Intraoral radiographic storage phosphor image mean pixel values and signal-to-noise ratio: Effects of calibration

Objective. The DIGORA intraoral radiographic storage phosphor system needs to be calibrated before images are made. Calibration involves inputting of the maximum exposure to be used. This investigation studied the effects of different maximum exposure calibration settings on the mean pixel value for selected regions of interest and the signal-to-noise ratio for images of a test phantom. Study design. A dental phantom containing a step wedge made of different thicknesses of homogeneously radiopaque boneequivalent material was imaged at 70 kVp with exposures ranging from 12.8 to 105.2 μC · kg −1. Images were displayed through use of imaging software, and a region of interest was set for each bone-step. The mean pixel values and their standard deviations were measured. Results. Except for very low exposures (