The present application discloses compositions and methods of use of 68Ga labeled molecules. Preferably, the 68Ga is attached to a peptide targetable construct and is used in a pretargeting technique with a bispecific antibody (bsAb). The bsAb comprises at least one binding site for a disease-associated antigen, such as a tumor-associated antigen, and at least one binding site for a hapten on the targetable construct. Exemplary haptens include In-DTPA and HSG. More preferably, the bsAb is administered about 24-30 hours before the targetable construct, and detection by PET imaging occurs about 1-2 hours after the targetable construct is administered. The methods and compositions are suitable for detection, diagnosis and/or imaging of various diseases, such as cancer or infectious disease.
