Saturday, December 12, 2009

Molybdenum Breakthrough

Molybdenum breakthrough refers to contamination of 99mtechnetium obtained by elution of a molybdenum-99 column. The 99mTc generated must be tested for molybdenum before administration to patients. The US Nuclear Regulatory Commission (NRC) allow no more than 0.15 μCi of 99Mo per 1 mCi of 99mTc at the time of administration. The last part is important. Because the half life of 99Mo is longer than that of 99mTc (66 hours vs 6 hours), if you let the eluate sit around, the relative concentration of 99Mo will rise, making it unusable.

Testing for molybdenum breakthrough is usually done by placing the eluate in a lead shield and using a commercial dose calibrator whose energy is set to that of 99Mo photons(740 keV and 780 keV).


Mettler FA and Guiberteau MJ. Chapter 3: Quality Control. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006. p 44.

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