Optimization of 99Mo measurement in 99mTc eluate samples using a scintillation detection system.

During elution of 99Mo-99mTc generators used in nuclear medicine, 99Mo might be extracted becoming a radionuclidic impurity. According to the International Atomic Energy Agency, the activity ratio between 99Mo and 99mTc in the eluate, at the moment of administration to the patient, should not exceed 0.015%. The aim of this work is to optimize a methodology to determine 99Mo activity in 99mTc eluates. Efficiency curves were obtained using a NaI(Tl)8"×4" scintillation detector. The methodology was validated by measuring a standard solution of 99Mo. It was concluded that the technique is sensitive to detect 99Mo in 99mTc eluates at levels below international limits.