Abstract
<title>Abstract</title> <p>Purpose To compare organ absorbed doses and effective doses between photon-counting detector CT (PCD-CT) and conventional energy-integrating detector CT (EID-CT) for head examinations in a 10-year-old child model, thereby providing measured data to support dose optimization in pediatric head CT. Materials and methods A 10-year-old anthropomorphic pediatric phantom (CIRS ATOM 706D) was instrumented with thermoluminescent dosimeters (TLDs) at organ-specific locations. Axial head scans were performed using PCD-CT (Siemens NAEOTOM Alpha) and EID-CT (Siemens SOMATOM Drive) at two dose levels (CTDIvol approximately 52 mGy and 32 mGy) with a nominal scan length of 130 mm. Absorbed doses were measured for 22 organs or tissues. Effective dose was calculated using the tissue-weighting factors recommended in ICRP Publication 103, and dose differences between the two scanners were compared at matched dose-length product (DLP) levels. Results The high-to-low dose ratios did not differ significantly between the two scanners (P = 0.845), indicating comparable dose modulation. At matched DLP levels (approximately 735 mGy·cm for the high-dose group and 456 mGy·cm for the low-dose group), the effective doses with PCD-CT were 2.200 mSv and 1.387 mSv, respectively, representing reductions of 11.36% and 12.30% compared with EID-CT (2.482 mSv and 1.582 mSv, respectively). Conclusion For pediatric head CT, PCD-CT reduced effective dose by approximately 11–12% at comparable radiation-output levels, demonstrating clear potential for dose optimization. This study used a pediatric anthropomorphic phantom and direct TLD measurements to provide reliable experimental evidence for radiation protection in pediatric head CT.</p>