Changes in Patient Marker Coordinates with High-Definition Motion Management System during Frameless Gamma Knife Radiosurgery.

Objective: 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.

Feasibility test of 3 dimensional patient specific quality assurance of gamma knife radiosurgery using novel mobile phospor probe system.

This study evaluates a novel three-dimensional (3D) quality assurance (QA) device, the Mobile Phosphor Probe (MPP), for pretreatment dose verification in Gamma Knife (GK) stereotactic radiosurgery. The MPP system consists of a cylindrical phantom with a phosphor screen, an imaging unit with a charge-coupled device (CCD) camera, and a motorized driving unit. Dose distributions are reconstructed from images using a lookup table, which correlates CCD pixel optical density with dose values, calibrated against EBT3 film readings.

Avoiding a Collision in Gamma Knife Radiosurgery : A Modified Mask Fixation Method.

Objective: The latest version of the Leksell Gamma Knife IconTM allows for mask- and frame-based fixation. Although mask fixation provides fractionated treatment and immobilization using a noninvasive method, it is not free from collision. The authors investigated the collision problem with a modified mask fixation method.

Hypofractionated stereotactic radiosurgery for large-sized skull base meningiomas.

Purpose: Although stereotactic radiosurgery (SRS) has been proven to be effective and safe for treating intracranial meningiomas, concerns have been raised about the use of SRS for large-sized tumors involving the skull base that frequently encroach onto adjacent critical neural structures. The purpose of this study was to investigate the role of hypofractionated SRS as a therapeutic option for large-sized skull base meningiomas.

Methods: Thirty-one consecutive patients (median age: 55 years, 9 men and 22 women) who had been treated with hypofractionated SRS using CyberKnife for large-sized skull base meningiomas (> 10 cm in volume, median of 18.

Single-fraction versus hypofractionated stereotactic radiosurgery for medium-sized brain metastases of 2.5 to 3 cm.

Purpose: Given recently suggested utility of hypofractionated stereotactic radiosurgery (SRS) in treating large brain metastases (BMs) > 3 cm, we sought to prospectively control tumor size variable to investigate the efficacy and safety of hypofractionated SRS for medium-sized BMs (2.5 to 3 cm) compared with single-fraction SRS.

Methods: Between 2011 and 2015, a total of 100 patients with newly diagnosed BMs (n = 105) of 2.

Cyberknife Dosimetric Planning Using a Dose-Limiting Shell Method for Brain Metastases.

Objective: We investigated the effect of optimization in dose-limiting shell method on the dosimetric quality of CyberKnife (CK) plans in treating brain metastases (BMs).

Methods: We selected 19 BMs previously treated using CK between 2014 and 2015. The original CK plans (CKoriginal) had been produced using 1 to 3 dose-limiting shells : one at the prescription isodose level (PIDL) for dose conformity and the others at lowisodose levels (10-30% of prescription dose) for dose spillage.

Experiences on two different stereotactic radiosurgery modalities of Gamma Knife and Cyberknife in treating brain metastases.

Background: In this study, we compared the dosimetric properties between Gamma Knife (GK) and Cyberknife (CK), and investigated the clinical implications in treating brain metastases (BMs).

Methods: Between 2011 and 2013, 77 patients treated with either single-fraction GK for small BMs (n = 40) or fractionated CK for large BMs >3 cm (n = 37) were analyzed. Among a total of 160 lesions, 81 were treated with GK (median, 22 Gy) and 38 (large lesions) with three- or five-fraction CK (median, 35 Gy).

Application of the gamma evaluation method in Gamma Knife film dosimetry.

Purpose: Gamma Knife (GK) radiosurgery is a minimally invasive surgical technique for the treatment of intracranial lesions. To minimize neurological deficits, submillimeter accuracy is required during treatment delivery. In this paper, the delivery accuracy of GK radiosurgery was assessed with the gamma evaluation method using planning dose distribution and film measurement data.