Purpose of barium in scan?

Cyndi is having a scan this morning. This is not unusual as she has lung mets. What is unusual is that today she had to drink two bottles of barium before the scan time. We are wondering why, what would this show that the normal cat scan would not show?
Cyndi did not ask the Dr. as she did not find out about the barium until she went to pre-admit for the scan.
As all of you know, anytime something changes in treatment with a BC patient the red flags start waving. Cyndi's doctor appointment is not until Feb. 11 so everyone pray that these scans show more shrinkage at least, NED at best.
ron

I always had to drink barium for my ct scans. I believe it picks up tumors clearer. Only one time I can remember the dr ordered no barium and the tech was wondering why.

the purpose is contrast but now I'm a little confused in your case. I have only had the barium when having a ct of the abdomen. when having a ct of the lungs, it has been done with and without iodine.
el

Cyndi had the scan yesterday Feb 02. They did a neck down scan, so we suppose the doc just wanted to see everything better. Probably will not have full results until next onc. visit Feb.11.
Thanks for the answers.
ron