title: Effective usage of a clearance check to avoid a collision in Gamma Knife Perfexion radiosurgery with the Leksell skull frame.
abstract: Skull frame attachment is one of the most significant issues with Gamma Knife radiosurgery. Because of the potential for suffering by patients, careful control of the frame position is required to avoid circumstances such as collision between the frame or the patient's head and the collimator helmet, and inaccessible target coordinates. This study sought to develop a simulation method to find the appropriate frame location on the patient's head by retrospective analysis of treatment plans for brain metastasis cases. To validate the accuracy of the collision warning, we compared the collision distance calculated using Leksell GammaPlan (LGP) with actual measured distances. We then investigated isocenter coordinates in near-collision cases using data from 844 previously treated patients and created a clearance map by superimposing them on CT images for just the frame, post and stereotactic fiducial box. The differences in distance between the simulation in LGP and the measured values were <1.0 mm. In 177 patients, 213 lesions and 461 isocenters, there was a warning of one possible collision. The clearance map was helpful for simulating appropriate skull frame placement. The clearance simulation eliminates the psychological stress associated with potential collisions, and enables more comfortable treatment for the patient.
authors: Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daikominami, Higashi, Nagoya, Aichi 461-8673, Japan Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan hnakazawa@kaikou.or.jp.
authors: Hisato
authors: H
authors: Nakazawa
authors: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors: Takahiko
authors: T
authors: Tsugawa
authors: Department of Radiology and Radiation Oncology, Aichi Medical University, Nagakute, Japan.
authors: Yoshimasa
authors: Y
authors: Mori
authors: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors: Masahiro
authors: M
authors: Hagiwara
authors: Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daikominami, Higashi, Nagoya, Aichi 461-8673, Japan.
authors: Masataka
authors: M
authors: Komori
authors: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors: Chisa
authors: C
authors: Hashizume
authors: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Yuta
authors: Y
authors: Shibamoto
authors: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors: Tatsuya
authors: T
authors: Kobayashi
mesh_terms: D001932:Brain Neoplasms / Q000601:surgery*; D006801:Humans; D016634:Radiosurgery / Q000295:instrumentation*; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D012886:Skull / Q000601:surgery*; D013238:Stereotaxic Techniques
keywords: Gamma Knife; collision warning; simulation; skull frame placement; stereotactic localization; stereotactic radiosurgery