Analysis of biological effect and clinical result of radiosurgery

放射外科是使用电离辐射对精确定义的颅内靶进行闭合颅骨破坏。与常规分割放射治疗相比，放射外科对每个病理实体的生物学效应尚不清楚。为了分析影响放射外科临床结果的因素，我们评估了1990年6月至1996年2月期间连续562例接受伽玛刀治疗的患者的技术和治疗参数。关于脑动静脉畸形（AVM），病变体积被认为是影响闭塞率的主要因素。我们发现，在精确的3-D信息的剂量计划下，该速率不依赖于体积。然而，放射性脑水肿的发生与治疗体积成比例。放射性神经功能恶化主要取决于病变部位。关于颅内良性肿瘤，如听神经鞘瘤或脑膜瘤，放射外科手术后仅观察到7-9%的肿瘤进展。颅底肿瘤的治疗相关神经系统疾病的发病率，特别是听神经瘤患者的听力下降率，明显优于显微手术切除。总之，立体定向放射外科手术被证明是一种有效和微创的管理选定的脑AVM和小良性脑肿瘤。然而，必须进行更长时间的随访和更详细的临床结果分析，以证明该技术未来的扩展作用。

Radiosurgery is closed-skull destruction of a precisely defined intracranial target using ionizing irradiation. Compared to conventional fractionated radiotherapy, the biological effect of radiosurgery on each of pathological entities are not well known. In order to analyze the factors influencing the clinical results of radiosurgery, we evaluate the technique, and treatment parameters of consecutive 562 patients who underwent gamma knife radiosurgery between June 1990 and February 1996. Concerning cerebral arteriovenous malformations (AVMs), the lesion volume has been believed to be the primary factor influencing the obliteration rate. We found the rate does not depend on the volume under dose planning with precise 3-D information. However, radiation-induced brain edema occurred in proportion with treatment volume. Radiation-induced neurological deterioration was mainly depends on the location of the lesions. Concerning intracranial benign tumors, such as acoustic neurinomas or meningiomas, neoplasmic progression was observed only 7-9% after radiosurgery. Treatment-associated neurological morbidity of skull base tumors, especially, hearing preservatio rate in patients with acoustic neurinomas, was significantly better than microsurgical resection. In conclusion, sterotactic radiosrugery prove to be a effective and less invasive managment of selected cerebral AVMs and small benign brain tumors. However, longer follow-up and more detailed analysis of clinical outcome must be required to testify the future expanding role of this technique.