Spectral optimization of iodine-enhanced CT

• Verfasst von: Brix, Gunnar [VerfasserIn]
• Verfasst von: Janssen, Sonja [VerfasserIn]
• Verfasst von: Henzler, Thomas [VerfasserIn]
• Titel: Spectral optimization of iodine-enhanced CT
• Titelzusatz: quantifying the effect of tube voltage on image quality and radiation exposure determined at an anthropomorphic phantom
• Verf.angabe: Gunnar Brix PhD, Ursula Lechel MS, Sonja Sudarski MD, Christoph Trumm MD, Thomas Henzler MD
• E-Jahr: 2016
• Jahr: 30 July 2016
• Umfang: 8 S.
• Fussnoten: Gesehen am 16.07.2019
• Titel Quelle: Enthalten in: Physica medica
• Ort Quelle: Amsterdam : Elsevier, 1996
• Jahr Quelle: 2016
• Band/Heft Quelle: 32(2016), 8, Seite 999-1006
• ISSN Quelle: 1724-191X
• DOI: doi:10.1016/j.ejmp.2016.07.618
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Contrast-enhanced CT
• Sach-SW: Image quality
• Sach-SW: Patient exposure
• Sach-SW: Spectral optimization
• K10plus-PPN: 1669221660

Abstract

Purpose - To provide an experimental basis for spectral optimization of iodine-enhanced CT by a quantitative analysis of image quality and radiation dose characteristics consistently measured for a large variety of scan settings at an anthropomorphic phantom. - Methods - CT imaging and thermoluminescent dosimetry were performed at an anthropomorphic whole-body phantom with iodine inserts for different tube voltages (U, 70-140kV) and current-time products (Q, 60-300mAs). For all U-Q combinations, the iodine contrast (C), the noise level (N) and, from these, the contrast-to-noise ratio (CNR) of reconstructed CT images were determined and parameterized as a function of U, Q or the measured absorbed dose (D). Finally, two characteristic curves were derived that give the relative increase of CNR at constant D and the relative decrease of D at constant CNR when lowering U. - Results - Lowering U affects the measured CNR only slightly but markedly reduces D. For example, reducing U from 120kV to 70kV increases the CNR at constant D by a factor of nearly 1.8 or, alternatively, reduces D at constant CNR by a factor of nearly 5. - Conclusion - Spectral optimization by lowering U is an effective approach to attain the necessary CNR for a specific diagnostic task at hand while at the same time reducing radiation exposure as far as practically achievable. The characteristic curves derived in this study from extensive measurements at a reference ‘person’ can support CT users in an easy-to-use manner to select an appropriate voltage for various clinical scenarios.