I had heard a similar thing when I was in the hospital for a different test a couple of months ago; I overheard my technician and a nurse discussing it. All they said was that whatever the stuff was, it wasn't going to be available for a long time. Now that I think of it I remember my doctor mentioning something about it too; if memory serves correctly it might have had something to do with the FDA? I'm really not sure.. but in any case, there is truth to this - just wanted you to know.
If you are talking about a HIDA scan with ejection fraction, I had a similar problem. I have been having gallbladder-type symptoms on and off for about a year, with the symptoms being pretty much constant for the past month.
In the past month, I have had an ultrasound, a regular HIDA scan (no EF), a CT abdomen/pelvis with contrast, an EGD (scope down the throat), various bloodwork, etc., all of which came back negative for any gallbladder problems or stones. My last chance to see if something was wrong with the gallbladder was to have the HIDA with Ejection Fraction. This test would show gallbladder dysfunction with or without visible stones. However, my doctor also told me that the substance they use to do the EF is unavailable. (It's called kinevac, by the way, and it is a hormone--you may hear of it referred to as CCK--that your gallbladder secretes whenever you eat something fatty to aid in digestion). Anyway, I wanted this test and I wouldn't take no for an answer, because I wanted to get to the bottom of my problem. I called around to different local hospitals, and eventually found one that had the kinevac and could perform the test. I had that done last Thursday and it showed an abnormal EF of 22% (the low normal is anywhere from 30-35%). I am meeting with a surgeon tomorrow to discuss my options.
Anyway, sorry for the long post, just wanted to say that you should call around to different places that do Radiology scans and just see if they can do it. Some places may be out of the kinevac, but there may be one or two that still have it. By the way, a HIDA scan is a nuclear medicine scan. They do use a dye at first and take pictures for about an hour, then they inject the kinevac and take more pictures for 30 minutes--this is what calculates the ejection fraction.
Good luck!