Imaging tumor vasculature noninvasively with positron emission tomography and RGD peptides labeled with copper 64 using the bifunctonal chelates DOTA, oxo-DO3a. and PCTA.

Two novel bifunctional chelates, 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (PCTA) and 1-oxa-4,7,10-triazacyclododecane-4,7,10-triacetic acid (Oxo-DO3A), were found to radiolabel antibodies with copper 64 (64Cu) well for positron emission tomography (PET).

(68)Ga small peptide imaging: comparison of NOTA and PCTA.

In this study, a bifunctional version of the chelate PCTA was compared to the analogous NOTA derivative for peptide conjugation, (68)Ga radiolabeling, and small peptide imaging. Both p-SCN-Bn-PCTA and p-SCN-Bn-NOTA were conjugated to cyclo-RGDyK. The resulting conjugates, PCTA-RGD and NOTA-RGD, retained their affinity for the peptide target, the α(v)β(3) receptor.

RGD conjugates of the H2dedpa scaffold: synthesis, labeling and imaging with 68Ga.

Introduction: The rekindled interest in the (68)Ga generator as an attractive positron emission tomography generator system has led us and others to investigate novel chelate systems for (68)Ga. We have previously reported our findings with the acyclic, rapidly coordinating chelate H(2)dedpa and its model derivatives.

Methods: In this report, we describe the synthesis of the corresponding bifunctional chelate scaffolds (H(2)dp-bb-NCS and H(2)dp-N-NCS) as well as the radiolabeling properties, transferrin stability, binding to the target using in vitro cell models and in vivo behavior the corresponding conjugates with the α(v)β(3) targeting cyclic pentapeptide cRGDyK (monomeric H(2)RGD-1 and dimeric H(2)RGD-2).