The present invention generally relates to a medical apparatus for irradiating living tissue with energy to treat or diagnose the living tissue. More particularly, the invention relates to an energy irradiating medical apparatus and an energy irradiating medical equipment used thereof including a temperature sensor disposed in an insert portion to be inserted into a living body for accurately measuring the temperature of the living body, which it is being irradiated with an energy during treatment or diagnosis, without the need for thrusting into the living body. The invention also pertains to a method of irradiating living tissue in a living body.
There have been known in the art energy irradiating medical apparatus having an elongate insert portion to be inserted into a living body through a body cavity or a small incision. When the insert portion is inserted into the living body, the insert portion irradiates a living tissue including an affected region with an energy such as a laser beam, a microwave, a radio wave, an ultrasonic wave, or the like to thermally modify, necrose, coagulate, cauterize, or evaporate the tissue of the affected region or a surrounding tissue including the affected region.
The energy irradiating medical apparatus generally directly apply the energy to the surface layer of a living tissue or the affected region positioned closely thereto. The energy irradiating medical apparatus are also used to treat, with heat, an affected region positioned deeply in a living tissue, such as a prostatic hypertrophy, a prostatic cancer, or a prostatitis.
For example, International Application Publication No. WO93/04727 discloses a technique proposing a process of applying a laser beam to solidify or contract some tissue of a cancer or a prostate. According to this technique, a coolant is introduced into a balloon to prevent the surface of a urethra held in contact with the balloon from being heated, while only the cancer or the prostate located inside is being heated. However, since the laser beam is applied from a fixed laser beam irradiator, the laser beam needs to be applied at a low output level to prevent the surface of a urethra from being heated. Hence, the laser beam needs to be applied for a long period of time. International Publication No. WO93/04727 reveals a balloon catheter having a thermocouple disposed in the balloon to be located in an intermediate position in a prostatic urethra for monitoring the temperature of a urethral tissue. The thermocouple is disposed within the balloon and held out of direct contact with the urethra, and the coolant is circulated through the balloon. Therefore, the temperature measured by the thermocouple does not appear to be accurately representative of the temperature of the prostatic urethra. U.S. Pat. No. 5,964,791 discloses a process of thrusting into a prostate with a temperature sensor to accurately measure the temperature of the urethra (direct measuring process).
US Patent No. U.S. Pat. No. 6,579,286 discloses, as an example of heat treatment device, a laser beam irradiating apparatus for guiding a laser beam into a urethra to treat a prostatic hypertrophy. The laser beam irradiating apparatus has a laser beam irradiation portion that is continuously movable to change the direction of the applied laser beam at all times. However, since the laser beam irradiating apparatus is arranged to concentrate the laser beam on a target region, the target region is heated to a high temperature while holding a surrounding tissue around the target region at a lower temperature. Even if the target region is positioned deeply in the living tissue, therefore, any damage to the living tissue that is located between the laser beam irradiator and the target region is minimized.
A therapeutic procedure for treating a prostatic hypertrophy with the laser beam irradiating apparatus will be described below. First, the doctor inserts the insert portion of the laser beam irradiating apparatus into the urethra of the patient. The insert houses therein a laser beam irradiator having a reflecting surface for reflecting a laser beam which is generated by a laser beam generator, guided by an optical fiber, and emitted from the tip end of the optical fiber. The insert portion also houses therein an endoscope, and inlet outlet pipes for a coolant for cooling the laser beam irradiator. Then, the doctor positions the laser beam irradiator while observing the urethra with the endoscope in the insert through an observation window disposed in the insert, and then applies the laser beam to a target region in the patient.
The heat treatment device referred to above needs to measure the temperature of a treated region in order to monitor the treatment in progress. The temperature of the treated region (the target region to be irradiated with the laser beam) positioned deeply in the living body can be measured by a process of thrusting into the living tissue with a temperature sensor to directly measure the temperature of the deep region (direct measuring process) or a process of bringing a temperature sensor into contact with the surface layer of the living body above the treated region to accurately measure the temperature of the surface layer of the living body and estimating the temperature of the deep region based on the measured temperature.
Though the direct measuring process is able to accurately measure the temperature of the treated region, it is disadvantageous in that it invites side effects such as hemorrhage and infectious disease because the living body is injured by being pierced with the temperature sensor, resulting in an increased number of days that the patient needs to stay in the hospital. For this reason, there has been a demand for a technique to accurately measure the temperature of the surface of the living body while it is being treated by an energy irradiation, thereby increasing the accuracy to estimate the temperature of a deep living tissue.
Problems that arise regarding the accurate measurement of the temperature of the surface of the living body will be described below. Conventional Temperature sensors have a temperature measuring element such as a thermistor and two leads connected thereto, which are placed in a tangle-free manner in a protective tube. However, the protective tube makes the insert portion to be inserted into the living body thick, posing an increased burden on the patient. The leads that are employed tend to cause the thermistor to be installed in different positions, making it impossible to measure accurate temperatures.
It may be proposed to place the temperature measuring element and the leads within the insert portion. If the temperature measuring element is placed in the insert portion of an energy treatment device where a coolant is circulated in the insert portion for cooling an energy emission unit and the living body contacted by the insert portion, then the coolant affects the temperature measuring element. Consequently, there has been desired a temperature sensor less susceptible to the coolant and is yet capable of accurately measuring the surface temperature of a living body.
One solution would be to attach the temperature measuring element and the leads to the outer surface of the insert. However, this approach needs to meet the following requirements:
1. The temperature measuring element will not be affected by the coolant.
2. The temperature measuring element will be installed easily and accurately in a desired position.
3. When the temperature measuring element and the leads are attached, the leads will not be damaged and will keep electrically connected to the temperature measuring element.
4. The insert portion will not have protrusions on its surface, which would otherwise be liable to damage the living body when the insert portion is inserted into the living body.
5. The temperature measuring element will not be directly affected by the energy that is applied to the living body.
It is therefore an object of the present invention to provide an energy irradiating medical apparatus and an energy irradiating medical equipment used thereof having a structure that is simple and inexpensive to manufacture and capable of accurately measuring the temperature of a living tissue when the doctor treats a prostatic hypertrophy or a prostatic cancer with heat, using the energy irradiating medical apparatus.
An energy irradiating medical equipment according to an embodiment of the present invention has an insert portion to be inserted into a living body, a temperature sensor disposed on the insert portion, and an energy irradiation window disposed on the insert portion for applying an energy to a living tissue. The temperature sensor includes a flexible thin-film substrate, at least first and second conductors disposed on the thin film substrate, and a temperature measuring unit electrically coupled to the at least first and second conductors. The temperature measuring unit is disposed on the energy irradiation window.
Preferably, the temperature measuring unit is disposed in a peripheral region within the energy irradiation window.
Preferably, the temperature measuring unit has first and second electrodes bonded and electrically coupled respectively to at least the first and second conductors disposed on the thin-film substrate, and a substantially plate-shaped thermistor element made of a metal oxide. The first and second electrodes are electrically coupled to the thermistor element.
Preferably, the thermistor element is made of an oxide of one of transition metals including Mn, Co, Ni, and Fe.
Preferably, the thermistor element has a first surface disposed on the first electrode, the first electrode is bonded and electrically coupled to the thermistor element, the thermistor element has a second surface opposite to the first surface, with the second electrode being disposed on the second surface, and the second electrode is not bonded to, but electrically coupled to the thermistor element.
Preferably, the flexible thin-film substrate is bent to place the second electrode on a second surface of the thermistor element which is opposite to a first surface.
Preferably, the thin-film substrate is disposed outwardly of the energy irradiation window and along a longitudinal direction of the insert portion.
Preferably, the energy irradiating medical equipment further has an output tube covering the insert portion. After an outer surface of the insert portion is covered with the outer tube, the outer tube is thermally shrunk to press the thermistor element and the second electrode against each other to electrically couple the thermistor element and the second electrode to each other.
Preferably, the energy irradiating medical further has a thin metal film for shielding the thermistor element from the energy.
Preferably, the thin metal film is disposed on the thin-film substrate, and the thin-film substrate is bent to cover the thermistor element with the thin metal film.
Preferably, the insert portion has a hollow cylinder and an opening portion defined in a side wall of the hollow cylinder to provide the energy irradiation window.
Preferably, an optically transparent resin film is applied to the hollow cylinder in covering relation to the opening portion.
Preferably, the resin film is scaled.
Preferably, the energy irradiating medical equipment further has an outer tube covering the resin film.
Preferably, the thin-film substrate has depth markers for indicating the length by which the insert portion is inserted into the living body by the user.
Preferably, the temperature measuring unit is disposed in a peripheral region within the energy irradiation window, and a plurality of the temperature sensors are disposed in different positions on the insert portion.
An energy irradiating medical equipment according to an embodiment of the present invention has an insert portion to be inserted into a living body, a temperature sensor disposed on the insert portion, and an energy irradiation window disposed on the insert portion for applying an energy to a living tissue. The temperature sensor includes a flexible thin-film substrate, at least first and second conductors disposed on the thin-film substrate, and a temperature measuring unit electrically coupled to the at least first and second conductors and including a thin-film metal resistor, the temperature measuring unit being disposed on the energy irradiation window.
Preferably, the temperature measuring unit is disposed in a range greater than the irradiated width of the energy which passes through the energy irradiation window.
Preferably, the thin-film metal resistor is made of one of metals including Al, Pt, Ti, W, Ni, Ag, Au, and Cu, or an alloy thereof.
Preferably, each of the first and second electrodes includes a thin metal film which is made of the same material as the thin-film metal resistor.
Preferably, the thin-film metal resistor and the first and second electrodes are made of Al.
Preferably, the thin-film metal resistor and the first and second electrodes are formed by deposition of Al on the thin-film substrate.
Preferably, the thin-film substrate is made of a optically transparent resin for passing the energy.
Preferably, the optically transparent resin is one of polyester, polycarbonate, and polyethylene terephthalate (PET).
Preferably, the thin-film metal resistor covers the energy irradiation window in a range greater than the diameter of an irradiated spot of the energy, and smaller than the width of the energy irradiation window.
Preferably, the thin-film metal resistor is in the form of a thin line having a width in the range from 10 to 20 μm and a length in the range from 50 to 100 mm.
Preferably, the thin line is made of Al and has a resistance in the range from 100 to 1000 Ω.
An energy irradiating medical apparatus according to the present invention has an insert portion to be inserted into a living body, a temperature sensor disposed on the insert portion, and an energy irradiation window disposed on the insert portion for applying an energy to a living tissue. The temperature sensor includes a flexible thin-film substrate, at least first and second conductors disposed on the thin-film substrate, and a temperature measuring unit electrically coupled to the at least first and second conductors. The temperature measuring unit is disposed on the energy irradiation window. The energy irradiating medical apparatus has maximum surface temperature estimating means for estimating a maximum surface temperature of a living tissue which is irradiated with the energy, based on a temperature measured by the temperature sensor.
Preferably, the temperature measuring unit is disposed in a peripheral region within the energy irradiation window, the temperature measuring unit having first and second electrodes bonded and electrically coupled respectively to at least the first and second conductors disposed on the thin-film substrate, and a substantially plate-shaped thermistor element made of a metal oxide, the first and second electrodes being electrically coupled to the thermistor element.
Preferably, the temperature measuring unit is disposed on the energy irradiation window, the temperature measuring unit having first and second electrodes disposed on the thin-film substrate and bonded and electrically coupled respectively to at least the first and second conductors, and a thin-film metal resistor bonded and electrically coupled to the first and second electrodes.
Preferably, the energy irradiating medical apparatus further has deep region temperature estimating means for estimating a deep region temperature of a living tissue which is irradiated with the energy, based on a temperature measured by the temperature sensor.
Preferably, the energy irradiating medical apparatus further has control means for controlling the energy applied to the living tissue based on the temperature measured by the temperature sensor.
Preferably, the energy irradiating medical apparatus further has irradiating means disposed in the insert portion for reflecting the laser beam with a reflecting surface and applying the laser beam through the energy irradiation window to the living tissue, moving means for reciprocally moving the irradiating means along a longitudinal direction of the insert portion, changing means for changing an irradiation angle of the irradiating means, and determination means for determining whether or not the reciprocating movement of the irradiating means is correctly controlled by the moving means, based on the temperature measured by the temperature sensor.
Preferably, the energy is a laser beam.
According to another aspect an energy irradiating medical equipment comprises an insert portion possessing a size permitting the insert portion to be inserted into a living body, with the insert portion comprising a hollow cylinder possessing an interior. An energy emitter is positioned in the interior of the hollow cylinder and is adapted to be connected to an energy generator to emit energy. A temperature sensor is disposed on the insert portion, an opening is provided in the hollow cylinder, and a cover covers the opening and permits transmission therethrough of the energy emitted by the energy emitter. The temperature sensor comprises a flexible thin-film substrate, at least first and second conductors disposed on the thin-film substrate, and a temperature measuring unit electrically coupled to the at least first and second conductors. The temperature measuring unit is positioned outside of the cover so that the cover is positioned between the interior of the insert portion and the temperature measuring unit
In accordance with another aspect, energy irradiating medical equipment comprises an insert portion possessing a size permitting the insert portion to be inserted into a living body, with the insert portion comprising a hollow cylinder having an interior. An energy emitter is positioned in the interior of the hollow cylinder and is adapted to be connected to an energy generator to emit energy to irradiate living tissue of the living body, and a temperature sensor is disposed on the insert portion. The temperature sensor comprises a flexible thin-film substrate, at least first and second conductors disposed on the thin-film substrate, with the at least first and second conductors being positioned exteriorly of the hollow cylinder, and a temperature measuring unit electrically coupled to the at least first and second conductors.
According to a further aspect, a method for irradiating living tissue of a living body involves inserting into the living body an insert portion in which a temperature sensor is disposed on the insert portion, with the temperature sensor comprising a flexible thin-film substrate, at least first and second conductors disposed on the thin-film substrate and a temperature measuring unit electrically coupled to the at least first and second conductors. The method also involves emitting energy from within the insert portion and through a window in the insert portion to irradiate the living tissue with the energy, and determining a temperature in the living body using output from the temperature sensor.
The energy irradiating medical apparatus, energy irradiating medical equipment and method according to the present invention permits accurate measurement of the temperature of a living tissue as it is treated with heat, though the energy irradiating medical apparatus through use of an apparatus and equipment that are relatively simple in structure and relatively inexpensive to manufacture. Therefore, the doctor who operates the energy irradiating medical apparatus can correctly monitor the temperature of the living tissue as it is treated with heat to cure a prostatic hypertrophy, for example, and hence can treat the living tissue with greater safety.
These and other objects of the invention will be seen by reference to the description, taken in connection with the accompanying drawing, in which:
A first embodiment of the present invention will be described below as being applied to an energy irradiating medical apparatus for treating, with heat, a prostatic hypertrophy. However, the principles of the present invention are not limited to such an energy irradiating medical apparatus for treating, with heat, a prostatic hypertrophy. A laser beam will be described as an example of energy used for treating, with heat, a prostatic hypertrophy. However, the energy is not limited to a laser beam, but an electromagnetic wave such as a microwave, a radio wave, or the like, or an elastic wave such as an ultrasonic wave, a sound wave, or the like may be used as the energy.
The laser beam that can be used may include a divergent beam, a parallel beam, or a convergent beam. An optical system for converting a laser beam into a convergent beam may be disposed in the path of the laser beam. Though the laser beam is not limited to any particular laser beams insofar as they can reach a deep region in a living body, the laser beam should preferably have a wavelength ranging from 500 to 2600 nm, more preferably from 750 to 1300 nm or from 1600 to 1800 nm. The laser beam may be generated by a gas laser such as an He—Ne laser or the like, a solid-state laser such as an Nd-YAG laser or the like, or a semiconductor laser such as a GaAlAs laser or the like.
[Energy Irradiating Medical apparatus (
As shown in
The insert portion 103 houses therein a laser beam irradiation portion 20 that is reciprocatingly movable in the longitudinal direction of the insert portion 103. A laser beam is guided by an optical fiber 12 extending through the applicator 110 and emitted from the distal end of the optical fiber 12. The laser beam emitted from the optical fiber 12 is reflected by the laser beam irradiation portion 20 and applied through a laser beam irradiating window defined in a side wall of the insert portion 103 to a target region T-1 to be irradiated in a living tissue T. The optical fiber forms an energy emitter from which energy (e.g., a laser beam in this disclosed embodiment) is emitted.
The laser beam irradiation portion 20 is coupled through a reciprocatingly movable member 23 (see
The drive unit 150 has a cam mechanism (not shown) for converting rotary motion of a motor 188 into reciprocating motion. Therefore, when the motor 188 is energized, its rotary motion is converted by the cam mechanism into reciprocating motion that is transmitted to the reciprocatingly movable member 23, which moves the laser beam irradiation portion 20 in the longitudinal direction of the insert portion 103.
The applicator 110 has a plurality of lumens (not shown) defined longitudinally therein and communicating with the insert portion 103 for circulating a coolant. The lumens are connected respectively to a coolant supply tube 185 and a coolant return tube 186 which extend from a coolant circulator 104. The coolant is supplied through the coolant supply tube 185 to the insert portion 103 to cool the laser beam irradiation portion 20 for thereby preventing the laser beam irradiation portion 20 from being overheated, and also to cool the surface of the body cavity U, which is held in contact with the insert portion 103 through the wall of the insert portion 103, for thereby preventing a correct body tissue, which is heated by the applied laser beam, from being damaged.
The coolant circulator 104 supplies the coolant at a preset rate through the applicator 110 to the insert portion 103 based on a control signal from a controller 106. A coolant temperature regulator 105 that is coupled to the coolant circulator 104 heats or cools the coolant in the coolant circulator 104 to regulate the temperature of the coolant based on a control signal from a controller 106. The motor 188 is energized to rotate a preset rotational speed based on a control signal from a controller 106.
The controller 106 has a console 108 serving as an input unit, a display 107 for displaying input information and apparatus information, a control unit (not shown) for controlling various parts of the controller 106, a memory (not shown) for storing various items of information, and an input/output unit (not shown) for inputting and outputting various items of information.
The coolant is supplied from the coolant circulator 104 through the coolant supply tube 185 to the insert portion 103, the motor 188 is rotated, and a laser beam generator 102 is operated to treat, with heat, a prostatic target region T-1 (target point) to be irradiated with a laser beam.
A laser beam generated by the laser beam generator 102 is transmitted through the optical fiber 12 to the laser beam irradiation portion 20 in the insert portion 103, which reflects the laser beam through the laser beam irradiating window to the target region T-1. At this time, the laser beam irradiation portion 20 is reciprocatingly moved axially in the insert portion 103 in periodic cycles at a frequency ranging from 2 to 10 Hz, preferably 3 to 9 Hz, periodically changing the angle of irradiation. Since all the paths along which the reflected laser beam travels cross the target region T-1 at all times, the target region T-1 is continuously irradiated with the laser beam and generates a large amount of heat. Therefore, the target region T-1 is kept at a high temperature and can effectively be treated with heat. On the other hand, the surface layer of the body cavity U is intermittently irradiated with the laser beam, generating a small amount of heat, and is cooled by the coolant supplied to the insert portion 103. Consequently, the surface layer of the body cavity U is protected from and hence is not susceptible to the heat of the laser beam.
[Insert Portion (
The insert portion 103 will be described in greater detail below.
The insert portion 103 includes an elongate hollow cylinder 14 made of a hard pipe material such as stainless steel or the like, with an opening 15 defined in a side wall of the hollow cylinder 14. A graduated window seal is applied over the opening portion 15, providing a laser beam irradiating window 17. A temperature sensor 11 is mounted on the hollow cylinder 14. As shown in
The insert portion 103 houses therein a pair of walls 40, 41 spaced laterally from each other, defining an inner space therebetween in the insert portion 103. The insert portion 103 also houses therein the laser beam irradiation portion 20 with the reflecting surface 21, the reciprocatingly movable member 23, a monorail pipe 25, nonparallel grooves 42, an endoscope 6, and coolant lumens. The reciprocatingly movable member 23 supports the laser beam irradiation portion 20. The monorail pipe 25 has the reciprocatingly movable member 23, which is reciprocatingly movable in the longitudinal direction of the insert portion 103. The nonparallel grooves 42 are defined in the respective walls 40, 41 for changing the angle of the laser beam irradiation portion 20 so that the laser beam reflected by the laser beam irradiation portion 20 is applied to the target region at all times. The endoscope 6 observes the living tissue. The laser beam irradiation portion 20 is rotatably supported on a pair of pivots 27 fixed to respective left and right sides of the reciprocatingly movable member 23 that is fixed to the distal end of the optical fiber 12. The laser beam irradiation portion 20 has a pair of lugs 26 mounted on respective left and right sides thereof and slidably fitted respectively in the nonparallel grooves 42 defined in the walls 40, 41. The nonparallel grooves 42 extend out of parallel with the longitudinal axis of the insert portion 103.
Major components of the insert portion 103 will be described below.
[Laser Beam Irradiating Window (
The glass with scale (graduation) strip 19A or 19B is fixed in position over the opening 15. An adhesive is applied to an end of the glass with scale strip 19A, and the glass with scale strip 19A is fitted into the opening 15 from above and bonded to the hollow cylinder 14, as indicated at (1) in (a) of
As shown in
[First Feature of Temperature Sensor (Thickness)]
A pressing electrode according to a second feature of the temperature sensor 11 will be described below. Prior to describing the pressing electrode, a process of assembling the temperature measuring unit of the temperature sensor 11 will first be described below with reference to
The reflecting surface 21 of the laser beam irradiation portion 20 disposed in the insert portion 103 will be described below. The reflecting surface 21 constitutes part of the laser beam irradiation portion 20, and has a smooth surface for reflecting the laser beam emitted from the distal end of the optical fiber 12 through the laser beam irradiating window 17 to the target region T-1.
[Monorail Pipe (
As shown in
The reciprocatingly movable member 23 serves to change the direction of the applied laser beam depending on the irradiating position thereof when the reciprocatingly movable member 23 moves on the monorail pipe 25 in the directions indicated by the arrows, i.e., in the longitudinal directions of the applicator 110, e.g., from the position (a) to the position (b) to the position (c) to the position (b) to the position (a). Therefore, the direction of the applied laser beam and the irradiating position thereof can continuously be changed to control the laser beam to irradiate the target position at all times.
The reciprocatingly movable member 23 supports the laser beam irradiation portion 20 for reciprocating movement therewith. The reciprocatingly movable member 23 is positioned on one end of the laser beam irradiation portion 20, and the lugs 26 are positioned on the opposite end of the laser beam irradiation portion 20. The laser beam irradiation portion 20 is mounted on the reciprocatingly movable member 23 by the pivots 27 for free angular movement with respect to the reciprocatingly movable member 23 for thereby allowing the angle of the reflecting surface 21 to be changed with respect to the reciprocatingly movable member 23. The lugs 26 are fitted in the respective nonparallel grooves 42 that are defined in the inner surfaces of the walls 40, 41 disposed in the insert portion 103.
The reciprocatingly movable member 23 is coupled to the drive unit 150 (see
[Direction of Applied Laser Beam (
As shown in
The laser beam reflected by the laser beam irradiation portion 20 is applied to the target region T-1 (target point) of the prostate T at all times when the reciprocatingly movable member 23 is in the positions P1 through P3. Therefore, the laser beam continuously irradiates the target region T-1, and intermittently irradiates other tissue regions such as the surface layer of the body cavity U. The target region T-1 that is continuously irradiated with the laser beam generates a large amount of heat and reaches a desired high temperature, whereas the surface layer of the body cavity U, which is intermittently irradiated with the laser beam, generates a small amount of heat and is not heated to a high temperature. Consequently, only the target region T-1 and its surrounding regions are selectively heated by the laser beam for treatment with heat.
The laser beam irradiation portion 20 for reflecting the laser beam is reciprocatingly moved on and along the monorail pipe 25 in periodic cycles at a frequency ranging from 2 to 10 Hz, preferably 3 to 9 Hz, in the longitudinal direction of the insert portion 103 while changing its angle.
[Nonparallel Grooves (
Structural details of the nonparallel grooves 42 will be described below with reference to
As shown in
Coolant outlet lumens 51, 52 for returning the coolant from the distal end of the insert portion 103 to the coolant circulator 104 are disposed between the circumferential wall of the hollow cylinder 14 and the walls 40, 41.
The position of the nonparallel grooves 42 at the position in
Likewise, the position of the nonparallel grooves 42 at the position in
Consequently, the laser beam reflected by the laser beam irradiation portion 20 is concentrated on the target region T-1 at all times based on the different vertical positions of the nonparallel grooves 42.
[Temperature Control System (
A temperature control system of the energy irradiating medical apparatus will be described below.
Operation of the control circuit will be described below. The console 207 includes a keyboard or the like. The user enters from the console 207 a signal for starting various processes for displaying a maximum surface temperature, displaying a deep region temperature, determining an incorrect irradiation timing, and controlling a laser beam output level. When the CPU 201 receives a command for executing the various processes, the CPU 201 operates according to the control program stored in the ROM 202 to receive measured values of the surface temperature from the temperature sensor 11 in the insert portion 103, store the measured values in the RAM 204, and control the laser beam generator 206 and the display 203 based on the measured values for displaying a maximum surface temperature, displaying a deep region temperature, determining an incorrect irradiation timing, and controlling a laser beam output level.
[Process of Estimating Maximum Cavity Wall Temperature (FIGS. 12 Through 14)]
A process of estimating a maximum cavity wall temperature upon laser beam irradiation from measured values of the surface temperature, which are produced by the temperature sensor 11 in the insert portion 103 when the doctor treats an affected region with the energy irradiating medical apparatus 10, will be described below.
First, measuring conditions will be described below. The temperature sensor 11 is disposed at a circumferential end of the laser beam irradiating window 17 shown in
Tmax=Tcool+(1+α)(Tu−Tcool) (1)
the maximum cavity wall temperature Tmax can be estimated from the surface temperature Tu upon laser beam irradiation according to the equation (1).
Based on the above experimental results, a control program for calculating the maximum cavity wall temperature Tmax from the surface temperature Tu upon laser beam irradiation is produced and stored in the ROM 202.
In step S301, Tcool and α are set. In step S302, the surface temperature Tu is measured. In step S303, the maximum cavity wall temperature Tmax is calculated according to the equation (1). In step S304, the measured surface temperature Tu and the calculated maximum cavity wall temperature Tmax are displayed on the display. If a next measuring cycle is to be performed in step S305, then control goes back to step S302, and the above process is repeated. If the present measuring cycle is to be finished in step S305, then control goes to step S306, putting the process to an end.
[Process of Estimating Deep Region Temperature (
A process of estimating a deep region temperature in a living body upon laser beam irradiation from measured values of the surface temperature, which are produced by the temperature sensor 11 in the insert portion 103 when the doctor treats an affected region with the energy irradiating medical apparatus 10, will be described below.
First, measuring conditions will be described below. The temperature sensor 11 is disposed at a circumferential end of the laser beam irradiating window 17 shown in
A process that is the same as the process described above with reference to
Tp=Tu0+α(Tu−Tu0) (2)
the deep region temperature Tp can be estimated from the surface temperature Tu upon laser beam irradiation according to the equation (2).
Based on the above experimental results, a control program for calculating the deep region temperature Tp from the surface temperature Tu upon laser beam irradiation is produced and stored in the ROM 202.
In step S401, Tu0 and β are set. In step S402, the surface temperature Tu is measured. In step S403, the deep region temperature Tp is calculated according to the equation (2). In step S404, the measured surface temperature Tu and the calculated deep region temperature Tp are displayed on the display. If a next measuring cycle is to be performed in step S405, then control goes back to step S402, and the above process is repeated. If the present measuring cycle is to be finished in step S405, then control goes to step S406, putting the process to an end. [Monitoring of reciprocating motion timing (
A process of monitoring irradiation timing upon laser beam irradiation from measured values of the surface temperature, which are produced by the temperature sensor 11 in the insert portion 103 when the doctor treats an affected region with the energy irradiating medical apparatus 10, will be described below.
First, measuring conditions will be described below. The temperature sensor 11 is disposed at a circumferential end of the laser beam irradiating window 17 shown in
[Detection of Laser Beam Output Level]
The output level of a laser beam emitted from the laser beam generator can be measured from the range of temperature changes shown in
Based on the above experimental results, a control program for determining whether the irradiation timing is correct or not from the surface temperature Tu upon laser beam irradiation is produced and stored in the ROM 202.
In step S501, the surface temperature Tu is measured for a certain period of time. In step S502, the measured surface temperature Tu is displayed. In step S503, the number of periodic temperature changes is measured in the above period of time from the measured values of the surface temperature Tu, and it is checked whether or not the measured number of periodic temperature changes agrees with a preset number of periodic temperature changes. If the measured number of periodic temperature changes agrees with the preset number of periodic temperature changes, then control goes to step S506 in which correct reciprocating motion timing is displayed. Then, control goes to step S507 to put the process to an end. If the measured number of periodic temperature changes does not agree with the preset number of periodic temperature changes, then control goes to step S505 in which incorrect reciprocating motion timing is displayed. Then, control goes to step S507 to put the process to an end.
[Control of Laser Beam Output Level (
A process of controlling a laser beam output level upon laser beam irradiation based on measured values of the surface temperature, which are produced by the temperature sensor 11 in the insert portion 103 when the doctor treats an affected region with the energy irradiating medical apparatus 10, will be described below.
First, measuring conditions will be described below. The temperature sensor 11 is disposed at a circumferential end of the laser beam irradiating window 17 shown in
In step S601, a temperature rise pattern Tutarget(t) of the surface temperature upon laser beam irradiation is determined. Specifically, the doctor selects a desired one of a plurality of preset temperature rise patterns, and the CPU 201 determines the temperature rise pattern based on a selection signal entered by the doctor. In step S602, an initial laser beam output level is set. In step S603, the target region is irradiated with a laser beam having the initial laser beam output level. In step S604, the surface temperature T(t) upon laser beam irradiation is measured. In step S605, the measured surface temperature T(t) is compared with the temperature rise pattern Tutarget(t). If Tutarget(t)<Tu(t) in step S605, then control goes to step S606 in which the laser beam output level P is changed to P−ΔP, after which control goes to step S609. If Tutarget(t)=T(t) in step S605, then control goes to step S607 in which the laser beam output level P is not changed, but maintained, after which control goes to step S609. If Tutarget(t)>T(t) in step S605, then control goes to step S608 in which the laser beam output level P is changed to P+ΔP, after which control goes to step S609. If a next output level controlling cycle is to be performed in step S609, then control goes back to step S603, and the above process is repeated. If the present output level controlling cycle is to be finished in step S609, then control goes to step S610, putting the process to an end.
In the above embodiment, the single temperature sensor 11 is disposed in the insert portion 103 as shown in
The energy irradiating medical apparatus according to the present invention should preferably be used to treat a prostate with heat to cure a prostatic disease such as a prostatic hypertrophy, a prostatic cancer, or the like while reducing damage to a correct living tissue, such as the urethra, the rectum, or the like, that is positioned closely to the prostate.
As described above, the temperature measuring unit of the temperature sensor according to the embodiment of the present invention described above has the electrodes disposed on the upper and lower surfaces of the temperature measuring element, the thin-film substrates disposed on the upper and lower surfaces of the electrodes, and the laser beam shield plates disposed on the upper and lower surfaces of the thin-film substrates. The electrode 114A is bonded to the temperature measuring element by the conductive adhesive, and the electrode 11-4B is not bonded to the temperature measuring element by the conductive adhesive. When the temperature sensor is bonded to the hollow cylinder of the insert, the temperature measuring unit is curved along the surface of the hollow cylinder, tending to develop tensile stresses in the electrode 11-4B. At this time, the electrode 114B, which is not bonded to the temperature measuring element, is positionally displaced depending on the developed tensile stresses, allowing the temperature sensor to be adjusted in length. Consequently, the temperature sensor is prevented from being broken or damaged. Therefore, the energy irradiating medical apparatus according to the present invention is capable of accurately measuring the temperature of a living tissue as it is treated with heat, though the energy irradiating medical apparatus is simple in structure and inexpensive to manufacture. Therefore, the doctor who operates the energy irradiating medical apparatus can correctly monitor the temperature of the living tissue as it is treated with heat to cure a prostatic hypertrophy, for example, and hence can treat the living tissue with greater safety.
A temperature sensor (thin thermistor) for use in an energy irradiating medical apparatus according to the first embodiment has useful application in a variety of respects. For example, when an insert portion having a laser beam irradiating window for applying a laser beam is inserted from a lumen such as urethra and the laser beam is applied from the laser beam irradiating window of the insert portion to the deep region of a living tissue to treat benign prostatic hypertrophy, for example, with heat, the energy irradiating medical apparatus can accurately measure the temperature of the living tissue being treated with heat, for increasing the curative effect. The thin thermistor has a temperature measuring unit including a temperature measuring element made of a transition-metal oxide containing Mn, Co, Ni, or Fe. The temperature measuring element has a thickness of about 200 μm which makes itself small in size. The temperature measuring element has a measuring area of 0.09 mm2, for example, and is suitable for measuring a local temperature (spot temperature). As shown in
The energy irradiating medical apparatus can estimate a maximum temperature of the surface of the lumen and a temperature (laser beam irradiation target temperature) of the deep region heated by being irradiated with the laser beam, from the measured temperature of the surface of the lumen. Therefore, the energy irradiating medical apparatus can continuously estimate and display, on a display portion, time-dependent changes of the maximum temperature of the surface of the lumen and the temperature of the deep region. The energy irradiating medical apparatus can be controlled so that when the measured temperature exceeds a preset temperature, the energy irradiating medical apparatus issues a light or sound warning to prompt the operator to pay attention or stops applying the laser beam. Therefore, the living tissue is prevented from being irreversibly damaged due to denaturization of protein (the living tissue is irreversibly damaged if exposed to the temperature of 55° C. for about 20 seconds, the temperature of 50° C. for about 5 minutes, and the temperature of 48° C. for about 10 minutes). The doctor monitors the maximum temperature of the surface of the lumen displayed on the display portion. Thus, the doctor can change the irradiation condition of the laser beam at the heat treatment so that the urethra is prevented from being damaged. The doctor can monitor the effectiveness of the heat treatment or control the application of the laser beam depending on the temperature of the deep region by monitoring the temperature of the deep region displayed on the display portion. For example, if the temperature of the deep region is too low, the doctor can intensify the application of the laser beam, and if the temperature of the deep region has reached a target temperature, the doctor can stop applying the laser beam.
Consequently, the energy irradiating medical apparatus according to the first embodiment is of a structure that is simple and inexpensive to manufacture, and which is capable of safely treating a living tissue with heat by accurately measuring the temperature of the living tissue while it is being treated with heat. Since the temperature measuring unit is thin, the insert portion may be reduced in size to alleviate the pain from the patient when the insert portion is inserted into the patient. As the temperature measuring element does not need to be connected to two leads and placed in a tangle-free manner in a protective tube unlike the structure in related art, the insert portion can be reduced in size. Since the temperature measuring element is not disposed in the insert portion, it is less affected by cooling water and can measure the temperature of the surface of the living body with high accuracy. Since the temperature sensor is not required to directly thrust into a living tissue to measure the temperature of the living tissue, the living tissue is prevented from being damaged by thrusting thereinto and also from a side effect due to an infectious disease.
According to the first embodiment described above, the energy irradiating medical apparatus 10 employs a thin thermistor as a temperature sensor. According to a second embodiment, an energy irradiating medical apparatus 110 employs a temperature sensor including a temperature measuring element in the form of a thin-film metal resistor. In the following description, the thin-film metal resistor is made of aluminum. However, the thin-film metal resistor is not limited to being made of aluminum, but may be made of Pt, W, Ni, Co, Ag, Au, Cu, or the like, for example. A temperature sensor whose thin-film metal resistor is made of aluminum is referred to as a temperature sensor (aluminum sensor). The energy irradiating medical apparatus 10 according to the first embodiment and the energy irradiating medical apparatus 110 according to the second embodiment have similar structural details except that they have different temperature sensors. Those parts of the energy irradiating medical apparatus 110 according to the second embodiment which are identical to those of the energy irradiating medical apparatus 10 according to the first embodiment are denoted by identical reference characters, and will not be described below. The detailed description below will be directed primarily at those parts of the energy irradiating medical apparatus 110 according to the second embodiment which are different from those of the energy irradiating medical apparatus 10 according to the first embodiment.
[Insert Portion (
The energy irradiating medical apparatus 110 according to the second embodiment for treating benign prostatic hypertrophy with heat has a system arrangement which is identical to that shown in
As shown in
The insert portion 1103 houses therein a pair of walls 40, 41 spaced laterally from each other, defining an inner space therebetween in the insert portion 1103. The insert portion 1103 also houses therein a laser beam irradiation portion 20 with a reflecting surface 21, a reciprocatingly movable member 23 which supports the laser beam irradiation portion 20 thereon, a monorail pipe 25 along which the reciprocatingly movable member 23 is reciprocatingly movable in the longitudinal direction of the insert portion 1103, nonparallel grooves 42 for changing the angle of the laser beam irradiation portion 20 so that the laser beam reflected by the laser beam irradiation portion 20 is applied to the target region at all times, an endoscope 6 for observing the living tissue, and coolant lumens. The laser beam irradiation portion 20 is rotatably supported on a pair of pivots 27 fixed to respective left and right sides of the reciprocatingly movable member 23 that is fixed to the distal end of the optical fiber 12 (energy emitter). The laser beam irradiation portion 20 has a pair of lugs 26 mounted on respective left and right sides thereof and slidably fitted respectively in the nonparallel grooves 42 defined in the walls 40, 41. The nonparallel grooves 42 extend out of parallel with the longitudinal axis of the insert portion 103.
Of the major components described above, structural details of the laser beam irradiating window 17 and the temperature sensor (aluminum sensor) 111, features thereof, and processes of manufacturing them will be described below. The description of other components disposed in the insert portion 1103, i.e., the reflecting surface 21 of the laser beam irradiation portion 20, the monorail pipe 25, the reciprocatingly movable member 23, and the nonparallel grooves 42, and the description of the relationship between the movement of the reflecting surface 21 of the laser beam irradiation portion 20 and the direction in which the laser beam is applied, are the same as those in the first embodiment, and will be omitted below.
[Laser Beam Irradiating Window (
First, a process of applying the temperature sensor (aluminum sensor) 111 to the laser beam irradiating window 17 will be described below.
The window seal with scale 18 whose reverse side is coated with an adhesive is bonded to an area including the opening portion 15 of the hollow cylinder 14 and fixed thereto, as indicated at (1) in
Then, as indicated at (2) in
Instead of the window seal with scale 18 described above, the graduated glass strip 19A or 19B as shown in
[Structure of Temperature sensor (Aluminum Sensor) (FIGS. 24A through 24C)]
Structural details of the temperature sensor (aluminum sensor) will be described below.
As shown in
The temperature measuring unit 111-7 is constructed of a thin-film substrate 111-5, the temperature measuring element 111-1, and the electrodes 1114. The temperature measuring element 111-1 and the electrodes 111-4 may be electrically connected to each other by being integrally manufactured or by being separately manufactured and then joined to each other. For integrally manufacturing the temperature measuring element 111-1 and the electrodes 111-4, an aluminum film is evaporated on the thin-film substrate 111-5, patterned to a predetermined shape, and then etched. The thin-film substrate 111-5 should preferably be made of a synthetic resin film with a smooth surface, e.g., a film of polyester, polycarbonate, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyamides or the like. It should preferably excel in optical penetration, thermal conduction and heatproof ability. Especially, the difference of thermal expansion between the radical material and the metal for the temperature sensor should be small to prevent the metal from flaking off from the radical material. Particularly, a PET film is preferable as the material of the thin-film substrate 111-5. The thickness of the thin-film substrate 111-5 is in the range from 16 to 80 μm, or preferably in the range from 38 to 50 μm. The temperature measuring element 111-1 preferably has a line width in the range from 5 to 40 μm and a total length in the range from 50 to 100 mm. Preferably, the temperature measuring element 111-1 has a resistance in the range from 100 to 1000 Ω. The temperature measuring unit 111-7 has a temperature measuring region 111-9 to be measured by the temperature measuring element 111-1, and the temperature measuring region 111-9 has an area of 9 mm2, for example. The area of the temperature measuring region should preferably be greater than the width of the laser beam that passes through the laser beam irradiating window or should preferably be greater than the diameter of the laser beam spot and smaller than the width of the laser beam irradiating window. If the temperature measuring element 111-1 (having a line width of 20 μm and a total length of 85 mm) shown in
The conductor assembly 111-2 is constructed of the thin-film substrate 111-3 made of an insulating material such as polyimide, nylon, polyethylene, PET, or the like, and four conductors 111-6 mounted on the thin-film substrate 111-3 and each in the form of a strip of a conductive material. Two of the four conductors 111-6 are used to detect a voltage, and the other two are used to introduce a constant current. The four conductors 111-6 may be replaced with two conductors 111-6. The thin-film substrate 111-2 has a plurality of position (depth) markers 111-8 thereon for the user to easily read the length of the temperature sensor (aluminum sensor) 111 which has been inserted into a living body, as shown in
[Features of Temperature Sensor (Aluminum Sensor) (Thickness)]
Features of the temperature sensor (aluminum sensor) 111 will be described below. According to a first feature of the temperature sensor (aluminum sensor) 111, the thickness of the temperature sensor can be reduced. A thin-film metal resistor that can be used as the temperature measuring element is a thin metal film of Al, Pt, Ti, W, Ni, Co, Cu, Ag, Au, or the like, for example. Since the thin-film metal resistor itself has a very small thickness in the range from 0.2 to 3 μm, the temperature sensor can be reduced in thickness. As metal has a large laser beam reflectance (e.g., 90% for Al), a metal film used as the temperature measuring element does not need to be covered with a laser beam shield plate, so that the temperature sensor can further be reduced in thickness. Additionally, it should preferably be high in light reflectance rate, electric resistance, and resistance temperature coefficient (TCR). As for this metal, the melting point should be low and the thermal conductivity should be high.
An example of thicknesses of the components of the temperature sensor (aluminum sensor) 111 wherein the thin-film metal resistor is made of aluminum will be described below. The thin-film substrate 111-5 has a thickness in the range from 16 to 80 μm, or preferably in the range from 38 to 50 μm, each of the temperature measuring element 111-1 and the electrodes 1114 has a thickness in the range from 0.2 to 3 μm, or preferably in the range from 0.5 to 1.5 μm. The conductors 111-6 have a thickness in the range from 10 to 20 μm. The thin-film substrate 111-3 has a thickness in the range from 10 to 20 μm. As shown in
In
[Second Feature of Temperature Sensor (Aluminum Sensor) (Measuring Region)]
A second feature of the temperature sensor (aluminum sensor) 111 will be described below. According to the second feature of the temperature sensor (aluminum sensor) 111, since a long thin-film metal resistor having a small line width is employed, it is possible to measure the temperature of a wide region (surface region or preferably a region wider than the diameter of the laser beam spot and smaller than the width of the laser beam irradiation window). For example, if the resistance of the thin-film metal resistor is in the range from 100 to 1000 Ω and the thin-film metal resistor is made of aluminum, then the thin-film metal resistor can be designed to have a line width ranging from 5 to 40 μm and a length in the range from 50 to 100 mm. For example, the thin-film resistor of aluminum having a shape shown in
The thin-film metal resistor made of aluminum is installed in a wide area (the area of the temperature measuring region: 9 mm2) extending from a position near the upper end of the laser beam irradiating window 17 to a position near the lower end of the laser beam irradiating window 17, as shown in
When the temperature of a wide area (surface area) is measured by the temperature sensor 111 wherein the temperature measuring region 111-9 shaped as shown in
If the temperature sensor (aluminum sensor) 111 capable of measuring the temperature of a wide region (surface region) is employed, then variations of temperature measurement due to manufacturing variations can be reduced. Manufacturing variations include variations of tilt of the laser beam irradiation portion 20 with respect to the laser beam irradiation window 17, and variations of the thickness of the temperature measuring unit. If such manufacturing variations occur, then when the temperature sensor measures the temperature of a small region (spot), the measured temperature is affected by the manufacturing variations. If insert portions are changed and used as when a plurality of insert portions are replaced and used, since the measured temperature is affected by the manufacturing variations, the temperature cannot accurately be measured. However, since the temperature sensor (aluminum sensor) 111 includes a long thin-film metal resistor having a small line width, it can measure the temperature of a wide region (surface region), and hence can measure, accurately at all times, the maximum temperature of the surface of the living tissue that is held in contact with the laser beam irradiation window 17 even though manufacturing variations occur.
[Process of Manufacturing Aluminum Sensor]
A process of manufacturing the temperature measuring unit of the temperature sensor (aluminum sensor) 111 will be described below. For simultaneously manufacturing the temperature measuring unit 111-7 and the electrodes 111-4 of the temperature sensor (aluminum sensor) 111 shaped as shown in
[Measurement of Temperature of Surface Layer Irradiated with Laser Beam (
An example of results produced when temperatures were measured using the temperature sensor (aluminum sensor) 111 is shown in
In
[Temperature Control System (
A process of estimating a surface temperature and various control processes with the energy irradiating medical apparatus 110 using the measured temperature will be described below. Since a control circuit of the energy irradiating medical apparatus 110 is the same as the control circuit of the energy irradiating medical apparatus 10 according to the first embodiment described above with reference to
A process of estimating a urethra surface temperature from the surface temperature actually measured by the temperature sensor (aluminum sensor) 111 mounted on the insert portion 1103 when the doctor treats the urethra with heat using the energy irradiating medical apparatus 110 will be described below.
Since the temperature sensor (aluminum sensor) 111 is disposed to cover a region (preferably a region wider than the diameter of the laser beam spot and narrower than the width of the laser beam irradiation window) shown in
If the inner surface (L0 in
γ=L2/L3=0.72 (3)
Using the corrective coefficient γ according to the equation (3), the urethra surface temperature Tmax can be obtained from the measured surface temperature Tu by the following equation:
Tmax=Tcool+(Tu−Tcool)/γ (4)
where Tcool represents the temperature of the coolant for cooling the interior of the insert portion 1103, and is 20° C., for example.
Based on the above experimental results, a control program for calculating the maximum temperature Tmax of the urethra surface from the surface temperature Tu measured when the living tissue is irradiated with the laser beam was generated and stored in the ROM 202.
In step S1301, Tcool (e.g., 20° C.) and the corrective coefficient β (e.g., 0.72) are set. In step S1302, the surface temperature Tu is measured. In step S1303, the urethra surface temperature Tmax is calculated according to the equation (4). In step S1304, the measured surface temperature Tu and the calculated urethra surface temperature Tmax are displayed on the display. If a next measuring cycle is to be performed in step S1305, then control goes back to step S1302 to repeat the processing from step S1302. If the measuring process is to be finished in step S1305, then control goes to step S1306 where the processing sequence is put to an end.
[Estimation of Temperature of Deep Region of Living Body]
The energy irradiating medical apparatus 110 according to the present embodiment is capable of monitoring irradiation timing for applying the laser beam from the value of the surface temperature measured by the temperature sensor (aluminum sensor) 111 mounted on the insert portion 1103 when the doctor treats the urethra with heat, as described above with reference to
[Controlling of Laser Beam Output Value (
The energy irradiating medical apparatus 110 according to the present embodiment is also capable of controlling the output value of the laser beam when the living body is irradiated with the laser beam (e.g., to heat the living tissue according to the temperature increasing pattern shown in
The embodiments described above are not described in order to limit the present invention, but various modifications may be made therein within the technical concept of the present invention. The energy irradiating medical apparatus according to the present invention should preferably be applied to the treatment of a prostate gland with heat while reducing heat-induced damage to a normal tissue such as a urethra or a rectum that is present in the vicinity of the prostate gland, in the treatment of a prostatic disease such as benign prostatic hypertrophy or prostatic cancer.
[Summary of Temperature Sensor According to Second Embodiment]
The features of the temperature sensor (thin-film metal resistor, metal sensor) used in the energy irradiating medical apparatus 110 according to the second embodiment will be summarized as follows: The energy irradiating medical apparatus 110 is capable of directly accurately measuring the surface temperature of a living tissue while it is being treated with heat, for an increased therapeutic effect, when the insert portion having the laser beam irradiation window for applying the laser beam is inserted from a lumen such as a urethra, and the laser beam is applied from the laser beam irradiation window to the living tissue to treat benign prostatic hypertrophy with heat. The temperature measuring unit of the metal sensor employs a thin-film metal resistor as a temperature measuring element, and has a thickness ranging from 0.2 to 3 μm which is suitable for making the temperature sensor smaller in size. The temperature measuring unit is suitable for measuring a wide region (surface region) having an area of 9 mm2, for example. The temperature measuring element of the thin-film metal resistor may be of a simple structure as there is no need for a laser beam shield plate because it has a large laser beam reflectance (90% for Al). As shown in
The maximum temperature of the surface of the lumen and the temperature (laser beam irradiation target temperature) of the deep region heated by being irradiated with the laser beam can be estimated from the measured temperature of the surface of the lumen. Therefore, the energy irradiating medical apparatus can continuously estimate and display, on a display, time-dependent changes of the maximum temperature of the surface of the lumen and the temperature of the deep region. The energy irradiating medical apparatus can be controlled so that when the measured temperature exceeds a preset temperature, the energy irradiating medical apparatus issues a light or sound warning to prompt the operator to pay attention or stops applying the laser beam. Therefore, the living tissue is prevented from being irreversibly damaged due to denaturization of protein (the living tissue is irreversibly damaged if exposed to the temperature of 55° C. for about 20 seconds, the temperature of 50° C. for about 5 minutes, and the temperature of 48° C. for about 10 minutes). The doctor can change laser beam irradiating conditions for the treatment with heat so as not to damage the urethra, by monitoring the maximum temperature of the surface of the lumen that is displayed on the display. The doctor can also monitor the effectiveness of the treatment with heat or control the application of the laser beam depending on the temperature of the deep region by monitoring the temperature of the deep region displayed on the display. For example, if the temperature of the deep region is too low, the doctor can intensify the application of the laser beam, and if the temperature of the deep region has reached a target temperature, the doctor can stop applying the laser beam.
Inasmuch as the temperature measuring unit of the metal sensor is suitable for the measurement of a wide region (surface region), even if the insert portion suffers manufacturing variations when it is manufactured, the temperature of the temperature measuring unit is not changed due to such manufacturing variations.
Though the energy irradiating medical apparatus according to the present embodiment is of a structure that is simple and inexpensive to manufacture, it is capable of safely treating a living tissue with heat by accurately measuring the temperature of the living tissue while it is being treated with heat. Since the temperature measuring unit is thin, the insert portion may be reduced in size to reduce the pain which the patient suffers when the insert portion is inserted into the patient. As the temperature measuring element does not need to be connected to two leads and placed in a tangle-free manner in a protective tube unlike the conventional structure, the insert portion can be reduced in size. Since the temperature measuring element is not disposed in the insert portion, it is less affected by the coolant and can measure the temperature of the surface of the living body with high accuracy. Since the temperature sensor is not required to directly thrust into a living tissue to measure the temperature of the living tissue, the living tissue is prevented from being damaged by thrusting thereinto and also from a side effect due to an infectious disease.
While preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made, and equivalents employed, without departing from the spirit and scope of the invention as recited in the following claims.
Number | Date | Country | Kind |
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2005-099305 | Mar 2005 | JP | national |
2004-106089 | Mar 2004 | JP | national |
This application is a continuation-in-part application of U.S. application Ser. No. 11/090,241 filed on Mar. 28, 2005, the entire content of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 11090241 | Mar 2005 | US |
Child | 11198508 | Aug 2005 | US |