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Dual-energy X-ray absorptiometry (DXA, or DEXA [1]) is a means of measuring bone mineral density (BMD) with spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient's bones. When soft tissue absorption is subtracted, the bone mineral density (BMD) can be determined from the absorption of each beam by bone. Dual ...
A scanner used to measure bone density using dual energy X-ray absorptiometry. Bone density, or bone mineral density, is the amount of bone mineral in bone tissue.The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to optical density per square centimetre of bone surface upon imaging. [1]
The improvement to DXA with DXL is that, for each pixel scanned by DXA, the exact thickness of the measured object is also measured using lasers. The DXL results allow for a more accurate estimation of bone density by using three separate inputs (low and high x-ray energies plus thickness) rather than two for each pixel in the measuring region.
The expensive and potentially dangerous radioactive sources used in SPA and DPA have been replaced by single X-ray absorptiometry (SXA) and dual-energy X-ray absorptiometry (DXA) since the late 1980s. Similar to DPA, the basic principle of DXA is to measure the high and low energy X-ray transmission of stable X-ray sources.
Similarly, a formal body composition test, such as a dual-energy X-ray absorptiometry (DEXA) can help, says Bryant Walrod, MD, a sports medicine physician at The Ohio State University Wexner ...
DXA is only able to provide the areal bone mineral density. High-resolution peripheral quantitative computed tomography (HR-pQCT) is better than DXA at detecting bone microarchitecture, modeling whole-bone geometry using 3-dimensional information from scans. This method allows estimation of bone strength and other mechanical properties. [20]
These methods include measuring waist circumference, determining the waist-to-hip ratio or using special equipment, such as a DEXA scan, which measures bone density, to figure out body fat percentage.
Commonly prescribed thyroid drug levothyroxine was linked with bone mass and bone density loss in a cohort of older adults in a recent study.