It is a procedure that views the interior lining of the large intestine.

This is the best screening technique for detecting polyps which can cause cancer.

While it is the most accurate screening procedure available it has major downfalls.

This technique involves the insertion of a flexible tube, called a colonoscope, through the anus and gently advanced until the end of the colon is reached.  

There is a miniature camera attached to the end of the scope which allows the radiologist to see if any polyps are present.

The patient must undergo bowel preparation to clean out the colon before having this procedure.

Air is also gently pumped into colon to provide a better view.

This procedure is an heavily medicated as patients need to be sedated for this procedure. There is also a risk of complications if the bowel is perforated.