Design and development of a new cryosurgical instrument utilizing the Peltier thermoelectric effect

Warts and some other dermatological conditions may be treated by the application of intense cold. This freezing has to be so severe as to form ice crystals which will rupture the cell membranes. The initial part of this project was to investigate the feasibility of using Peltier thermoelectric coolers (TECs) to cool down a suitable hand-held treatment tip to a temperature of approximately -50 degrees C. The results of these initial experiments showed how this could be accomplished and a prototype cryosurgical instrument, suitable for clinical trials, was designed and constructed. This new design is freestanding, self-contained and is operated from a standard 230 V mains supply. Unlike existing systems it does not use any disposable gases or liquids. A cryoprobe of this new design would allow reliable cryosurgery to be performed in a GP's treatment room where supplies of liquid nitrogen, nitrous oxide or carbon dioxide are not readily available. The design also has a built-in thermometer to measure the treatment tip temperature thus ensuring consistency in treatment. Clinical trials are being conducted at a number of GP practices to evaluate this new design.