Kamiryo T, Berr S S, Berk H W, Lee K S, Kassell N F, Steiner L
Department of Neurological Surgery, Virginia Neurological Institute, Charlottesville, USA.
Acta Neurochir (Wien). 1996;138(9):1103-7; discussion 1107-8. doi: 10.1007/BF01412315.
Stereotactic devices for experimental Gamma Knife irradiation and magnetic resonance imaging (MRI) have recently been developed for experimental studies using rats [6,7]. The present study examined the accuracy of these devices using the following two approaches. In the first approach, Gamma Knife irradiation was performed using the stereotactic device with targets based on a standard stereotactic atlas. Gadolinium-enhanced T1-weighted magnetic resonance imaging was performed using the MRI stereotactic device. Animals were then sacrificed after Evans blue injection, and the rat brain was sliced using an attachment to the stereotactic device. The center coordinates of the gadolinium-enhanced area from the MRI and Evans blue-stained area from the tissue sections were obtained using a computer-assisted image analysis system. These coordinates were compared with the target coordinates planned from the stereotactic atlas. In the second approach, a thermoluminescence dosimeter was implanted in the rat brain. Stereotactic MRI was performed using the stereotactic MRI device, and the coordinates of the implant were obtained. Gamma Knife irradiation was then performed at this target using the stereotactic device. The absorbed dose was measured and compared with the planning dose. These experiments demonstrated a spatial error of 0.6 mm (standard error +/- 0.07) between Gamma Knife irradiation based on a comparison of the atlas coordinates and the lesion, and a spatial error of 1.0 mm (standard error +/- 0.13) based on a comparison of the stereotactic MR images and the lesion. Gamma Knife irradiation based on MR images using the stereotactic device demonstrated a maximum error of 10% in absorbed dose at the target center. Together, the stereotactic devices for Gamma Knife irradiation and magnetic resonance imaging provide useful tools for Gamma Knife research in an animal model.
最近已开发出用于实验性伽玛刀照射和磁共振成像（MRI）的立体定向装置，用于大鼠的实验研究[6,7]。本研究采用以下两种方法检验了这些装置的准确性。在第一种方法中，使用基于标准立体定向图谱设置靶点的立体定向装置进行伽玛刀照射。使用MRI立体定向装置进行钆增强T1加权磁共振成像。然后在注射伊文思蓝后处死动物，并使用立体定向装置的附件对大鼠脑进行切片。使用计算机辅助图像分析系统获取MRI中钆增强区域和组织切片中伊文思蓝染色区域的中心坐标。将这些坐标与从立体定向图谱规划的靶点坐标进行比较。在第二种方法中，将热释光剂量计植入大鼠脑内。使用立体定向MRI装置进行立体定向MRI，并获取植入物的坐标。然后使用立体定向装置在该靶点进行伽玛刀照射。测量吸收剂量并与计划剂量进行比较。这些实验表明，基于图谱坐标与病变比较的伽玛刀照射之间的空间误差为0.6毫米（标准误差±0.07），基于立体定向MR图像与病变比较的空间误差为1.0毫米（标准误差±0.13）。使用立体定向装置基于MR图像的伽玛刀照射在靶点中心的吸收剂量最大误差为10%。总之，用于伽玛刀照射和磁共振成像的立体定向装置为动物模型中的伽玛刀研究提供了有用的工具。
