Kinetic analysis of99mTc-d, 1-HMPAO decomposition and the method of stabilization

The kinetics of99mTc-d, 1-HMPAO decomposition is studied using home kits. The results showed that99mTc-d, 1-HMPAO decomposition is a first-order reaction. The decomposition constant k is found to be 0.017±0.007h−1 under the experimental conditions of 20°C, 185MBq/ml, pH 7.0. The stability of99mTc-d, 1-HMPAO is affected not only by pH and radioactive concentration, but also by temperature. Using Immol/l gentisic acid as a stabilizer, 740MBq/ml of99mTc-d, 1-HMPAO can be stabilized for 3h with the radiochemical purity above 80%.