D. Ivanov

An in vitro L-band EPR study with whole human teeth in a surface coil resonator

L-band EPR measurements were done in vitro on extracted human teeth with the objective to evaluate the feasibility of retrospective in vivo EPR dosimetry. In a recent study, the relative contributions of individual tooth components (enamel, crown dentin and root) to the total response of a whole tooth inside an L-band surface coil resonator was investigated. In the present work, the gamma-dose response curves were evaluated for different EPR signal evaluation methods, using 35 whole teeth with absorbed doses in the range 1-100 Gy. The paper reports on the first attempt to deconvolute the single composite L-band EPR line in components due to CO2- and native radicals. The L-band EPR spectrum of teeth could be approximated by combining powder-simulated spectra of orthorhombic and quasi-axial signals of the CO2- radical and an isotropic signal of the native radicals. Among the applied EPR signal evaluation methods, the evaluation by spectrum deconvolution. revealed the lowest detection limit for absorbed dose. A detection limit of about 0.5 Gy was estimated for the currently available L-band equipment