三种调强放射治疗鼻咽癌布野方案的剂量学比较

摘要

目的：探讨常规调强放射治疗（IMRT）7野、9野及容积旋转调强治疗（VMAT）三种不同布野方案在鼻咽癌（Ⅰ~Ⅲ期）治疗中的剂量学特点及治疗效率。方法用 Eclipse 治疗计划系统对12例鼻咽癌患者（Ⅰ~Ⅲ期）分别用 IMRT 7野（A 组）、9野（B 组）及 VMAT（C 组）进行计划设计治疗，比较3组的肿瘤靶区剂量分布、危及器官的剂量和治疗时间。结果3组的剂量分布均能满足临床剂量要求，虽然在肿瘤靶区覆盖性、靶区适形度（CI）及靶区均匀性（HI）上差异无统计学意义（P >0.05），但 C 组的 HI 较高。在危及器官受量方面，3组对危及器官的保护均符合临床要求。在治疗时间方面，C 组的机器跳数及治疗时间较 A、B 组显著的缩短（P <0.001）。结论3种布野计划在Ⅰ~Ⅲ期鼻咽癌治疗中的剂量学均可满足临床要求。VMAT 有更好的治疗效率，应优先考虑。对于 IMRT 7野和9野应当视危及器官保护和靶区范围具体情况而进行选择。%Objective To compare step - and - shoot intensity modulated radiation therapy(IMRT)of 7 or 9 beam with volume modulate arc therapy(VMAT)for nasopharyngeal carcinoma(NPC,Phase Ⅰ - Ⅲ)patients with re-gard to the sparing effect on dosimetic quality and efficiency of delivery. Methods Twelve patients who diagnosed with NPC were treated with IMRT 7 beam,9 beam and VMAT by the eclipse planning system. Dosimetric comparisons among these 3 plans were analyzed including sparing of PTV,sparing of OARs and delivery time. Results All the 3 plans can meet the clinical dosimetric requirements. There was no significant difference in coverage,homogeneity(HI)or conformity (CI)of PTV among all the 3 plans. The protections of OARs in all the 3 plans were consistent with clinical requirement. However,significant lower machine hops and shorter delivery time were revealed in VMAT. Conclusion Our results in-dicate that all 3 therapy plans could meet the clinical dosimetric requirements for the NPC(Phase Ⅰ - Ⅲ),but VMAT provides better treatment efficiency. The choice between IMRT 7 and 9 beam shall be considered according to the protec-tion of OARs and general condition.