Cryosurgery, an operative method that applies freezing to produce a specific response in tissue, is probable and may be used in treatment of tumor. Liquid nitrogen, argon gas are used as cryogen, but these cryogen are weak controlling agents in freezing rate and thawing rate. Destroying tumors by hyperthermia treatment is known, but there are few studies including hyperthermia condition after cryosurgery, therefore the aim was to produce freezing-thawing rate controllable cryosurgery system and to investigate the effect of cryosurgery-hyperthermia in mice livers. Cryosurgery system includes Peltier device and Stirling refrigerator, using 1 cycle method of rapid freezing and slow thawing. Hyperthermia was performed after cryosurgery and contact probe were in contact all the time during freezing, thawing and heating. 24 hours after operations mice livers were stained by Hematoxylin-Eosin and observed under optical microscope. The result showed measured temperatures of rapid freezing and slow thawing during operations. Stained tissue showed necrosis and injury was more serious in cryosurgery-hyperthermia group. This suggests the possibility of electrical temperature rate control during cryosurgery and the effect of hyperthermia treatment after cryosurgery would supply a more effective treatment system. This method may contribute to cryosurgery in the future.

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