characterized in that, The incident angle direction includes multiple arc-shaped scanning angles obtained by uniform or non-uniform sampling along the rotation direction of the proton therapy gantry.

4. The system according to claim 1, characterized in that, The envelope interval calculation module includes: The water equivalent path length calculation module is used to calculate the water equivalent path length from the incident point on the body surface to the target voxel in the target area along multiple incident angle directions according to the electron density distribution model, and obtain the minimum and maximum water equivalent path lengths. The envelope interval determination module is used to determine the envelope interval based on the minimum value of the water equivalent path length and the maximum value of the water equivalent path length.

5. The system according to claim 4, characterized in that, The water equivalent path length calculation module includes: An incident point determination module is used to determine multiple incident points on the body surface based on the direction of each incident angle. The path construction module is used to construct multiple pencil beam paths from each of the said incident points on the body surface to each of the said target voxels; The path discretization module is used to discretize each of the pencil beam paths into several line segments, and then obtain the relative electron density of each line segment according to the electron density distribution model. An integration module is used to integrate the relative electron density of each line segment along each of the pencil beam paths to obtain the water equivalent path length. The extreme value determination module is used to determine the minimum and maximum values ​​of the water equivalent path length corresponding to each target voxel based on the water equivalent path length.

6. The system according to claim 1, characterized in that, The minimum energy layer number determination module includes: The threshold determination module is used to determine the water equivalent path length threshold. An effective range broadening determination module is used to determine the effective range broadening of a single-energy proton beam; The minimum energy layer number calculation module is used to determine the minimum energy layer number based on the effective range broadening when the maximum value of the water equivalent path length in the envelope interval is less than or equal to the water equivalent path length threshold. The early warning module is used to generate an early warning signal when the maximum value of the water equivalent path length in the envelope interval is greater than the water equivalent path length threshold.

7. The system according to claim 6, characterized in that, The effective range extension determination module includes: The factor determination module is used to obtain the energy broadening component, the range fluctuation component, and the system range error safety boundary; The effective range broadening calculation module is used to perform square root or addition operations on the energy broadening component, the range fluctuation component, and the system range error safety boundary to obtain the effective range broadening.

8. The system according to claim 6, characterized in that, The minimum energy layer number calculation module includes: A width calculation module is used to calculate the width of the envelope interval; The quantity calculation module is used to perform a ratio calculation on the width and the effective range expansion and take the integer value to obtain the minimum number of energy layers.

9. The system according to any one of claims 1 to 8, characterized in that, Each energy layer in the minimum energy layer set corresponds to a continuous arc-shaped scanning angle range, thereby reducing the number of energy switching operations.

10. A method for determining the minimum energy level set for proton arc scanning, characterized in that, Includes the following steps: Acquire the CT image to be processed, and construct an electron density distribution model based on the CT image to be processed; Based on the electron density distribution model, the water equivalent path length from the body surface to the target voxel in the target area is calculated along multiple incident angle directions to obtain the envelope interval; Determine the effective range broadening of a single-energy proton beam, and based on the effective range broadening, determine the minimum number of energy layers covering the envelope region; The set of minimum energy layers is determined based on the number of minimum energy layers.

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