歯槽骨X線像における濃度特性の定量的把握に関する実験的研究

(第1編) X線像の濃度特性に影響を及ぼす因子について

抄録

Findings on radiographic image of the alveolar bone may be a most useful clinical means if they enable us to objectively analyze the characteristics of the alveolar bone. As the first step, the author investigated on the quantitative analysis of the radiographic image of the alveolar bone.
Lower jaw bone of the human dry skull and patient were used as objects and their radiographs were taken under different conditions. These radiographs were taken together with step wedge having 8 steps made of a thin 18-8 steel plate (76-608μm). The density values by densitometric analysis on the radiographic image in a particular area were compared.
Results and Conclusions
1) Differences in the conditions of radiography and development have various effects on the density distribution of radiographic image, moreover, even if the degree of the differences is comparatively wide range which is possible to occur clinically, it may quantitatively compare the density in a particular area of the alveolar bone between multiple radiographic images obtained under different conditions by calibrating with the density of the image of the step wedge which come out together with that area.
2) The influences of individual variations in the thickness of the cortical bone on the density distribution of the internal structure image can be ruled out by converting the linear analytical value of the density distribution on the radiographic image of the alveolar bone into step wedge equivalent.