Dose response of a storage phosphor system for intraoral radiography.

OBJECTIVES

To determine the dose response function for the Digora(R) (Soredex Orion Corporation, Helsinki, Finland) storage phosphor system for intra-oral radiography.

METHODS

Specially designed software provided by the manufacturer was used to register data from the pre-scanning that takes place prior to readout. These data contain information about the signal from the photomultiplier and the amplification that forms the basis for the AD conversion to 8 bit image data. Dose response functions were determined for different calibration settings and also combined into one single function.

RESULTS

The dose response function is linear irrespective of calibration. The gray levels of the final radiographs are directly proportional to the amplified signal. The Digora(R) does not fully compensate for exposure differences. Increased exposure results in slightly darker radiographs.

CONCLUSIONS

Since the gray levels of the final radiographs are directly proportional to the amplified signal, the gray levels may be used as a relative measure of the exposure in the Digora(R) system provided that they are subtracted from the maximum value of 255.