简化适形调强技术与调强适形放疗在胸段食管癌放疗中的剂量学比较

目的 探讨简化调强适形放疗计划（sIMRT）与调强适形放疗计划（IMRT）在胸段食管癌放疗中的剂量学差异。方法 选择安徽医科大学第一附属医院肿瘤放疗科2016年5月至2017年2月收治的20例胸段食管癌患者，每例患者设计sIMRT、IMRT计划，并给予计划靶区剂量60 Gy/30次。通过剂量、体积等参数比较2种放疗计划方式在靶区、危及器官剂量学和照射野参数上的差异。结果 IMRT计划的靶区适形度指数及靶区剂量均匀度指数均优sIMRT计划，且IMRT计划的脊髓最大受照剂量更低，差异有统计学意义（P<0.05）。肺及心脏受量两者相近，差异无统计学意义（P>0.05）。sIMRT计划单次治疗机器跳数（MU值）及子野数少于IMRT计划，差异有统计学意义（P<0.05）。结论 IMRT计划及sIMRT计划均可满足胸段食管癌放疗计划要求。IMRT计划虽然在靶区剂量分布方面优于sIMRT计划，且能更好保护脊髓，但是sIMRT计划子野数和MU值明显减少，可以缩短治疗时间和减少机器耗损。

Dosimetric comparison between simplified intensity-modulation radiotherapy and intensity-modulation radiotherapy for patients with thoracic esophageal carcinoma

Objective To evaluate the dosimetric differences of simplified intensity-modulation radiotherapy(sIMRT) planning and intensity-modulation radiotherapy(IMRT) planning for radiotherapy of thoracic esophageal carcinoma. Methods In this study, 20 patients with thoracic esophageal carcinoma were randomly chosen from the Department of Radiotherapy of our hospital from May 2016 to Feb 2017. sIMRT and IMRT were generated to deliver 60 Gy in 30 fractions to the planning target volume(PTV). The dose and volume parameters of the target and the organs at risk and the parameters of the irradiation field were compared between the two planning methods. Results The conformity index(CI) and the dose homogeneity index(HI) of the target volume in IMRT planning were superior to those of sIMRT technique. The maximum exposure dose of the spinal cord in IMRT planning was lower than that in sIMRT planning(P<0.05). The doses of the lung and the heart were similar using these two planning methods(P>0.05). However, the monitor-unit(MU) value in a single fraction and the segment number in sIMRT planning were fewer than those in IMRT planning. Conclusion IMRT planning and sIMRT planning are both proved suitable for radiotherapy of thoracic esophageal carcinoma. IMRT planning has better dose distribution of the target volume and better protection of the spinal cord. However, the segment number and MU of sIMRT planning are reduced significantly, which can shorten the treatment time and extend the machine wear life.