Alanine pellets comparison using EPR dosimetry in the frame of quality assurance for a Gamma Knife system in Romania

Abstract

In the last decade, the use of alanine/Electronic Paramagnetic Resonance (EPR) system was extended to radiotherapy doses. In stereotactic radiosurgery, doses up to 70 Gy are delivered to the brain tumor preserving healthy tissues. This type of treatment is delivered using dedicated equipment, like Cyberknife or Gamma Knife. Alanine dosimeters are characterized by their small size (5 mm diameter) and by similarity with tissue. They are well adapted for this wide dose range for which the dosimeter response is linear, independent of dose rate and energy for the range around few MeV. Therefore Alanine/EPR system is a suitable method for accurate and stable dose measurements as passive dosimeters for narrow treatment beams, which makes it an excellent candidate for end to end testing of radiosurgery treatments using Gamma Knife. The present work describes the development of the alanine/EPR method at Horia Hulubei National Institute for Physics and Nuclear Engeneering (IFIN-HH) in Romania including the optimization of system parameters for the radiosurgery dose range in the frame of an IFIN-HH and the French national metrology institute Laboratoire National Henri Becquerel federated by the Laboratoire National de métrologie et d’Essais (LNE-LNHB) collaboration. Romanian alanine dose measurements capability is presented regarding a comparison of calibration curves between both National Laboratories using Bruker and Synergy Health alanine pellets.