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Failure Modes and Effects Analysis (FMEA) for Mask-Based Radiosurgery On Gamma Knife Icon

Andy Y. Xu*, Tony J.C. Wang, Mike Sisti, C.S. Wuu , Columbia University Medical Center, New York, New York


(Sunday, 7/29/2018) 4:00 PM - 4:30 PM

Room: Exhibit Hall | Forum 4

Purpose: The purpose of this study is to perform a failure modes and effects analysis (FMEA) on the mask-based Gamma Knife radiosurgery (GKRS) treatment approach and to develop a risk based quality management program for the Leksell Gamma Knife Icon.

Methods: More than 300 masked-based GKRS procedures (100 patients) have been performed on a Gamma Knife Icon at our institution since May 2017. The mask-based GKRS treatments were carried out following three different paths: a) single fraction GKRS; b) fractionated GKRS with 3 or 5 fractions; c) mask-based treatments following a frame based procedure (in order to avoid potential collision). A process tree and a failure mode table were created for the GKRS procedures on the Gamma Knife Icon with mask fixation. To prioritize the identified failure modes, a risk priority number was calculated for each failure mode as the product of the probability of occurrence, the severity, and the probability of no detection for failure mode.

Results: The process tree for mask-based GKRS on the Gamma Knife Icon consists of 11 sub-processes, including a sub-process for mask fixation and a sub-process for the delivery of the 2nd to 5th fractions. The failure modes that are directly related to the masked based GKRS approach include: 1) wrong mask or head cushion; 2) inadequate patient head fixation from loose mask or flat head cushion; 3) large inter-fraction setup difference that leads to inaccurate dose delivery; 4) large error in image registration resulted from poor CBCT imaging quality; 5) inappropriate use of the intra-fraction patient position monitoring system.

Conclusion: The results of the present study provide a basis for the development of a risk based quality management program for the clinical operation of a Gamma Knife Icon with both frame fixation and mask fixation.


Gamma Knife, Quality Control, Quality Assurance


TH- External beam- photons: gammaknife

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