Pierre M. Braillon MD, PhD, Presenter: Nothing to Disclose

To assess the differences in the results of whole body measurements performed with Hologic, Lunar-GE and Norland dual energy X-ray absorptiometry systems (DXA), for bone and soft tissues.

An anthropomorphic whole body phantom of a subject 145 cm height (12 year-old adolescent) was developed. It was made of polymers which mimic accurately the bone mineral content (BMC), lean tissue mass (LTM) and fat mass (FM) of every segment of the body. Three consecutive whole body scans of this phantom were performed on three different DXA systems from Hologic (Discovery), Lunar-GE (Prodigy), and Norland (XR46) to obtain three sets of BMC, LTM and FM values, as well as the total body weight W (W=BMC+LTM+FM) with each DXA system. In order to give the same relative weight to each measurement series, reference values for the bone and soft tissue components, and for the total body weight were conventionally defined as the mean of the nine BMC, LTM, FM and W measured values. For each component, and each DXA system, the mean measured value was then compared to its corresponding reference value.

Results obtained with the Hologic Discovery, Lunar-GE Prodigy and Norland XR46 systems used differed respectively from the reference values as follows: - 7.48 %, + 4.93 %, and + 2.55 %, for BMC measurements; - 2.78 %, + 1.67 %, and + 1.11 % for LTM measurements; + 9.10 %, - 14.01 %, and + 4.92 % for FM measurements; - 0.74 %, - 1.21 %, and + 1.95 % for W.

Good agreement between the DXA systems used was observed for weight assessment. However, the measured bone mineral content and soft tissue values differed significantly. In clinical studies, when whole body scan results are needed, these differences should be precisely known and properly corrected.

Cross-calibrations of DXA systems involved in studies with whole body scans should be done for each body component with an appropriate phantom.

Braillon, P, Cross-calibration of Dual Energy X-ray Absorptiometry Systems with a New Anthropomorphic Whole Body Phantom.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011569.html