Suggest Remedy For Recurring Diarrhea, Gas And Rumbling Stomach

I am experiencing diarrhea almost daily. Having lots of gas and rumbling stomach but no pain. No blood in stool. Once I take one antidiarrheal tablet, symptoms subside for a day or two but it starts all over again shortly thereafter. I know that I need to have a colonoscopy but I cannot find a way to clean the colon without major problems. I have a pacemaker and am 84 yr. old female, otherwise in fair health. Could you give me an idea about a CT scan and what it would provide to a doctor if I get it done? Thank you. My email address is: YYYY@YYYY .