Non-radiological technique for 3D imaging of intestinal endoscopes: computerised graphical 3D representation of endoscope and skeleton.

Colorectal cancer is a common malignancy but as yet there is no agreement regarding the optimal method for screening. Colonoscopy is theoretically the investigation of choice. The examination can, however, be difficult to perform and the average trainee requires at least 200 supervised examinations to become proficient. Colonoscopy takes on average about half an hour per patient and sedation is normally required because of painful instrument looping. The authors previously developed a non-radiological method of visualising the path of the endoscope using magnetic drive coils under the patient and a chain of sensors in the biopsy channel of the instrument. The computer-generated grey-scale images produced in real time were deemed unsatisfactory and the anatomical markers confusing. A new computer graphics system is described in which a much more realistic endoscope and, if necessary, skeleton can be produced. The wire-frame octagonal representation should help in the detailed analysis of colonoscopy using existing endoscopes and aid in future computer design and testing of novel instruments incorporating worm or snake-like properties.