Medical laser device

A medical laser device includes a device body and a laser probe connected to the body. In the device body are arranged a laser source for emitting laser beams and an air pump. The laser probe has an outer tube, a laser guide extending through the tube, and an air supply passage defined between the inner surface of the tube and laser guide. The laser beams emitted from the laser source are guided through the laser guide and ejected from the distal end of the laser guide. A drying unit is connected to the discharge side of the pump. Air streams are supplied from the pump to the air supply passage after being dried by the drying unit, and then ejected from the air supply passage toward the distal end of the laser guide.

BACKGROUND OF THE INVENTION 
This invention relates to a medical laser device, and more particularly to 
a medical laser device provided with air-feeding means. When laser 
treatment is applied to an internal organ, for example, the stomach in the 
coeliac cavity by means of a medical laser device, a laser probe is 
inserted into the coeliac cavity. Laser beams are irradiated through said 
laser probe. When, however, laser beams are sent into the coeliac cavity, 
smoke emanating from the burned organization, and blood and viscous 
liquids scatter from the walls of the coeliac cavity, and settle on the 
laser emitting end of the laser probe. When the scattered mass is attached 
to the laser emitting end, the laser energy is absorbed in the deposited 
scattered mass, thereby generating a large amount of heat at the emitting 
end and leading to damage of the laser probe. 
To avoid the above-mentioned drawbacks, there has been proposed a laser 
device which is designed to eject air streams from the tip of the laser 
probe to prevent the particles scattered with the coeliac cavity wall from 
being deposited on the tip of the laser emitting end. In this device, the 
air streams are produced by sucking air by an air pump and compressing it 
thereby, and supplying it to the air supply passage of the laser probe by 
the pump. 
Since, however, the air is supplied after being compressed by the air pump, 
air moisture is condensed into water particles. The water particles are 
carried through the air supply passage to the tip of the laser probe. When 
water particles settle on the laser emitting end, the laser beams undergo 
irregular reflections or refractions. Thus, the laser beams are prevented 
from being converged on the desired spot in the coeliac cavity, and 
irradiated on the tip of the laser probe to damage it. 
SUMMARY OF THE INVENTION 
This invention has been accomplished in view of the above-mentioned 
drawbacks, and is intended to provide a medical laser device which 
prevents water particles from being generated at the laser probe tip, 
thereby suppressing the irregular reflections and refractions of laser 
beams. 
To attain the above-mentioned object, the present invention provides a 
medical laser device which comprises: 
a laser source for emitting laser beams; 
air supply means for supplying air streams; 
a laser probe provided with a laser guide, having a laser emitting end, for 
guiding the laser beams emitted from the laser source and emitting the 
laser beams from the emitting end, and an air supply passage allowing for 
the passage of air streams drawn off from the air pump and the ejection of 
said air streams to the vicinity of the emitting end of the laser guide; 
and 
drying means, set between the air pump and laser probe, for drying the air 
streams conducted from the air pump.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Description may now be made with reference to the accompanying drawings of 
a medical laser device embodying this invention. As seen from FIGS. 1 and 
2, the subject medical laser device comprises a device body 10, wherein a 
laser source 12 and an air pump 14 are disposed. The device body 10 is 
connected to a laser probe 16 for conducting laser beams into the coeliac 
cavity of a patient. The laser probe 16 includes an outer tube 20 
connected at one end to the device body 10 by means of a connector 18. The 
distal end of the outer tube 20 is fitted with a nozzle 22. A laser guide 
24 extends through the outer tube 20 from the connector 18 to the nozzle 
22. Laser beams delivered from the source 12 are ejected from the nozzle 
22 while being conducted through the guide 24. The laser source 12 is 
provided with a laser rod 13, a resonance mirror 15, and a shutter 26 
between them. The emission of a laser beam from the source 12 is 
controlled by the shutter 26. 
In the laser probe 16, an air supply passage 28 is defined between the 
inner surface of the outer tube 20 and laser guide 24 and extends from the 
connector 18 to the nozzle 22. An air pipe 30 is set between the connector 
18 and the discharge side of the air pump 14. The air supply passage 28 
communicates with the air pump 14 through the air pipe 30. A valve 32 for 
opening and closing the air pipe 30 is provided on that side of the air 
pipe 30 which faces the connector 18. A drying unit 34 is set on the air 
pipe 30 between the valve 32 and air pump 14. Accordingly, air streams 
flowing from the air pump 14 are supplied to the air supply passage 28 of 
the laser probe 16 through the air pipe 30, after being dried by the 
drying unit 34, and later ejected to the outside at the nozzle 22 after 
being conducted through the air supply passage 28. 
As seen from FIG. 3, the drying unit 34 consists of a drying agent type 
dryer. The drying unit 34 comprises an outer case 36 and first and second 
drying cylinders 38, 40 held in the outer case 36. These drying cylinders 
38, 40 are filled with silica gel acting as a drying agent. The drying 
cylinders 38, 40 are respectively provided with bottom ports 42a, 42b. The 
bottom port 42a of drying cylinder 38 communicates with the air pipe 30 
through a connection pipe 43a, influx side changeover valve 44 and influx 
pipe 46. The bottom port 42b of drying cylinder 40 communicates with the 
air pipe 30 through a connection pipe 43b, the changeover valve 44 and 
influx pipe 46. The connection pipes 43a, 43b communicate with the outside 
of the outer case 36 respectively through the exhaust valves 48a, 48b. A 
connection pipe 50a is inserted into the drying cylinder 38, and the top 
end of the connection pipe 50a constitutes an upper port 52a of the drying 
cylinder 38. The connection pipe 50a communicates with the air pipe 30 
through an exhaust side changeover valve 54 and exhaust pipe 56. A 
connection pipe 50b is inserted into the drying cylinder 40, and the top 
end of the connection pipe 50b constitutes an upper port 52b of the drying 
cylinder 40. The connection pipe 50b communicates with the air pipe 30 
through the changeover valve 54 and exhaust pipe 56. An orificed bypass 
pipe 58a is provided between the exhaust changeover valve 54 and 
connection pipe 50a. An orificed bypass pipe 58b is provided between the 
exhaust changeover valve 54 and connection pipe 50b. 
When the influx changeover valve 44 and exhaust changeover valve 54 are set 
in the positions indicated in FIG. 3, air streams delivered from the air 
pump 14 are carried into the first drying cylinder 38 through the influx 
pipe 46, changeover valve 44 and connection pipe 43a. The air streams 
whose moisture is absorbed by the drying agent are carried into the air 
pipe 30 through the connection pipe 50a, exhaust valve 54 and exhaust pipe 
56. Part of the dried air streams are brought into the second drying 
cylinder 40 through the bypass pipe 58b and connection pipe 50b. After 
removing moisture from the drying agent in the second drying cylinder 40, 
the part of the dried air streams is discharged to the outside through the 
connection pipe 43b and exhaust valve 48b. 
As mentioned above, the drying unit 34 is so designed that while air 
streams are dried by one of the two drying cylinders, the drying agent 
held in the other drying cylinder is regenerated by being dried by part of 
the previously dried air streams. Consequently, the drying unit 34 can 
continuously dry the air streams delivered from the air pump 14 for many 
hours, by periodically changing the operation of the influx changeover 
valve 44 and exhaust changeover valve 54. 
Referring to FIGS. 4 and 5, the laser probe 16 includes an operation 
section 60 set in the intermediate part of the outer tube 20. An operation 
lever 62 is rockably fitted to the operation section 60. The distal end 
portion of the outer tube 20 is made thin to constitute a flexible portion 
64. An operation wire 66 extends through the outer tube 20, and is 
connected at one end to the operation lever 62 and at the other end to the 
nozzle 22. When, therefore, the operation lever 62 is rocked either to 
pull or push the operation wire 66, the flexible portion 64 of the laser 
probe can be turned in any desired direction. 
As seen from FIG. 5, the laser guide 24 includes a core 68 composed of an 
optical fiber and an outer covering 70 surrounding the outer peripheral 
surface of the core 68. A scale 72 is formed on the outer peripheral wall 
of that portion of the outer tube 20 which falls within the range between 
the nozzle 22 and the boundary set apart therefrom at a prescribed 
distance. The scale units are all formed of concave or convex portions or 
indicated in a color distinguishable from the surroundings. It is 
preferred that the scaled region be formed over a range measuring more 
than 50 mm from the distal end of the laser probe and the respective scale 
units be pitched at a distance ranging from 1 to 10 mm. When the scale 72 
is applied to measure the depth of a hole to be formed in the coeliac 
cavity for the medical treatment by the laser probe 16, it is preferred 
that the scaled region be formed over a longer range than 50 mm with the 
respective scale units pitched at a distance from 1 to 5 mm. 
Description may now be made of the operation of the laser device 
constructed as described above. When medical treatment is performed by 
means of the laser device, an endoscope is first inserted into the coeliac 
cavity. Then the laser probe 16 is introduced through the forceps channel 
of the endoscope. The distal end of the laser probe 16, that is, its 
nozzle 22 is allowed to protrude from the distal end of the endoscope. 
Since the distal end portion of the laser probe 16 is provided with the 
scaled region 72, it can be ascertained whether the distal end of the 
laser probe projects from the tip of the endoscope. After the laser probe 
nozzle 22 is turned in a prescribed direction by means of the operation 
lever 62, the laser source 12 and air pump 14 are actuated. When the 
shutter 26 is opened a laser beam delivered from the laser source 12 is 
carried into the affected portion of the coeliac cavity through the 
central port of the nozzle 22, while being guided by the laser guide 24. 
At this time, the air pump 14 sucks air from the outside of the laser 
device body 10. The air is supplied to the air pipe 30 while being 
compressed. The compressed air is supplied to the drying unit 34 to be 
dried. The dried air is brought to the changeover valve 32 through the air 
pipe 30. When the valve 32 is opened, the dried air streams flow into the 
air supply passage 28 through the connector 18, then to the distal end of 
the laser probe 16 and last are ejected to the outside through the central 
hole of the laser probe nozzle 22. 
The laser device constructed as described above offers the advantages that 
it sends forth not only laser beams but also air streams through the 
nozzle 22 at the time of medical treatment, thereby preventing, for 
example, blood or viscous coeliac fluids from being deposited on the 
distal end of the laser guide. Moreover, the air ejected from the laser 
probe nozzle 22 is dried by the drying unit 34 in advance, thus preventing 
water droplets from being formed on the inner wall of the nozzle 22 or at 
the distal end portion of the laser guide 24. Consequently, laser beams 
emitted from the distal end of the laser guide 24 are prevented from being 
subjected to irregular reflections or refractions, and the laser beams can 
be assuredly ejected in any desired direction. As a result, the laser 
probe 16 is prevented from being damaged. Further, the distal end portion 
of the laser probe 16 can be flexed in any desired direction by the 
actuation of the operation lever 62, thereby enabling laser beams to be 
perpendicularly ejected to the inner wall of the bronchial tube or 
alimentary canal. 
The medical laser device of this invention is not limited to the 
above-mentioned embodiments, but is applicable with various modifications 
without departing from the scope and object of the invention. For 
instance, the drying unit 34 of the foregoing embodiments which consisted 
of a drying agent type drier need not be limited to such type as shown in 
FIG. 3, but may be remodeled as indicated in FIG. 6. The drying unit 34 of 
FIG. 6 comprises a refrigeration cycle 74 enclosed in an outer casing 36. 
This refrigeration cycle 74 includes a compressor 76, condenser 77, and 
evaporator 78 connected in succession. An aftercooler 80 is set near the 
condenser 77. This aftercooler 80 is connected at one end to the air pipe 
30 through an inlet port 30a and at the other end to the outer tube 84 of 
a precooler 82. The outer tube 84 is set outside of the evaporator 78, and 
connected to the inner tube 86 of the precooler 82 through a drain 
separator 85. The inner tube 86 communicates with the air pipe 30 through 
the outlet port 30b of the outer casing 36. 
The drying unit 34 of FIG. 6 constructed as described above is 
characterized in that wet air streams delivered from the air pump 14 pass 
through the aftercooler 80 and the outer tube 84 of the precooler 82 in 
succession to be freed of moisture by cooling, then run through the inner 
tube 86 of the precooler 82 to be heated, and thereafter are carried into 
the air pipe 30 at the outlet port 30b. Therefore, the drying unit 34 can 
remove moisture from air streams supplied from the air pump without 
reducing the temperature thereof. 
Description may now be made with reference to FIG. 7 of a modification of 
the operation section 60 of FIG. 4. The operation section 60 according to 
the modification of FIG. 7 has a fixed ring 88 engaged with the outer 
periphery of the outer tube 20 and a ring 90 rotatably fitted to the 
outside of the fixed ring 88. A helical groove 92 is formed in the inner 
surface of the rotatable ring 90. A pin 94 is engaged at one end with the 
helical groove 92, and is connected at the other end to the operation wire 
66. 
With the modified operation section 60, the rotation of the rotatable ring 
90 causes the pin 94 to be shifted axially of the outer tube 20, thereby 
enabling the distal end portion of the laser probe 16 to be turned in any 
desired direction by means of the operation wire 66. 
In the aforementioned embodiment, a scale 72 is provided on the outer 
peripheral wall of the laser probe 16. However, as shown in FIG. 8, it is 
possible to let the core 68 of the laser guide 24 protrude from the distal 
end of the outer tube 20 and impress a scale 72 on the outer peripheral 
surface of the distal end portion of the core 68. Further, the shape of 
the distal end portion of the core 68 need not be limited to a round 
columnar form, but may take a spherical or round conical shape.