Technetium.-99m Glucoheptonate as a

Brain-Scanning Agent The evolution of brain scanning has seen a number of advancements in both radiopharmaceuticals and instrumentation. Mercury-203 or l97-labeled-chlormerodrin provided a significant increase in sensitivity over 1-131-labeled serum albumin; however, after the introduction of Tc-99m by Harper et al (1) the use of the mercury compounds decreased. Witcofsky, in a comprehensive study of brain scanning using Tc04 (2), found an 81.5 % sensitivity rate for proven neoplasms of the central nervous system. This study was performed in the mid-l960's and relied upon instrumentation in use at that time. Technetium-99m diethylenetriaminepenta-acetic acid (Tc-DTPA) has been advocated as a superior brain scanning agent when compared with TcO4 (3), and Waxman et at have demonstrated the advantages of Tc-99m glucohepeonate (TcGH) over Tc04 as a brain scanning agent in both tumor and infarction (4). Based upon previous reports of glucoheptonate accumulation in acutely infarcted myocardium, Rollo et at postulated that the improved detection oflesions was due to a combination of increased binding to abnormal tissue and a rapid blood clearance of the agent (5@. In a comprehensive paper comparing TCGH to Tc04 and TcDTPA as effective brain scanning agents, Rollo et at concluded that TcGH was the radionuclide of choice for the detection of central nervou