Spectral optimization of iodine-enhanced CT: quantifying the effect of tube voltage on image quality and radiation exposure determined at an anthropomorphic phantom
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 thermolumines...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
30 July 2016
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| In: |
Physica medica
Year: 2016, Volume: 32, Issue: 8, Pages: 999-1006 |
| ISSN: | 1724-191X |
| DOI: | 10.1016/j.ejmp.2016.07.618 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1016/j.ejmp.2016.07.618 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S1120179716307517 
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| Author Notes: | Gunnar Brix PhD, Ursula Lechel MS, Sonja Sudarski MD, Christoph Trumm MD, Thomas Henzler MD |
| Summary: | 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. |
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| Item Description: | Gesehen am 16.07.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1724-191X |
| DOI: | 10.1016/j.ejmp.2016.07.618 |