摘要目的 探讨物理优化与生物优化方法在肺癌大分割放疗中的剂量学差异.方法 选择10例非小细胞肺癌放疗病例,分别对每个病例使用物理函数(DV组)、生物函数-物理函数相结合(DV+EUD组、EUD+DV组)及生物函数(EUD组)优化方法重新进行VMAT计划设计;其中4个组计划约束函数不同,但约束条件与计算参数保持相同.通过计算与统计各项剂量学参数来评估4种计划优化方法在肺癌大分割放疗中的剂量学差异.结果 在靶区方面,EUD组与EUD+DV组的等效均匀剂量值相近,但这两组EUD值比另外两组分别高出2.8％～3.6％和3.2％～3.7％;EUD组与EUD+DV组的肿瘤控制率平均值也高于DV组和DV+EUD组(P＜0.05).均匀性指数值也不同(P＜0.05),而适形指数值相近(P＞0.05).在危及器官方面,正常肺组织的EUD、V5、V1o、V20、V30以及心脏与脊髓的剂量参数差异均相近(P＞0.05),但靶区使用生物函数的两组其全肺平均剂量较另外两组的略低.结论 生物函数在提高靶区的EUD与肿瘤控制率以及保护肺组织方面都具有一定的优势,临床工作中可以此为参考选择生物函数优化方法.

abstractsObjective To discuss the dosimetric differences in the planning methods between physical and biological optimization during thehypofractionated radiotherapy for lung cancer.MethodsTen cases of non-small cell lung cancer (NSCLC) receiving radiotherapy were selected in this retrospective study.The VMAT plans for all patients were re-designed by physical functions (DV group),biological combined with physical functions (DV+EUD group and EUD+DV group) and biological functions (EUD group).The constrained functions were different,whereas the constrained conditions and optimized parameters were identical among four groups.The dosimetric differences among four optimization methods during thehypofractionated radiotherapy for lung cancer were evaluated through calculating and analyzing each dosimetry parameter.Results For the target area,the equivalent uniform dose was approximate between the EUD and EUD+DV groups.The EUD in these two groups was approximately 2.8％-3.6％ and 3.2％-3.7％ higher than those in the DV and DV+EUD groups.The average tumor control probability (TCP) in the EUD and EUD +DV groupswas considerably higher than those in the other two groups (both P＜0.05).The homogeneity index (HI) significantly differed (all P＜0.05),whereas the conformity index (CI) did not differ (all P＞0.05).For the organ at risk (OAR) area,the differences of EUD,V5,V1o,V20,V30 of normal lung tissues and the difference of dosimetry parameters in heart and spinal cord were not statistically significant (all P＞0.05).The mean dose of all lungs in the EUD and EUD+DV groupswas slightly lower than those in the other two groups.ConclusionsBiological optimization method has certain advantages in increasing EUD and TCP in the target area and decreasing the irradiation dose of normal lung tissues,which provides references for selecting the optimization method with biological functions in clinical practice.