Spatial shifts in frame-based Gamma Knife radiosurgery: A case for cone beam CT imaging as quality assurance using the Gamma Knife® Icon™

M. Sean Peach, Daniel Trifiletti, Sunil W. Dutta, James M. Larner, David J. Schlesinger, Jason P. Sheehan

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Background: Cone beam CT (CBCT) imaging has been integrated into the most recent version of the Leksell Gamma Knife for the primary purpose to facilitate fractionated therapy. Case description: This case study presents three patients where the CBCT system of the Gamma Knife Icon discovered potentially clinically significant frame shifts. In each case, patients were imaged with volumetric MR prior to stereotactic frame placement. Immediately following frame placement, diagnostic stereotactic CT imaging was acquired with a stereotactic indicator box attached to the frame. Following treatment planning and immediately before radiosurgery, a CBCT was acquired using the on-board imaging functionality of the Gamma Knife Icon, which provides a registration of the patient’s anatomy to stereotactic space independent of that provided by the stereotactic frame/ fiducials. Co-registration of the CT and CBCT provides an estimate of the difference between these two estimates of stereotactic coordinates. The vector magnitudes of the differences measured at the center of stereotactic space were 0.93mm, 2.64mm and 2.18 mm for Case 1, Case 2 and Case 3 respectively. Conclusions: Use of the CBCT functionality of the Gamma Knife Icon to verify the consistency of frame placement can prevent clinically significant targeting errors due to frame slippage or frame adapter mounting errors, and allows any required adjustments to be made without interrupting the overall treatment workflow.

Original languageEnglish (US)
Pages (from-to)315-322
Number of pages8
JournalJournal of Radiosurgery and SBRT
Volume5
Issue number4
StatePublished - Jan 1 2018

    Fingerprint

Keywords

  • Cone beam CT
  • Frame shift
  • Gamma Knife
  • Quality assurance
  • Radiosurgery
  • Stereotactic frame

ASJC Scopus subject areas

  • Surgery
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this