[Fundamental study on morphological imaging and functional analysis of change in bone].

In this study a comparison was made in determining morphometrical changes in bone utilizing standard dental radiographic technique and dental xeroradiography. In terms of energy intensity, results demonstrated that spectrum analysis is consistent with visual evaluation and useful as a technique for objective evaluation of changes in bone. Changes in trabecular patterns were experimentally reproduced using quantitative determinations of calcium and phosphate. The relation between radiographic changes in bone associated with decalcification and variations in bone mineral content actually eluted from a particular site were examined. Changes in radiographic contrast and morphometry are important as indicators in radiographic interpretation, and their effects on visual evaluation of the radiograms were also studied. Also evaluated was the usefulness of the technique of using a spectrum analyzer to physically analyze the energy intensity distribution changes in bone. The findings in this study indicate that changes in both contrast and morphometry provide indicators for radiographic interpretation in DF, and that changes in contrast play a more dominant role with increasing bone density. It was also demonstrated that radiographic interpretation in DXR depends on morphometrical changes rather than changes in contrast as a major indicator. Since there was no difference in the efficiency of visual detection between DF and DXR, the use of DXR appears more beneficial in view of lower radiation exposure. When the detectability was 80%, actual variations in bone mineral content ranged from 24% to 38%. Thus, it may be possible to visually identify much smaller variations in bone mineral content on radiograms by using additional indicators such as pattern recognition and marginal changes of the lesion.