Abstract: A method of cooling a material including the steps of (i) providing a cryotherapy instrument, (ii) positioning a portion of the cryotherapy instrument adjacent the material to be cooled, and (iii) circulating a cryogenic fluid through the cryotherapy instrument under physical conditions near a critical point of a liquid-vapor system for the cryogenic fluid. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas, whereby vapor lock associated with cooling of the cryotherapy instrument is avoided.

Abstract: A method of cooling a material including the steps of (i) providing a cryotherapy instrument, (ii) positioning a portion of the cryotherapy instrument adjacent the material to be cooled, and (iii) circulating a cryogenic fluid through the cryotherapy instrument under physical conditions near a critical point of a liquid-vapor system for the cryogenic fluid. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas, whereby vapor lock associated with cooling of the cryotherapy instrument is avoided.

Abstract: A device for freezing body tissue, the device having a main driving system capable of generating nitrogen under physical conditions near a critical point of a liquid-vapor system for the nitrogen. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas and the physical conditions include a pressure of about 33.5 atm.

Abstract: A device for freezing body tissue, the device having a main driving system capable of generating nitrogen under physical conditions near a critical point of a liquid-vapor system for the nitrogen. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas and the physical conditions include a pressure of about 33.5 atm.

Abstract: A method of cooling a material including the steps of (i) providing a cryotherapy instrument, (ii) positioning a portion of the cryotherapy instrument adjacent the material to be cooled, and (iii) circulating a cryogenic fluid through the cryotherapy instrument under physical conditions near a critical point of a liquid-vapor system for the cryogenic fluid. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas, whereby vapor lock associated with cooling of the cryotherapy instrument is avoided.

Abstract: A method of cooling a material including the steps of (i) providing a cryotherapy instrument, (ii) positioning a portion of the cryotherapy instrument adjacent the material to be cooled, and (iii) circulating a cryogenic fluid through the cryotherapy instrument under physical conditions near a critical point of a liquid-vapor system for the cryogenic fluid. The critical point defines a point in a phase diagram of the liquid-vapor system where molar volumes are substantially equivalent for liquid and gas, whereby vapor lock associated with cooling of the cryotherapy instrument is avoided.

Abstract: A gas-based cryotherapy probe is provided with a shaft having a closed distal end adapted for insertion into a body. A supply conduit is disposed longitudinally within the shaft for flowing gas towards the distal end, and a return conduit is disposed longitudinally within the shaft for flowing gas from the distal end. The gas is maintained at a lower pressure within the return conduit than in the supply conduit. A heat exchanger is disposed within the shaft in thermal communication with the supply conduit and return conduit to exchange heat from gas in the supply conduit to gas in the return conduit. A vacuum jacket is adapted to provide thermal isolation of the heat exchanger from the shaft.

Abstract: A gas-based cryotherapy probe is provided with a shaft having a closed distal end adapted for insertion into a body. A supply conduit is disposed longitudinally within the shaft for flowing gas towards the distal end, and a return conduit is disposed longitudinally within the shaft for flowing gas from the distal end. The gas is maintained at a lower pressure within the return conduit than in the supply conduit. A heat exchanger is disposed within the shaft in thermal communication with the supply conduit and return conduit to exchange heat from gas in the supply conduit to gas in the return conduit. A vacuum jacket is adapted to provide thermal isolation of the heat exchanger from the shaft.

Abstract: A gas-based cryotherapy probe is provided with a shaft having a closed distal end adapted for insertion into a body. A supply conduit is disposed longitudinally within the shaft for flowing gas towards the distal end, and a return conduit is disposed longitudinally within the shaft for flowing gas from the distal end. The gas is maintained at a lower pressure within the return conduit than in the supply conduit. A heat exchanger is disposed within the shaft in thermal communication with the supply conduit and return conduit to exchange heat from gas in the supply conduit to gas in the return conduit. A vacuum jacket is adapted to provide thermal isolation of the heat exchanger from the shaft.