My son (12 years) had the HIDA scan done two weeks ago. Nothing to eat or drink after midnight the night before, they started an IV and injected the dye and he had to wait 20 minutes, then he was under the scan for about 45 minutes and I got to be in the room. We seen the results of his gall bladder right away and all was fine with him. Laying there and not moving is the hard part but she can sure take a nap if she wants. Good luck