DEVELOPMENT OF ~(99m)TC-ECD AS A NEW BRAIN IMAGING AGENT Ⅱ. KINETICS OF LIGAND EXCHANGE, STABILITY AND CLINICAL EVALUATION

The kinetics of the ligand exchange between ~(99m)Tc-GH and ECD was evaluated.The ligand exchange reaction is a second order reaction.The rate constant of the ligand exchange reaction was determined.The stability of ~(99m)Tc-ECD is quite well.The radiochemical purity of ~(99m)Tc-ECD is greater than 98% within 6 hours at 50℃.More than 30 volunteers were injected (74-111) ×10~7Bq of ~(99m)Tc-ECD, the brain uptake was 4.7% (I.D.) at 5minutes postinjection.