PET quantitation and imaging of the non-pure positronemitting iodine isotope 124I

A series of PET studies using phantoms is presented to characterize the imaging and quantitative performance of the positron-emitting iodine isotope I-124. Measurements were performed on the 2D-PET scanner GE 4096 + as well as on the Siemens PET scanner HR+ operated in both 2D and 3D modes. No specific correction was applied for the gamma-rays emitted together with the positrons. As compared to F-18, in studies with I-124 there is a small loss of image resolution and contrast, and an increase in background. The quantitative results varied between different scanners and various acquisition as well as reconstruction modes, with an average relative difference of -6 +/- 13% (mean+/-SD) in respect of the phantom radioactivity as measured with gamma-ray spectroscopy. We conclude that quantitation of a radiopharmaceutical labelled with I-124 is feasible and may be improved by the development of specific corrections. (C) 2002 Elsevier Science Ltd. All rights reserved.