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Dual-energy x-ray approach for object/energy-specific attenuation coefficient correction in single-photon emission computed tomography: effects of contrast agent

Lookup NU author(s): Dr Kheng-Lim GohORCiD


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© 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).Purpose: To investigate the influence of radiographic contrast agent on the accuracy of the photon counts arising from the emission of gamma rays of radionuclides in single-photon emission computed tomography (SPECT), when dual-energy x-ray CT (DXCT) is employed for providing object/energy-specific attenuation coefficient correction in SPECT. Approach: Computer simulation was performed for three transmission CT approaches, namely, the conventional (single kVp, unimodal spectrum) x-ray CT, DXCT (single kVp, bimodal spectrum) with basis material decomposition (BMD), and DXCT with BMD followed by basis material coefficients transformation (BMT), to study the effects of these approaches on the accuracy of the photon counts from the SPECT image of a thorax-like phantom. Results: All three CT approaches revealed that the error in the counts was both photon energy and iodine concentration-dependent. Differences in the trending increase/decrease in the errors with the respective increase in iodine concentration and photon energy were observed among the three CT approaches. Of the three, the BMT/SPECT approach resulted in the smallest error in the concentration of radionuclides measured, especially in the contrast agent-filled region, and the optimal level depended on the iodine concentration and photon energy. Conclusion: With a judicious choice of the basis materials and photon energy, it may be possible to take advantage of the benefits of the BMT method to mitigate the accuracy problem in DXCT for quantitative SPECT imaging.

Publication metadata

Author(s): Goh KL, Liew SC

Publication type: Article

Publication status: Published

Journal: Journal of Medical Imaging

Year: 2021

Volume: 8

Issue: 5

Online publication date: 31/05/2021

Acceptance date: 11/05/2021

ISSN (print): 2329-4302

ISSN (electronic): 2329-4310

Publisher: Society of Photo-Optical Instrumentation Engineers (SPIE)


DOI: 10.1117/1.JMI.8.5.052106


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