Moon Hyeong Cheol, Lee Doheui, Park Young Seok
Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, Korea.
Department of Neurosurgery, Asan Medical Center, Seoul, Korea.
J Korean Neurosurg Soc. 2025 Sep;68(5):616-621. doi: 10.3340/jkns.2025.0039. Epub 2025 Aug 11.
The Leksell Gamma Knife (LGK) Icon™ facilitates frameless (mask-based) fixation through its high-definition motion management (HDMM) system. However, the HDMM only records the intra-fractional motion values of patient marker without specifying changes along the X, Y, and Z axes. This study investigates the coordinate shifts in patient markers using the HDMM system during frameless gamma knife radiosurgery (GKRS) in patients with meningioma and metastases.
We conducted a retrospective study of patients diagnosed with meningioma or metastases who underwent frameless GKRS using the LGK Icon™ between January and September 2023. All patients were immobilized using a Nanor thermoplastic mask (Orfit Industries, Wijnegem, Belgium) for frameless fixation. Sequential data of the patients' nose marker coordinates (X, Y, Z) were imported into the LGK system, and subsequent coordinate changes were analyzed.
We evaluated patients with meningiomas (n=30) and metastases (n=30) who underwent GKRS with frameless fixation. None of the patients exhibited cognitive impairment or compliance issues. The median beam-on time was 44.2 minutes in patients with meningioma and 93.75 minutes in patients with metastases. In patients with meningioma, no significant intra-fractional displacements were found along the X (0.07±0.06 mm), Y (0.08±0.46 mm), and Z (0.08±0.04 mm) axes. However, in patients with metastases, the Y axis (0.57±0.37 mm, p<0.05) exhibited significantly greater intra-fractional displacements compared with the X axis (0.33±0.23 mm). No significant differences in intra-fractional displacement were observed between the X and Z (0.43±0.31 mm) axes or between the Y and Z axes. An analysis of movement over time revealed a significant increase in Y axis displacement after 30 minutes.
Y axis movement, as indicated by the HDMM, was most prominent in patients with metastases. We recommend pressing the forehead when securing a mask to minimize nose marker movement. Additionally, when creating treatment plans for managing patients with metastases using the LGK Icon™, we suggest adding a 0.5 mm margin to the Y axis.
Leksell伽玛刀（LGK）Icon™通过其高清运动管理（HDMM）系统实现无框架（面罩式）固定。然而，HDMM仅记录患者标记物的分次内运动值，未明确沿X、Y和Z轴的变化情况。本研究调查了脑膜瘤和转移瘤患者在无框架伽玛刀放射外科手术（GKRS）期间使用HDMM系统时患者标记物的坐标偏移。
我们对2023年1月至9月期间使用LGK Icon™接受无框架GKRS治疗的脑膜瘤或转移瘤患者进行了一项回顾性研究。所有患者均使用Nanor热塑性面罩（Orfit Industries，比利时维涅gem）进行固定以实现无框架固定。将患者鼻部标记物坐标（X、Y、Z）的序列数据导入LGK系统，并分析随后的坐标变化。
我们评估了接受无框架固定GKRS治疗的脑膜瘤患者（n=30）和转移瘤患者（n=30）。所有患者均未出现认知障碍或依从性问题。脑膜瘤患者的中位照射时间为44.2分钟，转移瘤患者为93.75分钟。脑膜瘤患者在X轴（0.07±0.06 mm）、Y轴（0.08±0.46 mm）和Z轴（0.08±0.04 mm）上均未发现明显的分次内位移。然而，转移瘤患者中，Y轴（0.57±0.37 mm，p<0.05）的分次内位移明显大于X轴（0.33±0.23 mm）。X轴和Z轴（0.43±0.31 mm）之间或Y轴和Z轴之间在分次内位移上未观察到显著差异。对随时间的运动分析显示，30分钟后Y轴位移显著增加。
HDMM显示Y轴运动在转移瘤患者中最为突出。我们建议在固定面罩时按压前额以尽量减少鼻部标记物的移动。此外，在使用LGK Icon™为转移瘤患者制定治疗计划时，我们建议在Y轴上增加0.5 mm的边界。
