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Investigators at the University of Michigan Medical School, Ann Arbor, have developed a radiopharmaceutical agent that permits the identification of pheochromocytomas—hypertension-causing tumors of the sympathetic autonomic nervous system—by scintigraphy. The drug,131I-metaiodobenzylguanadine (131I-MIBG), is structurally similar to the neurotransmitter norepinephrine and follows its pathway to the sympathetic nerves, according to James C. Sisson, MD, professor of internal medicine.
"The drug is avidly taken up by sympathetic nervous tissue," Sisson said, but in greater concentrations by the tumors than by small nerves or the adrenal glands. Thus, "we see no normal tissues; we look only at pheochromocytomas."
Using131I-MIBG and scintigraphy, Sisson and co-workers located the vascular tumors in all but three of 40 patients with difficult-to-locate lesions. In comparison, computed tomography (CT) successfully located tumors in fewer than half of the same group, Sisson said at a recent American Cancer Society seminar.
Most pheochromocytomas are located in
Bolsen B. Norepinephrine analog detects pheochromocytoma. JAMA. 1982;247(17):2341. doi:10.1001/jama.1982.03320420013008