基于γ分析的LNDM和MKM放疗计划处方剂量转换研究  

A study on the conversion of prescribed dose for radiotherapy of logistic nanodosimetry model and microdosimetric kinetic model based on gamma analysis

作　　者：杨静芬 张晖[1,2] 刘新国 戴中颖[1,2] 贺鹏博 马圆圆[1,2] 申国盛 陈卫强[1,2] 李强 Yang Jingfen;Zhang Hui;Liu Xinguo;Dai Zhongying;He Pengbo;Ma Yuanyuan;Shen Guosheng;Chen Weiqiang;Li Qiang(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院大学,北京100049

出　　处：《中华放射肿瘤学杂志》2023年第4期325-332,共8页Chinese Journal of Radiation Oncology

基　　金：国家自然科学基金(11875299);中国科学院“西部之光”交叉团队项目-重点实验室合作研究专项(E023222Y)。

摘　　要：目的在基于纳剂量学模型(LNDM)的治疗计划中,应用日本国立放射线综合医学研究所(NIRS)积累的临床经验,验证γ分析方法在LNDM和微剂量动力学模型(MKM)间处方剂量转换研究中的可行性。方法通过开源的多种射线放疗计划设计平台matRad,采用γ分析的方法对基于MKM和基于LNDM的碳离子治疗计划进行比较,得到不同模型的转换因子。通过水模体研究靶体形状及大小、靶体位置深度、处方剂量和照射方式对模型转换因子的影响,并采用C型靶模型和肝癌患者病例对转换因子进行初步验证。结果模型转换因子与靶体形状无关,与照射方式有关。在单野照射条件下,其与靶体大小、靶体位置深度及处方剂量成正相关。并且C型靶模型和肝癌患者病例成功验证了转换因子,其基于MKM和LNDM的治疗计划所生成的物理剂量分布的γ通过率(2%/2 mm)分别为92.79%和91.19%。结论本文所计算的转换因子(f=D_(LNDM)/D_(MKM))可用于指导基于LNDM的碳离子治疗计划设计时处方剂量的设置。γ分析可用于不同模型处方剂量间的转换研究。Objective To validate the feasibility of the gamma analysis method in the study of prescription dose conversion between logistic nanodosimetry model(LNDM)and microdosimetric kinetic model(MKM)basing on the Chinese self-developed model LNDM by applying clinical experiences of National Institute of Radiological Science(NIRS).Methods Physical dose distributions derived from the MKM-and LNDM-based carbon ion treatment plans were compared via the method of gamma analysis under the open-source treatment planning platform matRad.In this way,the prescribed dose conversion factor between the MKM-and LNDM-based treatment plans was obtained.Using water phantoms,the influence of geometric shape,size,depth of target volume(TV),prescribed dose and field setting on the conversion factor was investigated comprehensively.Moreover,preliminary verification of the acquired conversion factor was conducted on the C-shape model and a case of liver cancer patient.Results The conversion factor depended on the field setting rather than the TV shape.Under the condition of single field,the conversion factor was positively correlated with the size and depth of TV,and the prescribed dose.Moreover,the conversion factor was successfully verified using the C-shape model and the patient with liver cancer,where the gamma passing rates(2%/2 mm)of the physical dose distribution generated by the MKM and LNDM treatment plans were 92.79%and 91.19%,respectively.Conclusions The conversion factors(f=D_(LNDM)_(/DMKM))obtained in this study might provide guidance for the prescribed dose setting during the carbon ion treatment planning based on the LNDM.Besides,the gamma analysis method could be used for the study of the prescribed dose conversion between different models.

关 键 词：放射疗法 碳离子 放射治疗计划 生物物理模型 

分 类 号：R730.55[医药卫生—肿瘤]