Reduction of patient exposure in pediatric radiology: an observer performance study

To determine if presently used exposure levels in pediatric imaging can be reduced without loss of information or decrease in diagnostic accuracy, a method for multiple (stacked) image detectors and filters using a computed radiography system was used to obtain identical images of different exposure levels of neonates with either no active lung disease or hyaline membrane disease. Physical characteristics of the images were measured. A contrast-detail study and an ROC study were conducted to measure observer performance. Physical measurements and the contrast detail study revealed that all images were essentially x-ray photon noise limited. The ROC study indicated that diagnostic accuracy did not decrease significantly up to about 75% exposure reduction levels, although image quality rating data decreased with each exposure reduction. Decreasing exposure levels to about 75% of current levels may be acceptable in some clinical situations where dose is a concern, such as in pediatric imaging.