阅读说明：本技术 基于扩展收缩理论的放疗计划仿真设计方法及系统 (Radiotherapy plan simulation design method and system based on expansion and contraction theory ) 是由 刘博� 肖卓 周付根 于 2020-12-01 设计创作，主要内容包括：本发明公开了一种基于扩展收缩理论的放疗计划仿真设计方法及系统,包括：在医学影像中标记肿瘤目标,建立包含肿瘤目标TV区域和OAR区域的三维影像,对三维影像均匀采样,获取目标点云数据；设置包含放射治疗入针点的模板,随机生成针道序列P,在序列P中的针道设置若干放射粒子,计算若干放射粒子的剂量分布；对放射粒子的驻留点进行扩展收缩操作,调整放射粒子驻留时间,以优化放射粒子的剂量分布；打印三维影像的三维模型、针道序列P和放射粒子的驻留点。相比于现有技术,本发明提出的方案缓解了传统的放射治疗计划对物理师经验的高度依赖,利用基于扩展收缩理论的方法对针道中放射粒子的驻留位置进行迭代优化,提升了治疗计划制定的效能。(The invention discloses a radiotherapy plan simulation design method and a radiotherapy plan simulation design system based on an expansion and contraction theory, which comprise the following steps: marking a tumor target in the medical image, establishing a three-dimensional image comprising a tumor target TV region and an OAR region, uniformly sampling the three-dimensional image, and acquiring target point cloud data; setting a template containing a radiotherapy needle-inserting point, randomly generating a needle channel sequence P, setting a plurality of radioactive particles in a needle channel in the sequence P, and calculating the dose distribution of the radioactive particles; carrying out expansion and contraction operation on the staying points of the radioactive particles, and adjusting the staying time of the radioactive particles so as to optimize the dose distribution of the radioactive particles; printing a three-dimensional model of the three-dimensional image, a needle track sequence P and the dwell points of the radioactive particles. Compared with the prior art, the scheme provided by the invention relieves the high dependence of the traditional radiotherapy plan on experience of a physicist, and the residence position of the radiation particles in the needle channel is iteratively optimized by using a method based on an expansion and contraction theory, so that the efficiency of treatment plan formulation is improved.)

1. A radiotherapy plan simulation design method based on an expansion and contraction theory is characterized by comprising the following steps:

marking a tumor target in a medical image, establishing a three-dimensional image comprising a TV area and an OAR area of the tumor target, uniformly sampling the three-dimensional image, and acquiring target point cloud data;

setting a template containing radiotherapy needle insertion points, combining any needle insertion point and any point in target point cloud data into a needle path, and randomly generating a needle path sequence P, wherein line segments of any two needle paths in the sequence P have no intersection point;

setting a plurality of radioactive particles in a needle path in the sequence P, and calculating the dose distribution of the radioactive particles;

performing expansion and contraction operation on the residence point of the radioactive particles, and adjusting the residence time of the radioactive particles so as to optimize the dose distribution of the radioactive particles;

and printing the three-dimensional model of the three-dimensional image, the needle path sequence P and the resident points of the radioactive particles by using a 3D printing technology.

2. The method of claim 1, wherein the step of performing an expansion and contraction operation on the radiation particle dwell point to adjust the radiation particle dwell time comprises:

performing an expansion operation on any dwell point where no radiation particle is set in the needle track sequence P, wherein the expansion operation comprises setting a radiation particle at the dwell point, and adjusting the dwell time of the radiation particle placed in the needle track sequence P to optimize the dose distribution of the radiation particle;

performing a contraction operation at any dwell point of the radiation particles set in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the dwell point, adjusting the dwell time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, the contraction operation is not performed;

the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

3. The method of claim 1, further comprising, after said performing an expansion and contraction operation on the radiation particle dwell point to adjust the radiation particle dwell time:

recording the target value of the dose distribution as a first optimized value;

randomly replacing any needle track in the sequence P, wherein line segments where two needle tracks are located in the sequence P do not have intersection points after replacement;

performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle track replacement, and if the target value of the dose distribution after needle track replacement is better than a first optimized value, assigning the target value of the dose distribution after needle track replacement to the first optimized value;

and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed any more or the number of needle track replacement times exceeds a first threshold value.

4. A radiotherapy plan simulation design system based on an expansion and contraction theory is characterized by comprising the following components: the system comprises a computing device and a 3D printing device, wherein the computing device comprises an image processing module, a plan generating module and a plan optimizing module;

the image processing module is used for marking a tumor target in a medical image, establishing a three-dimensional image comprising a TV region and an OAR region of the tumor target, uniformly sampling the three-dimensional image and acquiring target point cloud data;

the plan generation module is used for setting a template containing radiotherapy needle insertion points, combining any needle insertion point with any point in the target point cloud data to form a needle path, and randomly generating a needle path sequence P, wherein line segments of any two needle paths in the sequence P are provided with no intersection point; setting a plurality of radioactive particles in a needle path in the sequence P, and calculating the dose distribution of the radioactive particles;

the plan optimization module is used for performing expansion and contraction operation on the residence point of the radioactive particles and adjusting the residence time of the radioactive particles so as to optimize the dose distribution of the radioactive particles;

and the 3D printing equipment is used for printing the three-dimensional model of the three-dimensional image, the needle channel sequence P and the resident points of the radioactive particles by utilizing a 3D printing technology.

5. The system of claim 4, wherein the plan optimization module performs an expansion and contraction operation on the radiation particle dwell point, and the step of adjusting the radiation particle dwell time comprises:

performing an expansion operation on any dwell point where no radiation particle is set in the needle track sequence P, wherein the expansion operation comprises setting a radiation particle at the dwell point, and adjusting the dwell time of the radiation particle placed in the needle track sequence P to optimize the dose distribution of the radiation particle;

performing a contraction operation at any dwell point of the radiation particles set in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the dwell point, adjusting the dwell time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, the contraction operation is not performed;

the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

6. The system of claim 4, wherein the plan optimization module is further configured to:

recording the target value of the dose distribution as a first optimized value;

randomly replacing any needle track in the sequence P, wherein line segments where two needle tracks are located in the sequence P do not have intersection points after replacement;

performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle track replacement, and if the target value of the dose distribution after needle track replacement is better than a first optimized value, assigning the target value of the dose distribution after needle track replacement to the first optimized value;

and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed any more or the number of needle track replacement times exceeds a first threshold value.

Technical Field

The invention relates to the technical field of virtual surgery, in particular to a radiotherapy plan simulation design method and system based on an expansion and contraction theory.

Background

The role and position of radiotherapy in tumor treatment are increasingly prominent, and the radiotherapy has become one of the main means for treating malignant tumors. Statistically, about 70% of cancer patients require radiation therapy in the course of cancer treatment, and about 40% of cancers can be cured by radiation therapy. Tumor radiotherapy is the use of high energy radiation to irradiate cancerous tumors, kill or destroy cancer cells, and inhibit their growth, proliferation, and spread.

Radiotherapy can be divided into brachytherapy and external irradiation according to the distance between a radiation source and a patient. The brachytherapy method is to implant radioactive particles into a tumor by an interventional puncture method using an applicator or a sealed radioactive source, and to continuously kill and irradiate a lesion area with rays continuously emitted from the radioactive particles. Radioactive seed implantation uses small radioactive sources (e.g., iodine 125, etc.) of the millimeter scale. In order to reasonably place the particle source and facilitate calculation, each puncture needle is discretized into a plurality of residence points, and the radioactive source can act for certain residence time at the residence position.

The traditional radiotherapy operation plan simulation is a continuous trial and error process, a physical engineer constructs a radiotherapy plan according to radiotherapy dose distribution by experience, the radiotherapy plan is evaluated, and if the radiotherapy operation plan does not meet the operation requirement, a doctor adjusts the radiotherapy dose distribution. This process is repeated until the radiotherapy plan meets the surgically required dose distribution. This method is highly dependent on the experience of the physicist and the resulting radiotherapy plan is difficult to achieve with an optimal dose distribution.

In view of this, the invention provides a radiotherapy plan simulation design method and system based on the expansion and contraction theory, so as to alleviate the defects of the prior art.

Disclosure of Invention

In a first aspect, the present invention provides a radiotherapy plan simulation design method based on an expansion and contraction theory, including: marking a tumor target in the medical image, establishing a three-dimensional image comprising a tumor target TV region and an OAR region, uniformly sampling the three-dimensional image, and acquiring target point cloud data; setting a template containing radiotherapy needle insertion points, combining any needle insertion point and any point in target point cloud data into a needle path, and randomly generating a needle path sequence P, wherein line segments of any two needle paths in the sequence P have no intersection point; setting a plurality of radioactive particles in a needle path in the sequence P, and calculating the dose distribution of the radioactive particles; carrying out expansion and contraction operation on the staying points of the radioactive particles, and adjusting the staying time of the radioactive particles so as to optimize the dose distribution of the radioactive particles; and printing a three-dimensional model of the three-dimensional image, a needle path sequence P and a dwell point of the radioactive particles by using a 3D printing technology.

Further, the step of performing an expansion and contraction operation on the radiation particle residence point to adjust the residence time of the radiation particles includes: performing an expansion operation on any dwell point without the radiation particles in the needle track sequence P, wherein the expansion operation comprises the steps of setting the radiation particles at the dwell point, and adjusting the dwell time of the radiation particles placed in the needle track sequence P to optimize the dose distribution of the radiation particles; performing contraction operation on any residence point of the radiation particles in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the residence point, adjusting the residence time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, not performing the contraction operation; the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

Further, after the expanding and contracting operation is performed on the radiation particle residence point to adjust the residence time of the radiation particles, the method further includes: recording the target value of the dose distribution as a first optimized value; randomly replacing any needle track in the sequence P, wherein no intersection point exists in line segments where two needle tracks are located in the sequence P after replacement; performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle channel replacement, and if the target value of the dose distribution after needle channel replacement is superior to a first optimized value, endowing the target value of the dose distribution after needle channel replacement to the first optimized value; and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed or the number of needle track replacement times exceeds a first threshold value.

In a second aspect, the present invention provides a radiotherapy plan simulation design system based on the expansion and contraction theory, including: the system comprises a computing device and a 3D printing device, wherein the computing device comprises an image processing module, a plan generating module and a plan optimizing module; the image processing module is used for marking a tumor target in the medical image, establishing a three-dimensional image comprising a tumor target TV region and an OAR region, uniformly sampling the three-dimensional image and acquiring target point cloud data; the plan generation module is used for setting a template containing radiotherapy needle insertion points, combining any needle insertion point with any point in the target point cloud data to form a needle path, and randomly generating a needle path sequence P, wherein line segments of any two needle paths in the sequence P are provided with no intersection point; setting a plurality of radioactive particles in a needle path in the sequence P, and calculating the dose distribution of the radioactive particles; the plan optimization module is used for performing expansion and contraction operation on the residence point of the radiation particles and adjusting the residence time of the radiation particles so as to optimize the dose distribution of the radiation particles; and 3D printing equipment, which is used for printing the three-dimensional model of the three-dimensional image, the needle channel sequence P and the resident points of the radioactive particles by using a 3D printing technology.

Further, the step of performing an expansion and contraction operation on the radiation particle residence point by the plan optimization module and adjusting the residence time of the radiation particles includes: performing an expansion operation on any dwell point without the radiation particles in the needle track sequence P, wherein the expansion operation comprises the steps of setting the radiation particles at the dwell point, and adjusting the dwell time of the radiation particles placed in the needle track sequence P to optimize the dose distribution of the radiation particles; performing contraction operation on any residence point of the radiation particles in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the residence point, adjusting the residence time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, not performing the contraction operation; the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

Further, the plan optimization module is further configured to: recording the target value of the dose distribution as a first optimized value; randomly replacing any needle track in the sequence P, wherein no intersection point exists in line segments where two needle tracks are located in the sequence P after replacement; performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle channel replacement, and if the target value of the dose distribution after needle channel replacement is superior to a first optimized value, endowing the target value of the dose distribution after needle channel replacement to the first optimized value; and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed or the number of needle track replacement times exceeds a first threshold value.

The invention has the following beneficial effects:

the technical scheme provided by the invention can have the following beneficial effects: the radiotherapy plan simulation design method and system based on the expansion and contraction theory are provided, a radiotherapy operation implementation plan is automatically generated, the dose distribution of the radiotherapy plan is simulated and optimized, the high dependence of the traditional radiotherapy plan on experience of a physicist is relieved, and the planning efficiency of the operation plan is improved. Iterative optimization is carried out on the resident positions of the radioactive particles in the needle channels by using an optimization method based on an expansion and contraction theory, and the efficacy of treatment plan formulation is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are one embodiment of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic flow chart of a radiotherapy plan simulation design method based on the expansion and contraction theory according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a radiotherapy plan simulation design system based on the expansion and contraction theory according to a second embodiment of the present invention.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and the described embodiments are some, but not all embodiments of the present invention.

The first embodiment:

fig. 1 is a schematic flow chart of a simulation design method of radiotherapy plan based on the theory of expansion and contraction according to a first embodiment of the present invention, as shown in fig. 1, the method includes the following four steps.

Step S11: tumor targets are marked in the medical images. Specifically, a tumor target is marked in a medical image, a three-dimensional image comprising a tumor target TV region and an OAR region is established, the three-dimensional image is uniformly sampled, and target point cloud data is obtained.

It should be noted that the Target area for TV (Target volume) therapy is a clinical Target area of CTV (clinical Target volume), including established Tumor and potentially invaded tissue, the Tumor area of gtv (gross Tumor) and surrounding subclinical lesions constitute CTV, and the purpose of radiotherapy is to kill Tumor cells in the TV area. The OAR (Organ At Risk) organ-At-risk area refers to the normal organs surrounding the radiotherapy area, and is usually affected during radiotherapy.

Step S12: a radiation therapy surgical plan is generated. Specifically, a template containing radiotherapy needle insertion points is set, any needle insertion point and any point in target point cloud data are combined into a needle path, a needle path sequence P is randomly generated, and line segments of any two needle paths in the sequence P are not provided with intersection points; and setting a plurality of radioactive particles in the needle path in the sequence P, and calculating the dose distribution of the plurality of radioactive particles.

Step S13: optimizing the radiation therapy surgical plan. Specifically, the stay point of the radiation particles is expanded and contracted, and the stay time of the radiation particles is adjusted to optimize the dose distribution of the radiation particles.

In a specific embodiment, the step of performing an expansion and contraction operation on the radiation particle residence point to adjust the residence time of the radiation particle comprises: performing an expansion operation on any dwell point without the radiation particles in the needle track sequence P, wherein the expansion operation comprises the steps of setting the radiation particles at the dwell point, and adjusting the dwell time of the radiation particles placed in the needle track sequence P to optimize the dose distribution of the radiation particles; performing contraction operation on any residence point of the radiation particles in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the residence point, adjusting the residence time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, not performing the contraction operation; the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

In an optional embodiment, after performing the expansion and contraction operation on the radiation particle residence point and adjusting the residence time of the radiation particles, the method further includes: recording the target value of the dose distribution as a first optimized value; randomly replacing any needle track in the sequence P, wherein no intersection point exists in line segments where two needle tracks are located in the sequence P after replacement; performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle channel replacement, and if the target value of the dose distribution after needle channel replacement is superior to a first optimized value, endowing the target value of the dose distribution after needle channel replacement to the first optimized value; and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed or the number of needle track replacement times exceeds a first threshold value.

Step S14: the three-dimensional model and the needle track data are printed. Specifically, a three-dimensional model of the three-dimensional image, the needle track sequence P, and the dwell points of the radioactive seeds are printed using 3D printing techniques.

It should be noted that printing the three-dimensional model and needle track data of the entity can reproduce the operation plan more intuitively.

Second embodiment:

fig. 2 is a schematic structural diagram of a radiotherapy plan simulation design system based on the expansion and contraction theory according to an embodiment of the present invention, and as shown in fig. 2, the system includes: the computing device 100 comprises an image processing module 101, a plan generating module 102 and a plan optimizing module 103.

The image processing module 101 marks a tumor target in the medical image, establishes a three-dimensional image including a TV region and an OAR region of the tumor target, and uniformly samples the three-dimensional image to obtain target point cloud data.

The plan generation module 102 is used for setting a template containing radiotherapy needle insertion points, combining any needle insertion point with any point in the target point cloud data to form a needle path, and randomly generating a needle path sequence P, wherein line segments of any two needle paths in the sequence P are provided with no intersection point; and setting a plurality of radioactive particles in the needle path in the sequence P, and calculating the dose distribution of the plurality of radioactive particles.

The plan optimization module 103 performs expansion and contraction operations on the residence points of the radiation particles, and adjusts the residence time of the radiation particles to optimize the dose distribution of the radiation particles.

In a specific embodiment, the step of performing an expansion and contraction operation on the radiation particle residence point to adjust the residence time of the radiation particle comprises: performing an expansion operation on any dwell point without the radiation particles in the needle track sequence P, wherein the expansion operation comprises the steps of setting the radiation particles at the dwell point, and adjusting the dwell time of the radiation particles placed in the needle track sequence P to optimize the dose distribution of the radiation particles; performing contraction operation on any residence point of the radiation particles in the needle track sequence P, wherein the contraction operation comprises withdrawing the radiation particles at the residence point, adjusting the residence time of the radiation particles placed in the needle track sequence P, and if the contraction operation cannot optimize the dose distribution of the radiation particles, not performing the contraction operation; the expansion and contraction operations are repeated several times, or stopped when the dose distribution of the radiation particles cannot be optimized by the expansion operation.

In an alternative embodiment, the plan optimization module 103 is further configured to: recording the target value of the dose distribution as a first optimized value; randomly replacing any needle track in the sequence P, wherein no intersection point exists in line segments where two needle tracks are located in the sequence P after replacement; performing expansion and contraction operation on the radiation particle residence point, adjusting the residence time of the radiation particles to obtain a target value of the dose distribution after needle channel replacement, and if the target value of the dose distribution after needle channel replacement is superior to a first optimized value, endowing the target value of the dose distribution after needle channel replacement to the first optimized value; and continuing to randomly replace any needle track in the sequence P until the first optimization value is not changed or the number of needle track replacement times exceeds a first threshold value.

The 3D printing apparatus 200 prints a three-dimensional model of a three-dimensional image, a needle track sequence P, and a dwell point of a radioactive particle using a 3D printing technique.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.