Intraindividual Comparison of Radiation Dose and Image Quality: Photon-counting versus Energy-integrating Detector CT in Obesity
In brief
Photon-counting CT improves obesity scans while lowering radiation dose by 30%
In this retrospective comparison of 51 patients with obesity scanned by both methods, photon-counting CT delivered about 30% lower volume CT dose and higher overall image-quality ratings than conventional CT. It also improved signal-to-noise in vessels and most organs, with the advantage growing at higher body mass index. The study does not establish whether these image improvements change diagnosis or patient outcomes.
- Journal
- Radiology (Q1)
- Published
- 1 October 2026
- Study design
- Cohort / observational study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Jan Hegmanns, Sebastian Zensen, Daniel Rosok, Marcel A Drews, Mathias Holtkamp, Yan Li, et al.
- PMID
- 42899938
- DOI
- 10.1148/radiol.260573
Why clinicians should know about it
- Picked for Medical Physics (paper of the day, 21 October 2026): Intraindividual CT dose and image-quality comparison in obesity
Abstract
Background Maintaining diagnostic CT image quality in patients with obesity remains challenging because increased x-ray attenuation is often offset by higher radiation exposure. Photon-counting CT (PCCT) has demonstrated improved dose efficiency and image quality, but intraindividual data in this population are limited. Purpose To compare radiation dose, quantitative image quality, and subjective image quality between PCCT and energy-integrating detector (EID) CT intraindividually in patients with obesity. Materials and Methods This retrospective study included patients with obesity undergoing thoracic and/or abdominal CT at both PCCT and EID CT between December 1, 2022, and January 31, 2025. Signal, image noise, and signal to noise ratio (SNR) were measured in vascular, parenchymal, muscular, and adipose tissue. Two radiologists independently rated image quality on a six-point Likert scale. Radiation dose parameters were volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose. The paired two-sided t test or Wilcoxon signed-rank test was used for group comparisons. Results This study included 51 patients with obesity (median age, 56 years [IQR, 51-66.5 years]; 33 male). Signal was higher with PCCT than EID CT in vascular structures, parenchymal organs, and muscle and more negative in subcutaneous fat (all P < .001), with similar image noise (P = .09-.84). SNR was higher with PCCT in vascular structures (ascending aorta: mean, 19.65 ± 6.47 [SD] vs 13.22 ± 4.83; P < .001) and most parenchymal organs (liver: 5.53 ± 1.69 vs 4.71 ± 1.89; P = .02). The difference in SNR increased with body mass index for vessels (r = 0.36) and parenchymal organs (r = 0.51) (both P < .001). Both readers rated overall image quality, contrast, and sharpness higher and artifact-related impairment lower for PCCT (all P < .001), whereas subjective image noise was similar (P = .16 and .14). CTDIvol (median, 11.99 vs 17.05 mGy) and DLP (median, 526.25 vs 709.32 mGy · cm) were lower with PCCT (both P < .001). Conclusion In patients with obesity, intraindividual comparisons demonstrated that PCCT had superior quantitative and subjective image quality at a lower radiation dose than EID CT. © RSNA, 2026 Supplemental material is available for this article.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.