基于分子动力学的后装治疗计划驻留时间优化算法

摘要

We propose a classical molecular dynamics (CMD)-based optimization algorithm for determining the optimal dwell time in brachytherapy.To obtain the optimal dwell time sequence,we modified the CMD-based optimization algorithm in intensitymodulated radiotherapy.With the quadratic sum of the difference between the prescribed dose and the actual dose at the reference points as the objective function and considering the requirement of dwell time in braehytherapy,we introduced the time smoothing factor to restrict the difference in the dwell time,which was merged into the total objective function.During the optimization,the objective function was the system energy of CMD,while the dwell time was the molecular position,and when the dwell time was optimal,the system energy was the lowest.The effectiveness of this modified algorithm was verified through analysis of clinical cases,and the results showed that this optimized algorithm met the requirements for clinical use.%介绍一种新的基于分子动力学的用于求解驻留时间的优化算法.为了获得后装治疗中驻留时间的最优序列,本文对用于放射治疗的基于分子动力学的调强优化算法进行了进一步发展.将投放到参考点的实际剂量与其处方剂量的差值的平方和作为目标函数,同时考虑到后装治疗对驻留时间的特殊要求,引入时间平滑因子的概念,以约束驻留时间的差异,并将其合并到总的目标函数中,在优化过程中予以综合考虑.优化过程中,目标函数为分子系统的系统能量,驻留时间为分子位置.驻留时间达到最优结果时,其系统能量最低.利用临床病例对算法的有效性进行了验证.临床病例中的数据验证表明,该优化算法能够满足临床应用的要求.