Han Eun Young, Luo Dershan, Kim Jong Oh, Tharp Kelly, Wen Zhifei, Briere Tina M
Department of Radiation Physics, Unit 94, University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, USA.
Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop Street, Pittsburgh, PA, USA.
J Radiosurg SBRT. 2019;6(3):217-226.
To perform dosimetric validation of the plan adaptation and high-definition motion management (HDMM) system of Gamma Knife® Icon in various clinical scenarios.
We built an assembly for a pitch-adjustable anthropomorphic head phantom. We then used films to measure dosimetric and positional accuracy in 13 clinical scenarios, including movement near HDMM thresholds, multiple plan adaptations, frequent coughing, and initial setup error.
The dose for the superiorly located 4-mm shot was decreased up to 7-13% near 2- to 3-mm HDMM thresholds in the chin-down position. Dosimetric deviation was within ±3.5% for initial pitch angles of up to 20°. Multiple treatment interruption and frequent coughing did not cause substantial dosimetric deviation (<2%).
Our results indicated that dosimetric accuracy of the Gamma Knife® Icon system is reliable even in extreme treatment conditions. However, the user should exercise caution for superiorly located small lesions with an HDMM threshold ≥2 mm or in the scenario of large initial setup error.
在各种临床场景中对伽玛刀Icon的计划适配和高清运动管理（HDMM）系统进行剂量学验证。
我们构建了一个用于俯仰可调的仿真人头模体组件。然后，我们使用胶片在13种临床场景中测量剂量学和位置精度，包括接近HDMM阈值的运动、多次计划适配、频繁咳嗽和初始设置误差。
在下颌向下位置，靠近2至3毫米HDMM阈值时，位于上方的4毫米射束剂量降低高达7 - 13%。初始俯仰角高达20°时，剂量学偏差在±3.5%以内。多次治疗中断和频繁咳嗽未导致明显的剂量学偏差（<2%）。
我们的结果表明，即使在极端治疗条件下，伽玛刀Icon系统的剂量学精度也是可靠的。然而，对于HDMM阈值≥2毫米的位于上方的小病灶或初始设置误差较大的情况，用户应谨慎操作。
