改良乳腺癌根治术后容积旋转调强放疗弧数目的选择
Selection of arcs number of volumetric modulated arc therapy after modified mastectomy for breast cancer
张尧 1李金凯 2王沛沛 2李彩虹 2李华玲 2昌志刚2
作者信息
- 1. 210029 江苏,南京医科大学第一附属医院放射科
- 2. 210029 江苏,南京医科大学第一附属医院放疗科
- 折叠
摘要
目的 研究改良乳腺癌根治术后容积旋转调强放疗(VMAT)计划中每野弧数目对治疗计划的影响.方法 改良左侧乳腺癌根治术后放射治疗(放疗)患者15例,在定位CT上勾画靶区及危及器官(OARs),处方剂量50 Gy/25次.在Monaco计划系统中对每例仅改变单个射野中的弧数目,分别设计单弧、双弧和三弧3种VMAT计划,分析其靶区和OARs的各项剂量学参数以及机器跳数和出束时间.结果 15例改良乳腺癌根治术后放疗计划的单弧、双弧和三弧计划均能满足临床要求.与单弧计划相比,双弧和三弧计划靶区的最大剂量D2％和平均剂量(Dmean)较低,最小剂量D98％较高,对侧乳腺Dmean、V5以及对侧肺Dmean较高,靶区的适形性和均匀性改善(P＜0.05).随着弧数目的增加,机器跳数和出束时间均增加(P＜0.05).结论 改良乳腺癌根治术后VMAT计划随着弧数目的增加,其靶区剂量分布更优,但部分OARs低剂量照射会增加,治疗时间延长,需结合临床情况综合考虑选择VMAT计划弧数目.
Abstract
Objective To study the effect of the number of arcs per field on the treatment plan of volumetric modulated arc therapy(VMAT)after modified mastectomy for breast cancer.Methods The plans of 15 patients with left breast cancer who received radiotherapy after modified mastectomy were selected.The target areas and organs at risk(OARs)were contoured on localized CT.The prescribed dose was 50 Gy/25 times to the target areas.The single arc(Arc1),double arcs(Arc2)and three arcs(Arc3)plans were designed by changing the number of arcs in a field in Monaco planning system on the same CT image sets.The dosimetry characteristics of target and OARs,monitor unit and the delivery time were compared among the three plans.Results Arc1 plan,Arc2 plan and Arc3 plan for 15 cases of breast cancer all were proved to meet the clinical requirements.Compared with Arc1 plan,the D2％and Dmean of target were lower,the D98％of target,Dmean and V5 of contralateral breast and Dmean of contralateral lung were higher in the Arc2 plan and Arc3 plan(P＜0.05),and the Arc2 plan and Arc3 plan achieved better conformity and homogeneity(P＜0.05).With the increase of arcs number,the monitor unit and the delivery time were increased(P＜0.05).Conclusion VMAT plan has the better target dose distribution with the increase of the number of arcs,while OARs low dose irradiation and treatment time are increased after modified mastectomy for breast cancer.Therefore,it is necessary to comprehensively consider the number of VMAT plan arcs based on clinical conditions.
关键词
乳腺癌/容积旋转调强放疗/Monaco计划系统Key words
Breast cancer/Volumetric modulated arc therapy/Monaco planning system引用本文复制引用
出版年
2024
NETL
NSTL
万方数据