ANATOMICALLY ADAPTED VARIATION OF THE TUB E CURRENT IN CT - STUDIES ON REDUCTION OF RADIATION-DOSE AND IMAGE QUALITY

Purpose: To assess the impact of a method for anatomically adapted tub e current variation. The resulting CT image quality was evaluated quan titatively and qualitatively. Methods: CT scans of 100 patients were p erformed with a constant tube current (Group 1) and another 100 patien ts with an anatomically adapted tube current (Group 2). The CT tube cu rrent was varied during a 360 degrees tube rotation reflecting the mea sured density values extracted from two perpendicular scout views. The standard deviation of densities of defined regions was measured. The image quality was ranked (1 = non-diagnostic-5 = excellent) by three r adiologists. Results: The effective tube current could be reduced by a n average of 8.9% (0-20.4%). The mean tube current reduction depended on the body region: pelvis (13.2%), abdomen (8.4%) and thorax (3.3%). The image:quality was not significantly reduced in Group 2. Conclusion : The method for anatomically adapted tube current variation leads esp ecially in the pelvis to a significant mAs reduction without considera ble loss of image quality.