I've just had another scan done today. I've already had one done at 20 weeks which was to check the heart and growth of the baby. That one was claimable to Medicare. As this scan was not nescessary I wasn't able to claim it. I think you can only claim a scan if there is something picked up that has to be followed up on later or if a problem develops with the baby.
The scan I had done was a 4D one for my own "amusement" so therefore is not claimable at all.