title: Comparison of Imaging Characteristics of (124)I PET for Determination of Optimal Energy Window on the Siemens Inveon PET.
abstract: Purpose. (124)I 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 (124)I PET based on image characteristics of reconstructed PET. Image characteristics such as nonuniformities, recovery coefficients (RCs), and the spillover ratios (SORs) of (124)I 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 (124)I 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 (124)I PET. In terms of the image quality of (124)I PET, our findings indicate that an energy window of 350~750 keV would be optimal.
authors.affiliation: Laboratory Animal Center, OSONG Medical Innovation Foundation, Osong, Chungbuk 28160, Republic of Korea.
authors.forename: A Ram
authors.initials: AR
authors.lastname: Yu
authors.affiliation: Department of Radiological Science, College of Health Science, Yonsei University, Wonju 26493, Republic of Korea.
authors.forename: Hee-Joung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea.
authors.forename: Sang Moo
authors.initials: SM
authors.lastname: Lim
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea; Korea Drug Development Platform Using Radio-Isotope (KDePRI), Seoul 01812, Republic of Korea; Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul 01812, Republic of Korea.
authors.forename: Jin Su
authors.initials: JS
authors.lastname: Kim
mesh_terms: D003287:Contrast Media / Q000737:chemistry* / Q000627:therapeutic use; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D007457:Iodine Radioisotopes / Q000737:chemistry* / Q000627:therapeutic use; D008962:Models, Theoretical; D017785:Photons; D049268:Positron-Emission Tomography / Q000379:methods*
chemical_list: D003287:Contrast Media; D007457:Iodine Radioisotopes