The CT Scans I have had are for my back. The first one was terribly painful, had contrast thru IV and did not like next day, I was only in 30s then. The last couple I have had in last six years have been a lot easier. Went to work right after. As for ct scan of functioning and cancer, I did not have any reaction to the barium stuff or the cancer one. IT was realatively easy and went to work right after. I guess it depends on the clinic doing the procedure and what you are having done. If were me, that would not stop me from going to quilt show if I got to go. To be sure, I would rescedule till got back if you can wait and does not affect your doctor appointment.