What is Quantitative computed tomography?

Quantitative computed tomography is a medical technique that measures bone mineral density using a standard X-ray Computed Tomography scanner with a calibration standard to convert Hounsfield Units of the CT image to bone mineral density values. Quantitative CT scans are primarily used to evaluate bone mineral density at the lumbar spine and hip.

In general, solid phantoms placed in a pad under the patient during CT image acquisition are used for calibration. These phantoms contain materials that represent a number of different equivalent bone mineral densities. Usually either calcium hydroxyapatite or potassium phosphate are used as the reference standard.