CT 定位扫描在伽玛刀治疗三叉神经痛中的应用

目的：探讨伽玛刀治疗三叉神经痛应用 CT 定位扫描的可行性。方法回顾性分析成都军区机关医院肿瘤科从2010年10月-2013年6月收治的因核磁扫描禁忌证而行 CT 定位的三叉神经痛患者12例，局麻下在前额隆突和枕骨粗隆以上水平安装定位框架，基环低于外耳孔下﹥1 cm，在 CT 定位扫描图像上寻找三叉神经根出桥脑处，行伽玛刀治疗：等剂量曲线50％，最高剂量84-90 Gy。术后电话随访，行疼痛缓解评级和面部麻木评级。结果按以上方法安装立体定位框架，很好地躲避金属伪影，CT 扫描图像中可显示三叉神经根。术后随访平均14（6-38）个月，11例（91.67％）疼痛分级从Ⅳ、Ⅴ级降低至Ⅲ级以下，其中6例（50.00％）疼痛完全缓解，平均起效时间6（3-10）个月。3例（25.00％）患者出现Ⅲ级以下面部麻木。结论在前额隆突和枕骨粗隆水平，基环低于外耳孔下﹥1 cm 的位置安装立体定位框架，可避免金属伪影，显示三叉神经根，满足伽马刀治疗定位的需要。CT 定位扫描可作为有核磁扫描禁忌证患者伽玛刀治疗的定位方式。

Applications of CT location scan to treatment of trigeminal neuralgia by Gamma-knife

Objective To explore the feasibility of CT location scan applied to treatment of trigeminal neuralgia by Gamma-knife. Methods A retrospective analysis was made to the clinical data of 12 cases with trigeminal neuralgia,who received CT location scan because of contraindication to MRI,hospitalized in the period from Oct. ,2010 to June,2013;the frame was fixed horizontally to prefrontal carina and occipital tuberosity with the base ring lower than external auditory meatus for about ﹥ 1 cm;the exit of trigeminal nerve root in the pons was decided in the CT location scanning image and gamma-knife treatment was performed with the isodose curve of 50% and the maximal dose of 84 to 90 Gy;postoperative follow-up by telephone was made and pain relief grading and facial numbness grading were evaluated. Results The trigeminal nerve root was well manifested in the CT scanning image;follow-up lasted from 6 months to 38 months with an average of 14 months;pain relief grade in 11 cases（91. 67% ）dropped from grade Ⅳ and Ⅴ down to below grade Ⅲ,6（50. 00% ）of the 11 had the complete relief of pain,the average time for effectiveness was 6 months（from 3 months to 10 months）;facial numbness grade in 3 cases（25. 00% ）were below grade Ⅲ. Conclusions The fixation of the frame horizontally to prefrontal carina and occipital tuberosity with the base ring lower than external auditory meatus for about ﹥ 1 cm avoids the metal artifacts and well-displays the trigeminal nerve root;CT location scan is a way of positioning in gamma-knife treatment for patients with contraindication to MRI.