MIBG is synthesized as follows: A mixture of m-iodobenzylamine (I) hydrochloride and cyanamide (II) is stirred and heated at 100 C for 4h. The resulting m-iodobenzylguanidine is converted to the bicarbonate salt by treatment with aqueous potassium bicarbonate. Addition of dilute sulfuric acid gives the guanidine sulfate. To prepare the labeled compound, the unlabeled m-iodobenzylguanidinium sulfate is dissolved in water and treated with carrier-free Na[131]I. Refluxing for 72h and passage through Cellex D anion exchange cellulose gives [131]iodobenzylguanidine sulfate. Another more efficient method of carrying out the exchange-labeling step has been reported.

MIBG is synthesized as follows: A mixture of m-iodobenzylamine (I) hydrochloride and cyanamide (II) is stirred and heated at 100 C for 4h. The resulting m-iodobenzylguanidine is converted to the bicarbonate salt by treatment with aqueous potassium bicarbonate. Addition of dilute sulfuric acid gives the guanidine sulfate. To prepare the labeled compound, the unlabeled m-iodobenzylguanidinium sulfate is dissolved in water and treated with carrier-free Na[131]I. Refluxing for 72h and passage through Cellex D anion exchange cellulose gives [131]iodobenzylguanidine sulfate. Another more efficient method of carrying out the exchange-labeling step has been reported.

MIBG is synthesized as follows: A mixture of m-iodobenzylamine (I) hydrochloride and cyanamide (II) is stirred and heated at 100 C for 4h. The resulting m-iodobenzylguanidine is converted to the bicarbonate salt by treatment with aqueous potassium bicarbonate. Addition of dilute sulfuric acid gives the guanidine sulfate. To prepare the labeled compound, the unlabeled m-iodobenzylguanidinium sulfate is dissolved in water and treated with carrier-free Na[131]I. Refluxing for 72h and passage through Cellex D anion exchange cellulose gives [131]iodobenzylguanidine sulfate. Another more efficient method of carrying out the exchange-labeling step has been reported.