JPH04198680A - Cryoprobe - Google Patents

Abstract

PURPOSE:To maintain good adiabatic property even under a vacuum and achieve flexibility as well as reduction of the diameter of a probe by a method wherein a gap retaining member, capable of contacting intermittently without contacting an outer tube with a conduit continuously at least in the axial direction thereof, is arranged on the surface of the conduit. CONSTITUTION:A polyester thread or a nylon thread, having a diameter proximated to about 1/2 A, are wound into reverse directions to each other or changing their winding pitches so as to intersect to each other while two threads 3 are constituted so that a gap 4, corresponding to the size of two threads, is constituted. In this case, the diameter of a pair of threads 3 is about 1/2 A and therefore, both tubes 1, 2 are never contacted along the whole length of the gap 4. Accordingly, intersecting points 7, whereat two threads are superposed, becomes supporting points between the outer tube 2 and the inner tube 1 which are supported concentrically. As a result, the annular gap 4 is supported with a proper distance whereby heat transfer loss is minimized and the threads 3 will never preclude the evacuation of the tube since the diameter of the thread is 1/2 A.

Description

[Detailed Description of the Invention] [Industrial Application Field J] The present invention can be used as an industrial ultralow-temperature cooling probe for localized areas, and can also be used to treat affected areas such as polyps, cancers, and tumors that have formed on biological tissues such as the throat, esophagus, and stomach. The present invention relates to a cryoprobe, which can also be used as a probe for freezing living organisms, and more particularly to a cryoprobe whose tip heat transfer part can be cooled using an ultra-low temperature liquid such as liquid nitrogen introduced through a thin tube.

``Prior Art'' Conventionally, for example, as shown in FIG. The cryoprobe is formed by forming communication between the inner tube 6 and the middle tube l through the cavity 9, and airtightly sealing the tip end side of the outer tube 2 located outside of the inner tube 6 with the tip plug 8. This probe is well known in the art (Japanese Patent Application No. 63-244506, etc., and FIG. 1 shows the main part of the present invention and is not a conventional example), and such a probe is, for example, inserted into the endoscope 20 as shown in FIG. The endoscope 20 is inserted into the living tissue 30 such as the urethra or stomach, and then monitored with the endoscope with the protruding tip of the probe in contact with the affected area 31. At the same time, the affected area is cooled and frozen through the tip plug 8 by colliding with the inner surface of the tip plug 8 from the cavity 9 an ultra-low temperature fluid such as liquid nitrogen conducted through the inner tube 6, and thawing is repeated several times. It is designed to eliminate so-called frostbite and remove the diseased root part of the affected area.

In this connecting probe, since the inner tube 6 and the middle tube 1 are connected through the cavity 9, the tip plug 8
Freezing of the biological tissue in contact with the tip plug 8 is performed by exhausting the vaporized liquid that has absorbed heat due to the collision with the tip plug 8 through the inner tube 1, and adjusting the exhaust amount as well as the temperature and introduction amount of the cryogenic fluid. The depth and freezing range can be set arbitrarily, and the injection of cryogenic fluid is stopped and the frozen affected area is thawed based on direct observation with an endoscope or judgment from external X-rays, and the freezing and thawing process is then repeated several times. By doing this, it is possible to completely freeze only the diseased root part of the affected area in three dimensions rather than two-dimensionally, and kill and remove it.The frostbitten part is naturally eliminated by expulsion, and as a result, surgical laparotomy can be performed. This makes it possible to remove and treat the affected area without any problems, and its practical value is extremely great.

Now, since the cryoprobe IO generally has a configuration in which it is inserted into in-vivo tissue using the esophagus, etc., if normal living tissue comes into contact with the outer periphery except for the tip plug 8, freezing and melting may occur. Therefore, in the above device, the space between the middle pipe 1 and the outer pipe 2 is placed under vacuum to maintain heat insulation.
In order to maintain a reduced pressure (vacuum) state between the two, the outer tube 2 must have enough strength to withstand the pressure resistance, and as a result, the outer tube 2 needs to be made thicker or made of a rigid material. was there.

However, forming the outer tube from a rigid material or increasing its wall thickness means sacrificing flexibility, which greatly reduces operability and allows the tip plug to be inserted into the desired position within the living tissue. It becomes difficult to make contact with the

Furthermore, if the wall thickness of the outer tube 2 is increased, the outer diameter of the probe 10 will inevitably increase, making it difficult to incorporate it into the endoscope 20 together with a fiberscope or the like.

In order to eliminate this drawback, we have developed a technique that involves laminating aluminum foil and resin mesh and wrapping it around the inner tube to evacuate the hollow part for insulation. Thread 1 having a diameter approximately equal to the inner space gap, for example, a resin thread such as polyester thread or nylon thread is wound around the inner tube l in a spiral manner, and the resin thread is used to prevent the outer tube from collapsing and maintain its strength. A technique for achieving this has been proposed as a prior art.

``Problems to be Solved by the Invention'' However, in the former method, the outer tube and the inner tube come into substantial surface contact through the mesh, which not only makes it impossible to obtain desirable heat insulation properties, but also reduces flexibility and costs. High, difficult to manufacture.

In addition, in the latter method, the resin thread has a so-called line contact structure in which it contacts the outer tube and the inner tube in a spiral manner.
However, the contact area of the thread becomes thick in the form of a band due to the crushing caused by the pressure difference between the thread and the outer tube, and even if the thread is made of resin yarn with high heat insulation properties, the inner tube may be penetrated through the thread. Cold heat is transferred to the outer tube and the desired effect cannot be achieved.

In view of the shortcomings of the prior art, the present invention provides a cryocooler that can achieve flexibility and diameter reduction while maintaining good heat insulation even when the space between the inner tube and the outer tube is placed under vacuum. It is an object of the present invention to provide probes, particularly - probes for freezing living organisms.

"Technical Means for Solving the Problem" The present invention provides an outer pipe that envelops the periphery of one or more conduits through a gap, through which cooling fluid is introduced/discharged toward a highly thermally conductive member disposed on the distal end side. The present invention also relates to a cryoprobe in which a gap between the outer tube and the conduit is maintained under reduced pressure.

That is, the present invention is not limited to probes for freezing living organisms, but also includes probes for industrially performing local cooling.

Furthermore, the conduit is not necessarily limited to concentric double pipes, but also includes heterocentric multiple pipes, and cold ready-to-use fluids also include gases in addition to liquids, and "under reduced pressure" refers to conditions other than vacuum conditions. Also includes under negative pressure.

In addition, the present invention provides a probe having the above configuration, in which there is no continuous contact between the outer tube and the conduit at least in the axial direction.
A cryostat characterized in that a gap holding member that can be contacted intermittently, more preferably substantially in point contact, is disposed on the surface of the conduit, thereby holding the outer tube and the conduit concentrically. Suggest a probe.

Although such a gap retaining member may have a large number of protrusions scattered on the surface of the conduit, it is difficult to make the height of the protrusions constant.

Therefore, in the present invention, a plurality of thread bodies are wound on the surface of the middle tube so as to intersect with each other, and the outer tube can be held using the intersection as a holding fulcrum, or a knot is formed on the surface of the middle tube. A cryoprobe is proposed in which one or more thread bodies having a thread body are wound around the thread body, and the outer tube can be held by using the knot as a holding fulcrum.

In addition, it is preferable to use a resinous or resin-containing thread that does not hinder flexibility and has high heat insulation properties for the thread, but is not limited to this.

For example, as shown in FIGS. 1 and 2, the outer tube 2 and the inner tube 1
By winding the threads 3 having a diameter a of 1/2 in opposite directions or with different pitches around the ring-shaped gap 4 around the inner tube l, the intersection point 7 where the threads 3 intersect has a diameter of 1/2. The two points overlap, and the height of the intersection 7 is equal to the ring-shaped gap 4.
is equivalent to

As a result, the contact between the outer tube 2 and the inner tube 1 is essentially a point contact, so that the heat transfer surface is much smaller than in the prior art, which is wound with a thread having the same diameter as the hollow diameter. Ta.

However, since the formation intervals of the intersection points 7 are almost constant and are set at symmetrical positions in the circumferential direction, the outer pipe 2 and the middle pipe 1
Since concentric circles are formed through the intersection point 7, in other words, the flow path for vacuum formation is reliably guaranteed without one side being crushed, so vacuum formation can be easily performed.

In addition, as described above, one or more threads 3 having a knot 7A are wound on the surface of the inner tube 1 without crossing the plural threads 3, and the outer tube 2 is held using the knot 7A as a holding fulcrum. Similar results can be obtained even if the configuration is made possible.

Therefore, according to the present invention, since the plurality of threads 3 are simply crossed or wound by providing a knot 7A, the material cost and assembly cost are both low, and the contact heat transfer area is Because the area has been significantly reduced, the insulation effect has been greatly improved.

"Embodiments" Below, effective embodiments of the present invention will be described in detail based on the drawings. However, unless there is a specific description, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. .

1 to 3 show a biological cryoprobe according to an embodiment of the present invention, and FIG. 1 is a cutaway sectional view of the tip thereof;
FIG. 2 is a front view showing the intermediate pipe section, and FIG. 3 is a side view thereof.

As already explained in the prior art section, for example, the inner tube 6
is a conduction tube through which nitrogen liquid passes, and has an outer diameter of approximately lφ and an inner diameter of 0.
．． Formed with an 8φ thin tube, outer diameter 2.2φ, inner diameter 2.0φ
It is inserted concentrically into the middle tube l of.

In this case, since the inner tube 6 is not fixed and is freely located within the middle tube 1, the return gas flows back through the space with less resistance.

A resin thread 3 such as polyester or nylon thread is wound around the outer circumference of the inner tube 1 to serve as a space retaining member 3 between the inner tube 1 and the outer tube 2, and a ring-shaped gap 4 between the inner tube 1 and the outer tube 2 is vacuum-sucked. are doing.

According to this probe, while liquid nitrogen 32 is being fed under pressure from the inner tube 6, the liquid nitrogen 32 is injected at the tip of the probe, expands and collides with the tip plug 8, and after the latent heat of vaporization acts as freezing heat, it is absorbed. The gas 33 that has been gasified is reversed and discharged to the outside through the inner gap 5 of the inner tube 6 and the middle tube 1.

At this time, since the liquid or gas flows through the middle pipe 1 and the inner pipe 6 under positive pressure, there is no need to provide a holding member, and on the contrary, the presence of a holding member causes resistance, which is undesirable and does not allow contact. Since it is inside the refrigerant, the effect of heat loss is small.

Since this point is already known, a detailed explanation of the structure will be omitted, and the winding structure of the resin yarn 3, which is the main part of the present invention, will be explained.

As shown in Fig. 2, polyester threads or nylon threads having a diameter of approximately 1/2A are wound around the middle tube 1 in opposite directions or at different winding pitches so as to cross each other. The structure is such that the two points (diameters) where the two threads 3 overlap at the intersection 7 serve as the holding fulcrum of the gap 4A. That is, since the diameter a of the pair of threads 3 is approximately 1/2A diameter, the two tubes do not come into contact with each other over the entire length of the gap except at the point where the passage 4 is as shown in FIG. 1. As a result, as shown in FIGS. As shown in the figure, the two wound threads 3 overlap, and the intersection point 7 where the two thread diameters overlap becomes a fulcrum that holds the outer tube 2 and the inner tube 1 concentrically.

FIG. 4 shows another embodiment in which the winding thread 3 is one winding, knots 7A are provided at appropriate gaps, and the height of the knots 7A is set to be approximately equal to the gap height A. , the knots 7A are positioned symmetrically in the circumferential direction.

Configure it so that As a result, the knot 7A maintains a gap between the outer tube 2 and the inner tube 1 at a point of contact.

As a result, even in the embodiment of the above-mentioned face surface, heat transfer loss can be minimized by supporting the ring-shaped void 4 at points at appropriate intervals, and the thread 3
Since the diameter is 1/2A, it does not hinder vacuum suction to the same extent.

In addition, in order to increase the heat insulation effect, the outer tube 2 and the inner tube 1
The effects of the present invention are further enhanced by forming the inner tube 6 from a flexible thin tube body made of gold having high flexibility and high reflection rate or whose surface is coated with gold.

[Effects] As described above, according to the present invention, even when the space between the inner tube 1 and the outer tube 2 is placed under vacuum, flexibility and diameter reduction can be achieved while maintaining good heat insulation properties. In particular, we have been able to provide a cryoprobe that can be used to freeze living organisms, and this has made it possible for the first time to put into practical use a probe for freezing living organisms that can be incorporated into endoscopes for observing inside living organisms, eliminating the need for surgical operations, and its practical value is extremely high. However, the present invention is not limited to this, and can also be used as an industrial local cryogenic cooling probe.

[Brief explanation of the drawing]

FIG. 1 shows the present invention. FIGS. 1 to 3 show a biological cryoprobe according to an embodiment of the present invention. FIG. 1 is a cutaway sectional view of its tip, and FIG. 3 is a front sectional view showing the same, and FIG. 3 is a side view thereof. FIG. 4 is a front sectional view showing an intermediate duct portion of another embodiment, and FIG. 5 is a front sectional view showing an intermediate duct portion of a biological cryoprobe according to the prior art. FIG. 6 is an operational diagram showing an example of the use of the biological cryoprobe. Patent applicant: Maekawa Seisakusho Co., Ltd.

Claims (4)

[Claims] (1) An outer tube is provided that surrounds one or more conduits through a gap for introducing/discharging cooling fluid toward a member with good thermal conductivity placed on the tip side, and a space between the outer tube and the conduit is provided. A cryoprobe in which a gap is maintained under reduced pressure is characterized in that a gap holding member is disposed on the surface of the conduit that can contact the outer tube and the conduit intermittently without continuous contact at least in the axial direction. cryoprobe (2) The gap holding member functions as an assembly of a large number of holding fulcrums capable of holding the outer tube and the conduit in substantial point contact, and the holding fulcrums hold the outer tube and the conduit concentrically. The cryoprobe according to claim 1) wherein the cryoprobe is retained. (3) A cryoprobe according to claim 1, wherein a plurality of strands are wound on the surface of the inner tube so as to intersect with each other, and the outer tube can be held using the intersection as a holding fulcrum. (4) The cryoprobe according to claim 1, wherein one or more thread bodies having a knot are wound around the surface of the inner tube, and the outer tube can be held using the knot as a holding fulcrum.