QUANTITATIVE ASSESSMENT OF THE MINERAL CONTENT OF BONE: PRELIMINARY INVESTIGATION.

Abstract

A number of methods for determining the quantity of mineral in bones have been considered. The use of radioisotopes of calcium and strontium in uptake studies of bone lesions has been briefly reviewed. Comparative sensitivities of the radiographic and radioisotopic methods have been indicated, and the use of 47Ca for sequential studies on skeletal tumours has been mentioned as a possibility. High accuracy in determining bone mineral concentration can be achieved by the use of transmission dose techniques provided that low energy X rays are used, but measurements are restricted to regions with only small quantities of overlying soft tissue. The morphological technique affords the simplest approach to an assessment of the patient's clinical condition, but the technique cannot be considered to give a reliable estimate of the quantity of bone mineral present. Microradiography eliminates the effect of soft tissue by the use of biopsy and a low X-ray kilovoltage, but evaluation at the same site at successive time intervals is not possible. Some problems encountered in the radiographic densitometry technique, and their solution by a suitable experimental method, have been described. The possible use of a double kilovoltage technique (currently under investigation) in bypassing the limitations of a single kilovoltage method has been outlined, and future applications of the technique have been proposed.