全脑全脊髓放疗骨髓保护的初步研究

摘要

目的 分析全脑全脊髓放疗患者骨髓受量与血液学毒性的关系,并初步探索HT及VMAT在全脑全脊髓放疗中骨髓的剂量学差异.方法 收集我院螺旋断层全脑全脊髓放疗20例患者临床资料及HT计划,将计划回传至MIM系统.在CT上依次勾画患者的颅骨、下颌骨、锁骨、胸骨、肩胛骨、肋骨、椎体骨、盆骨,在DVH图上读出上述骨结构及总骨的V2、V5、V10、V15、V20、V25、V30、V35、Dmean、Dmax值,分析上述指标与患者≥2级血液学毒性相关性.再从中选取6例患者为对象,将图像传输至Monaco计划系统并完成VMAT计划,对比两种计划上述骨结构剂量体积差异.采用Spearman相关性分析及Wilcoxon符号秩和检验.结果 患者≥2级白细胞减低与盆骨V25、总骨V5呈正相关(P=0.038、0.025),≥2级血小板减少与盆骨V20呈正相关(P=0.041),≥2级中性粒细胞减低与椎骨V10呈正相关(P=0.036).患者VMAT与HT计划相比,椎骨、盆骨的各剂量体积指标相近(P＞0.05).结论 全脑全脊髓放疗中患者≥2级白细胞减低与盆骨V25、总骨V5呈正相关,≥2级血小板减少与盆骨V20呈正相关,≥2级中性粒细胞减低与椎骨V10呈正相关.全脑全脊髓放疗患者VMAT与HT计划相比椎骨、盆骨各剂量体积相近.%Objective To analyze the relationship between the dose volume of bone marrow and acute hematologic toxicity in craniospinal irradiation (CSI),and preliminarily explore the dosimetric differences in bone marrow between helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT).Methods Clinical data and HT plans of twenty patients treated with CSI in the First Affiliated Hospital of Kunming Medical University were collected,and the HT plans were transferred back to the MIM system.The skull,mandible,clavicle,sternum,scapula,ribs,vertebrae and pelvis were successively delineated on the CT images and then the V2,V5,V10,V15,V20,V25,V30,V35,Dmax Dmean of each aforementioned bone and total bone were read on DVH images.The correlation between those indexes and the incidence of ≥ grade Ⅱ hematologic toxicity was subsequently analyzed.The images of 6 patients were selected and transferred to Monaco TPS and VMAT plans were completed.The dosimetric differences of those indexes were statistically compared between HT and VMAT.Statistical analyses were performed by using Spearman correlation analysis and Wilcoxon symbol rank-sum test.Results The incidence of ≥ grade Ⅱ leukopenia was positively correlated with the V25 of pelvis and the V5 of total bones (P =0.038);the risk of ≥ grade Ⅱ thrombocytopenia was positive associated with the V20 of pelvis (P=0.041);the incidence of ≥grade Ⅱ neutropenia was positively correlated with the V10 of vertebrae (P=O.036).There was no dosimetric difference of dose volume of vertebral and pelvis between HT and VMAT plans (P＞ 0.05).Conclusions There is a positive correlation between ≥ grade Ⅱ leukopenia and the V25 of pelvis and the V5 of total bones.The V20 of pelvis shows a positive correlation with ≥ grade Ⅱ thrombocytopenia.A positive correlation is found between ≥ grade Ⅱ neutropenia and the V10 of vertebrae.The indices of vertebral and pelvis between HT and VMAT plans show no significant differences.