Abdomen/Pelvis CT scan

I had an appointment with Dr. Summa this PM to discuss my weakness and lack of appetite. After checking vitals, discussion and his listening to my stomach area, he decided to do an Abdomen/Pelvis CT scan tomorrow morning at 10:00am at the Clinic. My preparation for the scan begins this evening when I drink half a 450ml bottle of (barium sulfate). I'm not to eat anything after that and then drink the 2nd full bottle 1 hour before examination time. I am to drink water up to appointment time and can take my morning pills. I understand that this barium sulfate will provide the Contrast in the CT scan.