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Targeting peptides and positron emission tomography
Author(s) -
Lundqvist Hans,
Tolmachev Vladimir
Publication year - 2002
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.10348
Subject(s) - positron emission tomography , chemistry , radionuclide therapy , nuclide , positron , peptide , nuclear medicine , radiochemistry , nuclear physics , physics , biochemistry , medicine , electron
Biologically active peptides have during the last decades made their way into conventional nuclear medicine diagnosis using single photon emission computed tomography (SPECT) and γ‐camera. Several clinical trails are also investigating the role of radiolabeled peptides for targeting radionuclide therapy. This has raised the question as to whether positron emission tomography (PET) can be used in order to obtain better quantitative information of the peptide distribution in tumor and healthy organs, i.e., to get a better dosimetry. Positron emitting analogs of the therapeutic radionuclides used have been produced and successfully applied in peptide pharmacokinetic measurements with PET. But the recent boom in 18 FDG‐PET ( 18 FDG = [ 18 F]2‐deoxy‐2‐fluoro‐D‐glucose), and with this a worldwide increasing number of PET systems, has also inspired several research groups to hunt for alternative labels to be used for peptide diagnostics and PET. The rapid kinetic of short peptides agrees well with the short half‐lives of standard PET nuclides like 11 C and 18 F. Especially, 18 F appears to be excellent for labeling bioactive peptides due to its favorable physical and nuclear characteristics. However, with present techniques labeling peptides with 18 F is laborious and time‐consuming, and is not yet a clinical alternative. Other halogens like 75, 76 Br and 124 I are, from the chemical point of view, easier to apply. But an even better labeling alternative may be positron emitting metal ions like 55 Co, 68 Ga, and 110m In since they tend to give better intracellular retention and thus a better signal‐to‐background ratio than the halogen labels. The main drawback with these radionuclides is that they are not readily available. Some of these radionuclides also emit γ in their decay that may affect the measuring properties of the PET equipment. This article reviews mainly the present situation of production and use of nonconventional positron emitters for peptide labeling. © 2003 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 66: 381–392, 2002