Journal of Nuclear Medicine Technology, Vol 26, Issue 4 262-264, Copyright © 1998 by Society of Nuclear Medicine
Technetium-99m radiopharmaceutical preparation problems: 12 years of experience
JA Ponto
Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City 52242, USA.
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.
