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50Gy/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(D_(mean))较低,最小剂量D_(98%)较高,对侧乳腺D_(mean)、V_(5)以及对侧肺D_(mean)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。
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 15patients 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 50Gy/25times 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 Arc1plan,Arc2plan and Arc3 plan for 15cases of breast cancer all were proved to meet the clinical requirements.Compared with Arc1plan,the D_(2%) and D_(mean)of target were lower,the D_(98%)of target,D_(mean)and V_(5)of contralateral breast and D_(mean)of contralateral lung were higher in the Arc2plan and Arc3plan(P<0.05),and the Arc2plan and Arc3plan 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.
作者
张尧
李金凯
王沛沛
李彩虹
李华玲
昌志刚
ZHANG Yao;LI Jinkai;WANG Peipei(Department of Radiology,First Affiliated Hospital,Nanjing Medical University,Nanjing 210029,CHINA)
出处
《江苏医药》
CAS
2024年第2期161-164,共4页
Jiangsu Medical Journal
