Digital X-ray radiogrammetry
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Digital X-ray radiogrammetry is a method for measuring bone mineral density (BMD). Digital X-ray radiogrammetry is based on the old technique of radiogrammetry. In DXR, the cortical thickness of the three middle metacarpal bones of the hand is measured in a digital X-ray image. Through a geometrical operation the thickness is converted to bone mineral density. The BMD is corrected for
porosity Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measur ...
of the bone, estimated by a texture analysis performed on the cortical part of the bone. Like other technologies for estimating the bone mineral density, the outputs are an areal BMD value, a
T-score In statistics, the standard score is the number of standard deviations by which the value of a raw score (i.e., an observed value or data point) is above or below the mean value of what is being observed or measured. Raw scores above the mea ...
and a
Z-score In statistics, the standard score is the number of standard deviations by which the value of a raw score (i.e., an observed value or data point) is above or below the mean value of what is being observed or measured. Raw scores above the mean ...
for assessing osteoporosis and the risk of bone fracture. Digital X-ray radiogrammetry is primarily used in combination with
digital mammography Mammography (also called mastography) is the process of using low-energy X-rays (usually around 30 kVp) to examine the human breast for diagnosis and screening. The goal of mammography is the early detection of breast cancer, typically through d ...
for osteoporosis screening, where same mammography machine that is used to acquire breast X-ray images is also used to acquire a hand image for BMD measurement. Due to high
precision Precision, precise or precisely may refer to: Science, and technology, and mathematics Mathematics and computing (general) * Accuracy and precision, measurement deviation from true value and its scatter * Significant figures, the number of digit ...
, DXR is also used for monitoring change in bone mineral density over time.


See also

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Dual-energy X-ray absorptiometry Dual-energy X-ray absorptiometry (DXA, or DEXA) is a means of measuring bone mineral density (BMD) using spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient's bones. When soft tissue absorption is subtracted ...


References

Radiology {{Bone, cartilage, and joint procedures