CT scanning usually does not require any special preparation. Remove jewelry in the area being scanned. If you are a woman and there is any chance that you may be pregnant, tell your doctor before your scan.
You may need to drink a liquid dye to make organs or blood vessels stand out more clearly on the CT scan. Sometimes, this dye, called a "contrast medium," is injected into your vein. Tell your doctor if you have ever had an allergic reaction to this sort of dye or if you have any allergies to medicines. If you take a diabetes medication called metformin (Glucophage), ask your doctor if you should stop taking it 48 hours before your test, because it may interact with the contrast dye.