Potential for Radiation Dose Reduction in Temporal Bone CT Imaging Using Photon-Counting Detector CT

Temporal bone computed tomography (CT) is frequently performed for pediatric patients with ear diseases. Advances in CT technology have improved diagnostic imaging quality, but reduction of radiation exposure remains a goal. We evaluated the potential for radiation dose reduction in temporal bone CT examinations using porcine ear ossicles and a photon-counting detector CT system. Three scans of the bilateral temporal bone were performed on each of three pig cadaver heads. In each of seven successive imaging sessions, the radiation dose was reduced by an additional one-seventh of the recommended dose (RD). Two board-certified radiologists independently scored the resulting images on a scale of 1 to 5 points, where 5 represented the image quality at the RD. Images scoring ≥ 4.5 points were considered acceptable. Noise was assessed in a 2-cm-diameter region near the ear ossicles, and standard deviation was measured for each of the seven decrements from the RD. As the radiation dose decreased, the noise progressively increased, and visual assessment scores progressively decreased. Acceptable image scores were obtained at six-sevenths (4.9), five-sevenths (4.8), four-sevenths (4.7), and three-sevenths (4.6) of the RD. Thus, acceptable porcine temporal bone CT images were obtained with a radiation dose reduction of approximately 50%.