Quantification aspects of patient studies with Fe-52 in positron emission tomography

Quantification accuracy in positron emission tomography (PET) using non-pur e positron emitters, such as Fe-52, may be influenced by gamma radiation em itted in the decay of these isotopes. High-energy positrons, emitted in the decay of the Fe-52-daughter Mn-52m, also affect the quantification accurac y. A specific problem of the Fe-52/Mn-52m decay chain in vivo is that the k inetics of iron and manganese are different, and that PET cannot discrimina te between the two nuclides. The effect of the decay properties of Fe-52/Mn -52m on the performance of PET was investigated using phantoms. Minor degra dation in PET performance was found for Fe-52/Mn-52m compared to the pure l ow-energy positron emitter F-18. A method is presented to obtain a correcti on factor for the Mn-52m radioactivity in blood. A model for correction of Mn-52m-radioactivity in organs, based on existing data on manganese kinetic s, is given. The presented corrections are discussed and illustrated in a p atient study. (C) 1999 Elsevier Science Ltd. All rights reserved.