Single photon absorptiometry
technique to measure density of bones
Single photon absorptiometry is a measuring method for bone density invented by John R. Cameron and James A. Sorenson in 1963.
History
Single photon absorptiometry (SPA) was developed in 1963 by Steichen et al. In 1976, it was an important tool for quantifying bone mineralization in infants. The single photon absorption method operates when a certain amount of gamma rays emitted by isotopes, pass through human tissues. There is an exponential function relationship between the number of gamma rays absorbed and the thickness of tissues, and the absorption characteristics of different tissues are different, but the effects of soft tissues and water on gamma rays are the same. Therefore, the influence of soft tissues can be eliminated by a water bath, and the number of gamma rays absorbed by bone tissues can be measured, and then calculated. The bone mineral content (BMC) was calculated. This method is mainly used for bone measurements of limbs and population census with the aid of the water bath.
Principle of use
Operations
In 1963, the single photon absorption Assay (SPA) invented by Cameron and Sorenson was the first quantitative analysis method applied to the diagnosis of osteoporosis. This method uses the principle that the absorption of radioactive substances by bone tissue is proportional to the bone mineral content.
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