Department of Radiation Oncology, Columbia University Irving Medical Center, New York, New York.
Herbert Irving Comprehensive Cancer Center, NewYork-Presbyterian/Columbia University Irving Medical Center, New York, New York.
Neurosurgery. 2020 Apr 1;86(4):509-516. doi: 10.1093/neuros/nyz227.
The Gamma Knife (GK) Icon (Elekta AB) uses a cone-beam computed tomography (CBCT) scanner and an infrared camera system to support the delivery of frameless stereotactic radiosurgery (SRS). There are limited data on patients treated with frameless GK radiosurgery (GKRS).
To describe the early experience, process, technical details, and short-term outcomes with frameless GKRS at our institution.
We reviewed our patient selection and described the workflow in detail, including image acquisition, treatment planning, mask-based immobilization, stereotactic CBCT localization, registration, treatment, and intrafraction monitoring. Because of the short interval of follow-up, we provide crude rates of local control.
Data from 100 patients are reported. Median age is 67 yr old. 56 patients were treated definitively, 21 postoperatively, and 23 had salvage GKRS for recurrence after surgery. Forty-two patients had brain metastases, 26 meningiomas, 16 vestibular schwannomas, 9 high-grade gliomas, and 7 other histologies. Median doses to metastases were 20 Gy in 1 fraction (range: 14-21), 24 Gy in 3 fractions (range: 19.5-27), and 25 Gy in 5 fractions (range: 25-30 Gy). Thirteen patients underwent repeat SRS to the same area. Median treatment time was 17.7 min (range: 5.8-61.7). We found an improvement in our workflow and a greater number of patients eligible for GKRS because of the ability to fractionate treatments.
We report a large cohort of consecutive patients treated with frameless GKRS. We look forward to studies with longer follow-up to provide valuable data on clinical outcomes and to further our understanding of the radiobiology of hypofractionation in the brain.
伽玛刀（GK）Icon（医科达公司）采用锥形束计算机断层扫描（CBCT）扫描仪和红外摄像系统，为无框架立体定向放射外科（SRS）治疗提供支持。目前，有关无框架 GK 放射外科（GKRS）治疗患者的数据有限。
描述我们机构使用无框架 GKRS 的早期经验、流程、技术细节和短期结果。
我们回顾了患者选择情况，并详细描述了工作流程，包括图像采集、治疗计划、基于面罩的固定、立体定向 CBCT 定位、配准、治疗和分次内监测。由于随访时间较短，我们仅提供了局部控制的粗略率。
报告了 100 例患者的数据。中位年龄为 67 岁。56 例患者接受了确定性治疗，21 例患者接受了术后治疗，23 例患者因手术切除后复发而行挽救性 GKRS 治疗。42 例患者患有脑转移瘤，26 例脑膜瘤，16 例前庭神经鞘瘤，9 例高级别胶质瘤和 7 例其他组织学类型肿瘤。转移瘤的中位剂量为单次 20 Gy（范围：14-21），3 次分割 24 Gy（范围：19.5-27），5 次分割 25 Gy（范围：25-30 Gy）。13 例患者在同一部位行重复 SRS。中位治疗时间为 17.7 分钟（范围：5.8-61.7）。由于能够对治疗进行分割，我们发现工作流程得到了改进，并且有更多的患者适合接受 GKRS 治疗。
我们报告了一系列连续的无框架 GKRS 治疗患者。我们期待进行更长时间随访的研究，以提供有关临床结果的有价值数据，并进一步了解脑内分次放射生物学。
