European Journal of Radiology, 15 (1992) 299 0 1992 Elsevier Science Publishers B.V. All rights reserved. 0720-048X/92/$05.00
Letter to the Editor
Acronyms in bone densitometry In response to our publication [ 11, Wilson and colleagues  proposed the adoption of a uniform terminology and corresponding abbreviation for dual X-ray absorptiometry (DXA). We supported this suggestion . Since then, the number of papers on DXA has increased considerably. Still, different abbreviations (DEXA, DER, DRA, QDR and DPX) for this technique for bone densitometry are used, several of which are proprietary in origin. DXA is the upgraded version of DPA (dual photon absorptiometry). The nuclear source has been replaced by an X-ray source and this improved technology has gained widespread acceptance and distribution. Recently, similar developments in SPA (single photon absorptiometry) have occurred, which will add yet another abbreviation to densitometry-terminology: SXA for single X-ray absorptiometry, not the alternative ‘SEXA’. Users and manufacturers of these techniques have now joined efforts in an International Standards Committee . In this Committee, standards of calibration, measurement units and terminology are discussed. There is a general agreement that standard abbreviations for bone densitometry techniques are necessary and the term DXA has been accepted. Therefore, again we would like to emphasize the use of the acronym DXA for dual X-ray absorptiometry and add the acronym SXA for single x-ray absorptiometry. When we confine ourselves to SPA, SXA, DPA and DXA, next to QCT for quantitative computed to-
mography, both researchers and clinicians will understand what we mean. Still, good acronyms for ultrasound attenuation and velocity measurements and for magnetic resonance measurements, both for quantifying bone mineral density and structure, have to be agreed upon. Acronyms such as QUS for quantitative ultrasound and QMR for quantitative magnetic resonance would be consistent with QCT. Such terminology, however, would clearly need consensus development.
References 1 Glner CC, Steiger P, Selvidge R, Elliesen-Kliefoth K, Hayashi C, Genant HK. Comparative assessment of dual-photon absorptiometry and dual-energy radiography. Radiology 1990; 174: 223228. 2 Wilson CR, Collier D, Carrera GF, Jacobson DR. Acronym for dual-energy X-ray absorptiometry. Radiology 1990; 176: 875. 3 Gltier CC, Steiger P, Genant HK. (Reply). Radiology 1990; 176: 875-876. 4 Nord RH, Stein JA, Mazess RB, Pommet RP, (Letter). Bone Miner 1991; 13: 85. Harry K. Genant Claus C. Gllier Kenneth G. Faulkner Sharmila Majumdar Steve T. Harris Klaus Engelke Cornelis van Kuijk Osteoporosis Research
Department of Radiology University of Cah$omia San Francisco San Francisco, CA 94143-0628.