Effects of calibration and automatic greyscale adjustment on detectability of simulated bone lesions using a storage phosphor system.
OBJECTIVE
To analyse the interaction of calibration, automatic greyscale adjustment and X-ray exposure on the evaluation of simulated bone lesions with the Digora (Orion Corporation Soredex, Helsinki, Finland) storage phosphor system.


METHODS
Exposures were made under five conditions based on the exposure time for Ektaspeed Plus film: A-calibration exposure 100%, exposure 100%; B-calibration exposure 100%, exposure 50%; C-calibration exposure 100%, exposure 10%; D-calibration exposure 50%, exposure 50%; E-calibration exposure 10%, exposure 10%. Series of images of artificial bone lesions were created each representing one of the five conditions, with or without automatic greyscale adjustment and including one of two lesion sizes. The series were evaluated by seven expert radiologists. Results were analysed by means of MANOVA statistics.


RESULTS
The large lesions were evaluated significantly better than the small lesions (P < 0.011). The two 10% exposure conditions were evaluated significantly worse than the other three (P < 0.029) which had comparable results. Automatic greyscale adjustment had no significant effect (P > 0.253).


CONCLUSIONS
The Digora should be calibrated for the highest exposure to be used to optimize the wide latitude. Automatic greyscale adjustment is not useful for the detection of simulated bone lesions.
Department of Oral Radiology, Academic Centre for Dentistry Amsterdam, The Netherlands.
C H
CH
Versteeg
G C
GC
Sanderink
F C
FC
van Ginkel
P F
PF
van der Stelt
D001847:Bone Diseases / Q000000981:diagnostic imaging; D002138:Calibration; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging*; D015999:Multivariate Analysis; D011829:Radiation Dosage; D019252:Radiography, Dental, Digital / Q000295:instrumentation*; D015203:Reproducibility of Results; D013679:Technology, Radiologic / Q000295:instrumentation