CRYOSURGICAL PROBE HAVING INSULATING AND HEATED SHEATHS
A cryosurgical probe (6) and method for treating cancer by cryosurgically destroying cancer cells by way of an ice ball (10) formed at the distal end (8) of the cryosurgical probe (6) and located in proximity to the cancerous tissue to be treated. The probe (6) is surrounded by a thermally insulating sheath (12, 14, 16, 20). By varying the length and thickness of the thermally insulating sheath (12, 14, 16, 20) as well as the length of the unsheathed distal tip (8) of the probe, the size and shape of the ice ball produced by the cryosurgical probe (6) can be tailored to correspond to the size, shape and location of the cancerous tissue so as to localize the cryogenic effect. Alternatively, the size and shape of the ice ball can be controlled by surrounding a cryosurgical probe (30) with a heated sheath (32) having a heating element (34) and a temperature sensor (38) to detect the temperature to which the sheath (32) is heated.