An accelerator gantry uniform rotation system for a proton therapy system

Abstract

The application discloses a kind of for the method, system, equipment and medium of proton arc therapy implementation, comprising: design proton arc therapy plan, based on proton arc therapy plan carries out proton treatment, in the course of proton arc therapy, tumor is divided into several equal-energy layers along depth direction, and each energy layer is correspondingly provided with control point and several irradiation points;The corresponding beam spot delivery time, beam spot conversion time and energy layer conversion time of each control point are calculated, and the dose delivery total time of each control point is calculated based on beam spot delivery time, beam spot conversion time and energy layer conversion time;With the equal goal of the dose delivery total time of each control point, the dose delivery total time corresponding to each control point is adjusted, and the uniform rotation of proton radiotherapy system gantry is realized.The technical scheme of the present application can reduce the mechanical burden of gantry while improving the dose rate.

Description

Technical Field

[0001] This invention belongs to the field of medical physics simulation and calculation technology, and in particular relates to a method, system, device and medium for implementing proton arc therapy. Background Technology

[0002] In recent years, radiotherapy, one of the three major cancer treatment methods, has been developing rapidly. Compared with photon radiotherapy, proton radiotherapy has better target conformity and can better treat deep tumors. Proton arc therapy has attracted much attention due to its ability to continuously deliver a proton beam during gantry rotation. Compared with intensity-modulated proton therapy (IMPT), proton arc therapy can significantly reduce damage to organs at risk and has the potential advantage of providing robust treatment planning quality.

[0003] Achieving continuous gantry rotation has been a major obstacle in proton arc therapy delivery technology. Proton gantry systems typically weigh over 100 tons, and rapid acceleration or deceleration leads to significant wear and tear, placing a heavy burden on mechanical systems such as gantry motors, circuit breakers, rolling floors, and wire magnets. To avoid any interference, the ideal approach is to deliver the proton arc therapy plan at a constant speed, similar to conventional CBCT acquisition. Different proton arc therapy plans using different optimized gantry systems may result in varying irradiation times for each beam, necessitating rapid acceleration or deceleration of the gantry to connect control points and ensure the proton arc plan rotates out of the beam for successful execution. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, device, and medium for performing proton arc therapy, in order to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides a method for performing proton arc therapy, comprising:

[0006] A proton arc therapy plan is designed based on the patient's target area, and proton therapy is performed based on the proton arc therapy plan. During the proton arc therapy, the tumor is divided into several iso-energy layers along the depth direction, and each energy layer is provided with control points and several irradiation points.

[0007] Calculate the beam spot delivery time, beam spot transition time, and energy layer transition time for each control point, and calculate the total dose delivery time for each control point based on the beam spot delivery time, beam spot transition time, and energy layer transition time;

[0008] With the goal of ensuring that the total dose delivery time at each control point is equal, the total dose delivery time corresponding to each control point is adjusted to achieve uniform rotation of the proton radiotherapy system gantry.

[0009] Optionally, the design of the proton arc therapy plan based on the patient's target location specifically includes:

[0010] The scanning angle is set based on the patient's target area location and the location of organs at risk, and the arc-shaped region is determined based on the scanning angle;

[0011] The equivalent water depth thickness along the beam path is calculated by combining the path tracking method. Cluster analysis is performed on the equivalent water depth thickness, and the optimal number of arc intervals and the corresponding angle range are determined based on the cluster analysis results.

[0012] Based on the optimal number of arc-shaped intervals and the corresponding angle range, the arc-shaped region is divided into several arc-shaped intervals; among them, the beam energy corresponding to the initial angle of each arc-shaped interval is the energy corresponding to the maximum equivalent water depth thickness of that interval.

[0013] Based on the division of the arc-shaped intervals to control the rotation of the gantry, the beam energy at each control point decreases sequentially during the rotation of the gantry, so as to achieve continuous beam output throughout the entire gantry rotation and complete the proton arc therapy plan.

[0014] Optionally, the proton therapy based on the proton arc therapy plan specifically includes:

[0015] Based on a preset depth dose, a fine proton beam is used to scan and cover the target area through a magnetic field. Proton irradiation is then used to scan and irradiate each isoenergy layer layer by layer until each isoenergy layer and its corresponding irradiation point are irradiated.

[0016] Optionally, the calculation process for the total dose delivery time at each of the control points specifically includes:

[0017] During proton arc therapy, once a point is irradiated by the proton beam, the beam is turned off, the scanning iron current is changed, and the beam is moved to the next point. Irradiation continues until the preset point is irradiated by the proton beam. The time for each point to be irradiated by the proton beam is the beam spot delivery time, the time from turning off the beam to moving the beam to the next point is the beam spot conversion time, and the conversion time between energy layers is the energy layer conversion time.

[0018] The total dose delivery time for each control point is calculated based on the beam spot delivery time, beam spot conversion time, and energy layer conversion time.

[0019] Optionally, adjusting the total dose delivery time corresponding to each control point specifically includes:

[0020] With the goal of making the total dose delivery time equal at each of the control points, the beam spot delivery time, beam spot conversion time, and energy layer conversion time corresponding to each of the control points are adjusted.

[0021] The adjustment process includes: adjusting the beam delivery time by controlling the beam intensity of the proton beam, adjusting the beam conversion time by controlling the beam scanning speed of the gantry, and adjusting the energy layer conversion time by controlling the buffer area between adjacent control points.

[0022] A system for implementing proton arc therapy, comprising:

[0023] The delivery plan design module is used to design a proton arc therapy plan based on the patient's target area location.

[0024] The dose delivery time calculation module is used to perform proton therapy according to the proton arc therapy plan. During the proton arc therapy, the tumor is divided into several isoenergy layers along the depth direction. Each energy layer is provided with a control point and several irradiation points. The module calculates the beam spot delivery time, beam spot conversion time and energy layer conversion time corresponding to each control point, and calculates the total dose delivery time of each control point based on the beam spot delivery time, beam spot conversion time and energy layer conversion time.

[0025] The proton radiotherapy system gantry control module is used to adjust the total dose delivery time corresponding to each control point with the goal of making the total dose delivery time of each control point equal, so as to achieve uniform rotation of the proton radiotherapy system gantry.

[0026] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to cause the electronic device to perform the method for implementing proton arc therapy.

[0027] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for performing proton arc therapy.

[0028] The technical effects of this invention are as follows:

[0029] The method provided by this invention enables the gantry to rotate at a constant speed, reducing the frequent acceleration and deceleration of gantry weighing over 100 tons, thus alleviating the mechanical burden of gantry rotation and extending its service life. After the gantry rotates at a constant speed, the total dose delivery time and dynamic dose delivery time calculated according to the dose delivery model are both reduced, thereby improving dose delivery efficiency. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 This is a flowchart illustrating the implementation process of making the proton radiotherapy system gantry rotate at a constant speed during proton arc therapy according to Embodiment 1 of the present invention.

[0033] Figure 2 This is a dose distribution diagram of Embodiment 1 of the present invention.

[0034] Figure 3 This is a dynamic relationship diagram of the original rack rotation speed, proton beam "on / off" delivery state, energy rise or fall, and rack cumulative angle obtained in Embodiment 1 of the present invention.

[0035] Figure 4 This is a dynamic relationship diagram of the rack rotation speed, proton beam "on / off" delivery state, energy rise or fall, and rack cumulative angle after adjusting the beam, obtained in Embodiment 1 of the present invention.

[0036] Figure 5 This is a dynamic relationship diagram of the rack rotation speed, proton beam "on / off" delivery state, energy rise or fall, and rack cumulative angle after adjusting the beam spot scanning speed, obtained in Embodiment 1 of the present invention.

[0037] Figure 6 This is a dynamic relationship diagram of the rack rotation speed, proton beam "on / off" delivery state, energy rise or fall, and rack cumulative angle after a specific buffer area is designed, obtained in Embodiment 1 of the present invention. Detailed Implementation

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0041] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] like Figure 1 - Figure 6 As shown, this embodiment provides a method for implementing proton arc therapy, including: designing a proton arc therapy plan based on the patient's target area location; performing proton therapy based on the proton arc therapy plan; during the proton arc therapy process, dividing the tumor into several isoenergy layers along the depth direction, with each energy layer corresponding to a control point and several irradiation points; calculating the corresponding speckle delivery time, speckle transition time, and energy layer transition time for each control point; calculating the total dose delivery time for each control point based on the speckle delivery time, speckle transition time, and energy layer transition time; and adjusting the total dose delivery time corresponding to each control point with the goal of making the total dose delivery time of each control point equal, thereby achieving uniform rotation of the proton radiotherapy system gantry.

[0045] This embodiment relates to a method for achieving uniform rotation of the proton therapy system gantry during proton arc therapy, comprising: step S1: designing a proton arc therapy plan; step S2: calculating the time according to the dose delivery mode of the proton therapy system; step S3: adjusting the beam intensity and beam spot scanning time of each beam, and designing a scanning buffer area at each control point; step S4: achieving uniform rotation of the gantry. This embodiment can reduce the mechanical burden on the gantry while improving the dose delivery effect, and promotes the development of proton arc therapy technology.

[0046] like Figure 1 As shown, three methods for rotating the proton therapy system gantry at a constant speed during proton arc therapy include:

[0047] Step S1: Arrange all beams within the arc-shaped region in an arc shape with fixed gantry angles as intervals. Divide the arc-shaped region using a clustering method to ensure that the energy of each beam in each sub-region is arranged in descending order, thereby realizing the proton arc-shaped therapy delivery plan.

[0048] S1.1. Arc Region Division: When designing proton arc therapy, an appropriate scanning angle is set based on the location of the patient's target area and the location of surrounding organs at risk. During proton arc therapy, the proton radiotherapy system gantry rotates and scans from a specified initial angle to another angle. In treatment plans without arc division, the gantry frequently accelerates and decelerates due to differences in beam energy at each control point. The proton therapy machine gantry weighs hundreds of tons, and frequent acceleration and deceleration during rotation can lead to mechanical wear. Previous studies have found that the gantry can achieve energy reduction conversion in a shorter time during rotation. However, when the required arc angle is large, it is difficult to achieve energy reduction conversion throughout the entire arc scanning process. Therefore, dividing the arc into segmented arc regions makes energy reduction conversion easier to achieve while avoiding frequent gantry acceleration and deceleration. The equivalent water depth thickness (WET) along the beam path from the incident point to the distal end of the tumor is calculated using the path tracing method. The WET is then clustered using a clustering method to divide the arc-shaped region into arc-shaped intervals, in order to determine the optimal number of arc-shaped intervals and the angular range included in each interval.

[0049] S1.2. Energy is arranged in descending order to achieve a proton arc therapy delivery plan. The initial angle of each arc segment corresponds to the beam energy of the segment with the maximum WET value. Within the arc segment, the beam energy at each control point decreases sequentially with the rotation direction. The entire plan can achieve proton arc therapy delivery while the gantry is rotating.

[0050] Step S2: Obtain the corresponding spot switch time (T) according to the different dose delivery modes of the proton radiotherapy system under study. sswt Spot Spill Time (T) sspt ) and Energy Switching Time (T est The total dose delivery time (Beam Delivery Time, T) can be calculated using the above time. BDT ).

[0051] S2.1, Intensity-Modulated Proton Therapy (IMRT), involves using a fine proton beam to scan and cover the outer edge of the target area via a magnetic field. The dose at different depths is controlled by using different proton beam energies and a range converter. The tumor is divided into different isoenergetic layers along the depth direction, each irradiated with protons of the same energy. Each layer has a certain number of irradiation points. Irradiation typically begins with the deepest layer. Once all irradiation points in that layer have reached the preset dose, the proton beam energy is changed, and the next layer is irradiated. This process is repeated layer by layer until all isoenergetic layers and irradiation points are irradiated. In this arc-shaped proton therapy, each control point corresponds to only one energy layer, eliminating the possibility of changing the beam within a control point.

[0052] S2.2, Dose Delivery Time: During proton rotation intensity-modulated dose delivery, after one irradiation point is irradiated, the beam is shut off, the scanning iron current is changed, and the beam is moved to the next irradiation point, continuing irradiation until all planned irradiation points are irradiated. The time spent irradiating at each irradiation point is called the spot spike time (T). SSPT The beam spot switching time (T0) is determined by the beam current intensity. The time required to switch the beam current off, change the scanning iron current, and move the beam to the next irradiation point is called the spot switching time (T0). SSWT The energy level is related to the rack rotation speed; the beam energy is different at each control point, and the transition time between energy layers is denoted as Energy Switch Time (T). EST Conventional proton therapy systems can calculate the total dose delivery time (Beam Delivery Time, T) at each control point using these time parameters. BDT The calculation formula is as follows:

[0053] T BDT =T SSWT +T SSPT +T EST .

[0054] Step S3, (1)T SSPT Depends on the beam current intensity; (2)T SSWT The beam spot scanning speed depends on the gantry; (3) there is a buffer zone between adjacent control points. The T of each control point can be adjusted by changing the beam intensity of each beam, the scanning speed of each control point, and by designing a specific buffer zone for each control point. BDT equal.

[0055] S3.1, T SSPT Depending on the beam intensity, the number of protons per beam spot is fixed after completing a proton therapy plan and optimizing the dosage. For the same number of protons delivered, a stronger beam intensity results in a higher Tg. SSPTThe shorter the beam, the greater the beam intensity and T. SSPT There is an inverse relationship between them.

[0056]

[0057] Where BI represents beam intensity; T i For the delivery time of the smallest unit (MU), and N particle The charge of a single proton.

[0058] S3.2, T SSWT Depending on the beam spot scanning speed of the gantry, proton arc therapy uses a fine proton beam to scan and cover the outer part of the target area via a magnetic field. The depth of the dose is controlled by using different proton beam energies and range converters. Once the proton beam has covered the target area, its beam spot delivery position is fixed. This embodiment aims to shorten the T-wave length by changing the gantry beam spot scanning speed between beams with the same spacing. SSWT .

[0059] S3.3. A buffer zone exists between adjacent control points. Due to the difference in beam energy, a buffer zone exists between adjacent control points for energy layer conversion. The gantry will not emit beams when scanning this region. Each control point has a fixed scanning angle, and each control point is designed with a specific buffer zone angle, enabling T-scanning at each control point. BDT same.

[0060] As shown in formula S2.2, by adjusting the beam intensity of each beam, the scanning speed of each control point, and by designing a specific buffer region for each control point, the T value of each control point can be optimized. BDT equal.

[0061] Step S4, T for each control point BDT Equal speeds can achieve uniform rotation of the proton therapy system gantry.

[0062] The frame rotation speed is defined as follows:

[0063]

[0064] θ=θ de +θ buf

[0065] Where v represents the rack rotation speed, and θ represents the fixed angle at each control point, the size of which can be defined according to specific circumstances. θ is determined by the output beam region θ de and buffer region θ buf Composed of [various components]. With θ as a fixed value, T is adjusted to each control point. BDT Equal speeds are achieved when the proton therapy system gantry rotates at a uniform speed.

[0066] Figure 2This is the dose distribution map obtained in this embodiment. It can be seen that the dose is evenly distributed in the target area with high conformity, meeting the prescription dose requirements of the target area.

[0067] Figure 3 This is a dynamic relationship diagram of the original rack rotation speed, proton beam "on / off" delivery state, energy rise or fall, and rack cumulative angle obtained in Embodiment 1. It can be seen that there is a significant rack rotation deceleration during each energy rise phase, and the rack rotation speed is inconsistent during the energy fall phase between beams.

[0068] Figure 4 This is a dynamic relationship diagram of the gantry rotation speed, proton beam "on / off" delivery state, energy rise or fall, and cumulative gantry angle after beam adjustment obtained in Embodiment 1. It can be seen that the gantry rotation speed reaches a constant speed during the dose delivery process.

[0069] Figure 5 This is a dynamic relationship diagram of the gantry rotation speed, proton beam "on / off" delivery state, energy rise or fall, and gantry cumulative angle after adjusting the beam spot scanning speed in this embodiment. It can be seen that the gantry rotation speed reaches a constant speed during the dose delivery process.

[0070] Figure 6 This is a dynamic relationship diagram of the gantry rotation speed, proton beam "on / off" delivery state, energy rise or fall, and cumulative gantry angle after the design-specific buffer zone obtained in Embodiment 1. It can be seen that the gantry rotation speed reaches a constant speed during the dose delivery process.

[0071] By comparing the planned quality before and after (1) adjusting the beam, (2) adjusting the beam spot scanning speed, and (3) designing a specific buffer area, the dose distribution of the target area and organs at risk meets the prescription requirements. In this embodiment, the gantry rotates at a constant speed, which reduces the frequent acceleration and deceleration of the gantry weighing more than 100 tons, reduces the mechanical burden of gantry rotation, and extends service life. After the gantry rotates at a constant speed, the total dose delivery time and dynamic delivery time calculated according to the dose delivery model are reduced, thus improving the dose delivery efficiency.

[0072] A system for implementing proton arc therapy, comprising:

[0073] The delivery plan design module is used to design a proton arc therapy plan based on the patient's target area location.

[0074] The dose delivery time calculation module is used to perform proton therapy according to the proton arc therapy plan. During the proton arc therapy, the tumor is divided into several isoenergy layers along the depth direction. Each energy layer is provided with a control point and several irradiation points. The module calculates the beam spot delivery time, beam spot conversion time and energy layer conversion time corresponding to each control point, and calculates the total dose delivery time of each control point based on the beam spot delivery time, beam spot conversion time and energy layer conversion time.

[0075] The proton radiotherapy system gantry control module is used to adjust the total dose delivery time corresponding to each control point with the goal of making the total dose delivery time of each control point equal, so as to achieve uniform rotation of the proton radiotherapy system gantry.

[0076] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to cause the electronic device to perform the method for implementing proton arc therapy.

[0077] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for performing proton arc therapy.

[0078] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A uniform rotation system for an accelerator gantry in a proton therapy system, characterized in that, include: The delivery plan design module is used to design proton arc therapy plans based on the target area location; The dose delivery time calculation module is used to calculate the dose delivery time of the control points based on the distribution of irradiation points. The processing procedure of the dose delivery time calculation module specifically includes: during proton arc therapy, dividing the tumor into several isoenergy layers along the depth direction, with each energy layer corresponding to a control point and several irradiation points; calculating the beam spot delivery time, beam spot conversion time, and energy layer conversion time corresponding to each control point; and calculating the total dose delivery time for each control point based on the beam spot delivery time, beam spot conversion time, and energy layer conversion time. The calculation process for the total dose delivery time at each control point specifically includes: during proton arc therapy, after a point is irradiated by the proton beam, the beam is shut off, the scanning iron current is changed, the beam is moved to the next point, and irradiation continues until the preset point is irradiated by the proton beam; wherein, the time for each point to be irradiated by the proton beam is the beam spot delivery time, the time from shutting off the beam to moving the beam to the next point is the beam spot conversion time, and the conversion time between energy layers is the energy layer conversion time; the total dose delivery time at each control point is calculated based on the beam spot delivery time, the beam spot conversion time, and the energy layer conversion time. The proton radiotherapy system gantry control module is used to adjust the total dose delivery time corresponding to each control point with the goal of making the total dose delivery time of each control point equal, so as to achieve uniform rotation of the proton radiotherapy system gantry. The processing procedure of the proton therapy system gantry control module specifically includes: The beam delivery time is adjusted by controlling the beam intensity of the proton beam, the beam conversion time is adjusted by controlling the beam scanning speed of the gantry, and the energy layer conversion time is adjusted by controlling the buffer area between adjacent control points. Equal total dose delivery time at each control point ensures uniform rotation of the proton therapy system gantry. The gantry rotation speed is defined as: θ=θ de +θ buf Where v represents the frame rotation speed, θ represents the fixed angle at each control point, and θ is determined by the output beam region θ de and buffer region θ buf Composed of a given value where θ is constant, the total dose delivery time T at each control point is adjusted. BDT Equal speeds are achieved when the proton therapy system gantry rotates at a uniform speed.

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