Relationship between Water-equivalent Diameter, Computed Tomography Dose Indices, and Image Noise in Pediatric Head Computed Tomography Under Active and Inactive Tube Current Modulation
Evi Setiawati, Choirul Anam, Bella Diani Safitri, Much Azam, Qidir Maulana Binu Soesanto, Agus MargiantonoPurpose:
This study investigated the relationships among water-equivalent diameter (D w ), volume computed tomography dose index (CTDI vol ), size-specific dose estimate (SSDE), and image noise in pediatric head computed tomography (CT) under active and inactive tube current modulation (TCM).
Subjects and Methods:
Fifty pediatric patients (0–14 years) undergoing noncontrast head CT were retrospectively analyzed. Scans were performed on a 128-slice CT scanner at 120 kVp. Twenty-five patients were examined using active TCM, and 25 with fixed tube current. CTDI vol and SSDE were calculated using IndoseCT software following American Association of Physicists in Medicine TG-293 recommendations. Image noise was quantified using the global noise index. Relationships among D w , CTDI vol , SSDE, and noise were evaluated using linear regression.
Results:
Active TCM reduced CTDI
vol
from 38.5 ± 7.1 mGy to 32.8 ± 6.4 mGy (15.4%,
Conclusion:
Active TCM improves dose–noise efficiency in pediatric head CT by reducing radiation dose while maintaining stable image quality. Integration of D w -based SSDE with automated noise analysis provides a quantitative framework for pediatric CT dose auditing and may support the development of size-specific diagnostic reference levels.