Development of a sensitive EPR dosimetry system
Dosimetry based on EPR spectrometry is since many years a well-established method mainly with the dosimeter material crystalline alanine. Alanine has very good dosimetric properties but is a little too insensitive for use in radiation therapy. During the last 15 years we have developed a number of promising dosimeter materials and after careful testing lithium formate has shown to be the most suitable one.
We have used lithium formate dosimeters for verification of calculated dose distributions both in external and brachy therapy and for testing the whole treatment procedure between different clinics in an audit. To improve the spatial resolution in dose mapping we succeeded to decrease the size of the dosimeters keeping the high accuracy by using a modern spectrometer equipped with a super high Q resonator.
Recently the proton therapy center started in Sweden and we will examine the properties of lithium formate regarding stability and response in a proton beam.
About the development of sensitive dosimeter system in:
E. Lund, et. al, 2005 “Formates and dithionates: sensitive EPR-dosimeter materials for radiation therapy.” Applied Radiation and Isotopes 62 (2005) 317-324.
About the careful testing procedure in:
Adolfsson E et al. 2014 “Optimization of an EPR dosimetry system for robust and high precision dosimetry”, Radiation Measurements 70, 21-28
Adolfsson E et. al 2010 “Response of lithium formate EPR dosimeters at photon energies relevant to the dosimetry of brachytherapy” Med. Phys. 37, 4946-4959
Adolfsson E et. al 2012 ”Investigation of signal fading in lithium formate EPR dosimeters using a new sensitive method” Phys.Med.Biol 57, 2209-2217
About dose and LET distribution in ion-irradiated potassium dithionate tablets in:
Håkan Gustafsson, Anders Lund and Eva Lund, “Potassium dithionate EPR dosimetry for determination of absorbed dose and LET-distributions in different radiation qualities”.2011, Radiation Measurements, (46), 9, 936-940.