Measurement of Absorbed Doses in Anatomical Phantoms

Purpose: Many theoretical models have been designed to predict exposure levels and absorbed doses under various exposure conditions. The aim of this report, however, is to obtain, through a practical method, a quantitative measure of the absorbed doses in patients undergoing routine X-ray examinations to various anatomical sites. Materials and Methods: Anatomical phantoms simulating patients’ extremities were exposed under routine radiography conditions. Radiation doses were recorded with (Dw) and without the phantoms (Dwo), and the subtraction of Dw from Dwo gave a quantitative measure of the absorbed dose in the specific anatomy. Results: Calculated absorbed doses are well below the internationally recommended Diagnostic Reference Levels (DRL) of a few mGy, where the measured absorbed dose in the wrist was lowest at 55.3 μGy, in the knee it was 94 μGy, while the highest absorbed dose was for the ankle at 112.3 μGy. Conclusions: Measured absorbed doses reported here, although calculated assuming no scattering processes, are very low. These absorbed dose values translate into effective doses in the range 0.05 to 0.112 mSv, that are comparable with the ICRP recommended levels of 0.01 mSv for routine radiography. Furthermore, it provides a practical quantification process that allows for the estimation of absorbed dose in patients undergoing repeated radiographical examinations.