Usefulness Estimate of Noise Reduction for Mobile Abdomen X-ray

This study is to evaluate the usefulness of noise reduction for mobile abdomen X-ray which could be the reason of unnecessary medical exposure by evaluating the exposure dose and image quality. GM85 (Samsung) was used for Mobile X-ray machine. SID was 110 cm and 80 kVp was used. Collimation size was 14″×17″. Phantom PBU-60 was used. Nero-max 8000, PCXMC program was used to calculate effective dose and ESD for dose evaluation. SPSS 18.0 program was used for statistical analysis. According to reducing mAs (6.4, 5.1, 4.0, 3.2) by the step, mobile abdomen images were acquired. Each images were applied by noise reduction of 6 steps(0, 1, 2, 3, 4, 5). All of them were evaluated quantitatively by Image J program. They are evaluated qualitatively by two residents who are majoring in Department of Radiology for 4 years. In the dose evaluation as the standard of the exposure condition (80 kVp, 8 mAs) DAP was 6.77 dGycm². When the value of mAs was decreasing, exposure dose was decreased by maximum 70% and effective dose was reduced by appropriately 60%. In the cases of stomach and urinary bladder, the value shows the biggest difference. In the image quality evaluation as the Standard of the exposure condition (80 kVp, 8 mAs) when the mAs was 4.0 and noise reduction was not used PSNR was decreased less than 30 dB. However, when mAs was 3.2 and 4 and 5 step of noise reduction were used there was no difference of image quality (each PSNR, 30.577 and 30.768 dB). In the qualitative evaluation, all images are possible to be read for medical image. When mobile abdomen X-ray exam was perform, if noise reduction method could be used with proper mAs, exposure dose would be decreased by maximum 70%. Moreover, it will decrease still unnecessary medical exposure