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

Abstract 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 di erent EPR signal evaluation methods, using 35 whole teeth with absorbed doses in the range 1-100 Gy. The paper reports on the ÿrst attempt to deconvolute the single composite L-band EPR line in components due to CO − 2 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 CO − 2 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

Dose Reconstruction with Electron Paramagnetic Resonance Spectroscopy of Deciduous Teeth.

In the present study the feasibility of using whole, naturally loose deciduous incisors for dose reconstruction with electron paramagnetic resonance (EPR) spectroscopy was investigated. The properties of EPR signals were analysed before and after laboratory irradiation. The parameters of the native EPR signal of deciduous incisors was found to be different front those from enamel of permanent molars. The native EPR signal of deciduous incisors with peak-to-peak line width of 0.65 mT was located at g = 2.0050. The evaluated parameters of the dosimetric EPR signal (CO2-) of deciduous incisors were ill agreement with those for enamel of permanent molars. A detection threshold for absorbed dose of about 100 mGy was estimated

Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry.

The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample preparation procedure. The variability in EPR sensitivity of enamel from Egyptian teeth was maximally 10% and the mean sensitivity was in good agreement with that of German teeth

Dosimetric properties of lithium borate glass doped with dysprosium.

Characterization of thermoluminescence (TL) properties of lithium borate glass samples doped with different concentrations of dysprosium (Dy) was carried out. Samples were prepared using a melting method at 1100 degrees C and irradiated with beta-particles. The glass samples doped with 0.1% Dy displayed the best TL dosimetric properties compared with other compositions. Deconvoluted analyses of the glow curves displayed five overlapping TL glow peaks located between 392.0 and 510.3 K. A good linear TL dose-response for beta-particles was obtained in the dose range 66.6 mGy to 33.3 Gy. The minimum detectible dose was evaluated to be 205.4 mu Gy and samples revealed thermal fading in 312 h to 29% of their original value

Investigation of TL dosimetric parameters of lithium borate glass doped with dysprosium.

The current work presents a study of the thermoluminescence (TL) properties of glow curves obtained from lithium borate glass samples doped with different concentrations of dysprosium (Dy). The first part of the study is aimed to analyse the TL glow curves, obtained from the glass samples irradiated with beta-particles, to determine the number of composing TL peaks and to extract the kinetic parameters of the samples using different methods. The second part is dedicated to characterizing the TL dosimetric properties of the individual TL peaks composing the recorded TL glow curves. The analysis has shown that the glow curves corresponding to the glass samples doped with different concentrations of Dy compose of five overlapping TL peaks with trap depths ranging from 0.733 to 1.289 eV. The kinetic parameters obtained from the different methods agree to good accuracy