Body composition analysis by DEXA by using dynamically changing samarium filtration

Abstract

Dual-energy X-ray absorptiometry (DEXA) has a high accuracy for body composition analysis but is influenced by beam hardening and other error sources in the extremes of measurement. To compensate for beam hardening, the Norland XR-36 introduces a dynamically changing samarium filtration system, which depends on the current-absorber thickness. With this system we found a good agreement (r = 0.99) between reference and measured amounts of tissue or fat percentages in a plastic phantom and in smaller (approximately 0.5-4 kg) and larger (approximately 5-20 kg) piles of tissue (ox muscle and lard). Scans of six healthy volunteers covered with combinations of beef and lard (approximately 5-15 kg) showed a good agreement (r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic filtration) has a high accuracy for body composition analysis. It has a potential for gaining status as a reference method in the future and may presently be used as a supplement to the traditional methods for body composition analysis.

Influence of orlistat on bone turnover and body composition

“…These differences are most likely to be explained by the precision error of the DXA weight estimate, which is approximately 2%. 20 We have made extensive studies on the accuracy errors of the Norland XR 36 also used in this study, 19 and using phantom measurements and measurements of large thicknesses of lard and ox muscle placed on the abdomen and thighs of healthy subjects, and found this apparatus to be very accurate for both BMC, BMD and fat percentage. In particular, we did not ®nd any signi®cant dependence on the total body BMC or BMD of changing the thickness and composition of these tissue materials.…”

“…The precision (CV%) for the DXA BMC and BMD measurements was 1 ± 2%, and the accuracy (SEE%) 3 ± 6%. 17,19,20 The precision (CV%) for DXA FFM, FM and FM% was 2 ± 3%, and the accuracy (SEE%) was 4 ± 15%. 18 ± 20 The precision (CV%) from the TBK measurement was 2.7% for FFM, 5.0% for FM, and 1.73% for FM%.…”

Can Aerobic Training Improve Muscle Strength and Power in Older Men?

“…However, the DEXA scanner that we used (Norland XR-36) employed a dynamically changing samarium filtration system that compensates for changes in tissue thickness. This filtration system is unique to the Norland XR-36 and has been shown to be highly accurate for body-composition analysis (Gotfredsen, Baeksgaard, & Hilsted, 1997).…”

Comparison of a GE Lunar DPX-IQ and a Norland XR-26 dual energy X-ray absorptiometry scanner for body composition measurements in pigs – <i>in vivo</i>

“…In vivo, this impact has not been confirmed as reported by LUKASKI et al (1999) who compared whole body scans of pigs lying in the prone or side position and reported no significant effect of body thickness in the range of 16-28 cm on accuracy. It is not clear to what extent Norlands dynamic filtration systems affects the comparability with Lunar, because GOTFREDSEN et al (1997) using a Norland XR-36 still found a small but significant impact of tissue thickness on %FAT and BMC, and even the Operator's Guide for the XR-26 notes that inaccuracies and imprecision may occur at tissue heights above 20 cm.…”