A NEW-TYPE OF HIGH STRIP DENSITY ANTISCAT TER GRID - EFFECTS ON IMAGEQUALITY AND RADIATION-DOSE

Purpose: Using a new type of a stationary high strip density grid (13/ 75) for plain films of the abdomen, the effect was evaluated with rega rd to quality and patient dose in comparison with an established movin g radiographic grid (12/40). Methods: The high strip density grid (13/ 75) was compared with a 12/40 grid using test objects and 100 patients per each grid type for plain films of the abdomen. The examinations w ere carried out via the screen-film system, speed class (SC) 400. Pati ents' weight, age and dose measurements were recorded. The image quali ty was evaluated via a multi-reader study using delineation of anatomi cal structures and a rating scale (score 1-5 or 1-3). Results: Both me asurements with test objects and patients abdominal plain films showed a decrease in radiation dose of 17% using the 13/75 grid, and 24%, re spectively. The delineation of 4 out of 7 anatomical structures was sl ightly reduced with the new high strip density grid (maximum score red uction: 0.4), the image contrast, as well as the radiologists' subject ive rating. Conclusion: Apart from an acceptable loss in image quality compared with the 12/40 grid, the new high strip density grid (13/75) enables a clear reduction in radiation dose.