MOTTLE ON COMPUTED RADIOGRAPHS OF THE CHEST IN PEDIATRIC-PATIENTS

PURPOSE: To investigate the relationship between radiation exposure an d perceived mottle at bedside pediatric chest examinations performed w ith screen-film and computed radiographic techniques. MATERIALS AND ME THODS: In a pediatric intensive care unit, chest radiographs were obta ined with both computed radiography (60 radiographs) and a 600-speed s creen-film system (14 radiographs). The relative radiation exposure wa s estimated by using the sensitivity value obtained in the processing of each computed radiograph. Five radiologists assessed the mottle pre sent in the computed radiographs and screen-film images. RESULTS: For computed radiographs, the perceived level of mottle was inversely rela ted to radiation exposure. For the same radiation exposure, the percei ved mottle on computed radiographs was significantly higher than that on screen-film images (P <.001 for small cassettes; P <.01 for large c assettes). CONCLUSION: Pediatric computed radiography of the chest req uires approximately twice the exposure of a 600-speed screen-film syst em to attain the same level of mottle.