Purpose: In emergency diagnostics, head CT and CT angiography (CTA) of craniocervical vasculature are indispensable for children, despite their increased radiation sensitivity. This study assesses the radiation dose metrics of head CT and CTA in pediatric patients managed in the trauma resuscitation unit (TRU). Methods: All patients aged 0–<15 years who underwent head CT and CTA in the TRU between April 2020 and August 2023 were included. CT dose index volume (CTDIvol) and dose-length product (DLP) were extracted from the Radimetrics Enterprise Platform, which also provided organ doses estimated via Monte Carlo simulations and effective doses (ED) derived from these estimates. Dose metrics were compared with national diagnostic reference levels (DRLs), defined for three pediatric age groups: I (0–<5 years), II (5–<10 years), and III (10–<15 years). Results: Of 212 pediatric TRU patients, 62.7% (133/212) underwent CT and 72.2% (96/133) received combined CT and CTA. Median CTDIvol and DLP increased with age, whereas ED decreased. For head CT, CTDIvol ranged from 18.9 mGy to 29.4 mGy, DLP from 282 to 460 mGycm, and ED from 1.6 to 1.3 mSv. For CTA, CTDIvol ranged from 1.4 to 2.2 mGy, DLP from 40 to 83 mGycm, and ED from 1.0 to 0.8 mSv. All doses remained below national DRLs. Conclusion: Head CT and CTA in pediatric trauma can be performed with radiation doses well below national DRLs. Careful dose management is important to reduce potential long-term cancer risks and deterministic effects such as lens cataract formation.

Objective: Chest computed tomography (CT) is a key component of the diagnostic assessment of people with cystic fibrosis (PwCF) and is increasingly replacing chest radiography. Due to improvements in life expectancy, radiation exposure has become a growing concern in PwCF. Photon-counting CT (PCCT) has the potential to reduce the risk of radiation-induced malignancies while maintaining diagnostic accuracy. This study aimed to compare the radiation dose and image quality of low-dose high-resolution (LD-HR) and ultra-low-dose high-resolution (ULD-HR) CT protocols using PCCT in PwCF. Methods: This retrospective study included 72 PwCF, with 36 undergoing a LD-HR chest CT protocol and 36 receiving an ULD-HR protocol on a PCCT. The radiation dose and image quality were assessed by comparing the effective dose and signal-to-noise ratio (SNR). Three blinded radiologists evaluated the overall image quality, sharpness, noise, and assessability of the bronchi, bronchial wall thickening, and bronchiolitis using a five-point Likert scale. Results: The ULD-HR PCCT protocol reduced radiation exposure by approximately 65% compared with the LD-HR PCCT protocol (median effective dose: 0.19 vs. 0.55 mSv, p < 0.001). While LD-HR images were consistently rated higher than ULD-HR images (p < 0.001), both protocols maintained diagnostic significance (median image quality rating of “4-good”). The average SNR of the lung parenchyma was significantly lower with ULD-HR PCCT compared to LD-HR PCCT (p < 0.001). Conclusions: ULD-HR PCCT significantly reduced radiation exposure while maintaining good diagnostic image quality in PwCF. The effective dose of ULD-HR PCCT is only twice that of a two-plane chest X-ray, making it a viable low-radiation alternative for routine imaging in PwCF.

In patients with obesity, intraindividual comparisons demonstrated that photon-counting CT had superior quantitative and subjective image quality at a lower radiation dose than energy-integrating detector CT.

Combined chest and abdomen computed tomography (CT) in paediatric trauma patients is rare and typically reserved for severely injured patients due to concerns about the potential radiation risks associated with CT in children. This study aims to analyse the radiation exposure of chest and abdomen CT in paediatric patients following trauma resuscitation. A retrospective single-centre study was conducted on patients aged 0–<15 years who underwent CT in the trauma resuscitation unit between 04/2020 and 08/2023. Patients were categorised into three age groups (AGs) (I: 0–<5years, II: 5–<10 years, III: 10–<15 years) and radiation exposure parameters were analysed age-stratified. Effective dose (ED) was calculated using conversion factors and organ doses were determined through Monte Carlo simulations. Out of 212 paediatric patients, 62.7% (133/212) received a CT scan, with 60.2% (80/133) undergoing combined chest and abdomen CT. In 70.0% (56/80), the standard protocol was applied, complete dose data available, and these were included in the dose calculation (median age: 6.2 years; IQR: 3.9–10.5 years; 37.5% female). Radiation exposure was as follows (median [IQR] CTDIvol, DLP, ED): chest: I: 0.7 mGy (0.5–0.8), 13 mGycm (10–16), 2.1 mSv (1.6–2.4); II: 1.4 mGy (1.1–1.9), 35 mGycm (25–49), 3.7 mSv (2.7–5.2); III: 2.7 mGy (2.2–3.2), 76 mGycm (66–95), 4.3 mSv (3.7–5.3); abdomen: I: 0.8 mGy (0.6–0.9), 24 mGycm (20–29), 2.0 mSv (1.6–2.5); II: 1.6 mGy (1.1–1.9), 60 mGycm (41–77), 3.2 mSv (2.2–4.2); III: 3.1 mGy (2.4–3.9), 143 mGycm (101–179), 4.3 mSv (3.0–5.4). In the organ dose analysis, the genital organs were particularly affected by increased radiation exposure. 16.1% (9/56) of patients were not scanned using age-adapted protocols. Chest and abdomen CT in paediatric trauma patients can be performed with moderate radiation exposure. Nonetheless, non-adherence to age-adapted protocols highlights the need for improved compliance to ensure optimal radiation safety in paediatric trauma imaging.

Purpose: Chest CT is central to the diagnosis and monitoring of acute respiratory distress syndrome (ARDS). Photon-counting detector CT (PCD-CT) may improve image quality and enable radiation dose optimization compared with Energy-integrating detector CT (EID-CT). However, evidence in critically ill ARDS patients undergoing contrast-enhanced chest imaging is limited. The purpose of this study was to intraindividually compare image quality and radiation exposure between PCD-CT and EID-CT in ARDS patients. Methods: This retrospective study included patients with ARDS who underwent both contrast-enhanced chest PCD-CT and EID-CT between April 2023 and May 2025. CT dose index volume (CTDIvol), dose–length product (DLP), effective and organ doses were extracted from dose monitoring software. Subjective image quality and diagnostic acceptability were rated independently by two radiologists using a Likert scale; inter-reader agreement was assessed with Cohen’s κ. Objective image quality was assessed using signal-to-noise ratios in representative anatomical regions. Intraindividual comparisons were performed using the Wilcoxon signed-rank test. Results: Among 531 ARDS patients, 80 (15.1%) underwent chest PCD-CT, including 59 (73.8%) contrast-enhanced examinations (median age: 51.7 years (IQR: 41.6–59.5); 62.7% male). Intraindividual imaging was performed in 32 patients (54.2%). PCD-CT demonstrated significantly higher subjective and objective image quality than EID-CT ( p < 0.005), with moderate inter-reader agreement. Median CTDIvol and DLP were not significantly different between PCD-CT (8.2 mGy; 435 mGycm) and EID-CT (7.7 mGy; 297 mGycm). Conclusion: In contrast-enhanced chest CT of ARDS patients, PCD-CT provides superior image quality without a significant difference in radiation dose, potentially facilitating more precise diagnostic assessment in this critically ill population. Trial registration: DRKS-ID: DRKS00037916, 15 September 2025, retrospectively registered. Graphical