等效均匀剂量优化方法对肿瘤调强放疗计划中危及器官保护的研究

Protective effect of equivalent uiform dose optimization on organ at risk of tumor treated with intensity-modulated radiation therapy

目的 探讨等效均匀剂量（EUD）优化方法对肿瘤调强放疗计划中危及器官的保护作用。方法 从已接受调强放疗的患者中用整群随机数字表法抽取鼻咽鳞状细胞癌8例、食管鳞状细胞癌10例、直肠癌6例，用物理约束条件优化设计放疗计划，将危及器官的物理约束条件改为EUD约束，同时保持靶区约束条件不变，为每例患者设计一个新计划，并比较新（PLANEUD组）、旧（PLANNO_EUD组）治疗计划。结果 PLANEUD组8例鼻咽癌患者危及器官都得到了更好的保护，与PLANNO_EUD组比较差异均有统计学意义（t值分别为2.590、2.352、3.656、2.148、2.283、3.683、2.192、2.353、2.146、2.276、2.126，均P＜0.05）；10例食管癌患者危及器官受量两组比较，差异无统计学意义（t值分别为0.408、0.427、0.902，均P＜0.05）；PLANEUD组6例直肠癌患者危及器官得到了更好的保护，与PLANNO_EUD组比较差异均有统计学意义（t值分别为2.332、2.693、2.279、2.244，均P＜0.05）。结论 在保证靶区剂量的同时，EUD优化方法能够降低危及器官的受照剂量，对减少正常组织放疗并发症具有重要意义，同时为靶区增量提供了空间。

Objective To evaluate the effect of an equivalent uiform dose optimization （EUD） based optimization algorithm in sparing the organ at risk （OAR） of tumor treated with intensity-modulated radiation therapy （IMRT）. Methods 10 patients of nasopharyngeal carcinoma （NPC）, 10 patients of esophagus cancer,6 patients of rectum cancer were randomly selected from all patients received IMRT treatment. Then physical optimization constraints （dose/dose-volume constraints） were designed as EUD optimization, while the physical objectives for targets and other OAR were unchanged. Results There was statistically significant difference in protecting OAR in 8 NPC patients of PLANEUD group compared with those of PLANNO_EUD group （t values were 2.590, 2.352, 3.656, 2.148, 2.283, 3.683, 2.192, 2.353, 2.146, 2.276, 2.126, P 〈 0.05）. There was no statistically significant difference in protecting OAR in 10 cases of esophageal cancer between PLANEUD group and PLANNO_EUD group （t value were 0.408, 0.427, 0.920, P 〉 0.05）. There was statistically significant difference in protecting OAR in 6 cases of rectum cancer of PLANEUD group compared with those of PLANNO_EUD group （t values were 2.332, 2.693, 2.279, 2.244, P 〈 0.05）. Conclusion EUD optimization can reduce the doses to OAR which may be quite helpful to reduce the occurrence rate of OAR complications.