Enhanced EPR Dose Reconstruction in Teeth

Currently electron paramagnetic resonance (EPR) retrospective biodosimetry with tooth enamel can measure doses as low as 30 mGy. This method uses commercial X-band (9.5 GHz) EPR spectrometers and specially prepared samples from tooth enamel. One of the disadvantages of X-band EPR dosimetry is the requirement to obtain isolated teeth from a cohort of interest. In vivo EPR retrospective biodosimetry in L-band (1.2 GHz) is being developed to address this shortcoming. The current LLD (0.5 1 Gy) for this non-invasive approach is sufficient for evaluating exposures that could lead to acute clinical effects but is not low enough for many radiation epidemiology studies. We propose the use of Q-band (34 GHz) for EPR dose reconstruction as a supplement to in vivo measurements. This approach requires considerably smaller sample amounts compared with Xand L-band instruments. Small portions (~10 mg) of tooth enamel can be removed by a dentist without significant tooth damage. In addition, the higher sensitivity of Q-band should yield an improved LLD compared to Xand L-band. A combination of EPR measurements made in vivo with L-Band and measurements at Q-band on biopsies of teeth should provide accurate dose reconstruction in a wide range of doses, while removing the necessity of relying on the availability of isolated whole teeth.