Ryan M J, Erickson R K, Levin D N, Pelizzari C A, Macdonald R L, Dohrmann G J
Department of Radiology, University of Chicago, Illinois, USA.
J Neurosurg. 1996 Aug;85(2):287-92. doi: 10.3171/jns.1996.85.2.0287.
The accuracy of a novel frameless stereotactic system was determined during 10 surgeries performed to resect brain tumors. An array of three charge-coupled device cameras tracked the locations of infrared light-emitting diodes on a hand-held stylus and on a reference frame attached to the patient's skull with a single bone screw. Patient-image registration was achieved retrospectively by digitizing randomly chosen scalp points with the system and fitting them to a scalp surface model derived from magnetic resonance (MR) images. The reference frame enabled continual correction for patient head movements so that registration was maintained even when the patient's head was not immobilized in a surgical clamp. The location of the stylus was displayed in real-time on cross-sectional and three-dimensional MR images of the head; this information was used to predict the locations of small intracranial lesions. The average distance (and standard deviation) between the actual position of the mass and its stereotactically predicted location was 4.8 +/- 3.5 mm. The authors conclude that frameless stereotaxy can be used for accurate localization of intracranial masses without resorting to using fiducial markers during presurgical imaging and without immobilizing the patient's head during surgery.
在10例脑肿瘤切除手术中确定了一种新型无框架立体定向系统的准确性。一组三个电荷耦合器件摄像头跟踪手持探针以及通过单个骨螺钉固定在患者颅骨上的参考框架上的红外发光二极管的位置。通过用该系统对随机选择的头皮点进行数字化处理并将其拟合到从磁共振（MR）图像得出的头皮表面模型，回顾性地实现患者图像配准。参考框架能够对患者头部运动进行持续校正，从而即使患者头部未固定在手术夹中也能保持配准。探针的位置实时显示在头部的横断面和三维MR图像上；该信息用于预测颅内小病变的位置。肿块实际位置与其立体定向预测位置之间的平均距离（及标准差）为4.8 +/- 3.5毫米。作者得出结论，无框架立体定向术可用于颅内肿块的精确定位，无需在术前成像时使用基准标记，也无需在手术期间固定患者头部。
