sentences:  The amount of time for this fast may vary, depending on the instructions given by the imaging facility and the area of the body to be scanned, but generally lasts for several hours prior to the scan.The patient generally skips one meal, along with abstaining from all liquids, clear or otherwise, during this time.Consumption of the barium sulfate suspension begins 90 minutes to two hours prior to the CT/Fluoroscopic scan, as instructed in the patient education provided.