Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
World Neurosurg. 2011 May-Jun;75(5-6):665-72. doi: 10.1016/j.wneu.2010.12.051.
To present our initial experience with the Elekta eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery.
The eXtend System comprises a carbon-fiber frame system known as the eXtend Frame, a vacuum cushion, and a vacuum pump/vacuum surveillance system. The eXtend Frame comprises a carbon-fiber frame, a mouthpiece with dental impression, and a configurable front-piece that accepts the mouthpiece and rigidly attaches to the carbon-fiber frame. Treatment preparation involves creating a dental impression, fitting the patient to the frame system at the Gamma Knife, acquiring a stereotactic computed tomography (CT) scan, and co-registering a volumetric magnetic resonance image. Measurements taken at the time of CT imaging using high-precision electronic probes locate the patient's head within the eXtend frame. These measurements are compared to measurements taken at the time of treatment to ensure the patient is in proper treatment position. Vacuum surveillance interlocks pause the treatment if the patient moves within the eXtend frame.
As of June 2010, we have treated four patients at the University of Virginia with the eXtend System. In all cases treated to date, we were able to complete all fractions of the prescribed treatments. In addition, while in some cases repositioning before a given fraction required several attempts, we were able to achieve a radial repositioning error of less than 1 mm without taking new reference measurements and repeating patient setup and imaging.
Gamma Knife radiosurgery (GKRS) has traditionally been a single-fraction treatment modality. The eXtend System expands the range of indications for GKRS to those that may benefit from multi-fraction or serial multi-session techniques. The relocatable eXtend frame can provide non-invasive head fixation while maintaining a high accuracy, high dose, and the steep gradients associated with GKRS.
介绍我们在 Elekta eXtend 系统方面的初步经验，该系统是一种用于多次分割或序贯多次分割放射外科的可重新定位框架系统。
eXtend 系统包括一个称为 eXtend Frame 的碳纤维框架系统、一个真空垫和一个真空泵/真空监测系统。eXtend Frame 由碳纤维框架、带牙印的接口和一个可配置的前件组成，该前件可接受接口并将其刚性连接到碳纤维框架上。治疗准备包括制作牙印、在伽玛刀上将患者与框架系统适配、获取立体计算机断层扫描（CT）扫描并对容积磁共振图像进行配准。在 CT 成像时使用高精度电子探头进行的测量可确定患者头部在 eXtend 框架内的位置。这些测量值与治疗时的测量值进行比较，以确保患者处于适当的治疗位置。如果患者在 eXtend 框架内移动，真空监测互锁会暂停治疗。
截至 2010 年 6 月，我们在弗吉尼亚大学使用 eXtend 系统治疗了 4 名患者。在迄今为止治疗的所有病例中，我们都能够完成规定治疗的所有分次。此外，虽然在某些情况下，在给定分次之前重新定位需要多次尝试，但我们能够在不进行新的参考测量并重复患者设置和成像的情况下，将重新定位误差控制在 1 毫米以内。
伽玛刀放射外科（GKRS）传统上是一种单次分割治疗方式。eXtend 系统将 GKRS 的适应证范围扩大到那些可能受益于多次分割或序贯多次分割技术的患者。可重新定位的 eXtend 框架可在保持高准确性、高剂量和与 GKRS 相关的陡峭梯度的同时，提供非侵入性的头部固定。
