立体定向放射外科治疗癫痫的剂量-体积与脑水肿的相关性研究

目的 研究立体定向放射外科治疗低剂量照射癫痫灶引起的放射性脑水肿与治疗剂量和体积的相关性.方法 回顾性分析1999年10月-2005年5月山东万杰医院及重庆大坪医院γ刀中心治疗的各种类型难治性癫痫患者136例.对136例患者采用立体定向放射治疗的靶区体积和剂量进行对比分析,绘出散点图,并进行相关数据的Logistic回归性分析,得出一定剂量、体积范围内预测放射性脑水肿发生概率的方程.结果 立体定向放射外科的靶区中心剂量＞ 18 Gy或靶区体积＞ 30 cm3时,发生放射性脑水肿反应的可能性最大.回归性分析后得到预测方程,经验证该方程的正确率为94.7％.结论 利用靶区体积和剂量作为参数,通过相关性分析得到的方程,可以预测立体定向放射外科治疗癫痫患者后发生放射性脑水肿的概率,该方程有一定的临床参考价值.

Correlation occurrence of radiation induced encephaledema with target dose and volume in stereotactic radiosurgery of epilepsy

Objective To study the correlation between the occurrence of encephaledema and the target dose-volume after the low dose stereotactic radiosurgery of epilepsy. Methods Totally 136 epilepsy patients treated by low dose stereotactic radiosurgery with Novalis System were analysed retrospectively. The target doses and volumes of the patients were analysed by drawing out the scatterplot and conducting the binary Logistic regression to all of the data. An equation was obtained to predict the occurrence of radiation induced encephaledema in certain range of target volume and dose. Results Among all of 136 patients, different degree of local encephaledema occurred in 19 cases after the radiosurgery. Higher occurrence of radiation induced encephaledema was observed when the target central dose (i.e. 90% isodose circling the target)was more than 18 Gy or the target volume more than 30 cm³. Moreover, in patients with multi-targets the doses of different targets devoted to each other, which could lead to the occurrence of local encephaledema. The equation to predict the occurrence probability was obtained by regression analysis. By testing this equation in all of 136 patients the coincidence percentage was 94.7%. Conclusions The target dose and volume could be effective parameters in certain range to predict the occurrence probability of radiation induced encephaledema. This equation would help to establish and optimize the therapeutic planning system. So it could finally reduce the side-effect of low dose stereotactic radiosurgey in epilepsy patients.The equation has some clinical value.