Engenhart R, Wowra B, Debus J, Kimmig B N, Höver K H, Lorenz W, Wannenmacher M
Department of Radiation Therapy, University of Heidelberg, Germany.
Int J Radiat Oncol Biol Phys. 1994 Oct 15;30(3):521-9. doi: 10.1016/0360-3016(92)90937-d.
Radiosurgery with external beam irradiation is an accepted treatment for small intracranial vascular malformations. It has been proven effective and safe for lesions with volumes of less than 4 cc. However, there is only some limited clinical data for malformations of grade 4 and grade 5, according to Spetzler and Martin.
At the Heidelberg radiosurgery facility equipped with a linear accelerator, 212 patients with cerebral arteriovenous malformations have been treated since 1984. Thirty-eight percent of the arteriovenous malformations treated were classified inoperable, 14% grade 5, 19% grade 4, and 29% grades 1-3. Radiation doses between 10 and 29 Gy were applied to the 80% isodose contour.
Above a threshold dose of 18 Gy, the overall obliteration rate was 72%. After 3 years, the obliteration rates were 83% with volumes of less than 4.2 cc, 75% with volumes of up to 33.5 cc, and 50% with volumes of up to 113 cc. Of the patients presenting with seizures and paresis, 83% and 56%, respectively, showed improvement, which correlated with the degree of obliteration. After a follow-up period of up to 9 years, the rate of radiation-induced severe late complications was 4.3%. In grade 5 lesions, the risk of side effects was 10%. No serious complications occurred if a maximum dose of less than 25 Gy was applied to treatment volumes of less than 33.5 cc.
The success of stereotactic high-dose irradiation of arteriovenous malformations depends on the dose applied. The incidence of radiation-induced side effects increased with the applied dose and treatment volumes. From our experience, doses of less than 25 Gy and treatment volumes of up to 33.5 cc are safe and effective. In the future, new techniques of radiosurgery with linear accelerators and dynamically reshaped beams will allow us to apply homogenous dose distributions. Additional use of magnetic resonance angiography for 3D treatment planning will help to identify the nidus more easily.
外照射放射外科是治疗小型颅内血管畸形的一种公认方法。对于体积小于4立方厘米的病变，已证明其有效且安全。然而，根据斯佩茨勒和马丁的分类，关于4级和5级畸形的临床数据有限。
自1984年以来，在配备直线加速器的海德堡放射外科设施中，已治疗了212例脑动静脉畸形患者。所治疗的动静脉畸形中，38%被归类为不可手术，14%为5级，19%为4级，29%为1 - 3级。10至29戈瑞的辐射剂量被应用于80%等剂量曲线。
高于18戈瑞的阈值剂量时，总体闭塞率为72%。3年后，体积小于4.2立方厘米的闭塞率为83%，体积达33.5立方厘米的闭塞率为75%，体积达113立方厘米的闭塞率为50%。出现癫痫和轻瘫的患者中，分别有83%和56%症状改善，这与闭塞程度相关。经过长达9年的随访期，放射诱发的严重晚期并发症发生率为4.3%。在5级病变中，副作用风险为10%。如果对体积小于33.5立方厘米的治疗区域应用的最大剂量小于25戈瑞，则未发生严重并发症。
动静脉畸形立体定向高剂量照射的成功取决于所应用的剂量。放射诱发副作用的发生率随所应用剂量和治疗体积增加。根据我们的经验，小于25戈瑞的剂量和达33.5立方厘米的治疗体积是安全有效的。未来，直线加速器和动态重塑射束的放射外科新技术将使我们能够应用均匀的剂量分布。在三维治疗计划中额外使用磁共振血管造影将有助于更轻松地识别病灶。
