Seneviratne Danushka S, Vallow Laura A, Hadley Austin, Malouff Timothy D, Stross William C, Herchko Steven, Pafundi Deanna H, Trifiletti Daniel M, Peterson Jennifer L
Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA.
Alaska Cancer Treatment Center, Anchorage, AK, USA.
J Radiosurg SBRT. 2020;6(4):277-285.
PURPOSE/OBJECTIVES: The Gamma-Knife radiosurgery (GKRS) (Elekta AB, Stockholm) platform delivers highly conformal and precise radiation; however, intracranial displacement during treatment allows for the potential of a marginal target-miss. Frameless (mask-based) GKRS using the Gamma Knife Icon system monitors nasal tip motion as a surrogate for intracranial motion by tracking an infrared marker using a high-definition motion management (HDMM) system. To date, there is limited data available regarding the incidence and severity of motion and factors that impact intrafraction motion when treating with frameless GKRS.
MATERIALS/METHODS: A retrospective study was performed to evaluate patients with brain tumors who were treated with frameless GKRS using the Gamma Knife Icon between May and December 2018. All patients underwent mask-based immobilization using a thermoplastic mask. Data on patient demographics, mask type, use of bite block, and number of treatments received, use of anxiolytics, treatment time, and whether a physics clearance check was performed prior to treatment were collected. For each treatment session, average displacement (mm), maximum displacement (mm) and total treatment time (min) were recorded and logistic regression analyses were performed.
Data was collected for 89 consecutive treatments (38 patients). Of these, an anxiolytic was used in 61 treatments and a physics clearance check was performed for 45 treatments. The median average and maximum displacement was 0.60 mm and 1.22 mm, respectively. An average displacement greater than 0.60 mm was seen with Eastern Cooperative Oncology Group performance status (ECOG) > 1, male gender, and malignant tumors (p < 0.05). Anxiolytic use prior to treatment was associated with a significant reduction in average displacement (p < 0.05). Significantly greater odds of observing a maximum displacement over 1.22 mm was seen with patients with ECOG > 1, male gender, and increased treatment time (p < 0.05). Age > 65 and anxiolytic use were associated with a significant reduction in maximum displacement (p < 0.05). Performance of clearance checks and use of bite block use did not impact average or maximum patient displacement.
This is the first study to evaluate patient and treatment-related factors that influence intrafraction motion during GKRS with mask-based immobilization through HDMM tracking. Increased intracranial displacement during frameless GKRS was associated with higher ECOG, male gender, increased treatment time and malignant tumors, while anxiolytics were shown to mitigate excessive motion. Radiosurgery teams should consider these patient factors when treating patients with mask immobilization.
目的/目标：伽玛刀放射外科手术（GKRS）（瑞典斯德哥尔摩医科达公司）平台可提供高度适形且精确的辐射；然而，治疗过程中的颅内移位可能导致边缘性靶区遗漏。使用伽玛刀Icon系统的无框架（面罩式）GKRS通过高清运动管理（HDMM）系统跟踪红外标记，将鼻尖运动作为颅内运动的替代指标进行监测。迄今为止，关于无框架GKRS治疗时运动的发生率、严重程度以及影响分次治疗期间运动的因素的数据有限。
材料/方法：进行了一项回顾性研究，以评估2018年5月至12月期间使用伽玛刀Icon接受无框架GKRS治疗的脑肿瘤患者。所有患者均使用热塑性面罩进行面罩固定。收集了患者人口统计学数据、面罩类型、咬块使用情况、接受治疗的次数、抗焦虑药的使用情况、治疗时间以及治疗前是否进行了物理清除检查等数据。对于每个治疗疗程，记录平均位移（mm）、最大位移（mm）和总治疗时间（min），并进行逻辑回归分析。
连续收集了89次治疗（38例患者）的数据。其中，61次治疗使用了抗焦虑药，45次治疗进行了物理清除检查。平均位移和最大位移的中位数分别为0.60 mm和1.22 mm。东部肿瘤协作组（ECOG）功能状态>1、男性以及恶性肿瘤患者的平均位移大于0.60 mm（p<0.05）。治疗前使用抗焦虑药与平均位移显著降低相关（p<0.05）。ECOG>1、男性以及治疗时间增加的患者观察到最大位移超过1.22 mm的几率显著更高（p<0.05）。年龄>65岁和使用抗焦虑药与最大位移显著降低相关（p<0.05）。清除检查的执行情况和咬块的使用并未影响患者的平均或最大位移。
这是第一项通过HDMM跟踪评估基于面罩固定的GKRS治疗期间影响分次治疗运动的患者及治疗相关因素的研究。无框架GKRS期间颅内位移增加与更高的ECOG、男性、治疗时间增加和恶性肿瘤相关，而抗焦虑药可减轻过度运动。放射外科团队在对面罩固定的患者进行治疗时应考虑这些患者因素。
