Stability of fractionated technetium-cold pyrophosphate solution
The cold solution of a pyrophosphate kit was prepared and dispensed into 2-ml fractions which were stored at -20 degrees C for one week. The solution was prepared by using two protection methods. The first was nitrogen purging to exclude air and the second one the addition of the well known antioxydant ascorbic acid. The aim was to determine the stability of Tc-99m(Sn)-PyP obtained by labeling these fractions prepared under the given experimental conditions. The content of Tc-99m-pertechnetate in the unprotected samples raises with time. Nitrogen purging provides some protection but already after a few days the content of pertechnetate exceeds 5%. The addition of ascorbic acid gave good results. The content of pertechnetate was 1-2% after seven days in the presence of 50 mu g of acid per mi of the cold kit.