Technetium-99m Radiopharmaceutical Preparation Problems: 12 Years of Experience

Abstract

Objective: Chemical reactions involved in preparing ^99mTc radiopharmaceuticals occasionally result in products of substandard purity. A retrospective examination of preparation problems that occurred in the author’s institution was conducted to better define the incidence, recognize patterns and identify causes of substandard ^99mTc radiopharmaceutical products.

Methods: All ^99mTc radiopharmaceutical preparation and quality control testing records for the years 1986-1997 were reviewed, and preparation factors associated with substandard products were identified and examined.

Results: Fifty of 20,972 (0.2%) ^99mTc products had substandard radiochemical purity; none were administered to patients. Twenty-eight of the 50 substandard products (56%) involved macroaggregated albumin with the remainder divided among in vitro red blood cells, exametazime, disofenin, sestamibi, mertiatide and sulfur colloid. Thirty-three of the 50 (66%) involved ^99mTc-pertechnetate obtained as the first elution of a new generator and/or ^99mTc-pertechnetate more than 12 hr old. Several of the substandard products involved other preparation factors and/or human error.

Conclusion: The majority of substandard ^99mTc radiopharmaceutical products involved the use of ^99mTc-pertechnetate containing excessive amounts of ⁹⁹Tc and/or oxidizing impurities to prepare products containing relatively small amounts of stannous. Although substandard products are an infrequent occurrence, radiochemical purity testing should be performed routinely on all ^99mTc radiopharmaceuticals before patient administration.