ESR dosimetry using tooth enamel

Stable radicals, detectable with electron spin resonance (ESR), are created by ionizing radiation in hydroxyapatite crystals in tooth enamel. As its ESR signal intensity is proportional to the received radiation doses, the method of retrospective dosimetry has been developed for human. It is now established so that an ISO standard of ESR (EPR) dosimetry has been published. The computer programs that separate dosimetric signal from interfering native signal are essentially important for dosimetry below 5 Gy and they contribute greatly to the progress of the method. The outline of the method is presented in the present paper where there are still important issues on human tooth enamel dosimetry, such as the detection limit of the method, the universal standard for calibration, and the background doses which can be varied from country to country. Other new directions of the research would be to utilize deciduous teeth and teeth of other mammals, and in-vivo and Q-band measurements. (author)