Variation of cell electrophoretic mobility (E.P.M.) of synchronized HeLa cancer cells caused by low-energy Ar laser irradiation with the energy density of 10mJ/cm2 were measured for the first. This low-energy laser irradiation on HeLa cells was performed at three phases of the cell cycle, namely G₁, S and G₂-M. Some differences between laser light irradiated cells and non-irradiated (control) cells were observed for the cases of cultured HeLa cells with G₁ and G₂-M phase irradiation in contrast to the S phase irradiated cells. These results appear to suggest the correlation between the effect of low-energy laser irradiation and the cell cycle.

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It is recognized currently that irradiation of low-energy laser light has a specific effect on biological systems, so called bio-stimulation effect. We have been studied bio-stimulation effect on head regeneration in decapitated hydra caused by low-energy laser irradiation. This paper reports for the first time the experimental results especially the dependence on laser wavelengths. The bio-stimulation effect of laser light is estimated by comparing regenerated tentacle numbers in irradiated group with non-irradiated controls. We used linearly polarized Ar and dye lasers for light source, and changed energy density between 0.1 and 2J/cm². It was found that the effect on head regeneration in hydra varies with the laser wavelength. For the wavelengths lower than 600nm and 600-640nm, inhibition and activation effects were observed, respectively. However, in the region of 650-670nm, no effect was measured. Also a large difference of the effect between the wavelengths of 514.5nm and 610nm was found at the laser energy density of 1J/cm².

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Laser irradiation with the wave length, variable generator (I.H.I.Co.) was given to aquaeous solutions of such inflamatory mediators as prostaglandin E₁, histamine and bradykinin or healthy human serum and effects of the wave length or energy density ranging from 266 to 780 nm or from 20 to 200 mw/cm² on their concentrations measured by fluolescence method or RIA were examined to get an insight into the possible mechanism for the RA laser therapy. When the laser with 266 nm of wave length was irradiated, an increase in the laser intensity or energy fluence caused a propotional decrease in the concentration of prostaglandin E₁, serum LDH and ALP activity and Albumin/Globulin ratio. Ten times increase in the laser intensity or fluence produced an decrease in prostaglandin E₁ to one fifth. When the laser with 180 mw/cm² of intensity was irradiated, the laser with the less wave length than 532 nm caused a clear decrease in bradykinin concentration. The laser with 266 nm of wave length but not with the other wave length produced a marked decrease in prostaglandin E₁, histamine, serum total protein, GOT, GPT, LDH and ALP.

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Light transmission at 410, 630 and 670 nm in the liver tissue was determined with models of the various liver diseases of rats and resected specimens of liver of 8 patients, who had primary hepatoma with hepatic cirrhosis in 4 cases and metastatic liver tumor without cirrhosis in 4. Penetration depth of the tumor tissues in three wavelengths was significantly longer than those of the liver tissues with normal, hepatitis or cirrhosis in rats. In the human liver, light penetrated deeply in the order of metastatic tumor., hepatoma, cirrhosis and normal liver. Examination of transmission in the various tissues may have potentiality in diagnosis and treatment for tumors in the liver.

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More recently, mounted efforts and therapeutic progress in the detection of lung cancer have been rewarded with a higher detection rate of lung cancer of synchronous origin, asynchronous origin and multifocal origins. The last type, however, frequently poses a therapeutic problem, and in many cases complete resection of the foci is completely impossible. With this in mind, we attempted to extend the range of therapeutic indications by performing PDT on the focus of lung cancer while it still seemed to be at an early stage.
We experienced ten cases of multifocal lung cancer, in which five cases were of the synchronous type and the remaining five cases were of the asynchronous type. In seven cases operation and combined treatment were performed, while in the other three cases PDT alone was used for treatment. Prognostically five patients died, while the other five have survived for a period ranging from 11 months to 65 months.

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Photodynamic therapy, which usually requires the injection of a photosensitizer with an affinity for malignant tissue, followed by treatment with low power laser light delivered via an endoscope, is attracting increasing attention.
From 1980 through June 1986 we performed photodynamic therapy (PDT) on 21 cases of lung cancer which seemed to be at an early stage endoscopically and which had either rejected operation or had been unable to undergo resection due to low pulmonary function. We studied five cases which survived for three years or more. In all five cases squamous cell carcinoma confined in the large space of the airway could be demonstrated.
Of these cases, the longest-lived survived for 86 months and even the shortest-lived survived for 44 months.

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Radical treatment with Nd-YAG Laser has been tried on many cases of early upper gastrointestinal cancer. PDT has also been conducted since 1985. Some problems have been found in treatment with Nd-YAG Laser and conventional PDT with spot exposure of lesions which cover a large area or have no demonstrable boundaries, and in the sites where the exposure at a high angle is impossible.PDT with highly diffusible microrod was conducted in those cases which had not responded to conventional therapy due to the above reasons. Two cases were treated with PDT. One was a case of circumferal superficial esophagal cancer which recurred or remained after six YAG Laser treatments and PDT with spot exposure. Another was a case of extensive early gastric cancer (IIb type) which remained after YAG treatment due to the large extent of lesion and a low angle of exposure. In the case of esophagal cancer, a biopsy conducted every two weeks for 6 months has revealed no cancerous lesion. In the case of early gastric cancer, the formation of large and superficial ulcer was found with no remaining lesion in its bed but slight lesions were found between folds in its marginal regions. Great effectiveness of the PDT with highly diffusible rod is expected for superficial lesions which have no demonstrable boundaries and for sites where exposure at a high angle is impossible. But its effect may be insufficient on obscured lesions because it produces less photoenergy on the exposure surface than spot-type tip.

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Since 1982, four advanced cases of inoperable rectal cancer were treated with YAG laser and four early cases of inoperable rectal cancer were treated with argon dye laser with HPD. A gold vapor laser with HPD was used on six cases with local recurrence and a YAG laser was used on six cases of anastomotic stricture after operation.
It was found that therapeutic treatment of four cases of advanced rectal cancer with the YAG laser improved the movement of the bowels in all the cases and exerted a hemostatic effect on three cases but had no such effect on one case which exhibited a tendency to bleed. The therapeutic treatment of four cases of early cancer with an argon dye laser contributed to a leveling of the transversal folds and to relief of ulcer. The gold vapor laser therapy used on six cases with local recurrence was found to be effective in the alleviation of bleeding in all six cases and in the relief of pain in three cases.
No recurrence was seen in two cases six months after treatment. The gold vapor laser therapy also alleviated stricture in five of six cases with anastomotic stricture but no relief was obtained in one case where recurrence occurred.

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In the field of conservative dentistry these days, clinical use of composite resin is becoming wide spread, however we can't but use the acid treatment and the application of the bonding agent together because we can't get complete adhesion between the composite resin and the dentin surface. Now, we have examined the dentin permeability, marginal leakage, and measured the contact angle of it after irradiation of YAG and CO₂ laser with comparative low energy density. It proved that the dentinal tubules on lased surface are blocked owing to the inhibition of the dye penetration, the marginal sealing between the composite resin and the lased dentin surface is improved, and the contact angle is decreased remarkably by YAG laser irradiation (Energy density is from 6 to 25 J/cm²).

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The author s previous experiments have revealed the fact that carious dental tissues have remarkably different optical characteristics to Nd-YAG laser light from intact dental tissnes. In this experiment Nd-YAG laser shot on the occlusal surface of extracted human teeth, and the occlusal surface temperature the reflection on the occlusal surface and the transmission from the side surface of the lased teeth were examined. The results of these data analysis proved that these photo thermal reactions of carious teeth to exposure to Nd, YAG laser remarkably different from that of intact teeth, and even the primary dental caries were able to be identified. The results of this experiment suggests that this system can newly develop a very sensitive diagnostic technique for dental caries.

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In the prezent study, the caries inhibitory effects on artificial enamel caries to which both Nd: YAG laser and APF had been applied were examined.
enamel surfaces of human young premolars were used. Artificial enamel caries of young premolars were treated by following procedures.
Group 1); No treated. Group 2); APF was applied for 4 minutes at 37°C. Group 3); AOQ-Nd: YAG laser was irradiated with 65J/cm² energy. Group 4) AOQ-Nd: YAG laser was irradiated after APF application. Group 5); APF was applied after Nd: YAG irradiation. Then all samples were exposed to 0.1 ml HC104 solution for 20 seconds by 5 times and amounts of Ca and F in each HC104 solution were determined. Another way, enamel surfaces of treated samples were observed with SEM.
The results were as follows.
(1) Inhibitory effect on enamel demineralization was most paticularly in Group 5) samples.
(2) The content of F were high in Group3) and 4) samples.
(3) It was seemed that there were fluoride-rich reaction products on the enamel surfaces of Group 2) and 4) samples by SEM observasion.

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This investigation was carried out to enhance the effect of acid resistance on enamel by low power laser irradiation with APF.
Laser unit used was Osada Nd: YAG laser (continuous wave, wave length 1.064μm, combination with lie-Ne laser for laser beam guide). Extracted humman molar teeth used for this study. Each of the teeth were cut off buccolingually, and half from each tooth was selected for using as samples of laser group, while its corresponding half used for samples of APE group. Samples of laser group were exposed to laser working at. the energy dens i ty of 10 V, and 0.5 sec/one exposure of 6times and were treated with APF and immediatery exposed again at the same working condition. Samples of APE group were treated for 4 min. with APE solution.
After the experimental treatment, some of samples were examined by scanning electric microscope. The others were soaked and incuvated in 0.1M lactate buffer (pH 4.5) at 37°C, and their dissolved Ca density were analized by atomic absorption spectrometer.
The results were that no change was found in the enamel surfase of laser group compared with APE group in this laser condition. Significant, less calcium was released into buffer solution from laser group than APF group.

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In therapeutic application of lasers' thermal analysis of tissues with the laser-treatment it is extremely important to know the effect and the area of the lasers on tissues. The authors have examined experimentally the thermal effects and the light distribution of Nd: YAG laser on the alveolar bone in the periodontal laser surgery using the author's original simulative system. As the results this method has been proved to be useful to predict both the therapeutic effect and the thermal damage on per tissues with its laser treatment. In addition to this bone healing effect of Nd: YAG laser in its periodontal surgery,it was confirmed to make a little damage in such a weak range of the laser exposure.

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An acid resistance and morphological alteration of lased enamel were compared with two types of Nd-YAG laser, normal pulse and AO Q-sw pulse. The tooth enamel was exposed with laser beam at energy density of 30 or 50J/cm². The acid resistance of the enamel was determined by the amount of dissolved calcium in 0.5M HC10₄ from the enamel surface and by the rate of demineralization of the enamel in lactate gel.
The acid resistance of the enamel exposed to normal pulse was more remarkable than that of AO Q-sw. The morphological changes of enamel surface were observed by means of SEM. The deep and wide cracks were observed on the enamel exposed with AO Q-sw, Whereas the microscopic fine and mosaic-like cracks were observed on the enamel exposed with normal pulse. In combination of acidulated phosphate fluoride (APF) treatment and laser irradiation, a large amount of fluoride was penetrated into the enamel treated with APF after an irradiation with normal pulse Nd-YAG laser.

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The bone changes on Nd-YAG laser irradiated wounds was observed in canine mandible by soft X-ray.
In defects by bone bur, new bone formation was observed after 2 weeks and the defects were filled with new bone nearly after 12 weeks.
In the YAG laser irradiated wounds, when the carbonized layer was removed, new bone formation was observed about 6 weeks later and filling was observed 12 weeks later than in bone bur wound. When the carbonized layer remained intact, new bone formation was observed about 14 weeks later than in bone bur wound and filling was not observed after 24 weeks yet, but defects were filled as a result of marrow ossification.

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We made the model that resembled a mean living body as nearly as possible. We selected the various combination of abutment teeth, and analyzed the movement of bridge. In order to observe the movement untouchedly and third dimensionally, we used the double exposure of laser holography. So we came to the following conclusion;
1. The ability of bridge that could stand the load was proportionate to the increase of the area of periodontal membrane. (i. e. the increase of abutment teeth)
2. The bridge, that had unbalanced area of periodontal membrane of the abutment teeth from side to side of deficient area, revolved on its larger area side.
3. The ability that could stand the load of the bridge, that had the balanced area of periodontal membrane and the shapely polygon combining the abutment teeth, increased very efficiently.We observed a case that the ability to the load increased three times by double area of periodontal membrane.

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A new thin coronary angioscope which has a function of complete balloon-catheter is described in this paper. It has been formed into very thin flexible catheter, 4F (1.33mm) in outer diameter. In this angioscope, the balloon has two major functions, that is, occlusion of the blood flow to decrease the flush material and manipulation to control the endoscope view. Clear view in left coronary artery anterior descending (LAD) and circumuflex (CX) of dog (15kg in weight) were carried out continuously (up to 20s) until occurring of ST segment change of ECG.

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A characteristics of the intensive contact CO laser irradiation from a optical fiber in water for the laser angioplasty is described. The light penetration and distribution of a high-intensity irradiation of CO laser from the fiber output end in water was measured. Clearly, CO laser light transmit in excess of transparency (0.3-0.4mm) in liquid water. A boiling water vapor cavity which occurred in front of the output end of the energy delivery fiber may be promote light penetration due to a reduction of water density. The drilled depth of both contact-irradiation in water and uncontact-irradiation in the air under same irradiation intensity were measured. The measured drilled depth in both case coincide with each other.

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With argon laser coupled to a fiberoptic system, we carried out experimental studies to establish the optimal conditions in improving obstructive arterial disease without any complications of the arterial wall.
This study was performed on human cadaveric aorta under air, blood and saline medium by using the bare-ended probe and the metal tip probe (0.7mm in diameter, 300μm core silica fiber).
First of all, the craters in the aortic wall created by laser irradiation were microscopically examined, and the depth of each crater was precisely measured. Subsequently it could be considered that 6watts in laser output and 3 seconds in irradiation time were optimal conditions in one radiation for laser ablation using the metal tip probe.
On the other hand, we also tried laser coronary angioplasty by using human cadaveric heart, and could get the coronary recanalization by repeated laser ablations (6w, 3sec, 7times).
But many kinds of degrees of sclerotic changes were surely recognized on the arterial wall among them. So selective applications of the metal tip probe or the bare-ended probe and both of them was very important for excellent laser ablation.
In addition, angioscopy was useful procedure to observe intravascular laser effects without arterial injuries. In conclusion, laser angioplasty under angioscopic guidance should be recommended from standpoints of its safety.

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Recently, the technical advance of laser medicine gives us a chance to measure the myocardial blood flow.
We experimentally established how to measure the myocardial blood flow using a laser flowmeter(He-Ne laser, wave length 632.8nm) and a small myocardial probe, and applied to the cases of coronary artery bypass grafting (CABG).
The probe was positioned between the heart and the elastic mesh bandage (“Presnet”), and fixed on the cardiac surface. The right and left ventricular myocardial blood flow in 14 cases of CABG were counted at pre- and post-bypass grafting.
The myocardial blood flow at the anterior wall of right ventricle which had no relation to bypass grafting did not change. The flow of noninfarcted bypassed region significantly(p 0.01) increased from the preoperative value of 78±12 ml/min/100gr to 87±12 ml/min/100gr after the bypass grafting.
In conclusion, the noninvasive measurement of myocardial blood flow is obtained by using the laser flowmeter and the specially producted myocardial probe. The coronary artery bypass grafting increases the myocardial blood flow at the noninfarcted ischemic area.

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Excimer laser which is a ultraviolet laser, showed a less thermal reaction around the irradiated area in comparison with the other lasers (CO₂, Argon, YAG, etc). This characteristics can be great advantage in laser angioplasty, that has the problem of thermal injury of the vessel wall with argon or YAG laser.
In order to evaluate the advantages of excimer laser (XeCl: 308nm) for laser angioplasty, the laser was irradiated to nomal aorta wall and atheroma that was made experimentally in female rabbit's aorta by high cholesterol diet. Excimer laser was concentrated to line or point by one or two cylindrical lenses and irradiated to these samples in saline under the various condition. The following results were obtained.
1)When the total energy was same, tissue destruction tended to be bigger as the irradiating frequency increased.
2)When the total energy was same, tissue destruction tended to be bigger in atheroma than in normal aorta wall.
3)Thermal degeneration layer was observed for more than 50Hz irradiation.
4)But the thickness of thermal degeneration layer was very thin (about 0.1mm) with even 200Hz irradiation.
These results showed that excimer laser was suitable for laser angioplasty.

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Last year, we had reported the accumulation of Hematoporphyrin derivative (HpD) in atheroma as shown by the fluorescence of HpD in vitro using the endoscopical excimer pulse dye laser fluorescence spectrophotomater. This time we tried the in vivo study. Atherosclerotic lesions were induced in rabbits by an atherosclerotic diet and balloon damage. The rabbits were received an injection of 5 mg/ kg of HpD in an ear vein, and detection procedures were started 24 hours later. As a light source, an argon dye laser was employed. The laser beam was transmitted via a quartz fiver inserted through the light guide of an ultra-thin angioscopic catheter. The spectral data of HpD were fed into polychrometer and detected by an optical multichannel analyzer.
A cut down was performed over just below the arch from which the fiberscope was introduced and pased into the left femoral artery for 1cm by 1cm. At all points, the spectra of fluorescence were detected and recorded after flushing with saline. In the normal area, only unshifted emission peaks at 610 nm and 670 nm were seen, and the ratio of the fluorescence intensity in the normal area to that in atheroma was 1:20. In the area of fatty plaque and atheroma, emission peaks at 630 nm and 690 nm were obserbed. However the emission peak at 660 nm appeared in atheroma. This study should provide impetus for further investigations regarding the affinity of HpD for atherosclerotic lesions and its possible clinical application.

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Fluorescence misroscopy and light microscopy were performed to investigate the affinity of photofrin II for atherosclerotic lesions and the effect of photofrin II in atherosclerotic rabbits aortas when vessels were dissected and submitted to laser radiation. Atherosclerotic lesions in rabbits were induced by 2%cholesterol diet and damage by Fogarty balloon catheter. Atherosclerotic rabbits were divided into two groups. Group P comprised atherosclerotic rabbits given photofrin II (5mg/kg) intravenously 24 hours before sacrifice. Group C comprised atherosclerotic rabbits that were not given photofrin II. Laser radiation was delivered with Argon Laser for 20 seconds (output 514.5nm) and the power was 500mW, 700mW, and 900mW. The photoradiated sites were sectioned and stained with Hematoxylin Eosin for light microscopy. Atherosclerotic lesions were frozen quickly and sectioned for fluorescence microscopy. Photofrin II was selectively localized within the intima of atherosclerotic arteries, and in Group P atherosclerotic lesions were vaporized by lower energy level than in Group C. This localization may sensitize atheroma to Argon Laser.

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Nd-YAG laser beam, with the energy of 15 watts and 100 msec, was projected onto a 0.5mm long cut slit edge of rat common carotid artery. An experimental aneurysm was unexceptionally induced 1 week after the procedure.
This simple and reliable method of inducing aneurysm might be utilized to investigate etiology and/or treatment of it.

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Cryosurgical ablation of the arrhythmogenic foci is an established operative method for arrhythmia surgery. Cryothermal lesion is characterized as well-demarcated dense fibrous scar, without wall thinning and having no tendency of inducing arrhythmia in itself.
We are currently investigating the use of LASER irradiation and see if it is able to make, at least, the same characteristic lesion as that achieved with cryosurgical application to canine myocardium.
7 mongrel dogs weighing 10 to 15kg were used in our experiment. Under general anesthesia with intravenous pentbarbital, right thoracotomy was performed. After pericardiotomy LASER beam was applied onto the cardiac surface of both right and left ventricles, as well as to the right atrioventricular groove after dissection of the epi-annular fat pad. A 600 micrometer diameter inner core quartz fiber coupled to an ND: YAG LASER source was utilized. The tip of fiber was positioned appproximately 5mm above the cardiac surface. Power of between 10 and 50 watts was used, and the duration of beam exposure varied between 3 and 20 seconds. Following irradiation the heart was excited and the formed lesion was measured of its depth and diameter. Irradiated myocardium was fixed and stained method for histological examination.
Histology showed a well-demarcated lesion consisted of contraction band necrosis which, in chronic stage, changed to a firm fibrous scar. As far as the power of irradiation was less than 40 watts, irrespective of the duration of beam exposure, central crater formation resulted from vaporization of the tissue was not recognized. There was a positive correlation (r=0.79; p<0.01) between the delivered LASER beam energy and the depth of the lesion formed.
During LASER irradiation no arrhythmia was acknowledged on the ECG monitor, nor any arrhythmia induced by post-irradiation programmed ventricular stimulation.

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Newly developed excimer dye laser system for cancer diagnosis and treatment was evaluated clinically. Diagnosis and treatment were performed photodynamically after the administration of HpD. Five patients with lung cancer consisting of four cases of squamous cell carcinoma and a single case of adenocarcinoma showed HpD-specific fluorescenc at the lesions. In the treatment, 50-140 joules/cm² photoradiation were administered to the lesions. All lesions showed significant remission. A case of early stage squamous cell carcinoma of the right upper lobe bronchus showed complete remission and is now disease free at 11 months. This system is more effective in the diagnosis and treatment than previous procedures.

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A new instrument is developed to visualize the microcirculation map using a dynamic laser speckle effect. The variation of the flow level in the area of interest is displayed in color graphics.
Several experiments are applied to an avasculised finger and four different types of skin flaps on the rabbit auricle. It is demonstrated that the color graphic image reflects the clinical state of local circulation very clearly.

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Recently, research and development of the new system which can easily perform micro-processing and microsurgery for living biological cells is strongly desired in the field of biotechnology and genetic engneering. We report here a novel type of this system employing highly collimated,low power laser beam with various wavelength being developed and tested in our laboratory.
Piezoelectoronic motors were utilized for micropositioning of the biological cell, which is achieved by these different modes of operating; randam, scanning, manual modes. Thus non-contact cell processing was realized with excellent spatial resolution incorporated with computer-controlled automatic laser irradiation technique.

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The correct recognition of laser light distribution on and in the lased tissues is crucial in the therapeutic application of lasers, but there used to be few practically useful techniques to survey the invisible near infrared laser distribution on and in tissues. Charge-coupeled device (CCD) image sensors have extremely high sesitivity for near infrared ray of shorter wave length than 1.2μm, so that the near infrared laser distribution on and in tissues can easily be observed as a visible image using TV camera provided CCD image sensor. This paper confirms that the CCD TV image has the intensity resolution to a near-infrared laser distribution on and in tissues. The clinical applicabilities of these imaging techniques are discussed in this paper. As the results these sensors have so high sensitivity to neare infrared laser that they are applicable even for low power diode lasers and some optical filters are necessary to high power infrared lasers such as Nd: YAG laser.

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We have applied endoscopic Nd-YAG laser therapy in the treatment of 168 cases of upper gastrointestinal diseases since March 1980. We irradiate laser chiefly by the noncontact method. It is because we want to utilize the characteristics of laser beam itself that it can provide energy with no contact.
However, some problems were pointed out conventionally for this irradiation therapy. Namely, this irradiation therapy is associated with problems such as contamination of the top of the optical fiber as well as back scatter and loss of energy by bending of optical fiber. To resolve these problems, we developed newly an improved endoscopic top hood with metallic protective cap. The aim of the present paper is to describe the hood developed by us.

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High-peak and high-average-power pulse lasers have the advantage of large tissue penetration and little thermal damage effect. The efficient transmission of these beams through light guides could have important implications for endoscopic applications. We have developed a high-peak-power Excimer Dye Laser (maximum energy 8mJ/shot, wavelength 630nm, pulse duration 5ns). It is difficult to transmit Excimer Dye Laser radiations down quartz optical fibers. The transmission is limited by surface damage to the fibers. The surface damage depends on the peak-power density of single laser pulses. We have obtained the approximate surface damage threshold value of 100MW/mm2.

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We have developed a fiexible CO₂ laser beam guide with metal and polymer compound hollow tube. In this paper, it was concentrated the research which the higher peak short pulse CO₂ laser beam transmission. The characteristics of incident beam is 500KW peak pulse power, 8Ons pulse width and 10Hz repeat pulse. One pulse energy is ca.40mJ. From the experimental result, the pulse beam transmittance was obtained ca.90%/m at straight shape power, 36mJ per pulse. In the bent shape tube with bending radius ca. 15cm, transmittance is ca. 80%/m, pulse shape is not change almost.
In this results, it was clarified that the hollow guide tube is useful flexible guide tube for higher pulse power CO₂ laser transmission.

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In the laser angioplasty, our in vitro study exhibited that the advantages of contact irradiation are 1)to have small burned area around ablated area, and 2)to obtain smooth surface at ablated area. And the combination of YAG laser and contact ceramic tip was turned out to be suitable for contact irradiation laser angioplasty. For coronary artery application, it was required to develop a small head of laser probe that includes contact ceramic tip and more flexible fiber. The purpose of this study is to develop laser probe using contact ceramic tip for coronary laser angioplasty.
In order to develop new probe, following points were improved.
1)Probe is disposable. 2)Contact.ceramic tip is not exchangable. 3)Most flexible quartz fiber with 400um diameter is used. 4)Frosting is processed at irradiating end of contact ceramic tip for easy carbonization at the point.
The new probe had a head with 1.7mm in maximum diameter and 11mm long. This probe was evaluated in female rabbit's atherosclerosing aorta made by high cholesterol diet. Atheroma was well ablated with less power (YAG laser with 25-30W ) in frosting than non-processing. This probe could go through inside of PTCA catheter. So, coronary application will be expected.

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This report constitutes the second part of a series of comprehensive investigations to develop techniques for intraoperative laser processing of synthetic surgical sutures⁽¹⁾. Laser welding for thermoplastic sutures has been reported in the first part⁽²⁾. The second part deals with CO₂ laser cutting of nylon, Dexon and Vicryl sutures. Experimental data have indicated a laser power-exposure time relationship of the forms P=K/_??_ and ΔTm=KP_??_ (ΔTm=temperature rise to the melting point ) for approximately 100%cutting frequency threshold for the sutures. (Fig.2) Results have fundamentally agreed with theoretically derived thermal models as shown in Fig.3.
These equations have been used to generate the family of isothermal curves, which can predict laser cutting threshold for various ambient temperatures. (Fig.4) These investigations provide informations pertinent to the proper choice of parameters for laser applications on surgical sutures. Some trials have proved practical applicability of the technique for clinical surgery.

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We studied on the tolerance of laser protective spectacles using absorptive glass filters for Nd-YAG laser(1,300nm) irradation. Two types of safety filters were tested, namely, glass filter and glass filter lined with plastic film. Twenty-two Watt, 13 seconds irradiation of the laser could not penetorate the glass filters and black paper set behind the spectacles showed no changes. Both types of the laser safety filters were cracked in process of cooling but not bracken into pieces. The fact indicates that the laser protective spectacles using both types of glass filters have satisfactory strength and safety for laser irradation.

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The CO₂ and Nd-YAG laser are very useful for surgery. However, since most of these are large and heavy, and need expensive high voltage and water cooling system, they are used only in fixed location. Recently a portable type CO₂ laser system has been developed by Pfizer co., Irvine, California, U. S. A. consisting of a main body (36×40×20cm, weight 18kg) laser probe (36×3×3cm, 390gr) and connection cords. This system only needs AC 100V current. The model 20 C yields a maximam of 20W power, in either continuous wave or 0.005-0.045 sec pulse shot waves. This system can be used for cutting, corgulating, ablating or vaporizing. We are treated cases of palmar wart, keloid behind ear, genital Condyloma Acuminata and so on.
Because of it's portability, it can be moved anywhere such as the outpatient department, bedside or office outside the hospital.

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To confirm the effect of laser nucleotomy on intradiscal pressure decrease, the relation between IDP and vertical load was measured and a new type needle for preventing the complications by the heat was developed.
The IDP was measured by pressure transducer with increasing vertical load for following three groups of rabbits' lumbar discs. 1) normal discs, 2) conventional intradiscal nucleotomy, 3) laser nucleotomy. The curves of the IDP of laser nucleotomy was almost same with that of conventional intradiscal nucleotomy.
Using a usual spinal needle, the quarts fiber and needle were often damaged by burn back and the heat injury of the tissue around the tissue was often occurred. To prevent these complications, a new type needle with Teflon coated double lumen and a connector for aspiration was developed. The needle could solved these problems.
Laser nucleotomy suggested to be applied clinically by its easiness and safety.

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The aim of this experiment is to analyse the effect of low power Nd-YAG laser irradiation on returning process of damaged peripheral nerves.
Facial nerves of rabbits were clashed and transcutaneous laser irradiation was given on the same regions every day. The returning process of nerve function was analysed by strength-duration curve electrophysiologically.
Significantly, threshould value was lower in laser irradiated group than in control group on the 14th postoperative day (P<0.05).

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From an aspect of effects on the general conditions, the laser therapy for 161 patients with Rheumatoid arthritis with Ga-Al-As diode laser (780 nm of wave length, 10 mw of power and 3.18 x 10⁴ mj/sec·cm² of c. w, Fuji Electric Co.) was evaluated on its usefulness., Each of their active inflamatory joints was irradiated until analgesia was obtained but for less than 5 min./each irradiated point and this therapy was succeeded once a obtained or every two weeks for 10-30 times.Information was obtained through a questionaire about disturbances graded into 5 in such ten items about malaise, sleep, appetite, body weight, mood, emotion, vigor, interest in the circumstances, chillness in extremities and general energy. After this therapy 72% of the patients improved in their general energy. Earliest and higher improvement rate was recorded in the item on general energy. Improvements in vigor, mood, sleep disturbance and emotional stability were also reported by 64.6, 57.8, 56.5 and 54.0% of patients, respectively. These facts indicate that the laser effects on the general conditions also support the usefulness of the laser therapy for the RA patients.

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We investigated the effect of low power laser (Ga-Al-As semiconductor laser, 830 nm) for the pain of after tonsillectomy.
The low power laser was used for 18 patients,over ten years old, after tonsillectomy in our hospital.
The laser exposure was done twice a day, since the following day of tonsillectomy to the day patients have no wound pain.
As a results, 70.7% showed effectiveness and 84% answered the treatment for pain is satisfactory. There is no adverse reaction or side effect.

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Cases of Acute Rhinitis were treated by application of a Low Power Laser (Ga-Al-As Diode Laser: 10mW, 800Hz, 40 sec per 1 point) to“INDO”, LI 20 (“GEIKO”), and “BITSU”.
The following results were obtained:
1) Rhinorrhea Among 40 cases, 7 showed remarkable improvement, 22 showed improvement, 10 showed moderate effectiveness and 1 showed ineffectiveness at 30 min after radiation.
2) Nasal Obstruction Among 35 cascs, 26 showed improvement, 7 showed moderate effectiveness and 2 showed ineffectivenenss at 30 min after radiation.
3) The effectiveness of Ga-Al-As Diode Laser was confirmed on the basis of the improvements observed.
4) No adverse reaction was observed in any case.

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A previous report described laser stimulation therapy using a Gallium-Aluminium-Arsenide diode for pain, ileus and asthma attach, with a rate of effectiveness of 88.7%.
This report laser stimulation therapy in cancer cases: 35 lung cancers, 4 breast cancers, 2 esophageal cancers, 1 gastric cancer, 3 rectal cancers, 1 thyroid cancer and 1 bladder cancer. The diode laser emits a 70mW beam of 830nm wavelength and a 10W beam of 890nm wavelength. Among 49 cases, 23 cases (46.9%) reported significant effectiveness, 20 cases (40.8%) reported some effect and 6 cases (12.0%) showed no effect. No case showed exacerbation. The effective rate was 87.8%. This method is effective in freeing cancer patients from pain without using sedatives which sometimes cause complications. They were no serious side effects.

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We have been continuing pain alleviating therapy using a low-power diode laser'panalas 4000', It operates at a wavelength of 830 nanometers and has a power output of 60 mW. Here, we would like to report the experience of 4300 cases more.
The patients in this study were treated over a 34 month period between April 1984 and February 1987, and the total number of patients came to 2.840, with a total of 4,374 complaints, Treatment was so effective that almost patients felt immediatly relief from pain. Result were about 840% effective cure rate.

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Low powered Ga. Al, As laser is used for the treatment of occipital neuralgia, neck-shoulder-arm pain and lumbaric pain cases. Effect of laser treatment is as follows;“Occipital neuralgia”, excellent 28.1%, good 53.1%, fair 12.5% poor 6.3%,“neck-shoulder-arm pain”, excellent 42.1%, good 36.8%, fair 14.1%, poor 7.0%,“Lumbaric pain”excellent 20.5%, good 29.1%, fair 37.6%, poor 12.8%. The period of pain relief is varid, but at least for more than 4~7 days pain relief is obtained.

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Ga-Al-As diode laser (10 mW of power, 780nm of wave length) was irradiated on rats to examine its effect on experimentaly induced inflamation. The marked decrease in the pressure pain threshold of rat's paw after the induction of inflamation by corrageenin recovered to the non-inflamatory level immediately after the 6 min irradiation of the laser on the paw and this analgesic effect was not interfared even after the i. p. injection of 1mg/kg of naloxan. Granuloma formation 7 days after the S. C. implanlation of carrageenin including cotton pellet was 25% suppressed after the 5 min/day irradiation of the laser for 7 days. The development of the 1st phase arthritis measured by the swelling volume after the S. C. injection of freund's complete adjuvant on the right kind paw was 20% suppressed by the 10 min/day laser irradiation on the injected paw for 10 days and the swelling of the non-injected paw on the 2nd phase decreased after the irradiation on this paw for 15 days.
These facts indicate that the laser is effective in relieving the inflamatory pain and suppressing the development of the chronic inflamation.

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Double blind test was introduced to make a comparative study for analgesic effect and thermographic change by 10 mW low energy laser irradiation.
Statistical result clearly showed the analgesic effect of irradiation and the difference of thermographic change on both groups in significant.
By classificatory analysis, laser irradiation was more effective for osteoarthritis and post-traumatic sequelae groups in analgesia, on the other hand thirmographic change was more obvious in rheumatoid arthritis group.
These experiments suggest the clinical usefullness of low energy laser and its analgesic effect are considered to be participated in increasing peripheral blood flow.

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Partial resection was performed by using Nd-YAG laser on 22 cases of the lung and mediastinal diseases including 13 primary lung cancers, 4 metastatic lung tumors, 3 mediastinal tumors, 1 tuberculosis, and 1 hamartoma. Ages varied from 20 to 76 years old with an average of 58.9 years old and ratio of male to female was 9:13.
In the partial resection with Nd-YAG laser, the contact type probe was used for cutting the normal lung tissue lcm distant from the lesion with an energy of 20-25W, and non contact type probe was used for tissue consolidation and hemostasis with an energy of 30-50W on the resected site of the normal lung. Blood vessel or bronchi more than 1mm in diameter were sutured in central side.
Postoperative hemorrhage were not recognized in all cases. Air leakage was disappeared within 2 days, in 18 or 22 cases, but continued more than 5 days in 2 cases because of severe emphysematous change of the lung and less irradiation enerty of Nd-YAG laser compared with wide resected field. Viseral pleura had to be sutured in such cases with severe emphysema. Tumor recurrences were not recognized in all cases 5 to 18 months postoperatively.
We considered Nd-YAG laser is one of the evaluable method in the partial resection of the lung.

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Between 1980 and 1986 we have treated 156 cases of airway lesions using an Nd-YAG laser. Among these, effective results were recognized in 127 (81.4%). Thirty cases of non-neoplastic lesion were treated by this procedure to widen the airway and effective results were obtained in 24 (80%). The 6 non-effective cases included 1 procedure for widening of tracheal stenosis due to trauma, 1 procedure for postoperative widening of the bronchial anastomotic portion and the remaining 4 cases for staged widening of tracheobronchial or bronchial stenosis due to TB. Analyzing the reasons for non-effectiveness, lack of horseshoe-shaped cartilage crescent in the case of tracheal stenosis due trauma, rapid regrowth of postoperative granuloma in the case of postoperative stenosis of bronchial anastomosis and longitudinal extent and/or existence of active TB granulomatous tissue in the remaining 4 cases were considered. Lesions of cicatricial stenosis are an indications for this therapeutic modality. However lesions extending 1cm or more longitudinally in length, and cases in which TB granulomatous tissue are obtained from the lesion should be excluded from the indications for this procedure.

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