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Salazar E, Liu LP, Perkins AE, Halliburton SS, Shapira N, Litt HI, Noël PB. Impact of scatter radiation on spectral quantification performance of first- and second-generation dual-layer spectral computed tomography. J Appl Clin Med Phys 2024:e14383. [PMID: 38801204 DOI: 10.1002/acm2.14383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 04/02/2024] [Accepted: 04/13/2024] [Indexed: 05/29/2024] Open
Abstract
OBJECTIVE To assess the impact of scatter radiation on quantitative performance of first and second-generation dual-layer spectral computed tomography (DLCT) systems. METHOD A phantom with two iodine inserts (1 and 2 mg/mL) configured to intentionally introduce high scattering conditions was scanned with a first- and second-generation DLCT. Collimation widths (maximum of 4 cm for first generation and 8 cm for second generation) and radiation dose levels were varied. To evaluate the performance of both systems, the mean CT numbers of virtual monoenergetic images (MonoEs) at different energies were calculated and compared to expected values. MonoEs at 50 versus 150 keV were plotted to assess material characterization of both DLCTs. Additionally, iodine concentrations were determined, plotted, and compared against expected values. For each experimental scenario, absolute errors were reported. RESULTS An experimental setup, including a phantom design, was successfully implemented to simulate high scatter radiation imaging conditions. Both CT scanners illustrated high spectral accuracy for small collimation widths (1 and 2 cm). With increased collimation (4 cm), the second-generation DLCT outperformed the earlier DLCT system. Further, the spectral performance of the second-generation DLCT at an 8 cm collimation width was comparable to a 4 cm collimation on the first-generation DLCT. A comparison of the absolute errors between both systems at lower energy MonoEs illustrates that, for the same acquisition parameters, the second-generation DLCT generated results with decreased errors. Similarly, the maximum error in iodine quantification was less with second-generation DLCT (0.45 and 0.33 mg/mL for the first and second-generation DLCT, respectively). CONCLUSION The implementation of a two-dimensional anti-scatter grid in the second-generation DLCT improves the spectral quantification performance. In the clinical routine, this improvement may enable additional clinical benefits, for example, in lung imaging.
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Affiliation(s)
- Edgar Salazar
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Engineering and Architecture, Universidad Privada Boliviana, La Paz, Bolivia
| | - Leening P Liu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Engineering and Architecture, Universidad Privada Boliviana, La Paz, Bolivia
| | | | | | - Nadav Shapira
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Harold I Litt
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Peter B Noël
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Horst KK, Cao JY, McCollough CH, El-Ali A, Frush DP, Siegel MJ, Ramirez-Giraldo JC, O'Donnell T, Bach S, Yu L. Multi-institutional Protocol Guidance for Pediatric Photon-counting CT. Radiology 2024; 311:e231741. [PMID: 38771176 DOI: 10.1148/radiol.231741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Performing CT in children comes with unique challenges such as greater degrees of patient motion, smaller and densely packed anatomy, and potential risks of radiation exposure. The technical advancements of photon-counting detector (PCD) CT enable decreased radiation dose and noise, as well as increased spatial and contrast resolution across all ages, compared with conventional energy-integrating detector CT. It is therefore valuable to review the relevant technical aspects and principles specific to protocol development on the new PCD CT platform to realize the potential benefits for this population. The purpose of this article, based on multi-institutional clinical and research experience from pediatric radiologists and medical physicists, is to provide protocol guidance for use of PCD CT in the imaging of pediatric patients.
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Affiliation(s)
- Kelly K Horst
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Joseph Y Cao
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Cynthia H McCollough
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Alex El-Ali
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Donald P Frush
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Marilyn J Siegel
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Juan Carlos Ramirez-Giraldo
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Tom O'Donnell
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Steve Bach
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
| | - Lifeng Yu
- From the Department of Radiology, Division of Pediatric Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 (K.K.H., C.H.M., L.Y.); Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham, NC (J.Y.C., D.P.F., S.B.); Department of Radiology, Division of Pediatric Radiology, NYU Grossman School of Medicine, New York, NY (A.E.A.); Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (M.J.S.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.G., T.O.)
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Liu LP, Hwang M, Hung M, Soulen MC, Schaer TP, Shapira N, Noël PB. Non-invasive mass and temperature quantifications with spectral CT. Sci Rep 2023; 13:6109. [PMID: 37059839 PMCID: PMC10104802 DOI: 10.1038/s41598-023-33264-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 04/11/2023] [Indexed: 04/16/2023] Open
Abstract
Spectral CT has been increasingly implemented clinically for its better characterization and quantification of materials through its multi-energy results. It also facilitates calculation of physical density, allowing for non-invasive mass measurements and temperature evaluations by manipulating the definition of physical density and thermal volumetric expansion, respectively. To develop spectral physical density quantifications, original and parametrized Alvarez-Macovski model and electron density-physical density model were validated with a phantom. The best physical density model was then implemented on clinical spectral CT scans of ex vivo bovine muscle to determine the accuracy and effect of acquisition parameters on mass measurements. In addition, the relationship between physical density and changes in temperature was evaluated by scanning and subjecting the tissue to a range of temperatures. The parametrized Alvarez-Macovski model performed best in both model development and validation with errors within ± 0.02 g/mL. No effect from acquisition parameters was observed in mass measurements, which demonstrated accuracy with a maximum percent error of 0.34%. Furthermore, physical density was strongly correlated (R of 0.9781) to temperature changes through thermal volumetric expansion. Accurate and precise spectral physical density quantifications enable non-invasive mass measurements for pathological detection and temperature evaluation for thermal therapy monitoring in interventional oncology.
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Affiliation(s)
- Leening P Liu
- Department of Radiology, University of Pennsylvania, Philadelphia, USA.
- Department of Bioengineering, University of Pennsylvania, Philadelphia, USA.
| | | | - Matthew Hung
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Michael C Soulen
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Thomas P Schaer
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA
| | - Nadav Shapira
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Peter B Noël
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
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Meyer S, Liu LP, Litt HI, Halliburton SS, Shapira N, Noël PB. Phantom-based quantification of the spectral accuracy in dual-layer spectral CT for pediatric imaging at 100 kVp. Quant Imaging Med Surg 2023; 13:924-934. [PMID: 36819257 PMCID: PMC9929380 DOI: 10.21037/qims-22-552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 11/07/2022] [Indexed: 01/05/2023]
Abstract
Background To determine the spectral accuracy in detector-based dual-energy CT (DECT) at 100 kVp and wide (8 cm) collimation width for dose levels and object sizes relevant to pediatric imaging. Methods A spectral CT phantom containing tissue-equivalent materials and iodine inserts of varying concentrations was scanned on the latest generation detector-based DECT system. Two 3D-printed extension rings were used to mimic varying pediatric patient sizes. Scans were performed at 100 and 120 kVp, 4 and 8 cm collimation widths, and progressively reduced radiation dose levels, down to 0.9 mGy CTDIvol. Virtual mono-energetic, iodine density, effective atomic number, and electron density results were quantified and compared to their expected values for all acquisition settings and phantom sizes. Results DECT scans at 100 kVp provided highly accurate spectral results; however, a size dependence was observed for iodine quantification. For the medium phantom configuration (15 cm diameter), measurement errors in iodine density, effective atomic number, and electron density (ED) were below 0.3 mg/mL, 0.2 and 1.8 %EDwater, respectively. The average accuracy was slightly different from scans at 120 kVp; however, not statistically significant for all configurations. Collimation width had no substantial impact. Spectral results were accurate and reliable for radiation exposures down to 0.9 mGy CTDIvol. Conclusions Detector-based DECT at 100 kVp can provide on-demand or retrospective spectral information with high accuracy even at extremely low doses, thereby making it an attractive solution for pediatric imaging.
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Affiliation(s)
- Sebastian Meyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leening P. Liu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harold I. Litt
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Nadav Shapira
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter B. Noël
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA;,Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, München, Germany
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