Human: I've been told I need to get a colonoscopy. What is a colonoscopy? Assistant: 
A colonoscopy is a procedure that uses a flexible tube called a colonoscope to examine the inside of your colon. It is used to detect and remove polyps, which are growths in the colon that may become cancerous if left untreated. The colonoscopy is performed by an experienced doctor or nurse practitioner who will insert the colonoscope into your rectum. After the scope is inserted, it is slowly advanced through the rectum and into the colon. During the examination, the doctor can look at the lining of the colon, as well as any polyps or other abnormalities. The entire procedure usually takes about 30 minutes.