Objective To discuss the dosimetric characteristics of simultaneous integrated boost intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for patients receiving breast-conserving surgery for left breast cancer.Methods Pinnacle310 planning system was adopted to design IMRT and VMAT plans for 16 patients after breast-conserving surgery for left breast cancer.The dosimetric parameters of the two radiotherapy plans were compared.Results The dosimetry in planning gross target volume and planning target volume of VMAT plan were better than that of IMRT,and only the comparison in conformity index showed statistical differences (P＜0.05).The monitor unit in VMAT plan was significantly lower than that in IMRT plan,with statistical differences (P＜0.05).Compared with IMRT plan,VMAT plan showed remarkably lower dose of left lung [statistical differences were found in mean dose (Dmean),V5 (percentage of volume receiving more than 5 Gy),V15,V20and V30 of left lung (P＜0.05)],lower heart dose [statistical differences were found in V5,V10,V15 and Dmean of heart (P＜0.05)],and higher right breast-Dmean and right lung-Dmean (P＜0.05).Conclusion Compared with IMRT plan,VMAT plan has significant advantages on the dose distribution in target area,and significantly shortens the treatment time.The protection of heart and left lung in VMAT plan is obviously better than that in IMRT plan,while the protection of right lung and right breast in IMRT plan is obviously better than that in VMAT plan.%目的:探讨左乳腺癌保乳术后瘤床同步加量静态调强(IMRT)和容积旋转调强(VMAT)的剂量学特点.方法:选取左乳癌保乳术后16例患者,采用Pinnacle3 10计划系统分别设计IMRT和VMAT计划,比较两种放疗计划的剂量学参数.结果:VMAT的靶区(PGTV和PTV)剂量学较IMRT整体上有明显优势,但只有适形指数差异有统计学意义(P＜0.05),其余参数差异无统计学意义(P＞0.05).VMAT的机器跳数明显低于IMRT(P＜0.05).VMAT的左肺剂量明显低于IMRT,其中V5、V15、V20、V30和平均剂量(Dmean)两者比较统计学有差异(P＜0.05);心脏剂量明显低于IMRT,其中V5、V15、V20和Dmean两者比较统计学有显著差异(P＜0.05);右乳Dmean明显高于IMRT(P＜0.05);右肺Dmean明显高于IMRT(P＜0.05).结论:整体上VMAT较IMRT在靶区剂量学分布上有一定的优势,并且VMAT的治疗时间较IMRT明显缩短.VMAT对危及器官左肺和心脏的保护明显优于IMRT,而IMRT对右肺和右乳的保护则明显优于VMAT.
展开▼
