CN103065054A - Method for processing radiotherapy precision data on basis of probability safety analysis - Google Patents

Abstract

Translated fromChinese

本发明涉及一种基于概率安全分析的放疗精确性数据处理方法，是概率安全分析方法在精确放疗系统中的实现途径，其特征是利用概率安全分析中的数据分析方法来分析精确放射治疗中对精确度有关键影响的各个参数的因果联系，通过建模处理数据分析精确性失效概率，评价各个系统以及人为因素对精确性的影响，找出关键问题，纠正关键偏差，从而提高精确放疗的质量。

The invention relates to a radiotherapy accuracy data processing method based on probabilistic safety analysis, which is a method for realizing the probabilistic safety analysis method in the precise radiotherapy system, and is characterized in that the data analysis method in the probabilistic safety analysis is used to analyze the accuracy of radiotherapy in precise radiotherapy. Accuracy has a key influence on the causality of each parameter, through modeling and processing data analysis accuracy failure probability, evaluating the impact of various systems and human factors on accuracy, identifying key problems, correcting key deviations, thereby improving the quality of precision radiotherapy .

Description

Translated fromChinese

一种基于概率安全分析的放疗精确性数据处理方法A radiotherapy accuracy data processing method based on probabilistic safety analysis

技术领域technical field

本发明涉及概率安全分析的技术领域，具体涉及一种基于概率安全分析的放疗精确性数据分析方法，其将概率安全分析中的数据分析方法应用于精确放疗中复杂系统的分析，利用故障树的建模方式分析精确性失败的事故序列，生成的数据可以应用于放疗计划系统，用来分析和评估放治疗精确射性。The present invention relates to the technical field of probabilistic safety analysis, in particular to a radiotherapy accuracy data analysis method based on probabilistic safety analysis, which applies the data analysis method in probabilistic safety analysis to the analysis of complex systems in precise radiotherapy, and utilizes the The modeling method analyzes the accident sequence of accuracy failure, and the generated data can be applied to the radiotherapy planning system to analyze and evaluate the accuracy of radiotherapy.

背景技术Background technique

随着医学物理和计算机科学的发展，放射治疗精确性要求越来越高，但总有一些因素制约着剂量或靶区适形的精确性，如靶区定位、治疗摆位、不同的调强技术和不同的操作者等，这就造成了放射治疗的不确定性，即精确性可能失败。现在对于结果精确性的研究仅限于对单个因素的分析，对单个因素造成的不同误差百分率进行对比，从而分析并择优利用。然而放射治疗过程是多因素的综合，多个因素协同作用下精确度大小尚无可以应用的评估方法。目前有人用概率安全分析方法来分析高剂量率后装放疗中剂量错误所发生的事故，仅是内照射治疗中的一个关于机械安全性的事件，不适用于外照射，更不能反映放疗精确性。With the development of medical physics and computer science, the accuracy of radiation therapy is getting higher and higher, but there are always some factors that restrict the accuracy of dose or target area conformity, such as target area positioning, treatment positioning, different intensity modulation Techniques and different operators, etc., this creates uncertainty in radiation therapy, that is, accuracy may fail. The current research on the accuracy of the results is limited to the analysis of a single factor, and the different error percentages caused by a single factor are compared, so that they can be analyzed and used optimally. However, the radiotherapy process is a combination of many factors, and there is no applicable evaluation method for the accuracy under the synergistic effect of multiple factors. At present, some people use the method of probabilistic safety analysis to analyze the accidents caused by dose errors in high dose rate afterloading radiotherapy. It is only an event related to mechanical safety in internal irradiation treatment, which is not applicable to external irradiation, let alone reflect the accuracy of radiotherapy. .

目前在核电站有多年运行经验的概率安全分析方法可以为上述多因素协同评价提供借鉴，利用类似于故障树的分析推理方法将每一步骤和最后的事故发生的可能性间接相关联。放射治疗中是可以建立原因和结果的对应关系的，并利用长期积累的数据，为分析做好基础准备。核电站普遍应用的概率安全评价系统不能直接应用于放射治疗精确性的分析，放射治疗必须建立自己的数据分析模式。本专利应用概率安全分析方法来分析精确放疗结果中违背精确性的事件发生概率，以及在此概率下放疗过程中各系统对事故的贡献大小，是针对精确放疗系统照射区适形度和吸收剂量精确性的分析，是各个因素综合作用的结果，可以作为精确放疗系统综合评价指标。At present, the probabilistic safety analysis method with many years of operating experience in nuclear power plants can provide reference for the above-mentioned multi-factor collaborative evaluation, using an analytical reasoning method similar to a fault tree to indirectly relate each step to the possibility of the final accident. In radiation therapy, it is possible to establish the corresponding relationship between cause and effect, and use long-term accumulated data to prepare for analysis. The probabilistic safety evaluation system commonly used in nuclear power plants cannot be directly applied to the analysis of the accuracy of radiotherapy, and radiotherapy must establish its own data analysis model. This patent uses the probabilistic safety analysis method to analyze the probability of occurrence of events that violate the accuracy in the results of precise radiotherapy, and the contribution of each system to the accident during the radiotherapy process under this probability, which is aimed at the conformity of the irradiation area and absorbed dose of the precise radiotherapy system The analysis of accuracy is the result of the combined effect of various factors, which can be used as a comprehensive evaluation index for the precision radiotherapy system.

发明内容Contents of the invention

本研究方法拓宽了概率安全分析方法的应用范围，提供了放射治疗精确性研究的系统分析途径，其前瞻性如下：The method of this study broadens the scope of application of the probabilistic safety analysis method, and provides a systematic analysis approach for the study of radiotherapy accuracy, and its prospective is as follows:

1、概率安全分析方法作为一种成熟的系统评价方法，目前主要应用于核电站、航天领域等涉及重大安全的事件分析。对于复杂系统共同作用的结果，不一定和安全相关，只要合乎此种方法的分析原理以及可以实现分析路径，就可以应用概率安全分析方法进行分析，本专利演示了具体实施过程，提供了可行性路径，拓宽了概率安全分析这种数据分析方法的应用范围，将在更多领域发挥作用。1. Probabilistic safety analysis method, as a mature system evaluation method, is currently mainly used in the analysis of major safety events in nuclear power plants and aerospace fields. The result of the joint action of complex systems is not necessarily related to safety. As long as the analysis principle of this method is met and the analysis path can be realized, the probabilistic safety analysis method can be used for analysis. This patent demonstrates the specific implementation process and provides feasibility. The path broadens the scope of application of probabilistic security analysis, a data analysis method, and will play a role in more fields.

2、将生成的数据和治疗计划系统集成，可以实时反映精确度和事后评价，为评价精确度和放疗方案优劣提供了量化标准。数据可以单独用于评价，也可以与放射治疗计划系统联合，将概率安全分析软件以及经验性数据设计作为放射治疗计划系统的一个辅助性的子系统，可以自动识别当前操作的初始事件，对每一个重要计划设计步骤显示经验错误概率和该系统的重要性大小，可以实时监测和验证放射治疗实施过程精确性。2. Integrate the generated data with the treatment planning system, which can reflect the accuracy and post-event evaluation in real time, and provide a quantitative standard for evaluating the accuracy and the quality of the radiotherapy plan. The data can be used alone for evaluation, or combined with the radiotherapy planning system, and the probabilistic safety analysis software and empirical data design can be used as an auxiliary subsystem of the radiotherapy planning system, which can automatically identify the initial event of the current operation, An important planning design step shows the empirical error probability and the importance of the system, which can monitor and verify the accuracy of the radiation therapy delivery process in real time.

本发明采用的技术方案为：一种基于概率安全分析的放疗精确性数据处理方法，将放射治疗过程各步骤对应于复杂系统的事件发生过程，建立故障树模型，利用概率安全分析软件处理概率数据，从而得出精确性失败的概率及各步骤重要性大小，其步骤如下：The technical solution adopted in the present invention is: a radiotherapy accuracy data processing method based on probabilistic safety analysis, which corresponds each step of the radiotherapy process to the event occurrence process of the complex system, establishes a fault tree model, and uses probabilistic safety analysis software to process probability data , so as to obtain the probability of accuracy failure and the importance of each step, the steps are as follows:

步骤（1）、利用现有的放射治疗技术收集初始数据，作为概率安全分析方法中的源数据，包括：基本事件概率及概率的误差数据、人因失误相关的数据、共因相关的数据；Step (1), using the existing radiotherapy technology to collect initial data, as the source data in the probabilistic safety analysis method, including: basic event probability and probability error data, data related to human errors, and data related to common causes;

步骤（2）、将放射治疗精确性失败作为顶事件，对放射治疗过程进行故障树建模，将所有对放射治疗有关键影响的因素分为剂量错误、摆位错误、靶区勾画错误、输出错误4大类，对每一类分别展开，分析直接导致其发生的所有因素，直到初始事件为止；将顶事件、中间结果、初始事件统称为事件，将单独发生就导致上一层事件发生的事件用或门连接，联合发生才导致上一层事件发生的事件用与门连接，从而可将所有事件链接成一棵故障树；Step (2), taking the failure of radiotherapy accuracy as the top event, modeling the radiotherapy process as a fault tree, and dividing all factors that have a key impact on radiotherapy into dose errors, setup errors, target delineation errors, and output There are 4 major categories of errors, expand each category separately, and analyze all the factors that directly lead to its occurrence until the initial event; the top event, intermediate result, and initial event are collectively called events, and if they occur alone, they will lead to the occurrence of the previous event Events are connected with OR gates, and events that lead to events on the previous layer are connected with AND gates, so that all events can be linked into a fault tree;

步骤（3）、将故障树模型中各初始事件概率数据及其它源数据输入概率分析软件，系统自动计算最小割集并进行定量分析，结果用于精确性评估及重要性分析。Step (3), input the probability data of each initial event in the fault tree model and other source data into the probability analysis software, the system automatically calculates the minimum cut set and conducts quantitative analysis, and the results are used for accuracy evaluation and importance analysis.

本发明在放疗精确度领域具有很高的指导意义和应用价值，其具体应用价值如下：The present invention has high guiding significance and application value in the field of radiotherapy accuracy, and its specific application value is as follows:

①、本发明能够评价不同的设计选择方案；①. The present invention can evaluate different design options;

②、本发明能够识别设计中的缺点；②, the present invention can identify the shortcomings in the design;

③、本发明能够在误差预防和改善精确度之间建立综合平衡；③. The present invention can establish a comprehensive balance between error prevention and accuracy improvement;

④、本发明能够从概率安全分析角度识别治疗过程中某个步骤重要性；④. The present invention can identify the importance of a certain step in the treatment process from the perspective of probabilistic safety analysis;

⑤、本发明能够找出人因错误相关的一些问题。5. The present invention can find out some problems related to human error.

附图说明Description of drawings

图1是本发明具体实施流程图；Fig. 1 is the concrete implementation flowchart of the present invention;

图2是建模示例。Figure 2 is a modeling example.

具体实施方式Detailed ways

如图1所示，一种基于概率安全分析的放疗精确性数据分析方法，其实施步骤如下：As shown in Figure 1, a radiotherapy accuracy data analysis method based on probabilistic safety analysis, its implementation steps are as follows:

（1）利用现有的放射治疗经验数据，或者模拟实验数据来收集初始数据，作为概率安全分析方法中的源数据，包括：基本事件概率及概率的误差数据、人因失误相关的数据、共因相关的数据；(1) Use the existing radiotherapy experience data or simulated experimental data to collect initial data as the source data in the probabilistic safety analysis method, including: basic event probability and probability error data, data related to human errors, total related data;

（2）将放射治疗精确性失败作为顶事件，对放射治疗过程进行故障树建模，将所有对放射治疗有关键影响的因素分为剂量错误、摆位错误、靶区勾画错误、输出错误4大类，对每一类分别展开，分析直接导致其发生的所有因素，直到初始事件为止，从而可将所有事件链接成一棵故障树；(2) Taking the failure of radiotherapy accuracy as the top event, modeling the radiotherapy process as a fault tree, and dividing all factors that have a key impact on radiotherapy into dose errors, setup errors, target area delineation errors, and output errors4 Large categories, expand each category separately, analyze all factors that directly lead to its occurrence, until the initial event, so that all events can be linked into a fault tree;

（3）将故障树模型中各初始事件概率数据及其它源数据输入概率分析软件，系统自动计算最小割集并进行定量分析，结果用于精确性评估及重要性分析。(3) Input the probability data of each initial event in the fault tree model and other source data into the probability analysis software, and the system automatically calculates the minimum cut set and conducts quantitative analysis, and the results are used for accuracy evaluation and importance analysis.

计算过程由概率安全分析软件实现，求顶事件发生概率计算公式如下：The calculation process is realized by the probabilistic safety analysis software, and the formula for calculating the probability of occurrence of the top event is as follows:

$\mathrm{<span><span>P</span>P</span>}<span><span>(</span>(</span>\mathrm{<span><span>T</span>T</span>}<span><span>)</span>)</span><span><span>=</span>=</span>\underset{\mathrm{<span><span>r</span>r</span>}<span><span>=</span>=</span>\mathrm{<span><span>1</span>1</span>}}{\overset{\mathrm{<span><span>k</span>k</span>}}{\mathrm{<span><span>\&Sigma;</span>\&Sigma;</span>}}}\underset{{\mathrm{<span><span>x</span>x</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>\&Element;</span>\&Element;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>r</span>r</span>}}}{\mathrm{<span><span>\&Pi;</span>\&Pi;</span>}}{\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>-</span>-</span>\underset{\mathrm{<span><span>1</span>1</span>}<span><span>\&le;</span>\&le;</span>\mathrm{<span><span>r</span>r</span>}<span><span>\&le;</span>\&le;</span>\mathrm{<span><span>s</span>the\; s</span>}<span><span>\&le;</span>\&le;</span>\mathrm{<span><span>k</span>k</span>}}{\mathrm{<span><span>\&Sigma;</span>\&Sigma;</span>}}\underset{{\mathrm{<span><span>x</span>x</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>\&Element;</span>\&Element;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>r</span>r</span>}}<span><span>\&cup;</span>\&cup;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>s</span>the\; s</span>}}}{\mathrm{<span><span>\&Pi;</span>\&Pi;</span>}}{\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>+</span>+</span><span><span>\&CenterDot;</span>\&Center\; Dot;</span><span><span>\&CenterDot;</span>\&Center\; Dot;</span><span><span>\&CenterDot;</span>\&CenterDot;</span><span><span>+</span>+</span>{<span><span>(</span>(</span><span><span>-</span>-</span>\mathrm{<span><span>1</span>1</span>}<span><span>)</span>)</span>}^{\mathrm{<span><span>k</span>k</span>}<span><span>-</span>-</span>\mathrm{<span><span>1</span>1</span>}}\underset{{\mathrm{<span><span>x</span>x</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>\&Element;</span>\&Element;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>\&cup;</span>\&cup;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>2</span>2</span>}}<span><span>\&cup;</span>\&cup;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>3</span>3</span>}}<span><span>.</span>.</span><span><span>.</span>.</span><span><span>.</span>.</span><span><span>\&cup;</span>\&cup;</span>{\mathrm{<span><span>E</span>E.</span>}}_{\mathrm{<span><span>k</span>k</span>}}}{\overset{\mathrm{<span><span>k</span>k</span>}}{\underset{\mathrm{<span><span>r</span>r</span>}<span><span>=</span>=</span>\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>\&Pi;</span>\&Pi;</span>}}}}{\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>i</span>i</span>}}$

式中：r、s、k—最小割集的序号，r＜s＜k；In the formula: r, s, k—the serial number of the smallest cut set, r<s<k;

1≤r＜s≤k—k个最小割集中第r、s两个割集的组合顺序；1≤r<s≤k—combination sequence of the rth and sth cut sets in the k smallest cut sets;

x_i∈E_r—属于第r个最小割集的第i个基本事件；x_i ∈ E_r — the i-th basic event belonging to the r-th minimum cut set;

x_i∈E_r∪E_s—属于第r个或第s个最小割集的第i个基本事件；x_i ∈E_r ∪E_s — the i-th basic event belonging to the r-th or s-th minimum cut set;

i—基本事件的序号；i—the sequence number of the basic event;

q_i—基本事件的发生概率。q_i —the probability of occurrence of the basic event.

将顶事件定义为精确性失败，即最终适形度或吸收剂量误差率>±5%为失去了精确的意义，故障树主干为主要的导致不精确的因素，追踪到整个放疗系统的初始事件，对于必然存在误差的初始事件，用误差率＞±5%表示错误，＜±5%范围内为正确，并使用逻辑门表达事件之间的逻辑关系，最终完成建模。Defining the top event as a precision failure, that is, the final conformity or absorbed dose error rate >±5% means that the meaning of precision is lost, and the trunk of the fault tree is the main factor leading to inaccuracy, which is traced to the initial event of the entire radiotherapy system , for the initial events that must have errors, use the error rate>±5% to indicate the error, <±5% to be correct, and use logic gates to express the logical relationship between events, and finally complete the modeling.

本发明未详细阐述的部分属于本领域公知技术。Parts not described in detail in the present invention belong to the well-known technology in the art.

尽管上面对本发明说明性的具体实施方式进行了描述，以便于本技术领的技术人员理解本发明，但应该清楚，本发明不限于具体实施方式的范围，对本技术领域的普通技术人员来讲，只要各种变化在所附的权利要求限定和确定的本发明的精神和范围内，这些变化是显而易见的，一切利用本发明构思的发明创造均在保护之列。Although the illustrative specific embodiments of the present invention have been described above, so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, As long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Claims (2)

Translated fromChinese

1.一种基于概率安全分析的放疗精确性数据处理方法，其特征是将放射治疗过程各步骤对应于复杂系统的事件发生过程，建立故障树模型，利用概率安全分析软件分析放疗治疗技术的精确性及各步骤重要性大小，其步骤如下：1. A radiotherapy accuracy data processing method based on probabilistic safety analysis, which is characterized in that each step of the radiotherapy process corresponds to the event occurrence process of a complex system, establishes a fault tree model, and uses probabilistic safety analysis software to analyze the accuracy of radiotherapy treatment technology and the importance of each step, the steps are as follows:步骤（1）、利用现有的放射治疗技术收集初始数据，作为概率安全分析方法中的源数据，包括：基本事件概率及概率的误差数据、人因失误相关的数据、共因相关的数据；Step (1), using the existing radiotherapy technology to collect initial data, as the source data in the probabilistic safety analysis method, including: basic event probability and probability error data, data related to human errors, and data related to common causes;步骤（2）、将放射治疗精确性失败作为顶事件，对放射治疗过程进行故障树建模，将所有对放射治疗有关键影响的因素分为剂量错误、摆位错误、靶区勾画错误、输出错误4大类，对每一类分别展开，分析直接导致其发生的所有因素，直到初始事件为止；将顶事件、中间结果、初始事件统称为事件，将单独发生就导致上一层事件发生的事件用或门连接，联合发生才导致上一层事件发生的事件用与门连接，从而可将所有事件链接成一棵故障树；Step (2), taking the failure of radiotherapy accuracy as the top event, modeling the radiotherapy process as a fault tree, and dividing all factors that have a key impact on radiotherapy into dose errors, setup errors, target delineation errors, and output There are 4 major categories of errors, expand each category separately, and analyze all the factors that directly lead to its occurrence until the initial event; the top event, intermediate result, and initial event are collectively called events, and if they occur alone, they will lead to the occurrence of the previous event Events are connected with OR gates, and events that lead to the occurrence of events on the previous layer are connected with AND gates, so that all events can be linked into a fault tree;步骤（3）、将故障树模型中各初始事件概率数据及其它源数据输入概率分析软件，系统自动计算最小割集并进行定量分析，结果用于精确性评估及重要性分析。Step (3), input the probability data of each initial event in the fault tree model and other source data into the probability analysis software, the system automatically calculates the minimum cut set and conducts quantitative analysis, and the results are used for accuracy evaluation and importance analysis.2.根据权利要求1所述的一种基于概率安全分析的放疗精确性数据处理方法，其特征是所述的对放射治疗过程进行故障树建模，将顶事件定义为精确性失败，即最终适形度或吸收剂量误差率>±5%为失去了精确的意义，故障树主干为主要的导致不精确的因素，追踪到整个放疗系统的初始事件，对于存在误差的初始事件，就用误差率>±5%表示错误，小于此误差为正确，并使用逻辑门表达事件之间的逻辑关系，最终完成建模。2. A kind of radiotherapy accuracy data processing method based on probabilistic safety analysis according to claim 1, it is characterized in that described radiotherapy process is carried out fault tree modeling, the top event is defined as accuracy failure, i.e. final The degree of conformity or the error rate of absorbed dose >±5% means that the meaning of precision is lost. The trunk of the fault tree is the main factor leading to the inaccuracy. It traces the initial events of the entire radiotherapy system. For the initial events with errors, use the error A rate >±5% means an error, and an error smaller than this is correct, and logic gates are used to express the logical relationship between events, and the modeling is finally completed.

Images