放射外科的发展(从头架到影像引导)

The Development of Radiosurgery

放射外科自Leksell发明伽玛刀以来,应用于临床已有30余年,治疗了数百万患者,使之避免了直接手术的痛苦。早期的放射外科是以框架为基础的,主要用于颅内病变的治疗,获得了极好的临床效果,上世纪80年代出现了基于直线加速器的放射外科,放射外科进入了无框架的时代,减轻了患者治疗时的痛苦,并且使颅外放射外科成为可能,但因为缺乏框架,其精确性受到影响,限制了其临床应用。进入90年代,随着影像技术及电子技术的不断进步,涌现了影像引导、多叶光栅、动态准直器、图像融合、扫描射线技术、逆向治疗计划系统等新技术,设备不断更新,精度更高,适形性更好,治疗范围越来越广,效果也越来越好。1994年放射外科手术平台射波刀初次用于临床,紧凑轻量的直线加速器安装在一个由计算机控制的6关节机械臂上,可以从不同方位沿不同轨道围绕患者自由运动,始终对准靶区,并且在治疗中可以利用X光照相机和同步呼吸追踪系统连续监测病灶的活动,并相应的调整加速器的位置来确保治疗的精确性。2001年获得了FDA批准,现已广泛地在世界各地应用于临床,取得了极佳的治疗效果。本文对放射外科的发展历程作一综述,同时着重介绍射波刀的治疗原理和临床应用。

Radiosurgery commenced when the Gamma Knife was invented by Lars Leksell in 1951. Thirty years have passed since radiosurgery was applied clinically. Millions of patients have benefited from it and have avoided traditional surgery. Early radiosurgery was frame-based and was mainly used for intracranial lesions, providing excellent clinical results. The linear accelerator-based radiosurgical technique was established in the 1980s, and radiosurgery entered a new epoch of framelessness. However, accuracy was not satisfactory and this limitation restricted its clinical application. Since 1990, with the development of imaging techniques and computer science, more and more new methods such as image guidance, multileaf collimators, dynamic field shaping, image fusion, scanning beam techniques, and inverse treatment planning systems have been applied in clinical practice. The first revolutionary Cyberknife radiosurgery system was used in the clinic in 1994. A compact, lightweight linear accelerator is always aimed toward the target as it moves along different trajectories around the patient via a computer-driven robotic arm with six degrees of freedom. It continuously monitors and corrects for changes in patient position and motion by comparing pretreatment CT-based digitally reconstructed radiographs to digital radiographs acquired throughout the radiosurgical treatment. The Cyberknife received FDA approval to be used throughout the body in 2001, and now it is widely used all over the world where it provides fantastic clinical results. We have summarized the general history of radiosurgery and have introduced the working principle and clinical application of the Cyberknife.