This paper presents a newly developed optical fiber waveguide system for CO₂ laser and its clinical assessment. The system is composed of two parts: fiber and its controller parts. The fiber part(10.8mm∅) consists of a fiber core(poly-crystalline of AgCl, 1.5mm∅) of 800mm in length, a cooling tube, thermistors, supporting wires, and covering sheets. This fiber system holds transmissivity of 20W maximum output and flexibility of 20cm minimum bending radius. In clinical application, the fiber unit is available for tumor vaporization, and it is strongly expected for endoscopical use.

View full abstract

The high-intensity power delivery of CO laser with As₂S₃ glass fiber is described in this paper. The As glass fiber of 400μm of core diameter which has FEP teflon cladding was used in this study. 16.9W of fiber output with 13.5kW/cm² of light-intensity was carried out during about 1 min. without occuring the fiber melting-down. However, small craters were found on the output end. Thus, this intensity seems to the upper limit of this fiber in the case of without cooling on the fiber. The allowable bending radius of this fiber was less than 30mm. The durability and the alternation of the fiber transmittance for bending were discussed experimentally.

View full abstract

A diode laser developed at this clinic has been used for 5 years in the treatment of pain. To date, over 1000 patients have been treated by the 60 mW semi-conductor laser with built-in power meter, probe, frequency control, etc. A combination of Western and Eastern methods were used and pressure points along neural routes, periosteum and other parts irradiated. Out of 166 cases treated for this study, 89.4% of pain, 67.8% of numbness, 47.3% of paralysis, and 100% of edema patients experienced relief of symptoms. Other vascular disorders like Raynard's and Berger's diseases can also be most likely treated in the future.

View full abstract

Percutaneous nephrolithotomy was performed on 175 cases in our clinic during these 33 months. Clinical success was recognized in 99% of cases (complete removal=92%). Ten percents of these cases were treated with continous wave YAG laser irradiation. Laser litholapaxy is more effective than the other two methods of stone disintegration (intensive ultrasound and electrohydraulic effect) in cases, where stones have dark colour, smooth surface or soft (organic) components.

View full abstract

In recent years, early detection of ectopic pregnancy has been remarkably improved using ultrasonography, assay of low titer hCG in urine and laparoscopy. We have actively attempted to perform laparoscopy to the patients suspected of ectopic pregnancy for the purpose of detecting as early as possible. We also have introduced YAG laser for hemostasis, adhesiotomy and photovapolization of endometriosis under laparoscopy. In this report, We could manage three ectopic pregnancies which were diagnosed by laparoscopy, radically with YAG laser. Indications for this new procedure will be as follows; 1) The patients who want no more child. 2) Unruptured ectopic tubal pregnancy in good condition. 3) The tumor mass of less than 3-4cm in diameter. This new technique have the advantage of incising easily tubal tissue in a bloodless condition under laparoscopy and reduced recovery period.

View full abstract

The characteristics of the CO₂ laser were demonstrated on cutting effects and the Nd-YAG laser on hemostatic coagulation effects. The Nd-YAG laser with a brade or a surgical rod possess both hemostatic and cutting effects. The advantages of the laser surgery for hepatectomy are as follows: 1. control of hemorrhage, 2. minimum insult to the remaining liver, 3. prevention of the lymph and bile leakage from the raw liver surface. 4. bactericidal effects 5. coagulation, vaporization and cauterization of the remaining lesion. For malignant liver tumor, the laser surgery has much above advantages and especially laser irradiation to the raw liver surface could be effective in preventing the local recurrence. It obtained better result on survival after hepatectomy compared with surgery without the laser instrument.

View full abstract

We have constructed a spectral image analyzer of Argon laser excited fluorescence and studied its condition to take good spectral pictures on the fresh non-fixed resected specimen of rectal cancer. A spectral image could not be taken through a narrow band pass filter alone, because it was not enough to exclude the reflected exciting laser beam. But by the conbination of both Kodak latten gelatin filter as a barrier filter and an interference filter was obtained a rather good spectral image. The difference could be detected in this system between intensities of laser excited fluorescence at the small area of the lesion, while it was difficult to clear it by the usual spectral analyzer.

View full abstract

Among the biological fluorescence induced by Argon laser, the fluorescence intensity originated from only porphyrins is higher at 630nm than at 620nm. We developed a new detection system. This system is composed of two interference filters (620.3nm and 631.6nm) attached to a lotating disc, a photomultiplier and a oscilloscope. In vitro and in vivo studies were carried out using this system compared with the fluorescence obtained by Optical Spectrum Analyser (OSA). The results were consisted with OSA's. Advantages of this system are summerized as follows; it is simple and inexpensive. It can selectively measure the porphyrin fluorescence.

View full abstract

We have studied and developed a new type of the plethysmograph using a light emitting diode (LED) as a compact and radiant light source for the diagnoses of microcirculation system. The detected signal was put into a microcomputer and processed by various statistical analysis in order to evaluate the microcirculation diseases. We defined the risetime of output pulse Tu,the delay time Td between signal pulse measured on the foot and the ear, and -10dB and -20dB decay frequencies in the pulse spectrum f1 and f2, respectively. Thus these parameters were derived by using a microcomputer, and compared for normal and diseased human subjects. It was found that they can descrive successfully human microcirculation conditions necessary for the diagnoses.

View full abstract

This work is intended to develope an endoscopic ESPI (electronic speckle pattern interferometry) system for medical measurements of the stiffness and extensibility of the tissues, the pulse propagation to the surrounding tissues, the movement due to respiration, etc. A ESPI system composed of a CCD camera, a frame memory, a 16 bit micro-computer and fiber optics, etc. was constructed. Using this system and several methods in data processing, speckle interferograms were sucessfully produced not only for metal objects but also for biological tissues. A method developed in this work has an advantage in applicability to inspections of transient phenomena using double pulsed lasers. A veiew of using this endoscopic ESPI system for medical diagnosis has been obtaind.

View full abstract

A new instrument is developed to monitor skin blood flow by analyzing the power spectra of laser speckle signals scattered from vascular tissues in skin surface. The system features the use of laser diode and a new quartz fiber probe which enable a long time monitoring of skin blood flow without suffering from mechanical vibration.

View full abstract

The analysis of the power spectral distribution (PSD) of the speckle fluctuation from the skin surface gives the useful information for the degree of skin blood flow. The ratio HLR of the high frequency component to the low one was calculated, averaged and printed out using a microcomputer. The variation of skin blood flow was measured at the palm, cheek, chest and leg. The value HLR was characterized by the region of the skin being measured.

View full abstract

Effect of Nd-YAG and CO₂ laser beam on micro-vasculature was examined in experimental animal. Soft x-ray microangiography and histological examination of brain after Nd: YAG laser exposure revealed broad avascular or oligovascular zone in the irradiated and the surrounding edematous tissue, in which the survived vessels showed narrowing and tapering without significant leak of blood. These findings seemed to correspond to high hemostatic capability of Nd: YAG laser. Vascular structure in the surrounding edematous layer after CO₂ laser exposure, on the other hand, was not so significantly affected by exposure as in Nd: YAG laser, and congested and sometimes ruptured vessels were found close to the central vaporized tissue defect in the coagulation layer, which might cause postexposure hemorrhage.

View full abstract

Spot beams of the high-peaked pulse wave form CO₂ (PW) and Nd: YAG (YAG) Laser were exposed on the brain surfaces of rabbits, using Model 130 YZ, coaxially and simultaneously. Sizes of lesions were 1.8-3.5mm in diameter, and 1.2-2.8 mm in depth, under the conditions of PW 1sec, 2, 4, 8w, and YAG 1, 2, 4sec, 10, 20, 40w, respectively. The more powers and times of laser exposure produced the larger lesion with occasional hemorrhage. Combined exposure of CO₂ and YAG laser is excellent in both cutting and coagulation. However, it should be considered that some hemorrhages might occur in the deep brain tissue, although the hemostasis of the brain surface appears to be completed.

View full abstract

Since January 1983, 51 cases of brain tumors have been operated in our clinic. We employed carbon dioxide laser in operation 17 cases of them. Histologically, meningioma were the most (11cases), followed by glioma (3cases), pineal teratoma (2cases), and metastatic brain tumor (1case).
Carbon dioxide laser has been the following surgical usefulness. 1) It is non-contact surgical unit as a “laser beam”; 2) enable to vanish the tumor by vaporization effect in focused beam, and 3) has coagulation effect by defocused beam. If we can utilize skillfully, being well aware of these peculialities, we can make it easy to remove 1) huge, 2) deep seated, 3) hard, and 4) vascular rich tumors, which is impossible or difficult to remove with conventional technique.
We presented 2 cases of huge pineal teratoma that were totally removed with CO₂ laser. In infratentorial supracerebellar approach for these located tumor, CSF and blood are drained spontaneously so the advantage of CO₂ laser is fully employed.

View full abstract

Intratumoral temperature and morphological change were studied in rat brain tumor model to assess the cause of anti-tumor effect by BPD photoradiation therapy.
At lower power density of the laser it was strongly suggested that tumor destruction was attributed to a photochemical reaction alone, but at high power density it was attributed to the effects of conbined photochemical reaction and hyperthermia.

View full abstract

Photoradiation therapy (PRT) is a recently introduced treatment for malignant Neoplasms, which depends on the tumor localization and retention of Hematoporphyrin derivative (HpD) activated by a proper light in the presence of oxygen.
PRT in combination of 50, 100, 150, 200mW power of Argon-pumped dye laser and 5, 10, 50μg/ml concentration of HpD can completely kill T9 cells in culture, and is effective to elongation of mean survival time of rat brain tumor models which were innoculated 10^5-6 T9 cells in the right parietal lobe.
(Control n=39 28.18±2.95 days, PRT n=4 41.0±7.97 days P<0.01)
The important side effect of PRT is considerable brain edema, so we should have a care for its clinical application.

View full abstract

Sixteen patients with glioma were treated by HPD-argon PDT. All patients underwent a partial or subtotal removal of the tumor, followed by PDT 72 hours after intravenous injection of 5mg/kg of HPD. The radiant energy exposure was 243-1564 joules/cm²·sec. During PDT a total of 10-25mg of HPD was locally injected into the residual tumor in all patients. It was suggested that energy exposure was under 311 joules/cm²·sec and residual volume of the tumor was large in the recurrence of the tumor within the exposed area.

View full abstract

It is important that the development and the improvement the laser techniques to success the medical application of lasers besed on the physiolosical aspects. This paper reports the techniques for the laser therapy devised by the authors. These are as follows:(1) Laser Protectors,(2) New laser handpieces,(3)Reputation laser exposing therapy,(4) Combined Nd⁺-YAG laser and CO₂ laser therapy for cancer,(5) Thermographic evaluation the therapeutic effect of lasers.(6) Treatment for melanouse gingiva using Ar⁺ laser,(7) Contact laser therapy using a ceramic surgical probe.(8) Low power laser therapy using Ga-Aslaser.

View full abstract

Conventional laser handpieces for medical laser equipment have some practical problems when used for treatment in such narrow fields of operation as body cavities. One of the greatest problems is that the location of the target for the laser is limited to some restricted parts of the surface of the subject region because of the fixed direction of the laser beam shot out from the laser handpieces. Another major problem is the difficulty of controling the field of laser exposure because a focul lens of a single focal length is used. The authors have developed two kinds of new laser handpieces with unigue functions as follows: one is a variable beam direction laser handpiece using a rotary reflector and another is a variable beam angle laser handpiece, both of which are extremely useful in laser surgery.

View full abstract

We studied an application of CO₂ laser to oral surgery. Since 1981, we have treated 24 patients, who suffered from oral malignant tumors, by means of a LASERY MODEL 60 (Nihon Sekigaisen Kogyo) at the oral surgery of Hokkaido University Dentai Hospital. The power of laser was adjusted to 5-10 W and the spot size to 1-2 mm for defocused beam. Almost all patients were treated under local anesthesia.
On the basis of our studies, we concluded as follows: For the best application of laser surgery to oral cavity, 1)The vessels larger than 0.5 mm in diameter must be coagulated by ligation or electrocauterization. 2) Retractors and traction suturs must used precisely. 3) The wounds must be left open in most cases.

View full abstract

We have used a high-powered carbon dioxide laser surgical unit ( Model 60 Z, Nippon intrarret indastrys Co., LTD.) since june, 1982 for clinical purposes in maxillofacial surgery. Up to now, laser surgery has been applied to 24 cases in total. This paper reports the results of our 20 cases, including benign and malignant tumors in maxillofacial region. The patients were 12 males and 8 females whose ages ranged from 18 to 68 years (mean 47 years). Cases involved 10 malignant tumors and 10 benign tumors.
Malignant tumors were treated with combined therapy, radiotherapy and chemotherapy (Pepleomycin) as well as surgery. In the operative procedures, surgical laser was used at the level of 10-15 W in the soft tissue and at NSP (Niic superpuls) 10-15 W or CW 40W in the bone. All of them except 2 cases have been progressing favorably with no sign of recurrence or metastasis. 2 patients followed by cerrvical metastasis received radical neck desection, but subsequently they died. In the cases of benign tumors, we were not bothered with excess bleeding even when hemangioma, and all surgical procedures were accomplished preferably. There was no postoperative infection. Postoperative pain was slight and operative wounds healed favorably.

View full abstract

The clinical application of CO₂ laser include its usages as a knife for incision and as a coagulator for hemostasis. We have made a study on the healing process of an incision wound in rat after treating with CO₂ laser as a knife, by H-E staining and microangiogrophy.
A minor incision was nude under onethesia along the middle gloove of the tongue with the focused befall of NIIC LASERY 60, Wine the topical site was left as open wound, microangiography was performed in 1 hour, 1, 2, 3, 4, 7, 10 and 14 days after the incision, and the tongue was extructed, H-E staining was made by the frontal part of the tongue, and a transparent specimen prepared from the rear part,
Incision with CO₂ laser inhibited the blood circulation in a wide resion around the incision wound on the tongue in rat. Observation of the resion made concurrently by H-E staining and microangiography produced interesting findings in the healing process with the lapse of time.

View full abstract

The submaxillary glands of dogs were resected and Nd-YAG laser was irradiated to the surface of the submaxillary glands. Power density of laser was 200W/cm². After irradiation of 1000J, clear shadow defects were not noted and leak of contrast medium were very rare in the sialography, so that it was considered that the irradiation part had been well sealed. In histo-pathologically, round necrotic lesion was noted and edema in interlobular connective tissue was remarkable on one day after. On 42-49 days after, a remarkable fibosis was noted in the interstice and necrotic lesion had been almost repaired. It was suggested that if laser was irradiated near the cloaca, there was in danger obliterating the duct.

View full abstract

The hemostatic effects of Nd-YAG laser were studied on tongues and buccal mucous membranes of dogs. After administration of heparin to the dogs, experimental hemorrhagic wound were produced on tongues and buccal mucous membranes. Power density of laser were established in 4 stages of 50, 100, 150 and 200W/cm². Total irradiation dose necessary for complete hemostasis was minimal in 150W/cm². When Warfarin had been given as maintenance dose to the dogs, post operative hemorrhage of laser hemostasis were clearly fewer than control. Epithelization of the wounds come to hemostasis with 150W/cm² were found after 2~3 weeks, healing without leaving a remarkable injury.

View full abstract

As the OSADA dental Nd-YAG laser apparatus with changeable four handpieces was offered, we have used to several oral tissues of rabbits and observed the histological changes of irradiated tissues. Thermal changes were also observed by SANEI non-contact infrared rays thermotracer. On clinicaly, we used this apparatus for oral surgery of 60 cases including 37 tumors, 19 cases of cystic lesions, 4 cases of mucosal lesions and others.
We recognized this apparatus is convenient for oral use.

View full abstract

Synersistic effect of laser irradiation and fluoride application on acid resistance of dental enamel was investigated. Sound human enamel specimens were soaked into an acidurated phosphate fluoride solution (APF) for 24 hours after irradiation of normal pulse Nd-YAG laser with an energy density 50J/cm². The enamel was obtained a remarkable resistance against acid decalcification compared with specimens of fluoride application alone and laser irradiation alone. The acquired zone of acid resistant of enamel reached from the enamel surface to 100μm in depth.

View full abstract

The authors have observed experimentally in pulp tissues of lased rat teeth the interesting phenomena that the secondary dentin formation growes reactively to fill the whole pulp cavity of the tooth within a few months after exposure to Ar laser or Nd-YAG laser. They have succeeded in producing similar changes in pulp tissues of rat teeth to that with Ar laser or Nd-YAG laser by using an Ar -dye laser with an extreamely low thermal effect after giving the rats HpD premedication. Recently in the case of human teeth exposed to the lasers similar changes to these experimental results in rat teeth have also been observed. These results will hopefully suggest the possibility of an epoch-making dentistry in biological endodontic therapy and biological root canal filling in the near future.

View full abstract

One of the authors has discovered the anesthetic effect of YAG laser on the exposed teeth. The outline of this technique is as follows: First of all the patient's tooth is exposed repeatedly to short pulses of YAG laser of low energy with feeling of no pain until it becomes completely insensitive to the laser shot and an anesthetic effect on the tooth for dental treatment is thus obtained without any damage to the pulp. In this stage it is possible to increase the laser energy in each pulse of the laser on the tooth without any sense of pain. Thus the dose of the laser energy in each pulse of the laser shot on tooth can be rased step by step and the anesthetic effect on the tooth can be confirmed. Recently the authors discovered that low power argon laser also has an anesthetic effect on exposed teeth.

View full abstract

Cytogenetic effects of argon laser irradiation were studied on human lymphocytes in terms of sister chromatid exchange. Argon laser irradiation of up to 300 Joule/cm² caused increase in SCE. The increment was more prominent when G1 lymphocytes were irradiated than GO cells. Slight suppression of the cell cycle progression was observed by laser irradiation. Although precise mechanism is still unclear, possible chromosomal damage relating to the cell division was suspected.

View full abstract

We developed a new method of analyzing porphyrins in the tissue by HPLC, using alkaline alcohol solvents for the extraction of porphyrins from the tissue. The column used was. porouspolymer-gel, and the elute solvents was 0.1N NaOH-methanol (1:9). A characteristic ability of the new method was the possibility of simultaneous extraction and estimation of metal porphyrin and heme, as well as free porphyrin, which was not possible with the conventional method using acetic acid-ethyl acetate as solvents. Using the new analytic method, it was proved that the protoporphyrin content in the cancerous tissue was definitely increased than in the non-cancerous tissue of rat hepatoma.

View full abstract

Laser photodynamic therapy (PDT) with homatoporphyrin derivertive has been given increase attation. Many investgators have recognized that PDT is an effective local treatment of eraly stage cancer. To clarify experimental and clinical effectiveness due to PDT, a bronchofiberscopic brushing cytology was performed chronologically. The change of cellular components were studied by means of a phase contrast microscopic system and electron microscopy.
The initial changes, halting of cellular movement, the degeneration of mitochondria, endoplasmic reticulum, and decrease of free ribosome, were recognized.

View full abstract

The effects of HpD photoradiation therapy with argon dye laser on cultured human lung cancer,pancreatic cancer and gastric cancer cells were studied. Five to 100μg/ml of HpD was added to culture plate, and after two hrs incubation, the plate was irradiated at an intencity of 10mw/cm² for 3 to 5 min respectively. The effects of the therapy was evaluated by measuring viability and number of cells on 24, 48 and 72 hours after the treatment. The cytotoxicity of HpD alone was observed after 72 hours incubation, and the viability was reduced to 0% in lung cancer 27% in pancreatic cancer and 38% in gastric cancer.
Laser irradiation increased the cytotoxicity to cancer cells. These effects were also related to the integrity of cancer cells. MMC also increased the effects of the photoradiation therapy.

View full abstract

The photochemical effect on seven cultured human cancer cell lines were studied. Each cell was irradiated by Ar laser light after HPD treatment. Cell survivals were measured by dye exclusion test and they decreased depending on the power density of Ar laser irradiation and HPD concentration. But the sensitivities to that effect were different among these cell lines. By laser-excited fluorescence microscope, it was found that HPD was uptaken mainly in cytoplasm. Ultrastructural studies showed that main change occured on mitochondria, rough endoplasmic reticulum, free ribosome, and nuclear membrane.

View full abstract

Hematoporphyrin studies including absorption and fluorescence measurements were performed using hematoporphyrin dihydrochloride (Hp. 2HCl) dissolved in ethanol and PBS solutions. Q-switched Nd: YAG laser original and its second harmonic beam were employed for their excitation. Thus the visible fluorescence generated by Nd: YAG laser irradiation was attributed to the two-photon absorption process in these solutions, although its intensity was about 10^-4 weaker than the case of second harmonic excitation. Survival rate of TE-2 cultured esophagus cancer cell uptaken Hp. 2HCl exhibited a linear decrease with the Nd: YAG laser irradiation time, and this photochemical effect was formed to be more appreciable for higher dye concentration.

View full abstract

We haved used the fluorescence-spectrum analyzer system to study the dynamics of hematoporphyrine derivative (Hpd) in the tumor-bearing mouse. The results show that Hpd has affinity to cancer tissue and perhaps rather strong accumulation in the cancer tissue. The greatest difference of concentration of Hpd between tumor and normal area is 24 hours after intravenous injection. Because this newly-developed system can examine accurately the relative concentration of Hpd in the tissue almost in real time, and because this system composed of a quartz fiber which can be inserted into the biopsy channel to detect the fluorescence of the stomach, we expect this spectrum analyzer system accompanying with using of Hpd can aid us to diagnosis gastrointestinal cancer.

View full abstract

Spectrum analysis of fluorescence of the various organs and gastrointestinal contents excited by argon laser was carried out in healthy rats, obtaining the results as follows.
1. The peaks of 630 and 680nm were not observed in the fluorescence of the gastrointestinal mucosa, liver, spleen and kedney.
2. The spectrum of fluorescence of the gastrointestinal mucosa in moe or less influenced by the contents in the gastrointestinal tract.
3. The gastrointestinal contents of fasting and polymyxin orally administrated fasting rat showed the spectra with the peaks at 630 and 680nm, being different from that of the rats on ordinary feed.
4. The gastrointestinal bacterial flora in the fasting rats and polymyxin administrated fasting rats were different from that of the rats on ordinary feed.

View full abstract

This paper presents a pilot study observing the fluorescence from the regions of contact between the cultured cells and the substrate. The technique utilizes the evanescent wave of a totally reflecting laser beam to excite only those fluorescent molecules within one light wavelength or less of the substrate surface. TIRF examination of cells apears to have promising applications, including visualization of the membrane underlying cytoplasmic structures at cell-substrate contacts, and mapping of fluorescent molrcules.

View full abstract

Nd-YAG laser was irradiated to the normal membranous portion of dog's trachea over one to four rings in the direction of major axis at 40W×2 seconds for a total of 14 places of 7 dogs and chronological changes from the pathological aspects were discussed. Each irradiation was applied at the distance of 10mm and by the angle of 30°C with the continuous wave until the mucous membrane turned white. The average dose was 650 joules per cm². The chronological changes after irradiation were classified into the ulceration stage, granulation stage, and scar stage The depths of irradiation reached to adventitia in the 7 places out of 9 which was irradiated over two rings or more in the direction of major axis. We should irradiate very carefully to the perforation of the membranous portion which is consisted without cartilage tissue.

View full abstract

We have performed endoscopic laser therapy to four cases with esophageal malignancies. Two cases were advanced esophageal carcinoma with malignant stricture, one case early esophageal carcinoma (type IIc) and one case carcinoma in cardia of the stomach. All cases were males of averagely seventy years old. In all cases, the operation was not indicated because of several conditions such as distant metastasis, association of other neoplasm and patient's refusal to surgical intervention. As a result, laser therapy was successfully performed to relieve esophageal malignant stricture with regression of the size of the tumor. By contrast, poor results were obtained to esophageal ulcerative lesions due to incomplete laser irradiation resulting from the fear of penetration through the thin-walled esophageal mucosa. Further study is needed for the application of laser therapy to esophageal ulcerative lesions. We concluded that laser therapy may provide a suitable palliative treatment for the malignant stricture of the esophagus.

View full abstract

Eleven cases, eight men and three women of inoperable gastric cancer were treated by YAG laser. Cases were included four Borrmann II, three Borrmann III, three Borrmann IV, in type and one postoperative. All cases had stenosis of cardia or antrum. Tumor size reduction was obtained in five cases. Improvement of stenosis was obtained in four cases. Improvement of symptom was recognized in four cases.
It is expected that YAG laser irradiation for inoperable gastric cancer is useful palliative treatment.

View full abstract

We examined the tissues damage of Nd-YAG laser irradiated gastric mucosa endoscopically, histologically in mongrel dog. Irradiated mucosal color was changed whitend and reddened toward the outside. After gastrostomy we made piled, continuous and discontinuous irradiation. Piled irradiation meaned to connect whitened area. Continuous irradiation meaned to connect reddened area. Discontinuous irradiation meaned to separate reddened area. Next, we marked between whitened area reddened area using ink spot.
Hitologically, piled irradiation made uniformal ulceration reached to muscle layer under condition of 50 watts output. In continuous irradiation, it was not enough to fall off the tissues at the borderline area. When we expect the local radical treatment of the tumor, it is necessary to make tissue damage of uniformal depth. So, We have reached the conclusion that the piled irradiation method is the best one.

View full abstract

We used a Q-switched Nd-YAG laser to perform posterior capsulotomies, anterior capsulotomies, iridotomies, and anterior vitrectomy. The iridotomy and anterior vitrectomy were ail successful and both anterior and posterior capsulotomies showed good resuits. Early and minor complication of capsulotomies were bleeding from the iris and the elevation of intra-ocular pressure. However, the bleeding was transient and most of the patients returned to IOP levels within a few days. Pits and cracks of the IOLs were observed after capsulotomies in the case of the poster-chamber IOL only, there were no damages to the anterior-chamber IOLs. However, pits and craks showed no effect on visual acuity.

View full abstract

CO₂ lasers has been used to drain subretinal fluid in retinal detachment surgery and to resect conjunctival hemangioma for the purpose of suppressing hemorrhage and protecting the surrounding tissues.
20 cases of retinal detachment were selected to drain subretinal fluid. After the sclera was incided about 2mm width to expose the choroid, wich was irradiated by CO₂ laser beam under the condition of 80μm in diameter, 2w and 0.05 sec. It was found that subretinal fluid was drained sufficiently with no complications, such as choroidal hemorrhage or retinal hole.
One of conjunctival hemangioma was experienced, and it has been resected by CO₂ laser beam of 1w c. w. mode successfully with minimum bleeding.

View full abstract

Pan-retinal photocoagulation treatment for diabetic retinopathy has a posttreatment affect on the visual function to induce constriction of visual field. In this study, we have performed pan-retinal photocoagulation treatment for the prolifelation diabetic retinopathy under the nearly identical conditions applying Arugon laser on one eye and Krypton laser on the Other, so as to observe the post operative effect on the visual field and thus to make the comparative examination of them with regad to the degree of the trouble.

View full abstract

For the last 19 years, there were ten case reports of accidental retinal burn by many kind of lasers in Japan. A case is a 22 years old student belong to faculty of technology, and an accidental reti retinal burn was caused by Q-switched pulsed Nd-YAG laser beam. The cause of this accident seemed to be the lack of the safety education to the student before experiments. safety considerations and caliculum in our laser laboratory are discussed.

View full abstract

We investigated the risk of intense flashback during in laser endoscopy. Two well-characterized models of reflections and the tissues are used to document flashback levels on fiberoptic endoscopes during Nd-YAG laser irradiation. In the safety viewpoint, filter attachment to endoscopic eyepiece is nesserary for adequate protection from flashback hazard.

View full abstract

Cryosurgery and other new surgical methods are developping.
The purpose of this study is to make-macro and microscopic examination of these new surgical therapies on the tongues of healthy adult dogs in a definite condition.
The therapies are cryosurgery, CO₂ LASER surgery, Nd-YAG LASER surgery, ultrasonic aspirator method, bipolar coagulator method, infrared coagulator method.
Immediately after these therapies, we have confirmed the follows; edema in cryosurgical method, carbonization in CO₂ LASER method, coagulation and carbonization in Nd-YAG LASER surgery, coagulation in bipolar coagulator method, and coagulation and erosion in infrared coagulator and ultrasonic aspirator methods.
One, two, three, and four weeks after these therapies, we found various changes of each methods.

View full abstract

In treating carcinomas of the tongue, we have employed three types of laser usage.
Carcinomas confined within the mucosa are treated by laser alone. For carcinomas invading the muscle to some extent, we make a mass reduction surgery by means of laser which is followed by (chemo) radiotherapy. Carcinomas with extensive muscular invasion are first treated with induction chemotherapy. If the chemotherapy is effective, we add laser surgery for the purpose of mass reduction and chemoradiotherapy follows.
26 patients were treated and none has developed local recurrence.

View full abstract