PT - JOURNAL ARTICLE AU - Douglas R. Smyth TI - Rapid Determination of the Radiochemical Purity of <sup>99m</sup>Tc-Antimony Trisulfide Colloid Prepared by Standard and Alternative Heating Methods DP - 2006 Sep 01 TA - Journal of Nuclear Medicine Technology PG - 174--178 VI - 34 IP - 3 4099 - http://tech.snmjournals.org/content/34/3/174.short 4100 - http://tech.snmjournals.org/content/34/3/174.full SO - J. Nucl. Med. Technol.2006 Sep 01; 34 AB - The purpose of this study was to validate a rapid quality control method for the lymphoscintigraphic tracer 99mTc-antimony trisulfide colloid (99mTc-ATC). Methods: ATC was labeled with 99mTc according to the manufacturer's instructions as well as by alternative heating conditions designed to provide a range of percentages of radiochemical purity (RCP): the tracer was prepared in a dry block heater with heating cavities of different sizes, the temperature of the heating block was varied from 70°C to 115°C, or the duration of heating was varied from 15 to 35 min. Anion-exchange minicolumns were trialled to separate any 99mTc-pertechnetate impurity from 99mTc-ATC with physiologic saline as the eluent. Quality control results were compared with the results from the manufacturer's recommended method, which uses an instant thin-layer chromatography (ITLC) strip with saline as the migrating solution. Results: The quality control results obtained with a cartridge method in 2−3 min compared favorably with those obtained with the ITLC method with saline when the tracer was prepared by heating at 115°C in a dry block heater for 35 min (RCPs, 99.4% ± 0.3% [mean ± SD] and 99.2% ± 0.3%, respectively; n = 25). The cartridge and ITLC quality control results also were in excellent agreement (correlation coefficient, 0.99) over a range of RCPs (80%–100%). An alternative anion-exchange cartridge that was tested in this study was not suitable for assaying the RCP of 99mTc-ATC because of the complete retention of 99mTc-pertechnetate on the sorbent. Conclusion: Compared with the established ITLC method, the cartridge quality control method tested in this study is rapid and provides a reliable assessment of the RCP of 99mTc-ATC. For the preparation of 99mTc-ATC, a dry block heater can be successfully substituted for a boiling water bath and is recommended for heating at high altitudes.