非小细胞肺癌脑部转移瘤适形与调强放疗的剂量研究

为探讨NSCLC脑部转移瘤调强放疗与适形放疗的剂量特点,本研究选取57例非小细胞肺癌脑转移瘤患者,其中单个脑转移灶患者5例,多个脑转移灶患者52例,分别设计全脑放疗+适形放疗与调强放疗计划,用均匀指数(HI)和适形指数(CI)评价靶区剂量,危及器官(OAR)剂量用近似最大剂量D_2%(串联)和中位剂量D_50%(并联)进行评价。研究发现,单个脑转移灶IMRT与WBRT+CRT比较中,CI为(PTV,(0.80±0.15) cGy,(0.34±0.19) cGy, p=0.00),HI为(PTV,(0.52±0.03) c Gy,(0.71±0.12) cGy, p=0.24),两者OARs剂量比较:脑干为((4 348±236) cGy,(4 593±149) cGy, p=0.01),脑垂体为((4 258±166) cGy,(4 581±123) cGy, p=0.02);在多个脑转移灶中,IMRT与WBRT+CRT比,较CI为(PTV,(0.59±0.33) cGy,(0.49±0.27) cGy, p=0.03),HI为(PTV,(0.93±0.01) cGy,(0.58±0.03) cGy, p=0.19),两者OARs剂量比较:脑干为((4 946±132) cGy,(4 843±196) cGy, p=0.51),脑垂体为((4 597±180) cGy,(4 705±149) cGy, p=0.70)。本研究的结果说明,单个脑转移灶患者,IMRT较WBRT+CRT有更好的靶区适形性、稍差的靶区异质性,脑干和垂体的IMRT剂量低于WBRT+CRT,而眼球、晶体的剂量两者差别不明显。多个脑转移灶患者,IMRT较WBRT+CRT有更好的靶区适形性、稍差的靶区异质性,而OARs剂量,IMRT较WBRT+CRT差异不明显。在临床实践过程中,应当根据患者不同的病灶情况选择合适的放疗方案,以获取更优的临床治疗效果。

A Dosimetric Study of CRT and IMRT for Brain Metastatic Tumors from Non-small Cell Lung Cancer

To study the dose characteristics of CRT and IMRT of brain metastatic tumors of NSCLC, 57 patients with brain metastatic tumors from non-small cell lung cancer were selected in this study. There were 5 patients with single brain metastatic tumor, and 52 patients with multiple brain metastatic tumors. WBRT +CRT and IMRT plans were designed, respectively. The homogeneity index(HI) and conformity index(CI) were used to evaluate the target dose,and the organs at risk(OAR) dose was evaluated by approximate maximal dose D2%(in series) and median dose D50%(in parallel). The study found that in the comparison between IMRT and WBRT+CRT in patients with single brain metastases, CI was(PTV,(0.80±0.15) c Gy,(0.34±0.19) c Gy, p=0.00), and HI was(PTV,(0.52±0.03) c Gy,(0.71±0.12) c Gy, p=0.24), their doses of OARs were compared to be: the brain stem was((4 348±236) c Gy,(4 593±149) c Gy, p=0.01), and the pituitary was((4 258±166) c Gy,(4 581±123) c Gy, p=0.02). In patients with multiple brain metastatic tumors, IMRT compared with WBRT+CRT showed that CI was(PTV,(0.59±0.33) c Gy,(0.49±0.27) c Gy, p=0.03), and HI was(PTV,(0.93±0.01) c Gy,(0.58±0.03) c Gy, p=0.19), their doses of OARs were compared to be: the brain stem was((4 946±132) c Gy,(4 843±196) c Gy, p=0.51), and the pituitary was((4 597±180) c Gy,(4 705±149) c Gy, p=0.70). It could be concluded in this study that in patients with single brain metastatic tumors, IMRT had better target conformity but slightly worse target heterogeneity than WBRT+CRT, the IMRT dose of brain stem and pituitary was lower than WBRT+CRT, and there was no significant difference in the dose of eyeball and eye crystal. In the patients with multiple brain metastatic tumors, IMRT had better target conformity but slightly worse target heterogeneity than WBRT+CRT.And there was no significant difference between IMRT and WBRT+CRT in OARs dose. In the process of clinical practice, the appropriate radiotherapy plan should be selected according to the different lesion condition of patients in order to obtain better clinical treatment effect.