bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the optical and thermal properties of biliary calculi using pulsed photothermal radiometry
Authors: Long Frederick H. , Nishioka Norman S. , Deutsch Thomas F. 
Published: March 2007

AbstractThe optical absorption coefficients for biliary calculi are important in understanding the mechanism of laser‐induced stone fragmentation. However, the heterogeneous composition of calculi and difficulties in producing optically thin samples prevent conventional spectrophotometric measurement techniqus from being used. To overcome these limitations, we used a pulsed photothermal radiometry system to measure the optical absorption coefficients and thermal diffusivities of various biliary calculi. In the wavelength range examined (350–1,060 nm), there was strong optical absorption which was greater for pigment stones than for cholesterol stones. The data support the theory that the initiation of the plasma accompanying laser fragmentation of calculi is a thermal process.
Characteristic autofluorescence for cancer diagnosis and its origin
Authors: Yuanlong Yang , Yanming Ye , Fuming Li , Yufen Li , Paozhong Ma 
Published: March 2007

AbstractThe autofluorescence spectra of human tissues excited with the 365‐nm line of pulsed xenon ion laser have been measured. The autofluorescence spectra of cancer tissues usually show characteristic peaks near 630 nm and 690 nm, which do not appear in the spectra of the corresponding normal tissues. This characteristic fluorescence can be taken as a criterion for cancer diagnosis; a consistency of 89% with the traditional biopsy method has been obtained in preliminary clinical application to the diagnosis of buccal carcinoma. Spectroscopic investigations suggest that the porphyrin compounds localized and retained in cancer tissues might be responsible for this characteristic autofluorescence.
Superpulse CO2 laser treatment of facial syringomata
Authors: Apfelberg David B. , Maser Morton R. , Lash Harvey , White David N. , Cosman Bard 
Published: March 2007

AbstractEight patients with facial syringomata have been treated with the superpulse 2 laser and followed for periods up to 3 years. Superpulse capability allows satisfactory photovaporization of overlying skin and exposure and liberation of the underlying cyst. Healing was satisfactory with minimal scarring and no persistence or recurrence of syringomata in five of eight cases.
Effect of pulse duration on selective ablation of atherosclerotic plaque by 480‐ to 490‐nanometer laser radiation
Authors: Lamuraglia Glenn M. , Murray Steve , Anderson R. Rox , Prince Martin R. 
Published: March 2007

AbstractThe effect of varying pulse duration on selective ablation of human arterial plaque was evaluated by measuring ablation thresholds and ablation efficiencies on fresh human fibrofatty plaque, calcified plaque, normal intima, deep media, and adventitia using 480‐ to 490‐nm laser radiation at 1, 8, and 50‐μsec pulse durations. For all tissues examined, the ablation threshold energy increased with increasing pulse duration, but the threshold for normal tissue ablation was approximately twice that of plaque at all pulse durations. Ablation efficiency was studied at a fluence that was twice the ablation threshold for plaque. For those fluences, normal intima had detectable ablation only at 50 μsec. The ablation efficiency of fibrofatty plaque was minimally reduced with prolongation of pulse duration; however, there was a substantial decrease in the ablation efficiency of calcified plaque when the pulse duration was lengthened from 8 to 50 μsec. These data show significant selective ablation of fibrofatty and calcified plaque at 1, 8, and 50 μsec and suggest that the optimal pulse width for selective ablation of all plaque in the 480‐ to 490‐waveband is less than 50 μsec.
Laser balloon angioplasty: Effect of tissue temperature on weld strength of human postmortem intima‐media separations
Authors: Jenkins Ronald D. , Sinclair I. Nigel , Anand Raj , Kalil Arthur G. , Schoen Frederick J. , Spears J. Richard 
Published: March 2007

AbstractDehiscence of portions of atheromatous plaques fractured during percutaneous transluminal coronary angioplasty may contribute to both abrupt reclosure and gradual restenosis. Laser balloon angioplasty has been shown to be effective in welding human plaque‐arterial wall separations in vitro by heating tissues with a Nd:YAG laser during balloon inflation. To define the potentially useful therapeutic range of tissue temperature required to achieve thermal welds, 220 1‐cm diameter discs of human postmortem atheromatous aortic tissue, the intimal plaque of which had been separated from the media, were exposed to 3–25 watts of Nd:YAG laser radiation delivered over a 12‐mm2 nominal spot size for 20 seconds via a 400‐μm core optical fiber. As measured with a thermistor, adventitial temperature reflected the temperature at the plaque‐media junction to within 10°C. The degree of tissue temperature elevation was related to delivered energy, while effective tissue penetration increased to maximum depth of 3 mm at the highest power density. Strength of tissue welds was defined as the force required to shear opposing layers of welded segments. Adventitial tissue temperatures below 80°C were not associated with appreciable welds, while equilibrium temperatures between 95°C and 140°C were consistently associated with effective mean weld strengths, which increased linearly from 25 to 110 g, respectively. Temperatures greater than 150°C were associated with rapid tissue dehydration and charring. These data suggest that the therapeutic range of tissue temperature that provides effective thermal fusion of intima‐media separations is broad and that the depth and degree of thermal coagulation can be controlled by manipulation of laser energy delivery.
Spectroscopic characterization of cardiovascular tissue
Authors: Clarke R. H. , Isner J. M. , Gauthier T. , Nakagawa K. , Cerio F. , Hanlon E. , Gaffney E. , Rouse E. , DeJesus S. 
Published: March 2007

AbstractWe present results of a series of laser spectroscopic measurements on in vitro samples of cardiovascular tissue. These include laser Raman scattering, Fourier transform infrared, plasma emission and fluorescence, and electron paramagnetic resonance spectroscopy. The results of these spectroscopic measurements are discussed in terms of their implications for the field of laser angioplasty.
Pulsed CO2 laser tissue ablation: Effect of tissue type and pulse duration on thermal damage
Authors: Walsh. Joseph T. , Flotte Thomas J. , Anderson R. Rox , Deutsch Thomas F. 
Published: March 2007

AbstractTissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and exposure duration. The effect of exposure duration has been studied in vivo by using CO2 lasers with pulse widths that vary from 2 μsec to 50 msec. Pulse widths of 50 msec, typical of a shuttered, continuous‐wave CO2 laser, produce damage regions 750 μm wide in normal guinea pig skin; the use of a 2‐μseclong pulse reduced this damage zone to as little as 50 μm. Using 2‐μseclong pulses, in vitro studies showed that the minimum zone of thermal damage varied significantly with tissue type. The thermal denaturation of these tissues has been studied and correlated with damage. The effect of denaturation temperature and pulse duration on the width of the damage zone is explained by a simple model.
Comparison of continuous‐wave, chop‐wave, and super pulse laser wounds
Authors: Lanzafame Raymond J. , Naim John O. , Rogers David W. , Hinshaw J. Raymond 
Published: March 2007

AbstractSome of the latest generation of CO2 lasers incorporate features that alter the wave form. The present study was undertaken to evaluate the relative zone of coagulation in acute laser wounds created in continuous‐wave (CW), chop‐wave (CPW), and super pulse wave (SPW) modes. The damage from single‐point impact sites and incisions was compared in a guinea pig model. Animals were anesthetized with pentobarbital, and wounds were created with a 125‐mm handpiece in focus (0.2‐mm spot size) on dorsal and flank skin sites with the Sharplan 743 and 1100 CO2 lasers (Sharplan, Ltd., Allendale, NJ). Point impacts of CW and CPW were compared at power levels of 5, 10, 25, 40, 60, and 80 W at time durations of 0.05, 0.1, 0.2, and 0.5 seconds. Incisions of 3.0 cm were created at 25 W in CW, CPW, and SPW modes. Histologic sections stained with hematoxylin and eosin and Van Giesen elastin stains were evaluated by a single observer (R.J.L.). Zones of coagulation for the point‐impact study varied from 79 to 257 ± 66 (SD) μm in width with no significant differences between any of the wounds. Greater thermal damage (coagulation) occurred as the time interval increased. The zones of coagulation in the incision study were 309 ± 83 (SD) μm for CW, 238 ± 51 (SD) μm for SPW1 (743), 260 ± 79 (SD) μm for CPW, and 194 ± 56 (SD) μm for SPW2 (1100). These results are significant to the P<0.01 level. The effects of wave chopping are minimal for point impacts, but there is significantly less damage along incisions made with chop wave mode. Super pulse produces a narrower zone of coagulation than does either CW or CPW. The width of the zone of coagulation is greater along the incision than from single‐point CW of CPW impacts.
532‐nanometer green laser beam treatment of superficial varicosities of the lower extremities
Authors: Smith Teruko , Apfelberg David B. , Maser M. Richard , Lash Harvey , White David N. 
Published: March 2007

AbstractGreen laser light at 532 nm was utilized in an attempt to thrombose and blanch superficial varicosities of the lower extremity in 14 patients. Selective vascular damage with sparing of overlying skin was the theoretical rationale for use of green light. Seven of the 14 patients achieved satisfactory results (total or near‐total obliteration of vessels without scarring) after a 6‐month period of observation.
Experimental ab interno sclerotomies using a pulsed‐dye laser
Authors: Latina M. , Goode S. , de Kater A. W. , Long F. H. , Deutsch T. F. , Epstein D. L. 
Published: March 2007

AbstractWe studied the use of a short‐pulse, flashlamp‐pumped dye laser, emitting at 666 nm, to create ab interno sclerotomies in cynomolgus monkeys using a fiberoptic delivery system. Because of the low optical absorption of the sclera in the visible portion of the spectrum, ablation of sclera by continuous wave lasers emitting in this region requires high energies and produces significant thermal damage to surrounding tissues. To enhance the optical absorption of sclera, methylene blue dye was applied iontophoretically; patent sclerotomies were obtained in all 10 eyes of six cynomologus monkeys, with energies ranging from 15 to 50 mj/pulse. Thermal damage to the adjacent sclera was confined to 300 μ/m. Complications included mild intraoperative hyphema at all pulse energies and iridodialysis at higher pulse energies. Filtration blebs routinely failed within 7 days; the use of 5‐fluorouracil postoperatively significantly prolonged bleb duration. The small incision technique described allows ab interno sclerotomies to be created with low pulse energies without the need for conjunctival dissection, thereby avoiding the problems associated with conjunctival wounds. An advantage of this technique is that it can be modified to create ab interno sclerotomies noninvasively by delivering pulsed visible radiation through the cornea with a gonioscopic‐slitlamp system.
Partial nephrectomy using the Nd:YAG Laser: A comparison of the 1.06 μ and 1.32 μ lasers employing different delivery systems
Authors: Johnson Douglas E. , Wishnow Kenneth I. , von Eschenbach Andrew C. , Grignon David , Ayala Alberto G. 
Published: March 2007

AbstractA comparative study of the 1.06 μ and the 1.32 μ Nd:YAG laser using a variety of delivery systems (focusing handpiece, freehand GI quartz fiber, or frosted laser scalpel) was undertaken to determine the usefulness of these modalities in performing partial nephrectomies in dogs. Variables evaluated included total operative time, total joules expended, estimated amount of blood loss, and extent of renal tissue damage. The contact laser scalpel provided the greatest precision and speed, but no hemostasis, and is therefore inappropriate for parenchymal renal surgery.Evaluation of the other delivery systems showed no discernible differences in the extent of renal damage that could be attibuted to either wavelength or wattage used. The usual depth of acute renal damage ranged from 1.0 mm to 1.8 mm when the tissue was fixed immediately after completing the polar nephrectomy, but the damage had extended to 3.0 mm when tissue was examined after 6 weeks. No consistent differences in extent of cellular damage could be demonstrated between the renal cortex and medulla.The lens system inherent in the focusing handpiece limited the total power (60 watts) that could be employed and surgery proceeded at a slower pace and required a greater expenditure of energy. Likewise, the maximal power that could be applied using the 1.32 μ laser was 25 watts and surgery also proceeded at a slower pace. Therefore, it was concluded that the optimal delivery system studied was the hand‐held GI quartz fiber, using the 1.06 μ, which provided maximum wattage, allowing surgery to proceed rapidly with minimal side effects (absence of “flashing,” heat build‐up) to the operative personnel and without increased tissue damage to the remaining renal parenchyma.
Protection of the rat lung from the harmful effects of laser smoke
Authors: Baggish Michael S. , Baltoyannis Pavlos , Sze Edward 
Published: March 2007

AbstractFourteen Sprague‐Dawley rats were exposed to CO2 laser exhaust that had first passed through smoke‐evacuator filters. Six rats breathed laser vapors that were filtered through commercially available, standard production model smoke‐evacuator systems. These animals demonstrated pulmonary lesions identical to but qualitatively less severe than those observed in animals breathing unfiltered vapor. Six additional rats were protected by the interposition of a cartridge filter plus an ultra‐low penetration air filter, which trapped 0.1 μm particles; the microscopic sections of the lungs of these experimental rats and two control rats were similar in appearance, i.e., no pathological changes were observed.
Pulsed CO2 laser tissue ablation: Measurement of the ablation rate
Authors: Walsh Joseph T. , Deutsch Thomas F. 
Published: March 2007

AbstractAblation of guinea pig skin using a CO2 laser emitting 2‐μsec‐long pulses has been quantified by measuring the mass of tissue removed as a function of incident fluence per pulse. The mass‐loss curves show three distinct regimes in which water evaporation, explosive tissue removal, and laser‐induced plasma formation dominate. The data are fit to two models that predict that the mass removed depends either linearly or logarithmically on fluence. Although the data are best fit by a linear dependence upon fluence, plasma formation at high fluences prohibited obtaining data over a wide enough fluence range to differentiate unambiguously between the two models. Ablation efficiency, ablation thresholds, and the optical penetration depth at 10.6 μm were obtained from the measurements.
Laser lithotripsy: Animal studies of safety and efficacy
Authors: Nishioka Norman S. , Kelsey Peter B. , Kibbi Abdul‐Ghani , Delmonico Francis , Parrish John A. , Anderson R. Rox 
Published: March 2007

AbstractThe safety and efficacy of pulsed tunable dye laser fragmentation of common bile duct stones was assessed in pigs. Laser pulses were conducted through a flexible quartz fiber that was in direct contact with stones that had been surgically implanted into the common bile duct. All calculi were rapidly fragmented into small pieces vithout significant damage to the common bile duct. The immediate and delayed effects of pulsed lasers on the common bile duct were also evaluated. The common bile duct demonstrated a high tolerance to laser‐induced damage even when the laser was discharged directly into the bile duct wall. These results suggest that laser lithotripsy can be performed in humans with a high degree of safety and efficacy.
Functional and histological restitution in the urinary tract after Nd:YAG laser coagulation
Authors: Pensel Jürgen , Sommer Konrad , Thomas Stephen , Lieck Petra , Baretton Gustavo 
Published: March 2007

AbstractCurrent development in endourologic equipment has made possible the endoscopic application of the Nd:YAG laser in the treatment of urothelial tumors of the whole urinary tract. The clinical results are rather promising.We controlled with various methods the healing processes of 14 rabbit ureters after Nd:YAG laser treatment as to morphological repair and physiological function. The ureters were irradiated transrenally with an energy of 60 J coagulating all wall layers. Healing of the laser lesions nearly to normal in all animals was observed 4 to 6 weeks after treatment.The prevailing histological and physiological changes in the ureter are extremely slight and do not disturb the normal ureteral function. The results show the complete healing process of the ureter after laser coagulation and make the application of Nd:YAG laser in the upper urinary tract much more predictable.
Vasovasostomy in the murine vas deferens: Comparison of the Nd:YAG laser at 1.06 microns and 1.318 microns to the CO2 laser
Authors: Lowe Bruce A. , Poage Matthew D. 
Published: March 2007

AbstractA comparison is made of laser anastomoses of the murine vas deferens at different energies with the neodymium (Nd):YAG laser at 1.06 μm and 1.318 μm and with the CO2 laser. A total of 28 welds were performed with a free‐hand technique employing a 600‐μm silicon fiber with the Nd:YAG and a hand piece with a 500‐μm spot size for the CO2. After 6 weeks, all animals were sacrificed and the vasa evaluated for patency. Fifteen out of 28 controls repaired with microsurgical techniques were found to be patent; 4/10 vasa were patent with use of the Nd:YAG at 1.318 μm at laser energies of 300 mW and 500 mW. At 1.06 μm, only 1/4 anastomoses was patent at a power setting of 1 W. None of the anastomoses performed with the CO2 laser was patent. Histologic study revealed intense fibrosis in all the lasered vasa, with sperm granuloma formation associated with most anastomoses. Although this is a preliminary study, it appears that the Nd:YAG laser at 1.318 μm and a power setting of 300–500 mW provides patency rates superior to the Nd:YAG at 1.06 μm and to the CO2 lasers and is equivalent to standard microsurgical techniques in the murine vas deferens.
Management of rhinophyma with carbon dioxide laser: Lahey clinic experience
Authors: Bohigian R. Kirk , Shapshay Stanley M. , Hybels Roger L. 
Published: March 2007

AbstractThe carbon dioxide (CO2) laser as a surgical tool for the difficult cosmetic problem of rhinophyma permits unprecedented refinement in treatment. Previously described conventional techniques have included the cold knife and the dermabrader. With these methods, hemostasis must be obtained with electrocautery, which if used extensively makes fine sculpting difficult. Seven patients with rhinophyma were treated with the CO2 laser at the Lahey Clinic from 1982 to 1987. We used a laser handpiece with a variable spot size. With this technique, we found the laser to be an excellent cutting tool while simultaneously providing superior hemostasis. In the followup period of up to 4.5 years, the cosmetic results have been excellent. Thus, the CO2 laser has become our treatment of choice for the management of patients with rhinophyma.
Changes in teeth and gingiva of dogs following laser surgery: A block surface light microscope study
Authors: Goultschin J. , Gazit D. , Bichacho N. , Bab I. 
Published: March 2007

AbstractThe effect of laser surgery on tissues of the periodontal apparatus was studied histologically in dogs using block surface light microscopy, a novel microscopical method. With this approach, changes in the hard and soft tissue components were concomitantly demonstrated; the method enabled preservation of the in situ relationship between these components. Following laser surgery, healing in the gingiva was delayed as suggested by the presence of epithelial ulcerations and dense inflammatory infiltrate. In the enamel and cementum the application of laser resulted in crater‐like defects that could be avoided only partially by insertion of a tinfoil shield into the gingival sulcus. In the vicinity of the cementoenamel junction these defects were filled with epithelium or periodontal ligament fibers; the close proximity of the hard and soft tissues at the defect sites suggested occurrence of new attachment. Enamel defects located coronal to the gingiva contained bacterial plaque. These histologic results do not demonstrate any substantial advantage of laser over conventional knife gingivectomy. Such advantage may be accomplished with the design of a special intraoral handpiece and further experiments.
Histopathology of human laser thermal angioplasty recanalization
Authors: White Rodney A. , White Geoffrey H. , Vlasak Jerry , Fujitani Roy , Kopchok George E. 
Published: March 2007

AbstractLaserprobe thermal‐assisted balloon, angioplasty (LTBA) has demonstrated promising initial clinical results in recanalizing stenotic or occluded superficial femoral and popliteal arteries. Over the past year we have obtained six specimens of laserprobe thermal (LT) and LTBA treated total occlusions (avg. length 12 cm) for histopathologic examination from patients who were treated for limb salvage. Three tissue specimens were obtained acutely, and one was obtained at 6,8, and 13 days, respectively, after laser angioplasty at the time of revision for complications or failed procedures. Serial histologic sections of the treated LT segments demonstrated recanalization of atherosclerotic lesions to approximately 60–70% of the probe diameter. The LT channels were lined by a thin layer of carbonized or coagulated tissue and several layers of cell necrosis. The histology of the thermal injury was similar regardless of whether it was produced by the heated metal cap or by free argon laser energy. Stellate balloon angioplasty fractures were frequently filled with thrombus. Analysis of these human LT and LTBA specimens revealed that the thermal device produces a confined injury through the path of least resistance. Balloon dilatation produces fragmented cracks in the vessel wall, which appear to be more thrombogenic than the carbonized LT surface. With improved guidance methods, LTBA shows potential for continuing development.
Nd:YAG laser‐induced hyperthermia in a mouse tumor model
Authors: Waldow Stephen M. , Morrison Paul R. , Grossweiner Leonard I. 
Published: March 2007

AbstractHyperthermic tumor response induced by 1,064‐nm radiation from an Nd:YAG laser was investigated in DBA/2J female mice bearing the SMT‐F mammary carcinoma. The measured temperature‐depth profiles indicate that hyperthermic temperatures can be achieved in tumors ranging from 3 to 8 mm thick at power inputs on the order of 1 W. For small tumors, a 5‐week complete response rate exceeding 50% required 45 minutes at 45.0°C. Control of large tumors (6–8 mm thick) was not achieved. The observed tumor response rates are consistent with semiempirical time‐temperature relations based on other heating modalities.
Technique for measurement of one‐dimensional instantaneous ablation velocity
Authors: Rastegar S. , Van Gemert M. J. C. , Welch A. J. 
Published: March 2007

AbstractAn oscillating mirror scanned a He‐Ne laser beam along the length of a thin rod while the rod was ablated by an argon laser beam. The shadow of the scanning beam on an image plane provides a picture of the instantaneous ablation velocity of the rod. This configuration provides a unique method for investigating onedimensional ablation.