Quality control of radiochemical purity and safety of 99mTc-HDP and 99mTc-phytate adiopharmaceuticals labeling

Background: The use of various types of radioactive drugs has increased the usefulness of nuclear medicine. The efficiency of the labeling radioactive isotope Tc is crucial for the accuracy and reliability of an examination. We conducted a survey on the quality control (QC) of radioactive isotopes (RI) by measuring their purity. Materials and Methods: The QC (always or necessary) of radiopharmaceuticals was confirmed in 12 medical institutions in a metropolitan area. The radiochemical purity (RCP) of Tc-HDP and Tcphytate was determined based on the measured radionuclide purity of Tc containing Mo. In addition, the effect of time after labeling and time after elution was analyzed. Results: None of the 12 hospitals regularly performed QC, and five hospitals administered QC when necessary. The average of 30 measurements of the Mo content in Tc from three manufacturers was 0.0109 for A, 0.0121 for B, and 0.0114 for C. The average labeling efficiency was 96.02% for Tc-HDP and 94.97% for Tc-phytate after labeling. The labeling efficiency of Tc-HDP with different times after elution was 97.56%, 95.41%, 94.86%, 93.76%, and 91.89% after 0.5, 2, 4, 6, and 8 h, respectively, and that for Tc-phytate was 97.21%, 97.21%, 94.42%, 93.35%, and 89.91% after 0.5, 2, 4, 6, and 8 h, respectively. Conclusion: We analyzed the degree of maintenance needed for labeling efficiency. The degree of change should be provided to the clinical practitioner as basic data for the QC of the radiopharmaceutical.