Here is something I found on the net. I hope this helps...
You will be injected intravenously with a small amount of a radioactive isotope. There is no reaction to this isotope. You will then lie on a table and the nuclear medicine camera will be above you. The camera tracks the isotope as it moves through your system. Scanning time is a minimum of one hour. The radiologist (the doctor who interprets the scan) may ask for additional views. This is completely normal and is requested to provide your physician with a more comprehensive report.
It sounds like just an injection - With the HIDA scan they put an IV in so they don't have to inject you twice if you have the CCK. ( I think )
Hope this helps! Good luck!