Abstract: Radioiodinated benzovesamicol analogs which selectively localize in presynaptic cholinergic neurons of the general formula: ##STR1## where X is selected from the group consisting of H, OH, NH.sub.2, NHCO-3-[I]-Ph, and a radioactive isotope of iodine, and Y is selected from the group of H and a radioactive isotope of iodine, Y being H is X contains iodine. Illustrative examples include: (.+-.)-trans-2-hydroxy-5-iodo-3-(4-phenylpiperidino)tetralin; (.+-.)-trans-3-hydroxy-5-iodo-2-(4-phenylpiperidino)tetralin; (.+-.)-trans-5-amino-2-hydroxy-8-iodo-3-(4-phenylpiperidino)tetralin; and (.+-.)-trans-2-hydroxy-5-(3-iodobenzamido)-3-(4-phenylpiperidino)tetralin. The novel radioiodinated benzovesamicol analogs may be used as radiopharmaceuticals to visualize cholinergic neurons with conventional imaging devices which are typically found in most nuclear medicine or radiology clinics.

Abstract: A novel compound, 4-amino-3-iodobenzylguanidine, in radioiodinated form is useful in radiopharmaceutical compositions in nuclear medicine as an imaging agent for the heart, adrenal medulla, and tumors of the adrenal medulla and can be used for treatment of tumors of the adrenal medulla. The radioactive compound can be readily made by reacting 4-aminobenzylguanidine and an N-chloro oxidant in the presence of a radioiodide.

Abstract: A new radiopharmaceutical composition for use in nuclear medicine comprises a radioiodinated meta-iodobenzylguanidine. The composition is used as an imaging agent for the heart, adrenal medulla, and tumors of the adrenal medulla and can be used for treatment of tumors of the adrenal medulla.