Radioiodinated meta-iodobenzylguanidine (MIBG) is used in the diagnosis and therapy of various neuroendocrine tumors. To investigate whether an additional guanidine function in the structure of MIBG will yield analogues that may potentially enhance tumor-to-target ratios, two derivatives—one with a guanidine moiety and another with a guanidinomethyl group at the 4-position of MIBG—were prepared. In the absence of any uptake-1 inhibiting ...
