Measurement of the secretion of technetium-99m hexamethylpropylene amine oxime into breast milk.

There are no published data for the activity of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) found in breast milk. The amount of radioactivity in breast milk following the administration of 500 MBq 99mTc-HMPAO for a brain perfusion study has been measured. The effective dose to the infant was calculated to be 0.26 mSv, so necessitating no interruption of breast feeding. Unbound 99mTc is readily secreted into breast milk and the effective dose will remain less than 1 mSv if the 99mTc-HMPAO labelling efficiency is >/=99% for the worse reported case, and could remain <1 mSv for the mean reported case for 99mTc-HMPAO labelling efficiencies down to 94%.