Densitometry is a medical examination method, which aims to measure the bone density and the densitometers are frequently used by osteologists.


The densitometer evaluates bone density, which is abbreviated as BMD (bone mineral density). Some densitometric machines operate on principle of ultrasound, but the majority functions on the principle of X-ray. The patient lies on an examination pad and the device scans the bones. The bone mass poses a certain resistance to X-ray radiation. The rays are more absorbed by tissue containing more minerals. The resulting images are evaluated by a scoring system that compares the outcome to bone density in healthy individuals of a given age and sex. The entire test takes only a few minutes.


Densitometry can be performed without any special preparation. The patient does not need to fast or take any special medications before the examination.


The examination is indicated in people who have risk factors of osteoporosis, or who are already suffering from this disease. The osteoporosis is a significant threat to older people, postmenopausal women, patients with certain hormonal disorders and any states leading to malabsorption of nutrients (including calcium). Very special subgroups of examined patients are castrated men due to hormonal changes that increase the bone demineralization. The castration may be performed as part of therapy of prostate cancer and in some countries; it is also a therapeutic method of male sexual deviants.


X-ray densitometers expose the examined person to radiation. However, the dose is minimal and the densitometry does not need to be frequently repeated.


The examination is quick, painless and relatively commonly available test that provides valuable information about the bone mass and treatment of osteoporosis.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources