Effectiveness of the air-gap method in pediatric CT examinations

Abstract Background: This study aims to investigate the suitability of the air gap method for radiation dose reduction in pediatric patients during computed tomography (CT) examinations.Methods: We use pediatric anthropomorphic phantoms with a 64 detector-row CT scanner while scanning the chest. A real-time skin dosimeter is placed on the scanner gantry and is positioned at the center of the phantom, on the dorsal surface of the body, and on the left and right mammary glands. In the conventional method, the distance between the CT table and the subject was 0 mm. In the air gap method, the distance between the CT table and subject was 150 mm. We perform a helical scan between the conventional and air-gap methods from the lung apex to the subdiaphragm. The values of the real-time skin dosimeter and image noise are measured and compared for each method.Results: Compared with the conventional method, it was possible to reduce the exposure dose and image noise by approximately 10% and 15%, respectively, using the air gap method (p < 0.05). Conclusion: The airs gap method was useful for reducing the radiation dose by approximately 10% during pediatric CT examinations compared with the conventional method.