顽固性癫痫的低剂量放射外科治疗

Radiosurgical treatment of intractable epilepsy with low radiation dose

目的 利用PET致痛灶定位,研究放射外科治疗顽固性癫痫的靶区设定原则,确定最佳周边剂量范围。方法 176例病人经18F-FDG PET显像致痫灶定位后,行直线加速器放射外科治疗,按所采用周边剂量的不同（9～11Gy;11～13Gy;≥13Gy）分为三组,随访3～16个月,观察各组不同随访时间的癫痫发作频率变化,评价治疗效果。结果 每组病例在3个时间段均可观察到癫痫发作频率较治疗前明显降低,与放射治疗前相比具有显著性差异。在各时间段不同病例组间比较无显著性差异。治疗后疗效Ⅰ～Ⅱ级和Ⅲ-Ⅳ级的病人分别占46.9％和41.5％。所有病例均未见明显并发症发生。结论 PET引导下的低剂量放射外科治疗顽固性癫痫具有较高的有效率、无明显并发症,是一种有效的癫痫微侵外科治疗新方法;采用9～11Gy的周边剂量照射PET提示的致痫灶和可疑致痫灶即可取得良好效果。

Objective To localize the epileptic foci with positron emission tomography (PET), and study the principles of target definition and method to determine the optimal range of exposure in radiosurgery for intractable epilepsy. Methods This study included 176 patients with intractable epilepsy, who received linear accelerator radiosurgery after 18F-FDG PET for epileptic foci localization. The patients were divided according to different peripheral doses used in the treatment into Group A in which radiation dose of 9 to 11 Gy was used, Group B with 11 to 13 Gy and Group C with exposure to over 13 Gy. Follow-up study was conducted in all the patients for a period ranging from 3 to 16 months, during which the frequency of seizure after treatment was recorded to evaluate the therapeutic effect. Results The seizure frequency significantly decreased after ra-diosurgical treatment in all the groups, but between the groups, the decrement evinced no significant difference. According to Wieser's classification of the effect after operation, 46.9% cases belonged to grade Ⅰ to Ⅱ and 41.5% to grade Ⅲ to Ⅳ. Obvious complications were not observed, nor did disability or mortality occurred in these cases. Conclusions Stereotactic radio-surgery with low radiation dose under the guidance of PET provides a safe, effective and minimally invasive surgical approach for patients with intractable epilepsy, and peripheral radiation doses of 9 to 11 Gy for the epileptic foci localized by PET is sufficient to ensure good clinical outcome.