ABSTRACT
A new radiopharmaceutical for liver scintigraphy has been prepared by reacting 169YbOCl with Na phytate under conditions which yield a labelling efficiency of more than 99% over a wide pH range. In rabbits the resultant colloidal preparation shows a rapid elimination from the blood and high initial uptake in liver. Subsequently about 90% of the liver activity is lost within 3 days, the remainder being eliminated more slowly. The radiopharmaceutical is non-toxic and has a shelf-life of about 3 months. Scintigrams obtained in patients with hepatomegaly suggest that this new agent gives better visualization of space occupying lesions of the liver than 99mTc-Sn colloid. The radiation dose to the patient from this agent is low and comparable with that from other radiopharmaceuticals used for liver scintigraphy.
Subject(s)
Liver/diagnostic imaging , Phytic Acid , Technetium Compounds , Tin Compounds , Ytterbium , Adult , Animals , Hepatomegaly/diagnostic imaging , Humans , Male , Rabbits , Radiation Dosage , Radionuclide Imaging , Technetium , Tin , Tissue DistributionABSTRACT
99mTc-Cu-EHDP has been prepared with high labelling yield applying for the first time the method of instantly formed cuprous ions in the mixture. A gel chromatography column scanning technique has been used to study the 99mTc fractions in the preparation. The study of the influence of pH-value on the amount of 99mTc-CU-EHDP fraction shows that pH 1.6 - 1.7 gave the best labelling results. The formation rate of 99mTc-Cu-EHDP complex with a high labelling yield was fast and achieved within a few mins. This suggests the reduction of 99mTc-pertechnetate to Tc (IV). The final preparation was found stable for at least 4 hrs after mixing the reactants with the 99mTc-eluate. Comparative biokinetic studies of 99mTc-Cu-EHDP and 99mTc-Sn-EHDP in rabbits and mice showed a high bone uptake and fast elimination of 99mTc-Cu-EHDP from the skeleton. No significant difference was found in the plasma protein binding of 99mTc-Cu-EHDP and 99mTc-Sn-EHDP in rats as assessed by the GCS-technique. Radionuclide imaging in rabbits, using a gamma camera, showed 99mTc-Cu-EHDP to be a good bone-imaging agent.
