title: Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast.
abstract: Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05).
authors.affiliation: Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Medical Radiation Physics Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana; Department of Nuclear Medicine, Charlotte Maxeke Johannesburg Academic Hospital, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Hasford
authors.initials: H
authors.lastname: Francis
authors.affiliation: Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana.
authors.forename: John Humphrey
authors.initials: JH
authors.lastname: Amuasi
authors.affiliation: Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana.
authors.forename: Kyere Augustine
authors.initials: KA
authors.lastname: Kwame
authors.affiliation: Department of Nuclear Medicine, Charlotte Maxeke Johannesburg Academic Hospital, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Mboyo Di Tamba
authors.initials: MD
authors.lastname: Vangu
keywords: Hot lesion; image contrast; image quality phantom; radionuclide activity