EPR study on biominerals as materials for retrospective dosimetry

Stable paramagnetic species, induced by irradiation in biominerals, can be successfully used as an EPR dosimeter in numerous domains of scientific activity. In hydroxyapatite, the main mineral component of bones, the most stable signal is assigned to CO2 - ion radical. The signal is dose dependent and allows to determine the absorbed dose in a wide range till 20 kGy, with detection limit for tooth enamel below 1 Gy. The additive dose method was applied to EPR dating of archeological objects and EPR dosimetry after accidental overexposing during radiotherapy. It was found that the age of remains excavated from the “tomb of giants” belonging to Nuraghic culture developed in Sardinia island is about 3160 years old (1160 years BC). The dose obtained by patients during the accident at the Białystok Oncological Center was evaluated at about 75 Gy. Searching for potential dosimeters among other biominerals shows that mollusc shells have very promising properties. The lowest dose detection limit was found for an Arcidae shell. Both fresh water and sea mollusc shells are useful to be used for dosimetry in the low dose range.