Definition

A radiopharmaceutical agent comprised of LM3, a human somatostatin receptor (SSTR) antagonist, chelated with 1,4,7-triazacyclononane,1-glutaric acid-4,7 acetic acid (NODAGA) and radiolabeled with gallium Ga 68, that may be used as an imaging agent for SSTR-expressing tumor cells upon positron emission tomography (PET). Upon administration of gallium Ga 68 NODAGA-LM3, the LM3 moiety targets and binds to SSTRs that are present on the cell membranes of many types of neuroendocrine tumors (NETs). This allows for visualization of SSTR-positive cells upon PET imaging. SSTRs have been shown to be present in large numbers on NETs and their metastases, while most other normal tissues express low levels of SSTRs.