Thermal treatment apparatus

This is a continuation of application Ser. No. 08/632,830 filed Apr. 16, 1996 now abandoned, which is a continuation in part of U.S. patent application Ser. No. 08/212,197, filed Mar. 11, 1994 now U.S. Pat. No. 5,549,559.

The present invention relates to a temperature-setting device which can be used to provide a desired temperature to a minimal quantity of fluid circulating in a closed system.

Also the present invention relates to a thermal treatment apparatus including such temperature-setting device for selectively treating a targeted tissue by applying fluid-induced thermal therapy, as disclosed in U.S. Pat. No. 5,257,977 and patent application Ser. No. 08/212,197.

Fluid induced thermal therapy is based on localized heating of a targeted tissue to a predetermined temperature by means of circulating fluid, while keeping the temperature of adjacent healthy tissues unchanged. Relative to therapy methods which use laser, microwave, radiofrequency and ultrasound to produce heat within a tissue, the fluid-induced thermotherapy allows better control of the temperature and the limits of the treated site.

Alternatively, a thermal treatment apparatus according to the present invention may be used for selectively preserving a portion of a tissue treated by cryosurgery, by selectively heating that portion of the tissue.

Various attempts have been made to provide devices for heating an amount of fluid circulating in a closed systems such as fluid-induced thermal therapy systems. Prior art includes heating bath circulators and a heater based on a container serving as a water reservoir. An example is disclosed in U.S. patent application Ser. No. 08/212,197.

However, such configurations consume a considerable amount of energy, since a large quantity of fluid has to be heated (or cooled). Moreover, a considerable damage may be caused in the event of system's failure, by the leakage of a large quantity of fluid into the body cavity.

There is thus a widely recognized need for, and it would be highly advantageous to have, a device which can provide a desired temperature to a minimal quantity of fluid which circulates in a closed system such as fluid-induced thermal therapy system.

It would be further advantageous to have such device which allows to alternately heat and cool a component of such closed system by alternately placing such component in embodiments of the device functioning as heaters and coolers.

It would be further advantageous to have a thermal treatment apparatus for selectively treating a targeted tissue by fluid-induced thermal therapy, which uses a minimal quantity of circulating fluid and therefore consumes minimal energy for heating (or cooling) the fluid, and minimizes the possible damage in the event of fluid leakage.

According to the present invention there is provided a temperature-setting device for providing a predetermined temperature to a minimal quantity of fluid circulating therethrough, comprising: (a) a tubular element having a relatively low electrical conductivity for receiving a quantity of circulating fluid; (b) a housing element for receiving and anchoring said tubular element therein, and for electrically connecting the tubular element to an electrical circuit; and (c) a transformer element electrically connectable to the electrical circuit.

According to further features in preferred embodiments of the invention described below, the tubular element has two ends connectable to electrically and thermally insulating tubular elements.

Further, the housing element includes fastening elements, comprising: a connector member having a relatively good electrical conductivity, connectable to an electrical circuit; and fastening member for anchoring the tubular member between the fastening member and the connector member.

According to still further features in the described preferred embodiments, the temperature-setting device may include a sensor for sensing the temperature of the tubular element.

The sensor and the transformer element may be electrically connected to a controller. In such configuration, the controller may control the duty cycle of the transformer according to the temperature sensed by the sensor. Alternatively, the controller may interrupt the operation of the transformer and the electrical circuit upon over-heating of the tubular element.

The tubular element and the insulating tubular elements may be disposable.

According to another embodiment, the housing element comprises a thermal conducting member disposed within a bath of a cooling substance, the thermal conducting member featuring a recess for receiving the tubular element therein. The recess preferably defines a lowered area relative to the surface of the cooling substance, for trapping cold air. The recess may be used for receiving a small quantity of fluid for improving the thermal coupling between the thermal conducting member and the tubular element.

According to further features of this embodiment, the thermal conducting member features extensions for increasing the area of contact between the thermal conducting member and the cooling substance.

The tubular element may alternately be place in embodiments functioning as heaters and embodiments functioning as coolers, thereby alternately heating and cooling the fluid circulating therethrough.

According to yet another embodiment, the housing element is in the form of two thermal conducting plates, each of which controllably connectable to a heating and/or cooling source such as a peletier heat pump element.

Each of the thermal conducting plates may feature a recess, the recesses defining a tunnel for receiving the tubular element therein, preferably under pressure.

The thermal conducting plates may alternately heat and cool the tubular element, thereby alternately heating and cooling the fluid circulating therethrough.

Also according to the present invention there is provided a thermal treatment apparatus which uses fluid-induced thermal therapy for selectively treating a targeted tissue adjacent to a subject's body cavity. The thermal treatment apparatus comprises a closed system of circulating fluid and a controller for controlling the closed system, the closed system including: (a) a temperature-setting device according to the present invention; (b) a catheter insertable into a body cavity, the catheter connectable to the temperature-setting device and including a thermal treating section for thermally treating a targeted tissue adjacent the body cavity by circulating fluid of a predetermined temperature through the thermal treating section; (c) a pump for pumping the fluid of predetermined temperature through the closed system; and (d) thermal sensor assembly for sensing the temperature of fluid circulating into the catheter.

According to further features in preferred embodiments of the invention described below, the thermal treatment apparatus may further include a second thermal sensor assembly for sensing the temperature of fluid circulating out of the catheter.

According to still further features in preferred embodiments of the invention described below, the thermal treatment apparatus may include an air trapping element, for trapping air circulating in the system.

The present invention successfully addresses the shortcomings of the presently known configurations by providing a temperature-setting device for providing a predetermined temperature to a minimal quantity of fluid circulating in a closed system.

Further, the present invention provides a thermal treatment apparatus for selectively treating a targeted tissue by fluid-induced thermal therapy, comprising a closed system of circulating fluid which uses a minimal quantity of fluid and therefore consumes minimal energy for heating (or cooling) the fluid, and minimizes the possible damage in the event of fluid leakage; and which further uses temperature control which is completely external to the patien't body.

The present invention discloses a novel temperature-setting device which allows to alternately heat and cool a component of such closed system, the component being in the form of a tubular element having relatively good thermal conductivity, by alternately placing the component in embodiments of the device functioning as heaters and embodiments functioning as coolers.

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic diagram illustrating an embodiment of a temperature-setting device and other main components of a thermal treatment apparatus according to the present invention;

FIG. 2 a is a transverse sectional view of another embodiment of a temperature-setting device according to the present invention, along lines A—A in FIG. 2 b.

FIG. 2 b is a longitudinal sectional view of the embodiment shown in FIG. 2 a , along line B—B.

FIG. 3 a is a transverse sectional view of yet another embodiment of a temperature-setting device according to the present invention, along lines A—A in FIG. 3 b.

FIG. 3 b is a top view of the embodiment shown in FIG. 3 a.

FIG. 4 a is a side view, partially in longitudinal section, of a catheter according to the present invention;

FIG. 4 b is a side view, partially in longitudinal section, of the catheter illustrated in FIG. 4 a rotated 90°.

FIGS. 5 a , 5 b and 5 c are transverse sectional views of the catheter shown in FIG. 4 b , along lines A—A, B—B and C—C.

FIG. 6 is a side view, partially in longitudinal section, of another embodiment of a catheter according to the present invention, in which the anchoring section is an integral part of the thermal treating section;

FIGS. 7 a , 7 b and 7 c are transverse sectional views of the catheter shown in FIG. 6 , along lines A—A, B—B and C—C.

FIG. 8 a is a longitudinal sectional view of a peristaltic pump according to the present invention, along line A—A in FIG. 8 b;

FIG. 8 b is a transverse sectional view of the peristaltic pump shown in FIG. 8 a , along line B—B;

FIG. 8 c is a fragmentary detail view along line C—C in FIG. 8 b;

FIG. 9 a is a top view of an embodiment of a thermal sensor assembly according to the present invention.

FIG. 9 b is a fragmentary detail view of the thermal sensor assembly shown in FIG. 9 a , along line B—B.

FIG. 9 c is a transverse sectional view of the thermal sensor assembly shown in FIG. 9 a , along line C—C.

FIG. 10 a is a transverse sectional view of another embodiment of a thermal sensor assembly, along line A—A in FIG. 10 b.

FIG. 10 b is a longitudinal sectional view of the thermal sensor assembly shown in FIG. 10 a , along line B—B.

The present invention is of a temperature-setting device for providing a desired temperature to a minimal quantity of fluid circulating in a closed system.

Also the present invention is of a thermal treatment apparatus including such device, for selectively treating a targeted tissue by fluid-induced thermal therapy using a minimal quantity of circulating fluid and consuming minimal energy for heating (or cooling) the fluid.

The principles and operation of a temperature-setting device according to the present invention and of a thermal treatment apparatus including such device may be better understood with reference to the drawings and the accompanying description.

FIG. 1 illustrates a thermal treatment apparatus which uses fluid-induced thermal therapy for selectively treating a targeted tissue adjacent a subject's body cavity. The thermal treatment apparatus comprises a closed system, including: a temperature-setting device 4 for providing a desired temperature to a minimal quantity of fluid circulating through the system; a catheter 2 insertable into the subject's body cavity and connectable to temperature-setting device 4 ; a pump 6 for pumping the fluid through the system, the pump connectable to temperature-setting device 4 ; and preferably two thermal sensor assemblies 8 and 10 for measuring the temperature of fluid circulating into and out of catheter 2 , respectively. Preferably, the closed system further includes an air trapping element 7 for trapping air circulating in the closed system.

The thermal treatment apparatus further includes a controller 12 for controlling the operation of temperature-setting device 4 and pump 6 , preferably according to the temperature sensed by thermal sensor assemblies 8 and 10 .

As shown in FIG. 1 , a temperature-setting device according to the present invention includes a resistive tubular element 3 having relatively low electrical conductivity and good thermal conductivity. Tubular element 3 may be made, for example, of stainless steel. Tubular element 3 is preferably disposable.

Preferably, temperature-setting device 4 further includes a housing element (not shown) having a recess for receiving tubular element 3 . The housing element preferably includes two fastening elements 5 for mechanically anchoring tubular element 3 in the housing element, and electrically connecting the ends of tubular element 3 to a transformer 11 . Each of fastening elements 5 comprises two components 5 a and 5 b . Component 5 a preferably includes a fatening member such as a screwing element for anchoring tubular element 3 between component 5 a and component 5 b . Component 5 b has relatively good electrical conductivity for allowing electrical connection between tubular element 3 and transformer 11 .

Since tubular element 3 has relatively low electrical conductivity, it functions as a resistor and converts electrical energy to heat, thereby heating the fluid circulating therethrough. This configuration allows to circulate a minimal quantity of heated fluid through the system. Preferably, the quantity of circulating fluid is about 20-50 ml.

The voltage produced by transformer 11 is preferably very low, about 1-5 volts, in order to provide the necessary safety while using the device.

Preferably, temperature-setting device 4 further includes a temperature sensor 92 located at the housing element, for sensing the temperature of tubular element 3 . The connection between sensor 7 and tubular element 3 is preferably established readily upon mounting of element 3 in the housing element, under pressure.

Sensor 7 is electrically connected to controller 12 . Controller 12 may control the duty cycle of transformer 11 according to the temperature sensed by sensor 7 , where the duty cycle refers to the time intervals during which transformer 11 provides electrical current or voltage to the system. Additionally, sensor 7 may function as a safety switch, so that when fluid circulation in the system is interrupted, sensor 7 heats up and consequently controller 12 preferably interrupts the operation of the overall system.

Alternatively, controller 12 may control the duty cycle of transformer 11 according to the temperatute sensed by thermal sensor assemblies 8 and 10 .

Referring now to FIGS. 2 a and 2 b , according to another embodiment of temperature-setting device 4 , the housing element comprises a thermal conducting member 14 disposed within a bath 13 of a cooling substance 15 , such as ice. Thermal conducting member 14 preferably features a recess 14 a for receiving tubular element 3 therein. Recess 14 a preferably defines a lowered area relative to the surface 15 a of cooling substance 15 , for trapping cold air. This configuration creates a local well of cold air defined by recess 14 a , for efficiently cooling tubular element 3 . Further, recess 14 a may be used for receiving a quantity of fluid for improving the thermal coupling between thermal conducting member 14 b and tubular element 3 . Preferably, thermal conducting member 14 further features extensions 14 b for increasing the area of contact between thermal conducting member 14 and cooling substance 15 . Preferably, the housing element is stored under freezing conditions while not in use.

Temperature-setting device 4 may be used to alternately heat and cool a minimal quantity of fluid circulating through the system, by alternately placing tubular element 3 in embodiments of the device functioning as heaters (e.g. the configuration shown in FIG. 1 ) and embodiments functioning as coolers (e.g. the configuration shown in FIGS. 2 a and 2 b ). While using the configuration of FIGS. 2 a and 2 b , transformer 11 is not used.

Referring now to FIGS. 3 a and 3 b , according to yet another embodiment of temperature-setting device 4 , the housing element comprises two plates 16 a and 16 b , made of a material having relatively good thermal conductivity such as aluminum. Plates 16 a and 16 b are controllably connectable to heating and/or cooling sources 17 and 18 , respectively. Heating and/or cooling sources 17 and 18 may be, for example, peletier heat pump elements. As shown, each of plates 16 a and 16 b may feature a recess, the recesses defining a tunnel for receiving tubular element 3 therein, preferably under pressure. This configuration allows better thermal coupling between thermal conducting plates 16 a and 16 b and tubular element 3 .

While using this configuration, tubular element 3 is places within the recess of plate 16 b . Plate 16 a is then placed on top of plate 16 b , covering tubular element 3 so that tubular elenemt 3 is preferably pressed within the tunnel defined by the recesses of plates 16 a and 16 b.

This configuration may be used as a heater and/or cooler, according to the function (heating or cooling) performed by sources 17 and 18 . While using this configuration, transformer 11 is not used.

Referring now to FIGS. 4-7 , thermal treatment apparatus according to the present invention further includes a catheter 2 connectable to temperature-setting device 4 and insertable into a subject's body cavity such as urinary bladder, prostatic urethra, uterus and esophagus, for selectively treating a targeted tissue within or near such cavity.

For example, selective treatment of a subject's prostate gland may be accomplished by inserting catheter 2 into the subject's urinary tract and anchoring catheter 2 within the subject's bladder. As shown in FIGS. 4 a , 4 b and 5 a , 5 b and 5 c , catheter 2 preferably includes a long slender tube 20 formed with an inflatable anchoring section 21 at the proximal end for anchoring the catheter in the subject's body cavity, and thereby locating an inflatable cylindrical thermal treating section 22 near the targeted tissue to be treated. The length of thermal treating section 22 may preferably be adapted according to the distance between the bladder neck and the verumontanum of the particular patient. The distal end of catheter 23 is to be located externally of the subject's body so as to be readily accessible for inflating anchoring section 21 and thermal treating section 22 .

A limited quantity of a fluid having a predetermined temperature is circulated through inflatable thermal treating section 22 via two passageways 24 a and 24 b having an inlet 25 and an outlet 26 at distal end 23 of the catheter. As shown in FIG. 1 , a valve member 2 a is connected to outlet 26 of the catheter for introducing fluid into the closed system.

Inflatable anchoring section 21 of the catheter is preferably inflated by an amount of unheated fluid introduced via inlet 27 at distal end 23 of the catheter. Inlet 27 preferably communicates with anchoring section 21 via an unheated-fluid passageway 28 and an opening 29 .

The portion of the catheter from distal end 23 to inflatable thermal treating section 22 is preferably thermally insulated from the subject's untargeted tissues by means of insulating chambers 30 enclosing passageways 24 a and 24 b . One of insulating chambers 30 preferably communicates with unheated-fluid passageway 28 through which unheated air is applied to inflate anchoring section 21 .

The catheter also includes an extension 31 at the proximal end, which extension is received within the subject's body cavity. Extension 31 is formed with an opening 32 for draining body fluids via draining passageway 33 passing through the length of the catheter and terminating in an outlet 34 attachable to a drain. Alternatively, passageway 33 may be used for introducing a drug into the subject's body cavity. Further, passageway 33 may be used for introducing a stiffening element for facilitating the insertion of the catheter to the subject's body cavity.

Catheter 2 and valve member 2 a are preferably disposable.

According to another configuration (not shown), catheter 2 includes only one chamber 30 for communicating with inlet 27 and passageway 28 through which unheated air is applied to inflate anchoring section 21 , so that passageways 24 a and 24 b along slender tube 20 are not insulated.

Yet another configuration of catheter 2 is shown in FIGS. 6 and 7 a , 7 b and 7 c . In this configuration, anchoring section 21 is made as an integral part of thermal treating section 22 , and passageway 28 is missing. Further, thermal treating section 22 may feature any geometrical shape, according to the specific geometry of the subject's body cavity. Such configuration may be used, for example, for endometrial ablation, where the geometry of thermal treating section 22 is adapted to fit the specific geometry of a subject's uterus, and insulating chambers 30 enable the use of a heating source for heating the fluid, which is completely external to the subject's body.

According to additional configuration (not shown), anchoring section 21 is made as an integral part of thermal treating section 22 , and all of chambers 30 , inlet 27 and passageway 28 are missing, so that passageways 24 a and 24 b along slender tube 20 are not insulated. Inflatable thermal treating section 22 may feature any geometrical shape, according to the specific geometry of the subject's body cavity. Such configuration may be used, for example, for selectively heating a portion of a tissue treated by cryosurgery, thereby preserving that portion.

Referring now to FIGS. 8 a , 8 b and 8 c , thermal treatment apparatus according to the present invention further includes a pump 6 connectable to catheter 2 and temperature-setting device 4 . Pump 6 is preferably a peristaltic pump, and includes a housing 60 formed with a cylindrical cavity 61 . Disposed within cylindrical cavity 61 is a rotor 62 connected by a drive shaft 63 to a gear motor (not shown) and including a pair of spaced discs 64 a , 64 b rotatably mounting between them a plurality ( 3 ) of rollers 65 within cavity 61 . Also located within cylindrical cavity 61 is a peristaltic tube 66 which is engageable by roller 65 for pumping the fluid through the tube during the rotation of rotor 62 . Assuming rotor 62 is rotated counter-clockwise in FIG. 8 b , the fluid will be pumped through peristaltic tube 66 from an inlet nipple 67 to an outlet nipple 68 .

As shown in FIG. 8 a , housing 60 further includes a lid 70 with a large central opening 71 for accommodating disc 64 a of rotor 62 . Lid 70 is formed with a depending skirt 72 which extends into cylindrical cavity 61 such that peristaltic tube 66 is located between the inner surface of skirt 72 and rollers 65 . Skirt 72 extends only for a part of the circumference of the lid, e.g., from 160° to 200°, to accomodate the inlet and outlet ends of peristaltic tube 66 . As shown in FIG. 8 b , skirt 72 extends slightly more than 180°; also, its leading edge 73 and its trailing edge 74 are tapered to provide a gradual application of pressure to the peristaltic tube by roller 65 , and a gradual release of the pressure. Peristaltic tube 66 is preferably disposable.

Preferably, housing 60 features two or more pins 75 , and lid 70 features two or more depressions 75 a respectively for receiving pins 75 therein. Such configuration prevents the rotation of lid 70 during rotation of rotor 62 .

The illustrated construction, including depending skirt 72 , facilitates the assembly of the peristaltic pump with peristaltic tube 66 between skirt 72 and rollers 65 . Thus, with the lid removed peristaltic tube 66 may be conveniently applied around rollers 65 . Lid 70 may then be applied with its skirt 72 received between peristaltic tube 66 and the inner surface of cylindrical cavity 61 formed in housing 60 , so as to squeeze the tube between skirt 72 and rollers 65 . Accordingly, the lower edge of skirt 72 is tapered, as shown at 76 in FIG. 8 a , for facilitating the application of the skirt.

The foregoing construction not only facilitates the assembly of the peristaltic pump, but also covers rollers 65 to minimize exposure to a person's fingers or the like. In addition, the thickness of skirt 72 influences the outlet pressure produced by the pump, so that lids 70 with different thickness of skirts 72 may be used to provide different outlet pressures. In addition, the inner surface of skirt 72 may be provided with one or more grooves, as shown at 77 in FIG. 8 b , to produce a pulsatile output.

Referring now to FIGS. 9 a , 9 b , 9 c , and 10 a , 10 b , thermal treatment apparatus according to the present invention preferably includes two thermal sensor assemblies 8 and 10 for measuring the temperature of fluid circularing into and out of catheter 2 , respectively. Thermal sensor assemblies 8 and 10 are preferably enclosed within a common housing 80 and closed by a common cover 81 . Thermal sensor assembly 8 near the inlet end of catheter 2 includes a thermal sensor element 82 received within a rectangular recess formed in a metal thermal coupling member 83 . The opposite face of the coupling member is formed with a recess for receiving a metal tube 84 connectible to an inlet tube 85 near the inlet end of the catheter. Thermal sensor assembly 10 similarly includes a thermal sensor element 86 received within a recess formed in another metal thermal coupling member 87 . The opposite face of member 87 is similarly formed with a recess for receiving a metal tube 88 adapted to be coupled to an outlet tube 89 near the outlet end of the catheter. Electrical connections are made to the two thermal sensor elements 82 and 86 via a cable 90 leading to controller 12 in FIG. 1 . Metal tubes 84 and 88 and inlet and outlet tubes 85 and 89 are preferably disposable.

The two thermal coupling members 83 , 87 , as well as the two tubes 84 , 88 , are of a metal, such as stainless steel, having relatively good thermal conductivity. Coupling members 83 , 87 include relatively thin web portions 83 a , 87 a , respectively, between thermal sensor elements 82 , 86 and metal tubes 84 , 88 , so as to provide a good thermal coupling between the fluid flowing through the two metal tubes and their respective thermal sensor elements. Cover 81 , fixed to the common housing 80 in any suitable manner, preferably presses metal tubes 84 , 88 firmly against their respective metal coupling members 83 , 87 .

As shown in FIG. 9 b , cover 81 may include extensions 81 a , and housing 80 may respectively include depressions 80 a for receiving extensions 81 a of cover 81 . Cover 81 is threaded into the chamber defined by depressions 80 a of housing 80 , pressing each of metal tubes 84 and 88 firmly against their respective metal coupling members 83 and 87 .

Another possible configuration is shown in FIGS. 10 a and 10 b , wherein housing 80 features the shape of “H”, and cover 81 presses each of metal tubes 84 and 88 firmly against their respective metal coupling members 83 and 87 , and the central segment of housing element 80 . Cover 81 may be fixed to the common H-shaped housing 80 in any suitable manner.

As shown in FIG. 1 , thermal treatment apparatus according to the present invention may further include an air trapping element for trapping air circulating in the closed system. Air trapping element 7 may be in the form of a hung container 7 c , which is preferably flexible and made of plastic, and controllably connectable to the closed system by means of two tubular elements 7 d and 7 e , and two valve members 7 a and 7 b . Container 7 c , tubular elements 7 d and 7 e , and valve members 7 a and 7 b are preferably disposable.

Valve members 7 a and 7 b may controllably allow or block fluid circulation into and out of container 7 c . When fluid is allowed to circulate through container 7 c , the air found in the circulating fluid is trapped within the container.

Air trapping element 7 is preferably used for priming the system.

Thermal treatment apparatus according to the present invention preferably includes a disposable set, including: (a) different configurations of catheter 2 for different types of treatments; and (b) a tubing assembly, including: tubular element 3 of temperature-setting device 4 ; peristaltic tube 66 of pump 6 ; metal tubes 84 and 88 of thermal sensor assemblies 8 and 10 ; air trapping element 7 ; valve members such as 2 a , 7 a and 7 b ; and other tubular elements constituting the closed system of circulating fluid.

The overall operation of a thermal treatment apparatus including a temperature-setting device according to the present invention is as follows:

The configuration of catheter 2 is selected according to the specific type of treatment; catheter 2 is then connected to the disposable tubing assembly; tubular element 3 is placed in a suitable embodiment of temperature-setting device 4 ; peristaltic tube 66 is placed in pump 6 ; and metal tubes 84 and 88 are placed within thermal sensor assemblies 8 and 10 respectively.

Valve members 7 a and 7 b are set to allow circulation of fluid through air trapping element 7 , and a minimal quantity (about 20-50 ml) of fluid is then introduced into the closed system via valve member 2 a . Priming of the system is then carried out by activating pump 6 and circulating the fluid through air trapping element 7 , thereby trapping air found in the system.

Valve members 7 a and 7 b are then set to block circulation of fluid through air trapping element 7 , thereby directing the fluid to circulate through the main tube of the system.

An additional quantity of fluid is added at this stage to inflate thermal treating section 22 to its operational volume, if required.

Pump 6 is then switched off, and a quantity of fluid is pumped out of the system via valve member 2 a , in order to deflate thermal treating section 22 and to allow the insertion of catheter 2 into the subject's body cavity.

Referring now to FIGS. 4 and 5 , catheter 2 is inserted into a subject's body cavity until inflatable anchoring section 21 at the proximal end passes through the neck of the cavity. An unheated fluid, preferably air, is introduced via inlet 27 and passageway 28 into the interior of anchoring section 21 to inflate it. This anchors section 21 in the subject's body cavity, whereupon heating section 22 of the catheter extends through the targeted tissue to be treated.

The quantity of fluid that was pumped out of the system for deflating thermal treating section 22 is now pumped into the system via valve member 2 a for inflating thermal treating section 22 while placed within the subject's body cavity.

Referring now to FIGS. 6 and 7 , wherein anchoring section 21 is made as an integral part of thermal treating section 22 , and thermal treating section 22 features any geometrical shape. while using this configuration, the quantity of fluid that was pumped out of the system for deflating thermal treating section 22 is now pumped into the system via valve member 2 a for inflating thermal treating section 22 while placed within the subject's body cavity. If required, an additional quantity of fluid is pumped into the system via valve member 2 a so as to fill the particular body cavity, thereby efficiently heating or cooling the tissues therein.

The fluid is then circulated by peristaltic pump 6 through the closed system including thermal treating section 22 of the catheter and tubular element 3 of the temperature-setting device.

During circulation, tubular element 3 which is electrically connected to transformer 11 (FIG. 1 ), converts electrical energy to heat, thereby heating the fluid circulating therethrough. Alternatively, tubular element 3 may be placed in the embodiment shown in FIGS. 2 a and 2 b , thereby cooling the fluid circulating therethrough. Thus, temperature-setting device 4 may be used to alternately heat and cool the fluid circulating in the system by alternately placing tubular element 3 within embodiments of the device functioning as heaters and coolers.

Alternatively, tubular element 3 may be placed in the embodiment shown in FIGS. 3 a and 3 b , thereby alternately heating and cooling the circulating fluid using the same embodiment.

Sensor assemblies 8 and 10 , electrically connected to controller 12 , sense the temperature of fluid near the inlet and outlet ends of the catheter, respectively. Controller 12 maintain the desired temperature by controlling the duty cycle of transformer 11 , and therefore the heating level of tubular element 3 .

Sensor 7 , electrically connected to controller 12 , senses the temperature of tubular element 3 . Controller 12 interrupts the operation of the overall system upon over-heating of tubular element 3 .

While using the configurations of catheter 2 shown in FIGS. 4-7 , only inflated thermal treating section 22 of the catheter is effective to heat a targeted tissue, because of the thermal insulation provided by the unheated air within insulating chambers 30 . While using the configuration shown in FIGS. 4 and 5 , the insulation is further provided by anchoring section 21 .

Accordingly, the fluid applied to inflatable thermal treating section 22 may be heated to a relatively high tempetature for application to the targeted tissues, with less danger of unduly heating untargeted tissues contacted by the catheter. The inflation of thermal treating section 22 also presses that section firmly against the targeted tissue to be thermally treated thereby further enhancing the heating effects.

Drain opening 32 at the proximal end of the catheter, and passageway 33 through the catheter, provide a drain for body fluids or enable the introduction of drugs into the body cavity.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.