EXPOSURE PARAMETERS AND THEIR EFFECTS ON DIAGNOSTIC-ACCURACY

A new method for analyzing diagnostic accuracy is introduced. A diagno stic accuracy curve may be obtained by plotting receiver operating cha racteristic analysis data, P(A), as a function of exposure. By means o f diagnostic accuracy curves the effects on diagnostic accuracy of tub e potential, exposure, and size of carious lesions was studied. It was found that the effect of the tube potential on the accuracy of caries diagnosis is negligible. About 25% of the variation in diagnostic acc uracy depends on the exposure and about 80% on lesion depth. With the lesion depth constant, about 75% of the variance in diagnostic accurac y depended on observer performance. The peak of a diagnostic accuracy curve indicates optimum performance. This is found at an exposure that gives a radiographic density of about 1 in enamel and dentin although the tolerable exposure increases with increased lesion depth.