No. III-08-003 

Contacts: Viktoria Mitlyng 630-829-9662 

 Prema Chandrathil 630-829-9663 

 February 5, 2008 

 E-Mail: opa3@nrc.gov 

Web site: www.nrc.gov

NRC ISSUES CONFIRMATORY ACTION LETTER AND SENDS SPECIAL 

INSPECTION TO MISSOURI COMPANY MANUFACTURING 

PRODUCTS FOR NUCLEAR MEDICINE 

 The Nuclear Regulatory Commission staff has issued a Confirmatory Action Letter to 

Mallinckrodt, Inc., a manufacturer of products used in nuclear medicine. The letter confirmed the 

company’s commitment to investigate a problem identified with its molybdenum-99/technetium99m generators used for diagnostic imaging. The company is located in Maryland Heights, Miss. 

 Technetium-99m is one of the most widely used isotopes for performing nuclear 

medicine diagnostic studies. Technetium-99m is delivered to nuclear pharmacies and hospitals in 

generators from which Technitium-99m can be extracted. Technetium-99m is produced from the 

radioactive decay of another nuclear isotope, molybdenum-99. The generators are designed to 

contain the molybdenum-99 while allowing the nuclear pharmacies and hospitals to withdraw the 

technetium-99m. NRC regulations require users to test the liquid the first time it is withdrawn 

from the generators to ensure that the liquid has acceptably low levels of molybdenum-99. 

 On Jan. 11, Mallinckrodt Inc. began receiving information from its customers that the 

liquid withdrawn from the generators showed higher levels of molybdenum-99. By Jan. 31, 

Mallinckrodt, Inc. had received information that more than 100 generators had higher levels of 

molybdenum-99 in the solution withdrawn from the generators. 

 The NRC learned on Jan. 24 of the increased levels of molybdenum-99 in the solution 

withdrawn from the generators produced by Mallinckrodt, Inc. The NRC initiated discussions 

with the company in order to understand the reasons for the increased levels of molybdenum-99 

and the actions the company was taking to address the issue and to prevent its recurrence. 

 On Feb. 1, the NRC issued a Confirmatory Action Letter to Mallinckrodt documenting 

the NRC’s understanding of the company’s commitments to address the event. 

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 In addition, the NRC dispatched a Special Inspection Team to evaluate the event, the 

company’s response to the event, the company’s past actions related to higher levels of 

moloybdenum-99 in solution withdrawn from the generators, and the company’s follow-up on 

commitments described in the Confirmatory Action Letter. 

 “We need to make sure we understand what caused the higher levels of molybdenum-99 

in the solution withdrawn from the generators and to evaluate the company’s response to the 

event,” said Mark Satorius, Deputy Regional Administrator for the NRC Region III Office. “We 

also need to gain confidence that this problem will not recur.” 

 Mallinckrodt has begun investigating the causes of the event. Based on preliminary 

investigation results, the company has taken actions to prevent a similar event. On Jan. 27, 

Mallinckrodt also began including a notification in all shipments to its generator customers 

regarding the presence of elevated levels of molybdenum-99 in solution withdrawn from some 

generators. 

 The special inspection will continue until the inspection goals are achieved. 

 The special inspection team will issue its report about 30-45 days after the completion of 

the inspection. The report will be available from the Region III Office of Public Affairs and in 

the agency=s online document library at: http://www.nrc.gov/reading-rm/adams/web-based.html. 

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