Abstract: A cryosurgical system and method for supplying cryogen to a probe. The system including a container filled with cryogen and having bellows of a pump submerged within said cryogen. Conduits fluidly interconnect the bellows and a probe that is outside the container to permit the cryogen to be forced from the bellows to the probe upon activation of pump. A pressure relief valve is fluidly coupled to the conduits and positioned between the bellows and the probe. After initially forcing cryogen to the probe at a pressure that establishes a colligative-based sub-cooling of the liquid cryogen, the pressure relief valve is activated to lower the pressure of the cryogen to a running pressure.

Abstract: Devices and methods for performing cryo therapy, cryo ablation or cryoplasty. A cryo therapy apparatus may comprise an elongate shaft, a cooling member disposed at the distal end of the shaft, and a pressure gauge coupled to the cooling member.

Abstract: The detachable cryosurgical probe includes a disposable probe assembly and a reusable probe assembly. The disposable probe assembly includes a breakaway collar which, when twisted away, activates a finger lock element which provides release of the disposable probe assembly from the reusable probe assembly. Additional features include a safety valve assembly for impeding cryogenic working fluid flow when the disposable probe assembly is detached from the reusable probe assembly and an electrical confirmation assembly for providing electrical confirmation that the disposable probe assembly is connected. Other embodiments include a sliding mechanism that allows for selectively positioning of the vacuum tube relative to the shaft to create an ice ball of the desired size and configuration.

Abstract: The present invention pertains to devices for causing cold-induced necrosis or apoptosis. The present invention includes a cryo therapy apparatus including a core member; a cryoplasty tube coupled to the core member, the cryoplasty tube having a proximal end and a distal end; wherein the distal end includes a coil disposed about at least a portion of the tubular sheath, the coil including at least one opening; an outer tube disposed over at least a portion of the cryoplasty tube; and a cooling member disposed over the coil and coupled to the outer tube. A method of causing cold-induced necrosis is also disclosed.

Abstract: A system for detecting leaks and occlusions in a cryoablation catheter requires monitoring pressure in the catheter at the end of two predetermined time intervals. The catheter includes a catheter tube, a cryo-chamber at the distal end of the catheter, and a supply line for introducing fluid refrigerant into the cryo-chamber. Also included is a pressure sensor mounted in the cryo-chamber for measuring a tip pressure. During the first time interval, fluid refrigerant is prevented from flowing through the catheter while the catheter is evacuated by a vacuum pump. The tip pressure is then measured to detect leaks. During the second time interval, fluid refrigerant is introduced into the cryo-chamber while evacuation continues, and the tip pressure is measured to detect occlusions.

Abstract: A cryosurgical probe system includes a fluid supply line connectable at an inlet section to a source of cryogenic fluid; a fluid connector assembly securely connected to an outlet section of the fluid supply line for receiving fluid from the outlet section of the fluid supply line; and, a detachable cryosurgical probe detachably connectable to the fluid connector assembly. The cryosurgical probe system includes the capability of providing return fluid flow.

Abstract: Low temperature lesion formation apparatus, systems and methods. The apparatus includes a base member and an inflatable element carried by the base member.

Abstract: A cryoablation device having a pressure monitoring system includes an elongated catheter tube that has a central lumen and is formed with a closed distal end. The distal end of a refrigerant supply line is positioned in the central lumen and distanced from the catheter tube's distal end to establish an expansion chamber therebetween. A return line, which can be established between the supply line and the catheter tube or can include a return tube, is provided to exhaust expanded refrigerant from the chamber. First and second pressure sensors are respectively positioned in the supply line upstream from the expansion chamber and in the return line. Typically, both sensors are positioned to remain at extracorporeal locations throughout a cryoablation procedure. Measured pressures are used together with the supply and return line dimensions to analytically estimate the chamber pressure and allow the expansion of refrigerant in the chamber to be monitored.

Abstract: A cryosurgery apparatus is disclosed. The cryosurgery apparatus an introducer having a hollow and a distal portion, the distal portion being sufficiently sharp so as to penetrate into a body, the hollow of the introducer being designed and constructed for containing a plurality of cryoprobes each of the cryoprobes being for effecting cryoablation, such that each of the plurality of cryoprobes is deployable through the distal portion of the introducer when the distal portion is positioned with respect to a tissue to be cryoablated.

Abstract: A cryosurgical system adapted for treatment of fibroadenomas within the breast of a patient. The system includes cryoprobes and a control system which operates the cryoprobes to accomplish freezing in two stages, including a high power freeze and a low power freeze.

Abstract: A device for cryoablating exposed tissue having a contoured contact surface includes a tube-shaped shaft and a flexible, thermally conductive enclosure that is attached to the distal end of the tube-shaped shaft. The enclosure is formed with a wall having an outer surface for contacting the target tissue and an inner surface which establishes and surrounds a cryochamber. A shapeable element is attached to the distal end of the shaft and extends into the cryochamber. The element can be permanently deformed into a pre-selected shape to cause a portion of the enclosure wall to conform to the contour of the target tissue. A high-pressure tube in the shaft passes a refrigerant through the shaft for expansion into the cryochamber. This expansion cools the wall of the enclosure, which in turn, extracts heat from the target tissue resulting in the cryoablation of the target tissue.

Abstract: A device and method for providing body cooling. The cooling device applies cooling to blood flowing in a vena cavae that is then distributed throughout the body. The cooling can be assisted by use of thermoregulatory drugs or warming devices to prevent shivering and vasoconstriction.

Abstract: A catheter includes a cryoablation tip with an electrically-driven ablation assembly for heating tissue. The cryoablation tip may be implemented with a cooling chamber through which a controllably injected coolant circulates to lower the tip temperature, and having an RF electrode at its distal end. The RF electrode may be operated to warm cryogenically-cooled tissue, or the coolant may be controlled to conductively cool the tissue in coordination with an RF treatment regimen, allowing greater versatility of operation and enhancing the lesion size, speed or placement of multi-lesion treatment or single lesion re-treatment cycles. In one embodiment a microwave energy source operates at a frequency to extend beyond the thermal conduction depth, or to penetrate the cryogenic ice ball and be absorbed in tissue beyond an ice boundary, thus extending the depth and/or width of a single treatment locus.

Abstract: Systems and methods for assessing the formation of an ice ball during a cryoablation procedure are disclosed. The system includes a reference electrode that is placed in contact with the patient and a cryocatheter having a cryotip. An electronic circuit is connected to both the cryotip and the reference electrode to measure the impedance therebetween which can be used to assess the formation of an ice ball during a cryoablation procedure. An exemplary measurement signal has a frequency of approximately 20 khz and an RMS voltage of approximately 0.5V. With the cryotip positioned proximate the target tissue, a reference impedance is measured. Next, the conductive tip member is placed in contact with the target tissue and cooled to form an ice ball. During cooling, impedance measurement(s) are taken and compared with the reference impedance to assess the formation of the ice ball.

Abstract: The invention relates to an insertion probe for sensing distributed temperature comprising a tube containing at least one optical fiber being inscribed with at least one Bragg grating, the tube being sealed at its distal end. The probe is characterized in that it consists of materials having low magnetic susceptibility. The invention also relates to the use of such a probe in cryosurgery to allow the use of magnetic resonance imaging.

Abstract: Disclosed is a skin cooling device which utilizes the sensory ability of the skin as an integumentary sense organ so that it is applicable to medical treatments and surgical operations, while being configured to use the heat absorbing effect of a thermoelectric element while having a small size to be easily handled. The skin cooling device includes a case having a size allowing the user to grasp the case by the hand, and a thermoelectric element installed in the case. The thermoelectric element has a heat emitting portion and a heat absorbing portion. The skin cooling device also includes a heat sink unit provided at the heat emitting portion of the thermoelectric element, and cold heat transfer unit provided at the heat absorbing portion of the thermoelectric element, and adapted to locally transfer cold heat from the thermoelectric element to the skin. Thus, the cold heat can be locally applied to the skin.

Abstract: A cryoplasty catheter and method for preventing or slowing reclosure of a lesion following angioplasty. The cryoplasty catheter includes a shaft having proximal and distal ends and a dilatation balloon disposed at the distal end. An intake lumen and exhaust lumen are defined by the shaft to deliver coolant to the balloon and to exhaust or drain coolant from the balloon. The method in accordance with the present invention includes cooling a lesion to aid in remodeling the lesion through dilatation and/or freezing a portion of the lesion adjacent the dilatation balloon to kill cells within the lesion to prevent or retard restenosis.

Abstract: A catheter-based system for performing a cryoablation procedure uses a precooler to lower the temperature of a fluid refrigerant to a sub-cool temperature (?40° C.) at a working pressure (400 psi). The sub-cooled fluid is then introduced into a supply line of the catheter. Upon outflow of the primary fluid from the supply line, and into a tip section of the catheter, the fluid refrigerant boils at an outflow pressure of approximately one atmosphere, at a temperature of about ?88° C. In operation, the working pressure is computer controlled to obtain an appropriate outflow pressure for the coldest possible temperature in the tip section.

Abstract: An enhanced method and device are provided to treat atrial fibrillation or inhibit or reduce restenosis following angioplasty or stent placement. A balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium. In another embodiment, blood perfusion is performed simultaneously.

Abstract: A method of cooling an operative surface of a cryoablation device, comprises the steps of providing a primary refrigerant under pressure and pre-cooling the primary refrigerant to a temperature below a critical temperature thereof using a non-charging refrigeration system to liquify the refrigerant in combination with the steps of expanding the pre-cooled primary refrigerant in proximity to an operative surface of the cryoablation device and removing the expanded primary refrigerant from the proximity of the operative surface.

Abstract: Devices and methods for performing cryo therapy, cryo ablation or cryoplasty. A cryo therapy apparatus may comprise an elongate shaft, a cooling member disposed at the distal end of the shaft, and a pressure gauge coupled to the cooling member.

Abstract: A mechanism and method for steering a surgical instrument inserted into an endoscope such as a ureteroscope, nephroscope, or cystoscope, and/or for steering the endoscope, utilizes a shape memory structure secured to the surgical instrument or to the endoscope, the shape memory structure having a transformation temperature slightly greater than that of the human body so that bending of the shape memory structure, and therefore of the surgical instrument or endoscope, may be carried out by raising a temperature of irrigation fluid in the working channel. The steering mechanism may be used as a supplement to a tensioned-wire steering mechanism, reducing stress on the endoscope shaft and extending the service life and repair interval of the endoscope. In addition, when the surgical instrument is a glass optical fiber, the steering mechanism may be used to ensure that a tip of the optical fiber is within the field-of-view of fiber optics incorporated into the endoscope.

Abstract: A self-contained cryotherapy apparatus adapted to be operated with one hand, using flashing temperature of a cartridge liquefied gas (CO2) sprayed in partly solid phase onto the epidermis. The cartridge support and the ejection and expansion system are aligned therewith and in the axis thereof, inside a housing whereof the median part acts as handle to be grasped by the adult user's hand, whereof the upper part includes an input for inserting the cartridge with its head down and into the housing axis and striking it or for removing it after use, and whereof the lower part includes a calibrated opening forming a passage for the sprayed gas substantially in the housing axis and elements for controlling its effect on the epidermis.

Abstract: This invention relates to the field of medical instruments and particularly to an apparatus used to apply cryotherapy to an injury. The apparatus is comprised of a vessel, a driver, and a directional controller. The vessel is configured such that when it is filled with a liquid and refrigerated, the resultant frozen solid formed within the vessel can be extruded via an exiting aperture. The driver forms a watertight seal with the vessel, allowing the vessel to be filled with liquid and frozen. The directional controller comprises flexible tabs that exert pressure on the sides of the frozen solid, limiting the movement of the frozen solid to one-way extrusion. The user applies force to the driver, thereby urging the frozen solid past the directional controller and out via the exit aperture.

Abstract: A laser energy delivery device and method are provided for irradiating a body tissue with relatively long wavelength laser energy in the presence of an aqueous liquid without significant absorption of the laser energy by the liquid. The device includes an elongate hollow sheath that is open at its distal end and closed at its proximal end, a laser energy conduit such as an optical fiber or hollow waveguide, within the sheath, the distal end of the conduit being disposed near the open distal end of the sheath, and the proximal end of the conduit being adapted for connection to a source of long wavelength laser energy. The sheath also includes an inlet port, spaced from the proximal end of the sheath, and adapted to receive and deliver a biologically compatible gas through the sheath to a body tissue site in contact with the open distal end of the sheath.

Abstract: A scanning optical system for delivering electromagnetic radiation onto tissue to be treated is cooperative with a lightguide or optical fiber. Radiation to be delivered is provided by a source thereof via the optical fiber. The optical system includes an optical projection arrangement comprising a plurality of lenses cooperatively arranged with the lightguide. A first of the lenses is arranged to receive radiation emerging from the lightguide. The beam of radiation is passed through the projection arrangement to form a treatment spot the radiation on the tissue. Scanning is effected by causing relative motion between the exit-end of said lightguide and at least the first lens, transverse to the optical axis of the projection arrangement. The treatment spot undergoes a related transverse motion over the tissue. In one example scanning is effected by moving the first lens with the lightguide fixed. The first lens is moved using an arrangement of piezo-electric actuators.

Abstract: The malleable cryosurgical probe includes a cryostat assembly and a cryoprobe assembly. The cryostat assembly includes an elongated shaft assembly having at least one malleable segment thereof and a closed distal end. The shaft assembly includes at least one freezing portion, at least one thermally insulated portion and a thermally insulating element positioned about the thermally insulated portion. A cryostat is operably associated with the elongated shaft assembly. It includes a cryostat inlet for receiving gas entering the cryostat, a cryostat outlet and a heat exchanger positioned between the cryostat outlet and the cryostat inlet. The heat exchanger receives gas from the cryostat inlet and provides heat transfer between gas flowing within the cryostat and fluid exterior thereto. At least one Joule-Thomson nozzle is in fluid communication with the cryostat outlet. The at least one Joule-Thomson nozzle expands gas expelled therefrom.

Abstract: The present invention pertains to devices for causing cold-induced necrosis or apoptosis. The present invention includes a cryo therapy apparatus including a core member; a cryoplasty tube coupled to the core member, the cryoplasty tube having a proximal end and a distal end; wherein the distal end includes a coil disposed about at least a portion of the tubular sheath, the coil including at least one opening; an outer tube disposed over at least a portion of the cryoplasty tube; and a cooling member disposed over the coil and coupled to the outer tube. A method of causing cold-induced necrosis is also disclosed.

Abstract: A cryosurgical system including a housing having a front portion and a rear portion. The front portion and rear portion are connectable to support a fluid supply. A control unit attached to the front portion, and has a regulator assembly connecting the fluid supply to the control unit. A medical device is connected to the control unit, the medical device including a handle, a shaft, and a thermally-transmissive region. The handle, the shaft, and the thermally-transmissive region defining a fluid pathway through the handle, shaft, and thermally-transmissive region. The shaft is malleable to retain a first shape until manipulated to a second shape.

Abstract: Post-angioplasty hyperplasia in blood vessels is treated using a cryosurgical balloon catheter. The balloon catheter is positioned at a target region within the blood vessel, and the balloon inflated by expanding a cryogenic fluid, such as liquid nitrogen, across an expansion orifice into a balloon. The balloon will be constructed so that cooling is achieved primarily in the central regions of the balloon, with the proximal and distal regions being less cold and acting to insulate adjacent regions of the blood vessel from excessive cooling.

Abstract: An enhanced method and device are provided to treat atrial fibrillation or inhibit or reduce restenosis following angioplasty or stent placement. A balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium. In another embodiment, blood perfusion is performed simultaneously.

Abstract: A system for cryoablating target tissue at a treatment site includes a cryo-element mounted at the distal end of a cryo-catheter. A balloon catheter is provided having a U-shaped balloon attached thereon. The cryo-element is threaded onto a pre-positioned guidewire and advanced within the patient's vasculature until the cryo-element is positioned at the treatment site. Next, the balloon is threaded onto the guidewire and advanced within the patient's vasculature using the balloon catheter. At the treatment site, the U-shaped balloon is interposed between the cryo-element and the target tissue. Saline solution is pumped into the balloon causing the U-shaped balloon to expand and contact both the cryo-element and the surrounding target tissue. Next, a refrigerant is expanded to cool the cryo-element, which in turn, freezes the saline solution. The resulting “ice ball” extracts heat from surrounding tissue resulting in the cryoablation of a substantially circumferential portion of tissue.

Abstract: An ECG-prep scan is used to set an optimum time phase in both systole and diastole of the heart. At each of the different time phases, an imaging scan is started to acquire a plurality of sets of echo data. An artery/vein visually separated blood flow image is produced from the echo data. The imaging scan uses a half-Fourier technique, for example. This provides high-quality blood flow images with shorter scan time, without injecting a contrast medium. Additionally, with a readout gradient pulse applied substantially parallel with a direction of slowly flowing blood, a scan is performed in synchronism with an optimally determined cardiac time phase. The readout gradient pulse has a dephasing pulse for enhancing differences in a flow void effect depending on blood flow velocities. This enables slow-speed flows, such as blood flows in the inferior limb, to be depicted without fail.

Abstract: A method of promoting blood vessel growth includes the steps of providing a cryocatheter having a thermally transmission region; placing the cryocatheter proximate an area of tissue to be treated; cooling the thermally transmissive region of the cryocatheter proximate the area of tissue to a temperature sufficient to injure the area of tissue; allowing the area of tissue to warm; and removing the cryocatheter from the area of tissue. Prior, during or after the cooling step, the area of tissue can be mechanically traumatized, and drugs can be injected into the tissue.

Abstract: The malleable cryosurgical probe includes a cryostat assembly and a cryoprobe assembly. The cryostat assembly includes an elongated shaft assembly having a bellows portion thereof and a closed distal end. The shaft assembly includes at least one freezing portion comprising the bellows portion, at least one thermally insulated portion and a thermally insulating element positioned about the thermally insulated portion. A cryostat is operably associated with the elongated shaft assembly. It includes a cryostat inlet for receiving gas entering the cryostat, a cryostat outlet and a heat exchanger positioned between the cryostat outlet and the cryostat inlet. The heat exchanger receives gas from the cryostat inlet and provides heat transfer between gas flowing within the cryostat and fluid exterior thereto. At least one Joule-Thomson nozzle is in fluid communication with the cryostat outlet. The at least one Joule-Thomson nozzle expands gas expelled therefrom.

Abstract: Biocompatible materials are propelled at the skin with sufficient velocity to cause desired resurfacing of tissue to the desired penetration depth. The materials, such as dry ice or water ice, are harmonious with the human body and thus eliminate foreign body reactions. Various materials may be used in combination, including local anesthetics and vasoconstrictors in solid or liquid form. The biocompatible solid or liquid particles are suspended in a cold carrier fluid and propelled through an insulated delivery system to the surface of the skin. The treatment of diseased skin lesions may be accomplished using the present invention as a drug delivery system.

Abstract: A surgical device includes a device body defining a sealed fluid path having a first end and a second end, a refrigerant supply in communication with the first end of the sealed fluid path; and a vacuum source in communication with the second end of the sealed fluid path. Leak detection apparatus can be provided in communication with the sealed fluid path.

Abstract: A cryocatheter system includes a first handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; a second handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; and a catheter having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path. The distal end of the first handle portion is matable with the proximal end of the second handle portion to place the respective first and second fluid flow paths of each handle portion in fluid communication; and the distal end of the second handle portion is matable with the proximal end of the catheter to place the respective first and second fluid flow paths of the second handle portion and the catheter in fluid communication.

Abstract: A surgical device includes a device body defining a sealed fluid path having a first end and a second end, a refrigerant supply in communication with the first end of the sealed fluid path, and a vacuum source in communication with the second end of the sealed fluid path. Leak detection apparatus can be provided in communication with the sealed fluid path.

Abstract: The invention proposes a cryosurgical instrument and its accessory system operating on the base of a refrigerant evaporation.

Abstract: An expandable apparatus for use with a surgical probe having a temperature-controlled portion includes at least one thermally-conductive elongated extension member and means for thermally connecting and attaching the extension member to the surgical probe. The expandable apparatus further includes means for attaching and moving the extension member between a closed configuration in which the extension member is substantially parallel to the surgical probe and an open configuration in which the extension member extends radially outward from the surgical probe. A method of using the expandable apparatus to ablate tissue that line a body cavity is also disclosed.

Abstract: Devices and methods for cold-treating lesions within the body. A temperature monitoring device for use with a cryo therapy apparatus may include a cryo therapy apparatus, one or more tubular members coupled to the cryo therapy apparatus, and a temperature monitoring member coupled to the tubular member. The temperature monitoring member may comprise a retractable needle, an infrared sensor, an ultrasound transmitter, or a stent having a plurality of spikes.

Abstract: The invention provides systems and methods for infusing a fluid into a patient. In one exemplary embodiment, a system comprises a volume of fluid and a temperature altering device in close proximity to the volume of fluid. The temperature altering device is employed to heat or cool the volume of fluid to a desired temperature. A positive pressure device is provided to place the volume of fluid under positive pressure while at the desired temperature. A transfer member is further provided to transfer at least some of the fluid into the patient while at the desired temperature.

Abstract: A software module for a software controlled device for performing cryosurgical procedures on a treatment region with a cryosurgical probe. The software controlled device is of a type that is responsive to user input settings. The software module includes a temperature feedback control system which is adaptive to the external heat load of a treatment region and utilizes user input settings for determining an optimal rate of gas flow through a cryosurgical probe thereby enabling the user to precisely monitor and deliver a cryosurgical treatment.

Abstract: An enhanced method and device are provided to inhibit or reduce restenosis following angioplasty or stent placement. A porous balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the porous balloon such that an exterior surface of the balloon, as well as a portion of the cold working fluid, from the microporosity contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium.

Abstract: A method and devices for treating a target tissue comprising providing thermal energy to the target tissue and simultaneously providing cryogenic energy to peripheral tissue adjacent or surrounding said target tissue adapted for shielding the peripheral tissue from any adverse effect of the thermal energy. The cooling may be accomplished with a cryogenic arrangement comprising two elements of different electromotive potential conductively connected at a probe junction, and passing an electrical current through the elements to reduce a temperature of the probe junction in accordance with the Peltier effect.

Abstract: A method for treating cardiac arrest includes defibrillating the patient and/or ventilating the patient and/or administering a cardiac arrest drug such as epinephrine to resuscitate the patient, and then cooling the patient using one or more cooling catheter positioned in the central venous system of the patient.

Abstract: A coolant system for a cryoablation or treatment probe such as a mapping or ablation catheter, or a treatment wand, includes a compressor and condenser having a low pressure inlet side and a high pressure outlet side, wherein the outlet side passes through a heat exchanger and is cooled by the inlet side and conditioned for injection to a catheter inlet. A vacuum return system connectable to the catheter outlet draws thermally expended coolant from the catheter and returns it to the low pressure inlet side. A motorized pressure regulator between the heat exchanger and the catheter inlet determines the pressure of coolant passing into the catheter and thus regulates the cooling rate for a selected mapping or ablation regimen. The low pressure compressor inlet supply preferentially conditions the pressurized coolant to ambient temperature or lower before injection into the catheter, allowing the coolant to travel through the body at ambient before expansion in the tip.

Abstract: The invention is a technique for dynamic measurements of the heat transfer coefficient to the outer layer of the skin surface using a high thermal conductivity metal in an insulating block as the standardized target. The coefficient is dependent on the specific design of the cryogen valve and nozzle, and values up to 11 500 W/m2K values were measured for a 100 ms long spurts. The values for longer spurts are dependent on air humidity, as ice/snow formation then tends to form a thermally insulating layer. The average value of the heat transfer coefficient for a 200 ms long spurt was determined to 8000 W/m2K for conditions of normal room humidity and temperature. The technique enables an improved prediction of the temperature profile and cooling efficiency during therapy, and may thereby contribute to an improved therapeutic outcome.

Abstract: The present invention provides a method and apparatus for controlling the internal body temperature of a patient. According to the present invention, a catheter is inserted through an incision into a large blood vessel of a patient. By selectively heating or cooling a portion of the catheter lying within the blood vessel, heat may be transferred to or from blood flowing within the vessel and the patient's body temperature may thereby be increased or decreased as desired. The invention will find use in treating undesirable conditions of hypothermia and hyperthermia, or for inducing a condition of artificial hypothermia when desired.