The use of deciduous molars in EPR dose reconstruction

Abstract

In the present study naturally loose deciduous molars were investigated. The feasibility of separating enamel from small size molars was analysed. EPR spectrum parameters of whole molars and separated enamel only were evaluated before and after laboratory irradiation. The Electron paramagnetic resonance (EPR) signal amplitudes of CO (2) (-) and native signals were determined by spectrum deconvolution, as a function of radiation dose in the range 0.1-10 Gy. A detection threshold of absorbed dose from deciduous molars of 198 and 21 mGy is estimated for massive (that contained both enamel and dentine) and grainy samples (that contained enamel only), respectively. The elimination of the organic material from the massive deciduous samples reduced the mean bias dose for the native signal from 90+/-18 to 34+/-13 mGy. A decay of the background signal within 2 weeks after irradiation was found, while the dosimetric signal was stable before and after the irradiation process. The presented results suggest deciduous teeth to be suitable for retrospective dose assessment. To get reasonable dose estimates, however, any organic material must be eliminated, and the measurements should be performed 2 weeks after the chemical and mechanical preparation and the irradiation process are done.

EPR dosimetry with tooth enamel: A review

“…El Faramawy and Wieser (2006). They concluded that deciduous tooth enamel is "similar" to permanent tooth enamel and deciduous teeth can thus be used for dosimetry purposes just like adult teeth.…”

“…However, this different degree of microcrystal arrangement seems not to result in different radiation sensitivity. Using the additive dose method, El-Faramawy and Wieser (2006) have found that the detection thresholds and radiation sensitivities for deciduous teeth and permanent teeth are comparable.…”

Ionizing Radiation Induced Radicals

“…Khan, et. al., 2004), other studies on the use of deciduous teeth have been performed (El-Faramawy, N.A., 2005, El-Faramawy, N., andWieser, A., 2006).…”

Experimental procedures for sensitive and reproducible in situ EPR tooth dosimetry

“…(Brady, et al, 1968) Since this seminal description, substantial progress has been made in EPR dosimetry of in vitro samples and precision as fine as ±2.5 cGy has been reported for low-dose measurements, with precision of ±10% for doses above 25 cGy. (Chumak, et al, 2005) EPR tooth dosimetry using samples of pure enamel that have been extracted from irradiated subjects are typically performed at an X-band frequency (∼9 GHz) with a standard TE 102 cavity resonator and may employ a goniometer to average out spatial anisotropy (El-Faramawy and Wieser, 2006, Gualtieri, et al, 2001b, Hayes, et al, 2000, Hayes, et al, 1998. The high RF frequency and resonator filling factor contribute to the sensitivity of such measurements.…”