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BioMed Research International
Volume 2016, Article ID 3067123, 8 pages
Research Article

Comparison of Imaging Characteristics of 124I PET for Determination of Optimal Energy Window on the Siemens Inveon PET

1Laboratory Animal Center, OSONG Medical Innovation Foundation, Osong, Chungbuk 28160, Republic of Korea
2Department of Radiological Science, College of Health Science, Yonsei University, Wonju 26493, Republic of Korea
3Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea
4Korea Drug Development Platform Using Radio-Isotope (KDePRI), Seoul 01812, Republic of Korea
5Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul 01812, Republic of Korea

Received 3 December 2015; Revised 4 February 2016; Accepted 7 February 2016

Academic Editor: Guang Jia

Copyright © 2016 A Ram Yu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose.124I has a half-life of 4.2 days, which makes it suitable for imaging over several days over its uptake and washout phases. However, it has a low positron branching ratio (23%), because of prompt gamma coincidence due to high-energy γ-photons (602 to 1,691 keV), which are emitted in cascade with positrons. Methods. In this study, we investigated the optimal PET energy window for 124I PET based on image characteristics of reconstructed PET. Image characteristics such as nonuniformities, recovery coefficients (RCs), and the spillover ratios (SORs) of 124I were measured as described in NEMA NU 4-2008 standards. Results. The maximum and minimum prompt gamma coincidence fraction (PGF) were 33% and 2% in 350~800 and 400~590 keV, respectively. The difference between best and worst uniformity in the various energy windows was less than 1%. The lowest SORs of 124I were obtained at 350~750 keV in nonradioactive water compartment. Conclusion. Optimal energy window should be determined based on image characteristics. Our developed correction method would be useful for the correction of high-energy prompt gamma photon in 124I PET. In terms of the image quality of 124I PET, our findings indicate that an energy window of 350~750 keV would be optimal.