鲁棒性优化在质子调强放射治疗中的应用

Applications of robust optimization in intensity modulated proton therapy

质子治疗过程容易受射程偏差、摆位偏差、患者解剖结构改变等不确定因素的影响,质子调强放疗的鲁棒性优化是将这些不确定因素考虑进计划的制定过程中,增加治疗计划鲁棒性的一种方法,在临床中有广泛的应用。鲁棒性优化的方法主要有4种:(1)概率法;(2)最差剂量法;(3)添加约束项;(4)多CT优化。本文综述了这4种方法的原理、优缺点和临床应用情况。同时,还介绍了治疗计划鲁棒性的评估方法。虽然目前剂量体积直方图束是最常用的评估治疗计划鲁棒性的方法,但是,剂量体积直方图束不能反映质子调强放疗计划对解剖结构改变的鲁棒性,因此,还急需建立一个简单易用并能被广泛接受的鲁棒性评估方法,方便质子调强放疗计划的对比和评估。

The intensity modulated proton therapy(IMPT) process is susceptible to factors such as range uncertainties, setup uncertainties and anatomical changes. The robust optimization of IMPT is a method to increase the robustness of treatment plan by taking these uncertainties into consideration in the process of optimization, which is widely used in clinical practice.There are four methods for robust optimization:(1) probability method;(2) worst dose method;(3) adding constraints;(4)multiple CT optimization. This paper reviews the principles, advantages and disadvantages of these four methods and their clinical application, and it also introduces the evaluation methods for robustness. Although the dose volume histogram(DVH) bands is the most commonly used method to evaluate the plan robustness, DVH bands cannot reflect the robustness of IMPT plan with anatomical changes. Therefore, it is urgent to establish a simple and widely accepted robustness evaluation method to facilitate the comparison and evaluation of IMPT plans.