Radiation dose to the patient and operator from a peripheral dual X-ray absorptiometry system

Although peripheral dual X-ray absorptiometry (pDXA) scanners for measuring bone mineral density (BMD) in the forearm are known to produce an exceptio nally low radiation dose to the patient, quantitative assessment of patient dose from pDXA procedures is important for reassuring patients about their safety. We have estimated the effective dose of radiation (ICRP-60) to the patient and also the scattered dose to the operator from a forearm BMD exa mination performed on a DTX-200 pDXA system (Osteometer Meditech, Hoersholm , Denmark). Measurements were performed using thermoluminescent dosimeters attached to the forearm phantom supplied by the manufacturer. The effective dose to a patient was estimated to be 0.1 mu Sv. At a distance of 1 m from the center of the forearm, the time-averaged scattered dose rate to the op erator assuming a throughput of five patients per hour was measured to be < 0.1 mu Sv/h. The dose rate over the outside surface of the DTX-200 in line with the primary X-ray beam was measured to be 1.4 mu Sv/h. These figures c ompare with a natural background radiation in the United Kingdom of 7 mu Sv /d. In conclusion, the radiation doses from forearm pDXA to both patients a nd operator were found to be truly trivial.