The virtual colonoscopy (colon = large bowel) is an examination method which is performed for colorectal cancer screenings. Contrary to the conventional coloscopy (endoscopy) this is a CT-guided technique. The CT-generated images represent the colon interior – layer by layer. A special software then converts the images to virtual, three-dimensional colour images. The special technique of virtual colonoscopy is available at the following location of RUHRRADIOLOGIE: Our practice in Dortmund.