Optimization of dose and image quality using self-produced phantom with various diameters in pediatric abdominal CT scan

Abstract

Computed tomography (CT) provides various advantages; however, the radiation exposure dose is high. In a pediatric CT scan, a reduction of the exposure dose would lead to a larger noise and lower image quality. Therefore, we investigated the optimization between the dose and image quality in a pediatric CT scan. We used a 128-channel CT device and self-produced computed-tomography-dose-index (CTDI) phantoms with various diameters (12, 16, 20, and 24 cm). Various exposure conditions were considered by varying the tube voltage and tube current. Evaluation parameters were the weighted CTDI (CTDIw), contrast, noise, and contrast-to-noise-ratio (CNR). In addition, we calculated the contrast-to-noise ratio dose (CNRD) to optimize the dose and image quality. The measured CTDIw increased with the tube voltage and tube current. The obtained contrast and noise values decreased, while the CNR was almost unaffected with the increase of the tube voltage. With the increase of the tube current, the contrast was not considerably affected, the noise decreased, and the CNR increased. The highest CNRD was obtained for the lowest tube voltage and tube current. Therefore, an optimized image quality was obtained using the minimum radiation exposure dose with a high CNRD in a pediatric abdomen CT scan.