Radiation dose from DXA scanning to reproductive tissues of females

The objective of this study was to use an anatomically arrayed whole-body phantom to measure radiation exposure to the ovaries and uterus during standard dual-energy Xray absorptiometry (DXA) scanning. DXA instrument manufacturers' published entrance skin exposure is about 3 mR (0.77 microC/kg), which is equivalent to the radiation exposure received during a transcontinental plane trip. Nonetheless, since DXA scanning is used more frequently with very young females, the need for pregnancy testing has become an issue that requires attention and formulation of research guidelines. We attached thermoluminescent dosimeters (TLDs) to anatomically arrayed balloon models for ovaries and the uterus, and placed these in the appropriate sites within a small human skeleton along with appropriate amounts of aqueous and fat soft tissue equivalents. Whole-body scanning with a Hologic QDR-2000W was performed 10 times with the pencil beam mode and, using separate TLD detectors, 10 times with the fan beam mode. Overall, the average exposures at skin entrance were 0.89 mR (0.23 microC/kg) with doses for the ovaries of 0.52 mrad (5.2 microgy) and 0.59 mrad (5.9 microgy) for the uterus. These doses are equivalent to 2 d of ambient background radiation in central Pennsylvania or 1 h of flying at 39,000 ft. Although different DXA models by Hologic and DXA instruments by other manufacturers will have different radiation outputs, we believe that these low radiation levels do not require pregnancy testing or questioning of whether the scan subject might be pregnant.