Fabrikant J I, Levy R P, Steinberg G K, Phillips M H, Frankel K A, Lyman J T, Marks M P, Silverberg G D
Division of Research Medicine and Radiation Biophysics, Lawrence Berkeley Laboratory, University of California, Berkeley.
Neurosurg Clin N Am. 1992 Jan;3(1):99-139.
Heavy charged-particle radiation has unique physical characteristics that offer several advantages over photons and protons for stereotactic radiosurgery of intracranial AVMs. These include improved dose distributions with depth in tissue, small angle of lateral scattering, and sharp distal fall-off of dose in the Bragg ionization peak. Under multi-institutionally approved clinical trials, we have used stereotactic helium-ion Bragg peak radiosurgery to treat approximately 400 patients with symptomatic, surgically inaccessible vascular malformations at the UCB-LBL 184-in synchrocyclotron and bevatron. Treatment planning for stereotactic heavy charged-particle radiosurgery for intracranial vascular disorders integrates anatomic and physical information from the stereotactic cerebral angiogram and stereotactic CT and MR imaging scans for each patient, using computerized treatment-planning calculations for optimal isodose contour distribution. The shape of an intracranial AVM is associated strongly with its treatability and potential clinical outcome. In this respect, heavy charged-particle radiosurgery has distinct advantages over other radiosurgical methods; the unique physical properties allow the shaping of individual beams to encompass the contours of large and complexly shaped AVMs, while sparing important adjacent neural structures. We have had a long-term dose-searching clinical protocol in collaboration with SUMC and UCSF and have followed up over 300 patients for more than 2 years. Initially, treatment doses ranged from 45 GyE to 35 GyE. Currently, total doses up to 25 GyE are delivered to treatment volumes ranging from 0.1 cm3 to 70 cm3. This represents a relatively homogeneous dose distribution, with the 90% isodose surface contoured to the periphery of the lesion; there is considerable protection of normal adjacent brain tissues, and most of the brain receives no radiation exposure. Dose selection depends on the volume, shape, and location of the AVM and several other factors, including the volume of normal brain that must be traversed by the plateau portion of the charged-particle beam. The first 230 patients have been evaluated clinically to the end of 1989. Using the clinical grading of Drake, about 90% of the patients had an excellent or good neurologic grade, about 5% had a poor grade, and about 5% had progression of disease and died, or died as a result of unrelated intercurrent illness. Neuroradiologic follow-up to the end of 1989 indicated the following rates of complete angiographic obliteration 3 years after treatment: 90% to 95% for AVM treatment volumes less than 4 cm3, 90% to 95% for volumes 4 to 14 cm3, and 60% to 70% for volumes greater than 14 cm3.(ABSTRACT TRUNCATED AT 400 WORDS)
重带电粒子辐射具有独特的物理特性，在颅内动静脉畸形的立体定向放射外科治疗中，与光子和质子相比具有若干优势。这些优势包括在组织中随深度改善的剂量分布、较小的侧向散射角以及在布拉格电离峰处剂量的急剧远端下降。在多机构批准的临床试验中，我们在劳伦斯伯克利国家实验室（UCB-LBL）的184英寸同步回旋加速器和质子加速器上，使用立体定向氦离子布拉格峰放射外科治疗了约400例有症状、手术难以触及的血管畸形患者。颅内血管疾病的立体定向重带电粒子放射外科治疗计划整合了来自每位患者的立体定向脑血管造影、立体定向CT和MR成像扫描的解剖学和物理信息，并使用计算机化治疗计划计算来优化等剂量线轮廓分布。颅内动静脉畸形的形状与其可治疗性和潜在临床结果密切相关。在这方面，重带电粒子放射外科比其他放射外科方法具有明显优势；独特的物理特性允许塑造单个射束以包围大的和形状复杂的动静脉畸形的轮廓，同时保护重要的相邻神经结构。我们与斯坦福大学医学中心（SUMC）和加州大学旧金山分校（UCSF）合作制定了一项长期剂量探索临床方案，并对300多名患者进行了超过2年的随访。最初，治疗剂量范围为45 GyE至35 GyE。目前，总剂量高达25 GyE被输送到体积从0.1 cm³至70 cm³的治疗体积中。这代表了相对均匀的剂量分布，90%等剂量面勾勒出病变周边；对相邻正常脑组织有相当程度的保护，并且大部分脑未受到辐射照射。剂量选择取决于动静脉畸形的体积、形状和位置以及其他几个因素，包括带电粒子束坪区必须穿过的正常脑体积。到1989年底，对首批230例患者进行了临床评估。根据德雷克的临床分级，约90%的患者神经功能分级为优或良，约5%为差，约5%疾病进展并死亡，或因无关的并发疾病死亡。到1989年底的神经放射学随访显示治疗后3年完全血管造影闭塞的比例如下：动静脉畸形治疗体积小于4 cm³的为90%至95%，4至14 cm³的为90%至95%，大于14 cm³的为60%至70%。（摘要截取自400字）
