Abstract:

To explore the effects of reducing mAs on diagnostic quality of images and the radiation dose to the lens undergoing sinus CT scanning. Methods160 cases were scanned in axial or coronary orientation at different mAs. Lens radiation dose was measured and image quality was evaluated. ResultsMean radiation dose to the lens was reduced in sequence with the reduction of mAs from 200?mAs to 100, 50, and 25?mAs. No significant difference of image quality in the coronary plane scanning groups was shown at 200, 100 and 50?mAs（P＞0.05）. Coronal reconstructed images in axial scanning were statistically poorer than coronal scanning images at groups 50 and 25?mAs（P＜0.05). Conclusion CT coronal scanning in mAs was reduced to 50?mAs without loss of diagnostic image quality. Coronal reconstructed images in axial scanning may take the place of coronal scanning images if mAs is not reduced below 50?mAs.

Key words: Key words： Low dose； Tomography, Xray computed； Nasal sinus