digital x rays (low exposure)Digital X-ray Radiogrammetry (DXR) 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 in the hand is measured in a digital X-ray image by a computer and is through a geometrical operation converted to bone mineral density. The BMD is corrected for porosity 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 and a Z-score for assessing osteoporosis and the risk of bone fracture.
Digital X-ray radiogrammetry is primarily used in combination with digital mammography 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, DXR is also used for monitoring change in bone mineral density over time.