PREPARATION AND CLINICAL-EVALUATION OF TC-99M DIMERCAPTOSUCCINIC ACIDFOR TUMOR SCINTIGRAPHY

We describe a simple method of pentavalent technetium-99m dimercaptosu ccinic acid [Tc-99m(V)-DMSA] preparation for the imaging of medullary carcinoma of the thyroid using commercially available kits. Tc-99m(V)- DMSA is available at high pH (approximately 7.5) by adding NaHCO3 solu tion in the presence of a small amout of reducing agent (SnCl2). On th e other hand, trivalent Tc-99m-DMSA [Tc-99m(III)-DMSA] can be obtained at low pH (below 3) in the presence of an excess amount of reducing a gent. In the clinical evaluation of a patient with a medullary carcino ma of the thyroid, only Tc-99m(V)-DMSA revealed an area of intense acc umulation.