A COMPARISON OF THE RESPONSE OF STORAGE PHOSPHOR AND FILM RADIOGRAPHYTO SMALL VARIATIONS IN X-RAY-EXPOSURE

Objective: To determine the response to small repeated variations in X -ray exposure of storage phosphor (SP) plates compared with Ektaspeed Plus dental film. Methods: Exposure of SP plates and Ektaspeed Plus de ntal him was varied within a small range [8.62 mu C kg(-1) to 9.03 mu C kg(-1), (5%)]. Radiographs were digitized and SP plates read with a laser-based scanner. Nested analysis of variance, analysis of covarian ce, and regression analysis were used to test the relationship between exposure and the resulting signal. Results: The relationship between exposure and signal for digital images of film radiographs was not sig nificant whereas the corresponding relationship for SP images was high ly significant (P<0.001, R-2 = 0.34). Conclusions: Over the narrow ran ge of X-ray exposures studied there was a significant direct linear re lationship between exposure and digital gray-scare values for SP image s but not for digital images of Ektaspeed Plus films.