Radiation doses and image quality of abdominal CT scans at different patient sizes using spectral detector CT scanner: a
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Radiation doses and image quality of abdominal CT scans at different patient sizes using spectral detector CT scanner: a phantom and clinical study Xinhui Duan1 · Lakshmi Ananthakrishnan1 · Jeffrey B. Guild1 · Yin Xi1 · Prabhakar Rajiah1,2
© Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract Purpose To compare radiation dose and image quality for abdominal CTs performed on a spectral detector CT (SDCT) and a comparable single-energy conventional CT scanner for patients of different sizes. Methods Four semi-anthropomorphic phantoms were scanned on an SDCT (IQon, Philips Healthcare) and a comparable single-energy CT (iCT 256, Philips Healthcare) under matched scan parameters. Image noise and radiation dose were compared. For the HIPAA-compliant, IRB-approved retrospective cohort patient study, radiation dose was compared after adjusting for patient water equivalent diameter. Difference in subjective and objective image quality was assessed on a subset of 50 patients scanned on both scanners by two readers. Results CTDIvol and noise from SDCT were higher than conventional CT for all phantoms, with a relative difference of 7.8% (range 5.3–14%) for radiation dose and average difference of 9.0% (range 5.5–11%) for noise. 718 SDCT and 937 conventional CT patients were included in the patient study. CTDIvol for SDCT patients tends to be lower for smaller patients (− 2%, 95% confidence interval (− 5%, − 0.2%) for 200 mm water equivalent diameter) and higher for larger patients compared to conventional CT (8%, (6%, 11%) for 400 mm). No difference was seen for subjective image quality, SNR, CNR, or image noise between the two scanners, except for higher image noise in the portal vein and higher signal in the aorta on SDCT. Conclusion Radiation dose for abdominal CT performed on SDCT is similar to the dose on a conventional CT for average size patients, lower for smaller patients, and slightly higher for larger patients. Image quality is similar between the two scanners. Keywords Radiation dosage · Tomography · X-ray computed · Abdomen · Phantoms · Imaging
Introduction Spectral or dual-energy CT (DECT) has been in clinical use for several years and offers additional diagnostic information in a variety of clinical settings [1–4]. Commercially available spectral CT systems include dual-source DECT (DSDECT), single-source DECT (SSDECT), and dual-layer spectral detector CT (SDCT). In DSDECT, two X-ray tubes are operated at different tube potentials. In SSDECT or rapid kVp switching technology, there is a single X-ray tube which * Xinhui Duan [email protected] 1
Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
2
oscillates between low and high tube potential for each X-ray projection. Dual-layer SDCT is a newer system, which uses a single X-ray tube and a dual-layer detector, with spectral separation occurring at the detector level u
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