bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature along the surface of modified fiber tips for Nd:YAG laser angioplasty
Authors: Verdaasdonk Rudolf M. , Holstege Frank C. , Jansen E. Duco , Borst Cornelius 
Published: March 2007

AbstractFor laser angioplasty probes, the thermal properties of the probes will primarily determine their mechanism of action. We examined the absorption, temperature increase, and probe degradation of transparent contact probes (hemispherical contact probe and ball‐shaped fibers) and metal laser probes coupled to a continuous‐wave Nd‐YAG laser. Temperature was recorded by means of thermocouples and the measurements were corrected for direct light absorption by the thermocouple. During 15 W, 1 s exposure, the peak temperature rise of the hemispherical contact probe in contact with tissue dropped from approximately 1,000°C at the front end to below 45°C (95% drop) at the lateral side. In contrast, during continuous exposure the peak temperature rise of metal laser probes in contact with tissue dropped from 560°C at the front end to near 400°C (30%drop) at the 5.5 mm proximal rear end. During exposure in blood or tissue, the transparent contact probes became contaminated. Their absorption increased from 5 to 33% and the probe deteriorated. Repeated use of metal laser probes in blood resulted in a higher temperature at the rear than at the front end due to backburing of the fiber. Owing to the large temperature drop along the surface of transparent contact probes, the area of thermal destruction is limited to the tissue in front of the probe, whereas along the entire surface of metal laser probes the tissue will be affected. The large difference between these temperature distributions should be respected during clinical application of the transparant contact probe and the metal laser probe.
Fluorescence localization of early colonic cancer in the rat by hematoporphyrin derivative
Authors: Bjorkman David J. , Samowitz Wade S. , Brigham Earl J. , Peterson Brian J. , Straight Richard C. 
Published: March 2007

AbstractLaser excitation of hematoporphyrin derivatives (HPD) localizing in tumors of the tracheobronchial tree and bladder is useful in the identification and treatment of those tumors. A comparable utility for HPD in the endoscopic localization of colonic tumors may be possible. In this study the ability of HPD to identify 1,2 dimethylhydrazine (DMH) induced colon cancer in rats is evaluated.A total of 111 rats were studied with HPD. Sixty‐nine rats received weekly injections of DMH (20 mg/kg) and 42 received injections of the vehicle alone. Twenty‐four hours after the intravenous injection of 5 mg/kg of HPD, 18 DMH‐induced tumors were identified by visual fluorescence using excitation by either a blue light (390–436 nm) or an argon laser (488 and 514 nm). This represented 100% of the visually or microscopically detected tumors. Seventy‐five fluorescent areas were noted that did not contain evidence of cancer. The majority (63) of false positive areas contained lymphoid follicles. All but 2 false positive areas (73/75, 97%, p < .001) were seen in DMH‐treated animals, suggesting that they were an artifact of DMH treatment. HPD fluorescence did not identify microscopic dysplasia.We conclude that HPD fluorescence is an effective method of identifying early colonic cancer and may have a potential clinical role in patients at high risk for colorectal cancer.
In situ testing of CO2 laser on dental pulp function: Effects on microcirculation
Authors: Friedman Shimon , Liu Mintsai , Dörscher‐Kim Jutta , Kim Syngcuk 
Published: March 2007

AbstractThe effect of CO2 laser irradiation on pulpal microcirculation was studied in cat canines. The enamel surfaces of 4 teeth were exposed with energy densities of 304‐1440J/cm2, using either a handpiece or a microslad, with a focal spot of 0.21mm and 0.33mm respectively. Pulpal blood flow (PBF) before and following lasing was recorded through the intact tooth surface by a laser Doppler flowmeter. CO2 laser irradiation caused an increase in PBF, which was immediate and transient. The PBF increase was higher in a large pulp than in a small pulp, and it was inversely related to the focal spot size. These findings confirm that the dental pulp is thermally affected by CO2 lasing of the tooth surface, however, without extensive pulp coagulation. It is concluded that the effects of laser irradiation on the pulpal microcirculation may be studied in situ by means of the presented methodology.
Contact diode laser application through a fiberoptic cutting tip
Authors: Peyman Gholam A. , Cruz Sergio A. , Ruiz‐Lapuente Carlos 
Published: March 2007

AbstractWe applied diode laser energy through a fiberoptic probe to cut ocular structures. The diameter of the probe's tip was 100 μm. The amount of energy used for cutting the lid, the cornea, or for perforation of the globe was 2.5 watts in the continuous mode. The incised border demonstrated coagulation into the healthy tissue ranging from 10 to 50 μm.
Nd:YAG laser‐induced hyperthermia treatment of spontaneously occurring veterinary head and neck tumors
Authors: Panjehpour Masoud , Overholt Bergein F. , Frazier Donita L. , Klebanow Edward R. 
Published: March 2007

AbstractConventional hyperthermia treatment of superficial tumors in the oral cavity is troublesome due to difficulty in accessing the lesion. A new hyperthermia technique employing near‐infrared radiation delivered through a flexible silica optical fiber is described. The system consisted of an Nd:YAG laser for tissue heating, a He–Ne laser for aiming beam, a computer‐controlled optical shutter, an interstitial thermometer, computer, and a printer. A 3‐m‐long 600‐μm silica fiber delivered laser energy to the tumor via surface illumination. Using the aiming beam, the spot size was adjusted to include 5 mm of surrounding normal tissue. A thermocouple implanted in the tumor base provided temperature feedback to maintain desired hyperthermic temperature within the lesion.Three spontaneously occurring canine (two squamous cell carcinomas on the gum, one pigmented melanoma on the hard palate) and one feline tumor (squamous cell carcinoma on the nose) have been treated with Nd:YAG laser hyperthermia. Hyperthermia was delivered at 43.5°C for 1 h. All animals received standard radiation treatment prior to hyperthermia. Nd:YAG laser hyperthermia allowed effective and efficient delivery of heat to veterinary nasal and oral lesions otherwise not treatable with conventional heating techniques.
Nd:YAG laser hyperthermia treatment of rat mammary adenocarcinoma in conjunction with surface cooling
Authors: Panjehpour Masoud , Wilke August V. , Frazier Donita L. , Overholt Bergein F. 
Published: March 2007

AbstractElectromagnetic radiation ranging from radiofrequency to microwave has classically been used to induce hyperthermia for treatment of cancer. This paper presents a new technique using near infrared radiation from an Nd:YAG laser in conjunction with surface cooling to induce hyperthermia in a rat tumor model.A CW Nd:YAG laser hyperthermia system was used to induce hyperthermic temperatures in chemically (DMBA) induced rat mammary adenocarcinomas. The laser was interfaced to a computer and a thermometry unit that provided feedback to control the tumor temperature between 43.2–43.5°C. A thermocouple was placed at the base of the tumor and its temperature was used to control laser exposure. All tumors were 10 to 20 mm in diameter.Surface cooling methods investigated included forced air flow from a fan, forced oxygen flow plus an IV drip, and forced moist oxygen flow from a nebulizer. Twelve rat mammary adenocarcinomas have been treated with Nd:YAG laser hyperthermia. In 4 treatments, no surface cooling was employed. In one treatment the surface was cooled using oxygen flow plus IV drip. In 7 treatments the skin was cooled using the nebulizer technique. The nebulization provided the most effective and reproducible surface cooling.Nd:YAG laser hyperthermia delivered in conjunction with nebulizer surface cooling produced efficient heating of rat mammary adenocarcinomas. A mean temperature of 42.1 °C was obtained at the base of the tumors while the mean surface temperature was 37.0 °C.
Presence of blood significantly decreases transmission of 630 nm laser light
Authors: Vincent G. Michael , Fox Jolene , Charlton Gerald , Hill J. Stan , McClane Robert , Spikes John D. 
Published: March 2007

AbstractApplication of 630 nm light in the presence of blood is often necessary during photodynamic therapy, particularly for proposed intravascular applications. The effect of blood on transmission of 630 nm light was studied using a three dimensional irradiation model and an integrating sphere for measuring light transmitted in any direction through blood layers of different hematocrit (25 to 75) and thickness (.15 to .98 mm). There was an inverse relationship between transmission and hematocrit and transmission and blood thickness, p=.000 for both. At a physiologic hematocrit of 46, transmission through blood layers of .98, .41, .28, and .15 mm were 21%, 33%, 29%, and 58% respectively. These blood thicknesses or more are likely in the clinical environment, and can be expected to result in significant transmission losses. The marked absorption of 630 nm light by blood indicates that removal of the blood or correction for power loss should be employed when 630 nm light is applied in a blood containing environment.
Effect of low level laser therapy on wound healing after palatal surgery in Beagle dogs
Authors: de Braekt Marcel M. H. In , van Alphen Frank A. M. , Kuijpers‐Jagtman Anne M. , Maltha Jaap C. 
Published: March 2007

AbstractThe effect of low level laser therapy on wound healing and wound contraction after palatal surgery in Beagle dogs of 12 weeks of age was investigated. A total of 30 Beagle dogs was used and assigned to a control group (Group C; n=6) and two experimental groups (Group L; n=12 and group LL; n=12). In both experimental groups, Von Langenbeck's palatal repair was simulated. Then in the LL group the denuded bony areas were treated with low level laser therapy using a continuous Ga‐As‐Al laser beam (830 nm) and energy output set at 30 mW. Per treatment a dosage of 1 J/cm2 wound surface area was used. Therapy was carried out three times a week with a total of ten treatments.Wound healing was observed clinically until wound healing was completed at 4 weeks p.o. and wound areas were measured at regular intervals on standardized intra‐oral photographs. Wound contraction was measured as the increments of the distances between tattoo points on the opposite wound margins. No significant differences were found in the quality and rate of wound healing between the two experimental groups. The same held true for the increments of the distances between opposite tattoo points. It was concluded that macroscopically low level laser therapy under conditions used in this study did not have an influence on wound closure or wound contraction.
Healing of infected wounds following Iodine scrub or CO2 laser treatment
Authors: Reid A. Bruce , Stranc Miroslaw F. 
Published: March 2007

AbstractThis study compares CO2 laser sterilization with iodine surgical scrub in infected pseudomonas wounds in the rabbit, and on frequency of wound breakdown secondary to sepsis. Thirty‐three New Zealand rabbits underwent bilateral flank incisions and infection with a standard solution of pseudomonas aeruginosa. After 4 days of incubation, the wounds were randomized to receive laser sterilization and routine iodine surgical scrub respectively. Following sterilization, excision of the wound, and suturing was carried out. After 12 days, the wounds were assessed for evidence of residual infection as well as wound breakdown in a double blind fashion. Clinical observation, qualitative microbiology, and in some cases histology, were used to document the presence of infection. Statistical analysis of wound breakdown secondary to infection revealed a significant difference in breakdown rates. Three laser and 12 iodine treated wounds displayed breakdown secondary to sepsis. We conclude that the CO2 laser sterilization technique is more effective than routine iodine surgical scrub.
Application of the argon laser to dentistry
Authors: Kelsey William P. , Blankenau Richard J. , Powell G. Lynn 
Published: March 2007

AbstractA review was conducted to determine specific areas of application of the argon laser to dentistry. When appropriate, comparisons between the argon laser and other treatment methods were made. It was concluded that the argon laser has applicability in composite resin placement, in enamel and dentin bonding procedures, in preventive dental therapies, and in endodontic procedures.
Contact Nd: YAG tonsillectomy: Effects on weight loss and recovery
Authors: Maloney Richard W. 
Published: March 2007

AbstractContact Nd: YAG tonsillectomy using synthetic sapphire blades appears to meet or exceed standards established by spot monopolar cautery. Subjects' percentage of weight loss and return to work/social activities was measured and the laser group displayed less percentage of weight loss, faster return to pre‐operative weight, and less recovery time than the comparative cautery group. Because of the unique nature of Nd: YAG laser light combined with sapphire blades, special consideration should be given to these accessories by physicians before attempting tissue cutting and vessel coagulation. The author believes that the extent of physician training and proficiency may be key to the success of soft tissue head and neck applications, such as tonsillectomy, which will have an effect on the outcome of clinical data.
Laser‐induced fluorescence emission: I. The spectroscopic identification of fibrotic endocardium and myocardium
Authors: Perk Masis , Flynn Gregory J. , Smith Carolyn , Bathgate Ben , Tulip John , Yue Wen , Lucas Alexandra 
Published: March 2007

AbstractLaser‐induced fluorescence has been developed as a guidance system for laser angioplasty. Laser ablation has been used for resection of arrhythmogenic ventricular scar. We have investigated the use of laser‐induced fluorescence for the detection of fibrotic and ischemic changes in endocardium and myocardium. Fluorescence emission spectra from human necropsy specimens were correlated with histologic examination. Normalized fluorescence intensity detected from both the endocardial and the myocardial surfaces of the fibrotic ventricular specimens was significantly higher than that of corresponding normal specimens at 440 to 475 nm. Fibrotic endocardium could be identified by a fluorescence emission intensity ratio less than 1.5 for wavelength ratio 375/450nm. Acutely infarcted endocardium was recognizable by a ratio of 1.5 to 2.0. The specificity and sensitivity of detection of scarred endocardium was 70 and 100%, respectively. Fibrotic myocardium was also consistently identified by fluorescence spectroscopy.Conclusion: Fluorescence emission spectroscopy can differentiate normal and fibrotic endocardium and myocardium, in vitro. This technique may be useful for guidance during laser ablation of arrhythmogenic ventricular scar.
Solid state ultraviolet laser (213 nm) ablation of the cornea and synthetic collagen lenticules
Authors: Gailitis Ray P. , Ren Qiushi , Thompson Keith P. , Lin J. T. , Waring George O. 
Published: March 2007

AbstractWe used a Q‐switched Nd:YAG laser with non‐linear optical crystals to produce the 5th (213 nm) and the 4th (266 nm) harmonic frequencies. Using these two wavelengths, we ablated fresh porcine corneas and type I collagen synthetic epikeratoplasty lenticules. For the 213‐nm ablation, radiant exposure was 1.3 J/cm2. The ablation rate was 0.23 μm per pulse for the epikeratoplasty lenticules. We examined all tissues with light microscopy, transmission electron microscopy, and scanning electron microscopy. Histology for the 213‐nm ablation showed a clean ablation crater with minimal collagen lamellae disruption and a damage zone less than 1μm. In comparison, the 266 nm radiation showed more charring at the edges with a damage zone approximately 25 μm deep with disruption of the stromal lamella.Our results show that this solid state UV laser is a potential alternative to the excimer laser for cornea surgery.
Technique for cellular microsurgery using the 193‐nm excimer laser
Authors: Palanker Daniel , Ohad Shoshanit , Lewis Aaron , Simon Alex , Shenkar Joseph , Penchas Shmuel , Laufer Neri 
Published: March 2007

AbstractA new cell surgery technique has been developed to produce well‐defined alterations in cells and tissue without detectable heating and/or other structural damage in the surroundings. The technique involves the use of an argon fluoride excimer laser, in the deep ultraviolet (UV) region of the spectrum at 193 nm, which is guided through a glass pipette filled with a positive air pressure. To demonstrate the method, holes were drilled in the zona pellucida of mouse oocytes. The diameter of the drilled hole was determined by the pipette tip size, and its depth by an energy emitted per pulse and number of pulses. Scanning electron microscopy of the drilled mouse oocytes showed uniform, round, well‐circumscribed holes with sharp edges. Oocytes that had their zona pellucida drilled with this new method fertilized in vitro and developed to the blastocyst stage in a rate similar to that of control group. These results demonstrate the nonperturbing nature of this cold laser microsurgical procedure. In addition to the extension of our results for clinical in vitro fertilization purposes, such as enhancement of fertilization and embryo biopsy, there are wide‐ranging possible uses of our method in fundamental and applied investigations that require submicron accuracy in cellular alteration.
Glucose administration combined with photodynamic therapy of cancer improves therapeutic efficacy
Authors: Nelson J. Stuart , Kimel Sol , Brown Lisa , Berns Michael W. 
Published: March 2007

AbstractBoth the scope and the levels of activity in basic research and in the clinical applications of PDT, have grown enormously during the past few years. Several studies have examined the synergism of hyperthermia and chemotherapeutic agents in combination with PDT to enhance tumor eradication. The present study investigates the synergism of glucose administration combined with phototherapy.The results of this study suggest that glucose administration is simple and well tolerated, and combined with PDT produces a larger percentage of animals cured than using PDT alone. Furthermore, the results indicate that this approach requires lower amounts of light and might enable dosage reduction of photosensitizer for optimal response, with minimal side effects, to the treatment of cancer. © 1992 Wiley‐Liss, Inc.
Effect of helium–neon laser irradiation on serum lipid peroxide concentrations in burnt mice
Authors: Zhang Dahong , Chen Tingren , Wang Channian , Wu Shimin , Fu Chengli 
Published: March 2007

AbstractThe effect of helium–neon irradiation on serum lipid peroxide concentrations in mice following 6–7% body surface area burns was investigated in a controlled study. Immediately following injury by an 8‐sec 100°C scalding, 25 mice were irradiated by a helium‐neon laser at 0.05 J/cm2. A control group of the same size underwent identical treatment but received only sham irradiation. Serum lipid peroxide concentrations increased markedly in the control group at 0.5–4 h (P<0.0001, two sample t‐test). In the laser treated group, the lipid peroxide concentrations remained relatively constant and were significantly depressed relative to the control group 4 h following burning (P < 0.0001, two‐sample t‐test). © 1992 Wiley‐Liss, Inc.
Laser and suture anastomosis: Passive compliance and active force production
Authors: Dalsing Michael C. , Packer C. Subah , Kueppers Peter , Griffith Steven L. , Davis Thomas E. 
Published: March 2007

AbstractOne carotid from each dog underwent a laser anastomosis and the other carotid an interrupted suture repair. One or eight weeks later (n ≥ 4 dogs/time period); four rings (1 mm in length) containing the laser or suture anastomosis or the normal artery (two/dog) were removed. Using a photoelectric force transducer and lever system, the ring was stretched in increments and passive force measured. At each length, the arterial muscle was stimulated and active force measured.The mean laser and control passive length/tension (L/T) curves were not different (P > 0.05), but the suture curve was shifted downward (P<0.05). The mean laser and suture active L/T curves were similar at 1 week ( > 0.05) and lower than the control curve (P < 0.04). At 8 weeks, the laser‐repaired vessels produced an active force similar to control muscle (P > 0.05) but the suture repairs could not generate this active force (P<0.05).These data suggest that the laser repair and normal artery are more mechanically compatible than the suture repair as studied by this method. © 1992 Wiley‐Liss, Inc.
A special irrigation liquid to increase the reliability of laser‐induced shockwave lithotripsy
Authors: Reichel Erich , Paltauf Günther , Schmidt‐Kloiber Heinz , Groke Karl 
Published: March 2007

AbstractFor the laser‐induced Shockwave lithotripsy (LISL) the laser‐pulses of a Q‐switched Nd:YAG laser produce an optical breakdown in the irrigation liquid surrounding the urinary stone. Subsequently high‐pressure Shockwaves are emitted causing stone fragmentation. Since the LISL is an endoscopic technique, problems arise from the transmission of the laser pulses through optical fibers. The intensity threshold for an optical breakdown in commonly used saline solution amounts to 21 GW/cm2, in optical silica fibers, to about 3 GW/cm2. Therefore bare fibers cannot be used without being destroyed by a breakdown. So we have developed an irrigation liquid by adding small quantities of metal ions to saline solution to lower the threshold intensity. The most suitable ion was Fe3+ in a concentration of 0.02 mmol/1, which shows a lowering to 5 GW/cm2. In combination with a spherically shaped fiber exit the intensities that have to be transmitted are below the threshold of the fiber material. Using this irrigation liquid the overall reliability of the method could be significantly increased and several stone fragmentations can be performed with a single optical fiber. © 1992 Wiley‐Liss, Inc.
Effect of coolant flow on the performance of round sapphire tips in a saline field
Authors: Royston David D. , Waynant Ronald W. , Elliott Ariann M. , Oshry Stacy 
Published: March 2007

AbstractRound sapphire and silica tips have been studied as surgical probes for focusing Nd:YAG laser radiation during various surgical indications. Since most of these data have been obtained with silica tips from Surgical Laser Technology, there are limited data on the physical performance of round sapphire tips. An investigation of round sapphire tip performance during tissue ablation was undertaken. Nd:YAG laser power was delivered in repetitive 2‐sec exposures to a round sapphire tip placed on fresh skinned chicken breast. Total exposures of 1,000 J were performed at different saline perfusion rates. The tip's performance in terms of tissue perforation rate, blanched tissue area, tissue heating rate, and forward transmission was measured. Best tip performance occurred at the lowest cooling rates and was independent of the tip's forward transmission value. No physical deterioration of the tip's optical surface was observed. Round sapphire tip performance in a saline field is primarily determined by the tip's temperature. © 1992 Wiley‐Liss, Inc.