Determination of 226 Ra, 232 Th and 40 K in teeth by use of gamma spectroscopy.

This study entails the measurement of the specific activity of natural radionuclides (226 Ra, 40 K and 232 Th) in 18 tooth samples obtained from the clinic of the Universiti Sains Malaysia (USM), Penang, by using an HPGe detector. The specific activity of 226 Ra, 40 K and 232 Th was measured to estimate the hazard index of the radionuclides, radium equivalent activities (Raeq ), external, internal hazard indices (Hex , Hin ), and absorbed dose (Dout , Din ). The maximum values of concentration of 226 Ra, 232 Th and 40 K in the tooth samples were found to be 60.82, 60.29 and 594.22 Bq kg-1 , respectively. Maximum values of Raeq , Hex , Hin , Dout and Din were found to be 192.78 Bq kg-1 , 0.520, 0.685, 89.29 and 169.81 nGy h-1 , Iγ and Iα as 0.702 and 0.304, respectively. The results were lower than the average world value (UNSCEAR). In addition, a strong correlation was found between the concentrations of 226 Ra and Raeq , between energy and net area, as well as between radionuclides (226 Ra, 40 K and 232 Th) in tooth samples and age of volunteers. This study showed that the concentrations and hazard indices of tooth samples are below the recommended safe levels; therefore, the study area is considered safe in terms of radiological health hazards.