title: Investigation of signal fading in lithium formate EPR dosimeters using a new sensitive method.
abstract: The aim of this study was to investigate signal fading in lithium formate electron paramagnetic resonance (EPR) dosimeters used for clinical applications in radiotherapy. A new experimental method for determination of signal fading, designed to resolve small changes in signal from slowly decaying unstable radicals, was used. Possible signal fading in lithium formate due to different storage temperatures was also tested. Air humidity was kept at a constant level of 33% throughout the experiments. The conclusion drawn from the investigations was that the EPR signal from lithium formate is stable during at least 1 month after irradiation and is not sensitive to variations in storage temperature <40 °C when kept at a relative air humidity of 33%. This makes lithium formate a suitable dosimeter for transfer dosimetry in clinical audits.
authors.affiliation: Department of Medical and Health Sciences-IMH, Radiation Physics, Linköping University, SE 581 85 Linköping, Sweden. emelie.adolfsson@liu.se
authors.forename: Emelie
authors.initials: E
authors.lastname: Adolfsson
authors.forename: Mattias
authors.initials: M
authors.lastname: Karlsson
authors.forename: Gudrun
authors.initials: G
authors.lastname: Alm Carlsson
authors.forename: Asa
authors.initials: A
authors.lastname: Carlsson Tedgren
authors.forename: Eva
authors.initials: E
authors.lastname: Lund
authors.forename: Sara
authors.initials: S
authors.lastname: Olsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Gustafsson
mesh_terms: D016477:Artifacts; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005561:Formates; D011874:Radiometry / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D005561:Formates; C030544:formic acid