The half life of technetium 99 is about 6 hours.  97% of all the stuff
is cleared from the mother in 5 half lives, or 30 hours.  However, there
is no need to wait until 97% is gone.  In 6 hours 50% will be out of the
mother's body, and even when the mother just received the technetium,
the blood levels are low and the amount that gets into the milk very
low.

It is complete hysteria to go through all that stuff.  I would say the
mother could nurse within about 4 or 6 hours, 12 if she wants to be
extra careful.  Babies get this isotope *all the time*.

Why does she need the test at all?  I'll bet she doesn't.  And I would
suggest she wait before going ahead with it.

Jack Newman, MD, FRCPC