Threshold perception performance with computed and screen-film radiography: implications for chest radiography.
Images of a phantom obtained with computed radiography and standard screen-film imaging were compared to evaluate observer threshold perception performance with a modified contrast-detail technique. Optimum exposure necessary for performance with the imaging plate technique to match that with screen-film techniques was determined, as was comparative performance with variation in kilovoltages, plate type, spatial enhancement, and hard-copy interpolation method. It was found that computed radiography necessitates about 75%-100% more exposure than screen-film radiography to optimally match performance with Ortho-C film with Lanex regular or medium screens (Eastman Kodak, Rochester, NY) for detection of objects 0.05-2.0 cm in diameter. However, only minimal loss of detection performance (approximately 10% overall) was experienced if standard screen-film exposures were used with computed radiography. Little change in observer performance was found with variation in plate type, spatial enhancement, or method of hard-copy interpolation. However, perception performance with computed radiographic images was better at lower kilovoltages.
Dobbins
J T
JT
Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Rice
J J
JJ
Beam
C A
CA
Ravin
C E
CE
D006801:Humans; D008961:Models, Structural; D015588:Observer Variation; D011856:Radiographic Image Enhancement; D013902:Radiography, Thoracic; D014963:X-Ray Intensifying Screens