Compositions, methods of using and methods of making a cyclic peptide analog imaging agent that includes at least portions of a peptide or protein that binds specifically to the GLP-1 receptor (GLP-1R) and the cyclic analog has one or more conformational restrictions including, but not limited to, lactam bridges, disulfide bridges, hydrocarbon bridges, and their combinations, salts and derivatives thereof wherein the cyclic analog is more stable than a non-cyclic analog when incubated in the presence of enzymes that degrade GLP-1 and have an increased serum half-live, wherein the cyclic analog comprises at least a portion of a GLP-1 peptide or at least a portion of an Exendin peptide salts, derivatives or combinations thereof.
