Colonoscopy is considered the gold standard for detection and removal of precancerous polyps in the colon. Being a difficult procedure to master, exposure to a large variety of patient and pathology scenarios is crucial for gastroenterologists' training. Currently, most training is done on patients under supervision of experienced gastroenterologists. Being able to undertake a majority of training on simulators would greatly reduce patient risk and discomfort. A next generation colonoscopy simulator is currently under development, which aims to address the shortfalls of existing simulators. The simulator consists of a computer simulation of the colonoscope camera view and a haptic device that allows insertion of an instrumented colonoscope to drive the simulation and provide force feedback to the user. The simulation combines physically accurate models of the colonoscope, colon and surrounding tissues and organs with photorealistic visualization. It also includes the capability to generate randomized case scenarios where complexity of the colon physiology, pathology and environmental factors, such as colon preparation, can be tailored to suit training requirements. The long term goal is to provide a metrics based training and skill evaluation system that is not only useful for trainee instruction but can be leveraged for skills maintenance and eventual certification.

Abstract-This paper describes the instrumentation of a clinical colonoscope needed for a novel colonoscopy simulation framework. The simulator consists of a compact and portable haptic interface and a virtual reality environment to provide real-time visualization. The proposed instrumentation enables tracking different functions of the colonoscope while keeping the ergonomic unchanged.

A series of experiments have been conducted to determine the flexural and torsional rigidity of an Olympus colonoscope CF-140S and torsional rigidity of a Pentax colonoscope EC-3870 and the dependency of these properties on temperature and on the presence of loops. Along the length of the colonoscope, the flexural rigidity of the Olympus colonoscope varied between 260 and 400 Ncm2 and the torsional rigidity varied between 68 and 88 Ncm2/deg, with an average of 76 Ncm2/deg for tests involving 0.86 Nm of anticlockwise torque. Results show a significant decrease of 10 per cent in torsional rigidity between clockwise and anticlockwise torque. For the Pentax colonoscope flexural rigidity was not tested; its torsional rigidity varied between 34 and 76 Ncm2/deg, with an average of 46 Ncm2/deg for tests involving 0.43 Nm of anticlockwise torque. An increase in temperature of the Olympus colonoscope from 24 to 37 °C reduced the flexural rigidity by an average of 17 per cent and torsional rigidity by an average of 7 per cent. A right-handed loop caused a significant increase in flexural rigidity, but other looping configurations had no significant influence.