CT模拟定位在鼻咽癌常规放射治疗中的应用

目的对比观察两种不同模拟定位方式对鼻咽癌常规放射治疗的疗效及不良反应的影响。方法147例首程治疗的鼻咽癌病例随机分成研究组（CT模拟定位组）74例和对照组（X线片模拟定位组）73例，研究组用三维治疗计划系统（TPS）勾画靶区和危机器官，然后用TPS的射野方向观（BEV）功能进行计划设计及后续的计划调整；对照组用X线模拟定位片完成。两组计划设计及后续的计划调整模式完全相同，放射治疗在同一台加速器上进行。结果随访5～59个月，两组鼻咽原发灶、颈部淋巴结转移灶近期疗效差异均无统计学意义（P〉0．05）；研究组、对照组3年局部复发率分别为5.4％（4／74）及16．4％（12／73），差异有统计学意义（P〈0．05）；两组远处转移率分别为12．2％（9／74）及19．2％（14／73），差异无统计学意义（P〉0．05）；1年与3年累积生存率研究组分别为98．5％、77．4％，对照组分别为92．9％、64．7％，经Log—Rank检验，两组差异有统计学意义（P〈0．05）；对照组Ⅱ、Ⅲ度口咽黏膜放疗反应较研究组明显增多（P〈0．05）；对照组发生2例放射性脑病，1例视神经损伤；但两组均无严重的皮肤、软组织纤维化及放射性后组颅神经损伤发生。结论应用CT模拟定位能提高鼻咽癌常规放射治疗疗效，减少复发和放射不良反应。

Application of CT simulation for nasopharyngeal carcinoma conventional radiotheraphy

Objective To compare and observe the effect and side effect of two different kinds of simulation mode for nasopharyngeal carcinoma conventional radiotherapy. Methods 147 cases were randomly divided into the study group (74 cases, CT simulation) and the control group (73 cases, X-ray radiography simulation). In the study group three-dimensional treatment planning system (IPS) was used to draw target volume and organ at risk, and then beam eye view (BEV) function was utilized to design treatment plan and subsequent plan modulation. In the control group X-ray simulation radiography was used. Two groups of plan design and subsequent plan modulation mode were exactly the same, and the radiotherapy were performed on the same accelerator. Results For these two groups, there were 5-59 months follow-up. The recent therapeutic effect of nasopharyngeal carcinoma primary site and cervical lymph node metastasis was regular,and no statistical significance (P >0.05). For the study group 3-year local recurrence rate was 5.4 % (4/74) while the control group was 16.4 %(12/73), and there was obvious statistical significance between two groups. About one year and three year accumulated survival rate, the study group was 98.5 %, 77.4 %, and for the control group was 92.9 %, 64.7 %. Two groups survival curves were examined by Log-rank test: the survival curves showed statistical significance between two groups(P <0.05). In control group, stage II and III radiotheray reaction of oralis mucosa was significantly increased compared with that of the study group (P < 0.05). There were two cases radioactivity cerebral palsy and one case optic nerve damage in the control group, but no serious dermatosis, soft tissue fibrosis and radioactivity posterior cranial nerve damage. Conclusion The CT simulation which is applied to nasopharyngeal carcinoma conventional radiotheraphy could improve therapeutic effect and reduce cancer recurrence and radiation side effect.