Dosimetric and Mechanical Stability of CyberKnife Robotic Radiosurgery Unit: 5 Years’ Clinical Experience

Abstract

The purpose of the present study was to investigate dosimetric and mechanical stability of CyberKnife Robotic Radiosurgery System (Accuray Inc., Sunnyvale, CA, USA) in short- and longterm period.METHODSOutput factor measurements and automated quality assurance (AQA) tests performed on CyberKnife unit 2009-2013 at radiation oncology department of Hacettepe University, Turkey, were analyzed retrospectively.RESULTSAccording to the analysis, more than 95% of the output measurements over 5 years were within the tolerance limit ≤2%. In AQA test analysis, 144 AQA test results were within the tolerance limit from 2009 to 2011. However, 7 of the 51 measurements taken in 2012, and 4 of the 47 measurements performed in 2013 exceeded 1 mm radial error.CONCLUSIONOutput and AQA data of CyberKnife system indicate that it is quite stable in daily and long-term period. Nevertheless, daily measurements should be performed on CyberKnife unit since high radiation dose per fraction is usually delivered to target volume