Big big hugs, you must be feeling quite anxious about all of this. The Medela Symphony seems to be the pick of breast pumps to gain maximum yield! Double pumping or pumping on one side whilst your baby feeds from the other also helps to yield maximum milk.

You should discard the milk you express for the 24 hours post the scan. The very reason that you can't feed your baby is that the milk will have traces of the medium in it. You could contact the nuclear medicine department and ask if there is another option or if you could delay the scan an extra couple of days so that you have enough milk...

Thinking of you - I too was faced with these decisiions and difficulties whilst pregnant and after Imogens birth. It is tough. Sending you big hugs...