16 March 2007 Atomic number resolution for three spectral CT imaging systems
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The material specificity of computed tomography is quantified using an experimental benchtop imaging system and a physics-based system model. The apparatus is operated with different detector and system configurations each giving X-ray energy spectral information but with different overlap among the energy-bin weightings and noise statistics. Multislice, computed tomography sinograms are acquired using dual kVp, sequential source filters or a detector with two scintillator/photodiodes layers. Basis-material and atomic number images are created by first applying a material decomposition algorithm followed by filtered backprojection. CT imaging of phantom materials with known elemental composition and density were used for model validation. X-ray scatter levels are measured with a beam-blocking technique and the impact to material accuracy is quantified. The image noise is related to the intensity and spectral characteristics of the X-ray source. For optimal energy separation adequate image noise is required. The system must be optimized to deliver the appropriate high mA at both energies. The dual kVp method supports the opportunity to separately engineer the photon flux at low and high kvp. As a result, an optimized system can achieve superior material specificity in a system with limited acquisition time or dose. In contrast, the dual-layer and sequential acquisition modes rely on a material absorption mechanism that yields weaker energy separation and lower overall performance.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Eric Tkaczyk, J. Eric Tkaczyk, Rogerio Rodrigues, Rogerio Rodrigues, Jeffery Shaw, Jeffery Shaw, Jonathan Short, Jonathan Short, Yanfeng Du, Yanfeng Du, Xiaoye Wu, Xiaoye Wu, Deborah Walter, Deborah Walter, William Leue, William Leue, Daniel Harrison, Daniel Harrison, Peter Edic, Peter Edic, } "Atomic number resolution for three spectral CT imaging systems", Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 651009 (16 March 2007); doi: 10.1117/12.709905; https://doi.org/10.1117/12.709905

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