Measurement of Radionuclidic purity and Chemical purity in Free Tc99m Pertechnetate

Abstract

The safety of Tc99m and Tc99m radiopharmaceuticals compound depends mainly on radionuclidic and chemical purity of Tc99m pertechnetate. The radionuclidic impurities increase the patient’s overall radiation dose and impact the image quality while the chemical impurities may cause toxic or undesirable interactions. The main objectives of this study were to determine the radionuclidic purity (Mo99 impurity) and chemical purity (Al+3 impurities) of Tc99m pertechnetate before reconstitution with pharmaceuticals kits. The radionuclidic Mo99 impurity was determined by the use of dose calibrator and 6-mm thick lead cylinder. The chemical Al+3 impurities were determined by comparing the intensity of Tc99m pertechnetate spot to intensity of standard aluminum spot on aluminum indicator paper. 51 Samples of Tc99m elutions were taken from three different radiopharmacy units (Khartoum Oncology Centre, Alneelain Medical Diagnostic Centre and Royal Care Hospital) and form different type of generators (POLATOM, MON.TEK MONOROL and Mallinckrodt pharmaceuticals). Samples were tested for Mo99 impurity and all the samples were in the acceptable limit. The mean radionuclidic purity resulted was 0.0026% with STD 0.0018 for all samples. 41 Spot samples of Tc99m elutions were taken from three different radiopharmacy units (Khartoum Oncology Centre, Alneelain Medical Diagnostic Centre and Royal Care Hospital) and form different type of generators (POLATOM, MON.TEK MONOROL and Mallinckrodt pharmaceuticals). Samples were tested for Al+3 impurity and all the samples were in the acceptable limit. It is recommended to assay each Tc99m pertechnetate elution for Mo99 impurity and Al+3 impurities prior to the administration of Tc99m and Tc99m radiopharmaceuticals patients.