The Third International Intercomparison on EPR Tooth Dosimetry: part 2, final analysis

Abstract

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation.

EPR dosimetry with tooth enamel: A review

“…A more elaborate analysis of the results has revealed a correlation of the dosimetry accuracy with the modulation amplitude, spectrum decomposition algorithm, and time elapsed between the sample preparation and the EPR reading (Wieser et al, 2006a). Because of the small statistics, this result can probably be taken just as a general trend and should not be overly emphasized.…”

“…The results of these intercomparisons will be described in a later chapter of this review. It is worth noting the number of the participating institutions: (1 st ) 1994-1995, 9 participants (Chumak et al, 1996a); (2 nd ) 1999, 18 participants Wieser et al, 2000c); (3 rd ) 2003-2004, 14 participants Wieser et al, 2006a); (4 th ) 2006, 10 participants Ivannikov et al, 2007). While writing this review, another intercomparison has started involving 16 participating laboratories.…”

“…The optimal sample mass is a compromise between the maximal achievable SNR and the minimization of the aforementioned mass effects. Nowadays, most laboratories use 100-mg samples (Wieser et al, 2006a). However, tooth enamel samples from diseased or incisor teeth may be smaller than 100 mg, and procedures to correct for the massdependent effects should be available in every laboratory.…”

“…Several international intercomparisons were undertaken in the past years, in which blind tests were performed in a varying number of laboratories (from 9 to 18) (Chumak et al, 1996a;Wieser et al, 2000b;Wieser et al, 2000c;Wieser et al 2005;Wieser et al, 2006a;Hoshi et al, 2007;Ivannikov et al, 2007;Chapter 1). Four of these intercomparisons were performed in the framework of EU-sponsored projects (Chumak et al, 1996a;Wieser et al, 2000b;Wieser et al, 2000c;Wieser et al 2005), and three of them had numeric titles, i.e., the 1st (Chumak et al, 1996a), the 2nd (Wieser et al, 2000c) and the 3rd Wieser et al, 2006a).…”

“…Four of these intercomparisons were performed in the framework of EU-sponsored projects (Chumak et al, 1996a;Wieser et al, 2000b;Wieser et al, 2000c;Wieser et al 2005), and three of them had numeric titles, i.e., the 1st (Chumak et al, 1996a), the 2nd (Wieser et al, 2000c) and the 3rd Wieser et al, 2006a). Another intercomparison is commonly called "Semipalatinsk Intercomparison" because one of its goals was to collectively measure doses to teeth of residents of the Semipalatinsk region (Chapter 18) Ivannikov et al, 2007).…”