Maybe it's a CT scan with contrast (iV infusion) to better highlight areas. I can't have it due to my kidneys, so I always have a non contrast CT scan. Some places, give you some barium swallow flavored drink too, to highlight the gastrointestinal area, which I had for an abdominal CT, and with my full body PET/CT scans. They always have eating, drinking restrictions before so e scans, usually nothing after midnight, so is best to find out before since they can send you home, especially with PET/CT scans.
Good luck.