Schwartz M
Sunnybrook Health Science Centre, Toronto, Ont.
CMAJ. 1998 Mar 10;158(5):625-8.
Radiosurgery can be defined as 3-dimensional stereotactic irradiation of small intracranial targets by various radiation techniques. The goal is to deliver, with great accuracy, a large, single fraction dose to a small intracranial target, while minimizing the absorbed dose in the surrounding tissue. This article describes certain technical aspects of radiosurgery and compares the different methods of performing such treatment. The 2 most frequently used types of devices for radiosurgery are units with multiple cobalt sources (e.g., the Gamma Knife) and those based on a linear accelerator. In the former, highly collimated beams of radiation from the cobalt sources intersect at the target. In the latter, the source of a highly collimated beam of high-energy photons directed at the target turns through an arc or set of arcs. The accuracy of target localization, the steepness of fall-off of the radiation dose outside the target and the ability to irradiate an irregularly shaped target are all comparable for these 2 types of devices, despite claims to the contrary.
放射外科可定义为通过各种放射技术对颅内小靶点进行三维立体定向照射。其目标是以极高的精度将大剂量单次照射给予颅内小靶点，同时使周围组织的吸收剂量最小化。本文描述了放射外科的某些技术方面，并比较了进行此类治疗的不同方法。放射外科最常用的两种设备类型是具有多个钴源的装置（例如伽玛刀）和基于直线加速器的装置。在前者中，来自钴源的高度准直的辐射束在靶点处相交。在后者中，指向靶点的高能光子高度准直束的源通过一个弧或一组弧旋转。尽管有相反的说法，但对于这两种类型的设备，靶点定位的准确性、靶点外辐射剂量的下降陡度以及照射不规则形状靶点的能力都是相当的。
