论文部分内容阅读
目的探讨直肠癌术前静态调强放疗(intensity-modulated radiotherapy,IMRT)和弧形调强放疗(intensity-modulated ARC therapy,IMAT)的剂量学特点,为直肠癌术前精确放疗方法的选择提供依据。方法对17例Ⅱ~Ⅲ期中低位直肠癌术前同步放化疗的患者分别进行IMRT5野、7野、9野和IMAT的计划设计,肿瘤原发病灶和转移淋巴结(GTV)及高危受累区域和区域淋巴引流区(CTV)统一给予2 Gy/次、5次/w、总剂量50 Gy/25次的照射。利用剂量体积直方图评价靶区剂量的分布以及危及器官的照射剂量。结果 4种治疗计划均能满足靶区处方剂量及危及器官剂量限制要求,IMAT计划靶区适形指数(conformity index,CI)优于IMRT各野计划,差异有统计学意义(P<0.05);IMRT计划5野、7野、9野和IMAT计划剂量均匀指数(homogeneityindex,HI)优于IMAT计划,差异有统计学意义(P<0.05)。IMAT计划对危及器官膀胱的保护优于IMRT各野计划,两两比较差异均有统计学意义(P<0.05)。IMAT计划机器跳数较IMRT机器跳数明显减少,差异有统计学意义(P<0.05),IMRT各野计划间的机器跳数比较差异有统计学意义(P<0.05)。结论直肠癌术前放疗IMAT计划较IMRT计划能更好地保护膀胱,同时缩短照射时间。
Objective To investigate the dosimetric features of intensity-modulated radiotherapy (IMRT) and intensity-modulated ARC therapy (IMAT) in preoperative rectal cancer, and to provide a basis for the selection of preoperative radiotherapy for rectal cancer . Methods Seventeen patients with stage Ⅱ ~ Ⅲ low and middle rectal cancer undergoing preoperative concurrent chemoradiation were enrolled in the design of IMRT5 field, 7 field, 9 field and IMAT respectively. The primary tumor and metastatic lymph nodes (GTV) and the regions and regions of high risk involvement Lymphatic drainage area (CTV) given uniform 2 Gy / time, 5 times / w, the total dose of 50 Gy / 25 times the irradiation. The dose volume histogram was used to evaluate the dose distribution of the target and the irradiation dose to the organ. Results All the four treatment plans were able to meet the prescription dose and organ dose limiting requirements of the target area. The conformity index (CI) of the target area of IMAT was superior to that of the IMRT. The difference was statistically significant (P <0.05). IMRT plan 5 wild, 7 wild, 9 wild and IMAT plan uniformity index (homogeneity index, HI) is better than the IMAT plan, the difference was statistically significant (P <0.05). The IMAT plan is superior to the IMRT plans for the protection of organ endangered organs, with any significant difference (P <0.05). The number of hops in the IMAT planner machine was significantly lower than that of the IMRT machine machine, with significant difference (P <0.05). There was significant difference in machine hops between IMRT plans (P <0.05). Conclusion The preoperative IMAT schedule for rectal cancer is better than IMRT in protecting the bladder and shortening the irradiation time.