A novel closed cycle cryosurgical system

Cryosurgery is a well established technique that can offer considerable advantages to the patient. To date cryosurgical instruments have predominantly employed either liquid cryogens or the J–T expansion of high-pressure gases in an open cycle. The handling of cryogens or high pressure gases in a surgical environment poses logistical problems. A two-stage vapour cycle cryosurgical system has been designed to use either R23 or R508B in the low temperature stage and R404A for pre-cooling. This paper reports the results of trials of the prototype using R23 in the low temperature stage. The cooling performance achieved equals that of existing, open cycle, cryosurgical systems.