Dose Coefficients for Irradiation of Tooth Enamel within ICRP Adult Mesh-type Reference Computational Phantoms for Idealized External Photon Exposures

In the present study, the tooth enamel dose coefficients (DCs) were established for idealized external photon exposures using the International Commission on Radiological Protection (ICRP) adult mesh-type reference computational phantoms (MRCPs), coupled with Geant4 Monte Carlo radiation transport code, for use in electron paramagnetic resonance (EPR) dosimetry. The DCs were calculated for 10 distinct tooth enamel regions (buccal and lingual enamel regions for front, front-left, front-right, left, and right teeth sites) for six irradiation geometries of uniform external photon fields (AP, PA, LLAT, RLAT, ROT, and ISO) across the energy range of 10 keV to 10 GeV. The results revealed substantial variations among different enamel regions, particularly for photon energies below 0.1 MeV, with differences in DC magnitude of up to 2,251-fold between the front buccal and left lingual enamels at 0.015 MeV in the adult male MRCP. Furthermore, compared to DCs derived from the Golem voxel phantom, the MRCP-based DCs exhibited differences of up to several orders of magnitude at low energies, primarily due to the more detailed anatomical representation of enamel structures within the adult MRCPs. The enamel DCs are expected to be used beneficially to estimate individual radiation doses for exposed adult populations through the conversion of the measured EPR signals in extracted teeth, to include both individual organ doses as well as the whole-body effective dose.