Fig. 3. Variable arm positions on CT scout images.

A. CT scout image shows that both arms are horizontal, which is greatly disadvantageous in terms of image quality and radiation dose, as compared with both arms raised up. B. CT scout image shows that both arms are down beside body trunk, which may slightly degrade image quality and increase radiation dose, as compared with both arms raised up. C. CT scout image shows that right arm is raised up and left arm is horizontal, which may cause asymmetric image quality degradation in left shoulder region and increased radiation dose, as compared with both arms raised up.