Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation
Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation
复制标题
基于实时6D位置监测和自适应头部运动补偿的无框架立体定向放射外科系统的开发
DOI：
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发表时间：
2010
影响因子：
3.5
通讯作者：
K. Yenice
中科院分区：
文献类型：
--
作者：
R. Wiersma;Z. Wen;M. Sadinski;K. Farrey;K. Yenice
立体定向放射外科以极高的空间精度提供辐射。为了实现颅内 SRS 的亚毫米精度，将头环牢固地固定在颅骨上以创建固定参考。对于一些患者来说，环的侵入性可能会非常不舒服并且不能很好地耐受。此外，放置和取出环需要神经外科医生的特殊专业知识，并且患者进行 SRS 的准备时间通常可能很长。为了减少侵入性、硬件限制和设置时间，我们正在开发一种无需使用头环即可执行精确头部定位的系统。所提出的方法使用实时 6D 光学位置反馈来打开和关闭治疗光束（选通）并引导电机控制的 3D 头部运动补偿台。该装置由中央控制计算机、光学患者运动跟踪系统和连接到 LINAC 沙发前面的 3D 运动补偿平台组成。聚苯乙烯泡沫塑料头铸件是为患者支撑而定制的，并安装在补偿台上。控制计算机处理标记的运动反馈，并使用刚体模型计算目标的最终运动。如果目标偏离预设位置 0.2 mm，则使用步进电机进行自动位置校正，通过沙发安装运动平台调整头部位置。如果目标偏离超过 1 毫米，则会激活安全继电器开关并关闭治疗光束。该概念的可行性通过五名健康志愿者进行了测试。在 15 分钟的治疗时间内使用和不使用运动补偿来获取头部运动数据。平均而言，在没有进行运动校正的情况下，测试对象在 86% 的时间里超过了 0.5 毫米的公差，在 45% 的时间内超过了 1.0 毫米的公差。经过修正后，对于 0.5 毫米和 1.0 毫米公差，该百分比分别降至 5% 和 2%。
Stereotactic radiosurgery delivers radiation with great spatial accuracy. To achieve sub-millimeter accuracy for intracranial SRS, a head ring is rigidly fixated to the skull to create a fixed reference. For some patients, the invasiveness of the ring can be highly uncomfortable and not well tolerated. In addition, placing and removing the ring requires special expertise from a neurosurgeon, and patient setup time for SRS can often be long. To reduce the invasiveness, hardware limitations and setup time, we are developing a system for performing accurate head positioning without the use of a head ring. The proposed method uses real-time 6D optical position feedback for turning on and off the treatment beam (gating) and guiding a motor-controlled 3D head motion compensation stage. The setup consists of a central control computer, an optical patient motion tracking system and a 3D motion compensation stage attached to the front of the LINAC couch. A styrofoam head cast was custom-built for patient support and was mounted on the compensation stage. The motion feedback of the markers was processed by the control computer, and the resulting motion of the target was calculated using a rigid body model. If the target deviated beyond a preset position of 0.2 mm, an automatic position correction was performed with stepper motors to adjust the head position via the couch mount motion platform. In the event the target deviated more than 1 mm, a safety relay switch was activated and the treatment beam was turned off. The feasibility of the concept was tested using five healthy volunteers. Head motion data were acquired with and without the use of motion compensation over treatment times of 15 min. On average, test subjects exceeded the 0.5 mm tolerance 86% of the time and the 1.0 mm tolerance 45% of the time without motion correction. With correction, this percentage was reduced to 5% and 2% for the 0.5 mm and 1.0 mm tolerances, respectively.