Dose optimization for pediatric chest CT: a comparative study of energy-integrating and photon-counting detector CT using 70 kV and 100 kV protocols with tin filtration regarding image quality and dose exposure

OBJECTIVE: Pediatric thoracic imaging requires radiation dose optimization. Common strategies include protocols with low (70 kV) or medium tube voltages (100 kV) with tin filtration (100Sn). Photon-Counting CT (PCCT) promises further dose reduction without compromising image quality. This study compares radiation dose and image quality between energy-integrating CT (EICT) and PCCT, using thermoluminescent dosimeter (TLD) measurements and clinical data. MATERIALS AND METHODS: DLP, organ dose coefficients, and effective doses (ICRP 103) were analyzed at constant image quality for 70 kV and 100Sn protocols on both CT systems using an anthropomorphic phantom of a one-year-old. Additionally, 121 pediatric chest CTs (PCCT: 66, EICT 55; ages 1 - 149 months) with 100Sn protocol were retrospectively evaluated for image quality, effective dose and size-specific dose estimates. RESULTS: and effective doses than EICT. Organ dose coefficients were comparable. Abdominal shielding was more effective at 70 kV, while 100Sn exhibited greater scatter outside the field. The retrospective analysis of clinical data revealed that doses were significantly higher for PCCT than EICT (0.23 mGy ± 0.07 mGy vs. 0.17 mGy ± 0.09 mGy, p = 0.0002). At the same time both objective (SNR) and subjective (Likert score) image quality indicator were significantly better for PCCT (SNR 1.02 vs. 0.35 for soft tissue and 6.97 vs. 4.30, p < 0.0001 for lung; Likert score 2.43 vs. 2.65 for soft tissue, 1.6 vs. 2.18 for lung), demonstrating the potential for clinical dose optimization. CONCLUSION: The phantom study showed that PCCT enables significant dose reduction in pediatric chest CT while maintaining image quality, especially with 100Sn protocols. This needs to be transferred to clinical practice to decrease pediatric radiation exposure.