陀螺刀和容积调强治疗肺部小病灶的剂量学比较

摘要

Objective To analyse the dose distribution characteristics of Co-60 Gyro knife and volume modulated arc therapy (VMAT) treatment for small lung masses, and compare differences with two kinds of plan in the conservation of OAR and the range of low dose.Methods 48 patients with small lung masses (including primary lung cancer and pulmonary metastatic carcinoma, a total of 56 masses), were designed into Gyro knife and VMAT plan group, respectively.Dose volume histograms were used to evaluate the target and OAR dosimetry parameters and compare the differences between the two plans.Results PTVDmean, PTVDmax, homogeneity index, V5, V10 and average dose in whole lung, V5, V10, V20, V30 and average dose in involved lung of Gyro knife plan were significantly higher than those of VMAT plan (P<0.05), while target volumn conformal index, V5, V10 and average dose in the healthy lung, the largest dose in spinal cord, average dose in heart and spinal cord of VMAT plan were significantly higher than those of Gyro knife plan (P<0.05).Conclusion Gyro knife and VMAT plans can meet dose requirement of gross tumor volume and dose constraints of the normal tissue in the treatment for small lung masses.Advantages of Gyro knife plan are high dose in PTVDmean and low dose in the healthy lung, and advantages of VMAT plan is higher in conformal degree of gross tumor volume, lower in V5, V10 and average dose in the whole lung and involved lung.%目的 分析Co-60陀螺刀和容积调强(VMAT)治疗肺部小病灶剂量学分布特点,比较两种计划在危及器官(OAR)保护和全身低剂量区体积大小的差异.方法 对48例肺部小病灶患者(含原发性肺癌及肺转移癌,共56个病灶),分别设计陀螺刀和VMAT计划,采用剂量体积直方图对靶区和OAR剂量学参数进行评估,并比较两种计划的差异.结果 陀螺刀计划的计划靶区平均剂量(PTVDmean),计划靶区最高剂量(PTVDmax),均匀指数,全肺V5、V10和平均受量,患侧肺V5、V10、V20 、V30和平均受量均显著高于VMAT计划(P<0.05),而VMAT计划的靶区适形指数,健侧肺V5、V10和平均受量,脊髓最大受量,心脏和脊髓平均受量均显著高于陀螺刀计划(P<0.05).结论 陀螺刀计划和VMAT计划在治疗肺部小病灶时均能达到肿瘤靶区剂量要求和正常组织剂量约束;陀螺刀计划优势是PTVDmean,健侧肺组织受量低;而VMAT计划优势为肿瘤靶区适形度高,全肺及患侧肺V5、V10和平均受量低.