JPS649860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a medical laser device that cauterizes and treats living tissue.

In this type of medical laser device, the method of controlling the degree of ablation of biological tissue by laser light is mainly to adjust the irradiation time, number of irradiations, and beam output at the tip of the laser probe by adjusting data based on experiments and experience and visual observation of the irradiated area. I was doing this.

However, it is difficult in reality to confirm the effect of laser light on the irradiated area during irradiation.
Moreover, it is impossible to accurately predict the desired effect before laser irradiation. For this reason,
There was a risk that the living tissue would be insufficiently cauterized or that it would be excessively cauterized and perforated.

On the other hand, there is also a known method (West German Patent Publication No. 2829516) that attempts to control the output of laser light by measuring thermal radiation from the surface of the irradiated area.
This not only makes it impossible to accurately know the effect on the irradiated site before laser irradiation, but also makes it unclear whether the ablation state is accurately detected during laser irradiation by simply detecting the surface temperature. As described above, it is not possible to accurately confirm the degree of cauterization of living tissue. For this reason, there remained a risk that the living tissue would be insufficiently cauterized or that it would be excessively cauterized or perforated.

By the way, it has been confirmed that when living tissue is generally cauterized with laser light, the cooling effect of blood in the vicinity of the irradiation site makes a significant difference in the cauterization effect. Therefore, the idea was to accurately determine the state of blood flow near the irradiation site and control the output of the laser beam accordingly.

That is, the present invention provides a medical laser device that measures the blood flow in living tissue near the laser beam irradiation site and controls the output of the laser beam based on the measurement results to obtain an appropriate and safe ablation effect. The purpose is to

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 schematically shows the entire medical laser device. In the figure, 1 is a laser oscillator that emits therapeutic laser light, and this laser oscillator 1 is caused to oscillate by a laser oscillation device 2. As shown in FIG.
A shutter 3 and a condensing lens 4 are installed on the output optical path of the laser oscillator 1. The laser beam emitted from the laser oscillator 1 is condensed by a condensing lens 4, then enters a laser beam transmitting body 5, and is guided to the side to be treated 6. A focusing lens 7 is provided on the output end side of the laser beam transmitting body 5 and facing it.
is installed to focus the laser light emitted from the laser light transmitting body 5 onto the treated region 6.

A heating device 8 that heats the target area 6 with optical energy and a detector 9 that detects thermal radiation from the target area 6 are installed near the output end of the laser beam transmitter 5. The heating device 8 uses, for example, an infrared lamp 10 as a light source and irradiates infrared rays emitted from the infrared lamp 10 to the vicinity of the region to be treated 6 through a condenser lens 11 . The detector 9 is made of an infrared sensing semiconductor, receives infrared rays emitted due to a rise in temperature of the region 6 to be treated, focused by a focusing lens 12, and outputs an electric signal according to the intensity of the infrared rays.

Further, the output end of the detector 9 is connected to an amplifier 13 , and the output end of this amplifier 13 is connected to a control device 14 . Further, the control device 14 together with the detector 9 constitutes a measuring device 15 that determines the blood flow rate based on the detected value obtained thereby. Further, the control device 14 is connected to a memory 16 for storing measured values of blood flow and a display section 17. Furthermore, the control device 14
is also connected to the heating device 8 and controls its heating operation.

Further, the drive section 18 of the shutter 3 is operated by an emission control circuit 19 controlled by the control device 14, and a safety device 20 is operated to control the irradiation of laser light.
It consists of

Next, the operation of the above medical laser device will be explained.

It is generally known that the blood temperature of the human body is approximately constant at about 37°C. Furthermore, when the body tissue is heated to an extent that does not denature proteins, etc., the temperature of the heated area is in a monotonically decreasing relationship with the blood flow rate for a constant heating energy. This is because the larger the blood flow, the greater the cooling effect of the blood flow, and the lower the temperature of the heated area becomes. Therefore, the blood flow rate can be indirectly known by measuring the temperature of the heated area.

Therefore, the operation of the medical laser device will be explained according to the flowchart shown in FIG. First, before cauterizing the region 6 to be treated with laser light, the infrared lamp 10 of the heating device 8 is turned on to heat the vicinity of the region 6 to be treated with a certain amount of energy. Therefore, the temperature of the treated region 6 irradiated with infrared rays rises to a constant temperature. Since the treated part 6 emits thermal radiation according to its temperature, the detector 9 detects this and outputs an electric signal having a value according to the temperature. This output is amplified by an amplifier 13 and input to a control device 14. In the control device 14, the value of the electric signal is A/D converted, subjected to arithmetic processing according to the sensitivity of the measurement system, etc., and inputted into the memory 16 for storage, and displayed on the display section 17. That is, the blood flow rate in the treated region 6 is measured from the temperature information.

Only then can laser light irradiation be performed. Therefore, the laser oscillator 2 is activated to excite the laser oscillator 1 and oscillate the laser beam, thereby irradiating the target part 6 with the laser beam through the laser beam transmitting body 5. Note that since laser light has an extremely high energy density, in order to prevent excessive cauterization of living tissue, the laser light is not irradiated continuously, but is irradiated discontinuously at intervals.

Further, during the non-irradiation time of this interval, the heating device 8 is operated to heat the treated region 6, the detector 9 detects thermal radiation, and the blood flow is measured in the same manner as described above.

If the laser beam irradiation is continued in this manner, the proteins in the treated region 6 are denatured, affecting the blood vessels 21 in the vicinity, and the blood flow rate changes (decreases). Then, a comparator or a calculator in the control device 14 determines whether the measured blood flow value is smaller than an appropriate set value predetermined based on medical experiment data, or whether the change is larger than the set value. Determined by processing. Based on this determined detection signal, the control device 14 sends an emission prohibition signal to the emission control circuit 19, and upon receiving this, the emission control circuit 19 operates the drive section 18 to close the shutter 3 and keep it closed. Therefore, laser light irradiation is stopped. Further, in conjunction with this, the oscillation operation of the laser oscillator 1 is stopped. Note that in this state, even if a switch for irradiating laser light is turned on, irradiation will not be performed.

On the other hand, in the case of insufficient cauterization, the above-mentioned prohibition of irradiation is not carried out. Therefore, sufficient cauterization can be achieved by repeating discontinuous irradiation and blood flow measurement, and by continuing to irradiate the laser beam until irradiation is prohibited.

Note that the present invention is not limited to the above embodiments. For example, the intensity of the laser beam used for cauterization as the heat source of the heating device 8 may be controlled to be low. Furthermore, if a laser beam with a wavelength of 400 to 600 nm, particularly a wavelength of about 580 nm or less, is used, blood energy absorption is good and blood flow can be measured with high sensitivity. Further, a thermistor or the like may be used as the detector. Furthermore, the present invention is applicable regardless of the external lumen of a living body.

As explained above, the present invention heats the area to be treated that is irradiated with laser light using optical energy emitted from a heating device, detects thermal radiation from the area to be treated at this time, and measures blood flow in the area to be treated. The laser beam irradiation can be controlled while doing so. Therefore, an appropriate cautery effect can be obtained. In particular, by measuring the blood flow in the treated area to be irradiated with laser light to accurately determine the degree of ablation and controlling laser light irradiation, it is possible to significantly reduce variations in the degree of ablation due to differences in blood flow. . Furthermore, since control is performed to prohibit laser beam irradiation based on the blood flow measurement results, perforation due to excessive cauterization or insufficient cauterization can be reliably prevented. Furthermore, since the blood flow is measured optically and without contact, it is easy to operate and there is no risk of damage to the detection section due to laser light.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram schematically showing the overall structure thereof, and FIG. 2 is a flowchart thereof. 1... Laser oscillator, 2... Laser oscillation device,
3... Shutter, 5... Laser light transmission body, 6...
Part to be treated, 8... Heating device, 9... Detector, 1
0...Infrared lamp, 14...Control device, 15...
...Measuring device, 18...Drive unit, 19...Emission control circuit, 20...Safety device.

Claims (1)

[Claims] 1. In a medical laser device that irradiates a treatment target part of a living body with a laser beam to cauterize and treat the body tissue in that part, a temperature that is higher than the normal temperature of blood in the treatment target part and at which proteins are denatured. A heating device that heats the treated area with light energy by controlling the heating to a lower temperature, detects thermal radiation from the treated area heated by this heating device, and determines the blood flow rate in the treated area from the value. 1. A medical laser device comprising: a measuring device; and a safety device that controls laser light irradiation based on blood flow information obtained by the measuring device. 2. The medical laser device according to claim 1, wherein the measuring device uses an infrared sensing semiconductor in a detection section that detects thermal radiation. 3. The medical laser device according to claim 1, wherein the measuring device uses a thermistor as a detection section for detecting thermal radiation. 4. The medical laser device according to claim 1, wherein the heating device uses laser light having a wavelength in the range of 400 to 600 nm.