Quantitative dental radiography with a new photostimulable phosphor system

Objective. The purposes of this report are to present a quantitative model for digital oral radiography and to evaluate a new photostimulable phosphor system for bone mass measurements. Study design. Noise, linearity, and precision were measured from stepwedge images and blank images through use of a special least-squares calibration method. The model was used to estimate lower limits of detection for observing small changes in bone mineral content. Results. The response was virtually linear, and the noise level of 2% to 3% is less than that of digitized film images. The precision of measurements averaged over a region of interest was generally better than 0.5%. Conclusions. If the scatter fraction is measured for each patient bone loss can be measured by using only extraoral standards. Assuming a scatter fraction of 50% and considering only instrumental errors, the detection limit is <0.02 g/cm(2) for large image areas (greater than or equal to 7 mm(2)) and <0.3 mg over areas of 1 mm(2) or smaller.