两种不同放疗技术治疗鼻咽癌的疗效及计量学差异比较

目的:分析探讨两种不同放疗技术治疗鼻咽癌的疗效及计量学差异。方法:选取我院于2016年4月至2019年4月期间收治的63例鼻咽癌患者，根据鼻咽癌2008分期，其中T4期鼻咽癌患者有21例，T3期鼻咽癌患者有21例，T1-2期鼻咽癌患者有21例；所有入选患者均根据其具体情况制定固定野IMRT计划和旋转容积调强放疗计划，分别比较各期患者两套计划的计量学参数；分析两套计划的治疗时间和跳数、危及器官剂量、靶区覆盖等差异。结果:两种不同放疗技术均具备较好的靶区剂量分布，其中PTV1和PGTV的适行性和均匀性相当，两者剂量分布差异并没有统计学意义（均P>0.05）。IMRT组的PTV2剂量显著高于RapidArc组，并且前者的均匀性显著优于后者（均P<0.05），但是RapidArc组的剂量分布也能够满足临床需要。在按照患者T分期进行分层比较时，T3期患者和T1-2期患者的两种不同放疗技术靶区剂量分布相似，并且适形性和均匀性均相当。对于T4期患者而言，RapidArc组的PTV2、PTV1、PGTV靶区剂量均显著高于IMRT组（均P<0.05）；RapidArc组T4期患者的PGVT均匀指数优于IMRT组，两组数据比较差异虽无统计学意义（P=0.059），但P值接近0.05。RapidArc组治疗时间和治疗跳数分别为（185.92±32.19）s和（651.29±112.20）MUs，分别低于IMRT组的（522.29±73.39）s和（1 891.28±253.39）MUs，两组数据比较差异具有统计学意义（t=13.283，t=22.192，均P<0.05）。结论:对鼻咽癌患者采用9野IMRT和RapidArc治疗均能够达到临床要求，但是后者的治疗时间和治疗跳数更短，可以显著降低正常器官的剂量，在T4期鼻咽癌患者的治疗方面可以将高剂量区集中在靶区，从而大大减少正常器官的受照剂量，值得在临床上加以推广运用。

Comparison of therapeutic effect and metrological difference between two different radiotherapy techniques in the treatment of nasopharyngeal carcinoma

Objective:To analyze the curative effect and metrological difference of two different radiotherapy techniques for nasopharyngeal carcinoma (NPC).Methods:Sixty-three patients with nasopharyngeal carcinoma admitted to our hospital from April 2016 to April 2019 were selected.According to the stages of nasopharyngeal carcinoma in 2008，21 patients with stage T4 nasopharyngeal carcinoma，21 patients with stage T3 nasopharyngeal carcinoma，and 21 patients with stage T1-2 nasopharyngeal carcinoma.According to their specific conditions，IMRT plans of fixed field and IMRT plans of rotational volume modulated radiotherapy were developed for all the enrolled patients.The differences between the two sets of planned treatment time，number of hops，dose of critical organs，and target area coverage were analyzed.Results:The two different radiotherapy techniques had good target dose distribution，in which PTV1 and PGTV had similar fitness and uniformity，and the difference in dose distribution between them was not statistically significant (all P>0.05).The PTV2 dose of IMRT group was significantly higher than that of RapidArc group，and the homogeneity of the former group was significantly better than that of the latter group (all P<0.05)，but the dose distribution of RapidArc group could also meet the clinical needs.When stratified comparison was made according to the patient's T stage，the dose distribution in the target area of the two different radiotherapy techniques for patients with stage T3 and T1-2 was similar，and the conformal and homogeneity were similar.For T4 patients，the target dose of PTV2，PTV1 and PGTV in RapidArc group was significantly higher than that in IMRT group (all P<0.05).The PGVT evenness index of stage T4 patients in RapidArc group was better than that in IMRT group.Although there was no statistically significant difference between the two groups (P=0.059)，the P value was close to 0.05.The time of treatment and the number of hops in RapidArc group were (185.92±32.19)s and (651.29±112.20)MUs，which were lower than those in IMRT group (522.29±73.39)s and (1 891.28±253.39)MUs，respectively.The difference between the two groups was statistically significant (P<0.05).Conclusion:The treatment of nasopharyngeal carcinoma patients with 9 fields of IMRT and RapidArc can meet the clinical requirements，but the latter has shorter treatment time and shorter hop count，which can significantly reduce the dose of normal organs.In the treatment of patients with T4 nasopharyngeal carcinoma，the high dose area can be concentrated in the target area，so that the irradiation dose of normal organs can be greatly reduced，and it is worth popularizing and applying in clinical practice.