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Laser Applications (laser + application)
Selected AbstractsLaser applications and system considerations in ocular imagingLASER & PHOTONICS REVIEWS, Issue 5 2008A.E. Elsner Abstract We review laser applications for primarily in-vivo ocular imaging techniques, describing their constraints based on biological tissue properties, safety, and the performance of the imaging system. We discuss the need for cost-effective sources with practical wavelength-tuning capabilities for spectral studies. Techniques to probe the pathological changes of layers beneath the highly scattering retina and diagnose the onset of various eye diseases are described. The recent development of several optical-coherence-tomography-based systems for functional ocular imaging is reviewed, as well as linear and nonlinear ocular-imaging techniques performed with ultrafast lasers, emphasizing recent source developments and methods to enhance imaging contrast. [source] Effect of Er:YAG laser and EDTAC on the adhesiveness to dentine of different sealers containing calcium hydroxideINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2003F. Picoli Abstract Aim, To evaluate the effect of 15% EDTAC solution and Er:YAG laser irradiation on the adhesiveness to dentine of root canal sealers containing calcium hydroxide. Methodology, The crowns of 60 maxillary human molars were ground until dentine was exposed. The teeth were divided into three groups of 20 teeth: group I, the dentine surface received no treatment; group II, 15% EDTAC solution was applied to the dentine; group III, the dentine received Er:YAG laser application (11 mm focal distance with perpendicular incidence to dentine surface; 4 Hz frequency; 200 mJ energy; 2.25 W potency; 62 J total energy; 1 min application time). Aluminium cylinders filled with the sealers, Sealer 26, Apexit, Sealapex and CRCS, were then applied to the treated surfaces. Adhesiveness was measured with a universal testing machine, with traction results given in MegaPascals (MPa). These results were submitted to anova tests. Results, Statistical analysis showed significant differences (P < 0.01) amongst adhesiveness values of the sealers and treatments tested. Thus, sealers could be ranked in decreasing adhesiveness values: Sealer 26, CRCS, Apexit, Sealapex. Er:YAG laser irradiation and EDTAC solution application increased adhesiveness values only for Sealer 26 and Apexit. Laser irradiation was superior to EDTAC application only for Sealer 26 adhesiveness values. Conclusions, Er:YAG laser is as efficient as EDTAC solution in increasing adhesiveness of root canal sealers containing calcium hydroxide to human dentine. [source] Inadvertent sclerostomy with encysted bleb following trans-scleral contact diode laser cyclophotocoagulationCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2006Viney Gupta MD Abstract A 22-year-old woman underwent 360° trans-scleral contact diode laser cyclophotocoagulation for refractory glaucoma. Conjunctival burns and scleral thinning were noticed inferonasally at the last laser application. Intraocular pressure in the first week was normal. Six months later the patient presented with encysted filtering bleb and high intraocular pressure. Ultrasound biomicroscopy revealed a full thickness sclerostomy. This report suggests that inadvertent sclerostomy may present with encysted bleb months after trans-scleral contact diode laser cyclophotocoagulation. [source] Striae Distensae (Stretch Marks) and Different Modalities of Therapy: An UpdateDERMATOLOGIC SURGERY, Issue 4 2009MOHAMED L. ELSAIE MD BACKGROUND Striae distensea (SD; stretch marks) are a well-recognized, common skin condition that rarely causes any significant medical problems but are often a significant source of distress to those affected. The origins of SD are poorly understood, and a number of treatment modalities are available for their treatment, yet none of them is consistently effective, and no single therapy is considered to be pivotal for this problem. With a high incidence and unsatisfactory treatments, stretch marks remain an important target of research for an optimum consensus of treatment. OBJECTIVE To identify the current treatment modalities and their effectiveness in the treatment of stretch marks. MATERIALS AND METHODS Review of the recent literature regarding clinical treatment of stretch marks with emphasis on the safety and efficacy of the newer optical devices and laser applications. RESULTS No current therapeutic option offers complete treatment, although there are a number of emerging new modalities that are encouraging. CONCLUSION The therapeutic strategies are numerous, and no single modality has been far more consistent than the rest. The long-term future of treatment strategies is encouraging with the advance in laser technologies. [source] Enhanced Solid-State Luminescence and Low-Threshold Lasing from Starburst Macromolecular Materials,ADVANCED MATERIALS, Issue 3 2009Wen-Yong Lai High solid-state quantum efficiency (,PL,,,0.90) materials with attractive properties for OLED and laser applications are reported. Our results show that long fluorene chain-lengths are not a necessary prerequisite for efficient solid-state luminescence. Isolated-molecule-like solid-state emission, stable pure-deep-blue electroluminescence, and low-threshold lasing (,laser,=,437,nm, Ethlaser,,,0.4,nJ/pulse, 1.3,µJ cm,2) are demonstrated. [source] Supercooled Barium Boric Oxide Melts: X-Ray Diffraction Measurements and Glass FormationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007Seiichi Matsumura It is well-known that oxide melts easily form a glass state from a supercooled state; however, it is difficult for some oxides to transform to the glass state from the corresponding supercooled state. ,-BaB2O4 (,-BBO) crystals are important materials for laser applications. The ,-BBO crystal easily grows from the supercooled melt, and it is therefore difficult to form the BBO glass state. We attempted to make BBO glass by a containerless technique using the conical nozzle gas-jet levitation (CNL) method. We were successful in making BBO glass with a diameter of 2 mm from a highly supercooled melt without rapid quenching. In order to clarify the phase selection mechanism of the BBO melt, we performed high-energy X-ray (113.6 keV) diffraction experiments on the glassy and supercooled liquid BBO using the CNL technique at the BL04B2 beamline of SPring-8. From these experiments, the structure factor S(Q) of BBO glasses and supercooled melts were found to have almost the same features. From these S(Q), we obtained the radial distribution function T(r)=4,rg(r). The analysis also showed that BBO glass and the BBO-supercooled melt have the same short-range distances. For phase selection between crystalline and glassy phases, we discuss a structure model of the BBO melt, including medium range structure based on the short-range structure obtained in this experiment. [source] Laser applications and system considerations in ocular imagingLASER & PHOTONICS REVIEWS, Issue 5 2008A.E. Elsner Abstract We review laser applications for primarily in-vivo ocular imaging techniques, describing their constraints based on biological tissue properties, safety, and the performance of the imaging system. We discuss the need for cost-effective sources with practical wavelength-tuning capabilities for spectral studies. Techniques to probe the pathological changes of layers beneath the highly scattering retina and diagnose the onset of various eye diseases are described. The recent development of several optical-coherence-tomography-based systems for functional ocular imaging is reviewed, as well as linear and nonlinear ocular-imaging techniques performed with ultrafast lasers, emphasizing recent source developments and methods to enhance imaging contrast. [source] Computer modeling of optical properties of gold ellipsoidal nanoparticles at laser radiation wavelengthsLASER PHYSICS LETTERS, Issue 2 2005V. K. Pustovalov Abstract Processes of laser interaction with metal (gold) nanoparticles are of great interest for laser applications in nanotechnology, engineering, and medicine. Optical properties of nanoparticles determine photophysical and photochemical processes during laser treatment. Computer calculation of efficiency factors of absorption, scattering and extinction of radiation by ellipsoidal gold nanoparticles (two-dimensional ellipsoids of revolution) with small semiaxes in the range 5,100 nm, for some values of aspect ratio and angle of orientation of ellipsoid with respect to direction of laser radiation propagation and for some laser wavelengths is performed. The estimation of absorbed and scattered laser radiation energy by gold ellipsoidal nanoparticles, their maximal temperatures and comparison with experimental data is made. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Increasing the Photovoltaic EfficiencyLASER TECHNIK JOURNAL, Issue 1 2010Laser Doping of Crystalline Solar Cells Driven by falling prices and competitive pressure manufacturers of photovoltaic cells are seeking for new methods and cell concepts to reduce production costs and increase cell efficiency. Developments which have been of more academic interest over the past years are close to find their way into volume production. While laser applications are already standard for structuring of thin film PV glass panels, they are not yet widely established in the silicon-wafer-based cell manufacturing, which still represents more than 80% of the photovoltaic market. However, without adding too much complexity to the process flow most of the new cell concepts are only feasible by introduction of laser processes. [source] Continuous changes in the optical properties of liver tissue during laser-induced interstitial thermotherapyLASERS IN SURGERY AND MEDICINE, Issue 4 2001Joerg P. Ritz MD Abstract Background and Objective Laser-induced thermotherapy (LITT) is a promising treatment for irresectable liver tumors. To predict the effects of laser applications and to optimize treatment planning in LITT, it is essential to gain knowledge about light distribution in tissue, tissue optical properties (absorption, scattering, anisotropy, penetration depth), and their continuous changes during therapy. Study Design/Materials and Methods Measurements of optical properties were performed with a double integrating-sphere system and a laser diode (830 nm). Porcine liver tissue samples were examined in a native state (35°C) and after exposure to different temperatures (45°C to 80°C). Results Rising temperature was accompanied by a decrease in the absorption coefficient and anisotropy factor and an increase in the scattering coefficient. These changes were only significant in the temperature range of 50° to 65°C (P,<,0.01). The optical penetration depth decreased from 3.1mm in the native state to 1.7mm at 65°C (P,<,0.01). Above 65°, there was no significant change in the tissue optical properties. Conclusions The optical properties of liver tissue change significantly under the influence of tissue heating, resulting in a decreased optical penetration depth. These changes occur mainly in the temperature range of 50°C to 65°C, corresponding to protein denaturation. To ensure a safe and effective procedure, an adjustment of the laser power to the actual penetration depth is recommended during therapy. Lasers Surg. Lasers Surg. Med. 28:307,312, 2001. © 2001 Wiley-Liss, Inc. [source] Optical-thermal simulation of tonsillar tissue irradiationLASERS IN SURGERY AND MEDICINE, Issue 4 2001Rahul K. Shah MD Abstract Background and Objective Despite laser applications targetted toward tonsillar tissue, there has been no characterization of underlying optical and thermal events during laser irradiation of tonsillar tissue. Study Design/Materials and Methods The optical properties of canine and human tonsils were determined at 805 nm (diode laser) and 1,064 nm (Nd:YAG laser). An optical-thermal simulation was developed to predict the temperature rise in irradiated human tonsils. Results The optical properties of human and canine tonsillar tissue are similar at both wavelengths. The optical-thermal simulation was validated and predicts that at 10 W and 1 minute of irradiation, the heat will be contained within the human tonsil. The diode laser causes more superficial heating than the Nd:YAG laser. Conclusions The safety of irradiating human tonsils was shown. The diode laser is superior to the Nd:YAG laser because less heat affects collateral structures. The optical-thermal simulation detailed in this study can be used to predict the temperature rise in tissues undergoing irradiation. Lasers Surg. Med. 28:313,319, 2001. © 2001 Wiley-Liss, Inc. [source] Introduction of the flash-lamp pulsed-dye laser treatment of facial port-wine stains in childhood: A case of health care technology assessmentLASERS IN SURGERY AND MEDICINE, Issue 2 2001C.A.J.M. De Borgie MSc Abstract Background and Objective Lasers have been used in the treatment of port-wine stains (PWS) for more than 30 years. With the introduction of the flash-lamp pulsed-dye laser (FPDL) it was assumed that infants could be treated safely, effectively, and probably more efficiently. Nowadays, FPDL treatment is an established form of treatment of PWS in childhood. Study Design/Materials and Methods On the basis of the iterative Health Care Technology Assessment (HCTA) loop, we examined whether sufficient evidence from evaluations has been present to support the introduction of FPDL treatment for facial PWS at an early age. Such an assessment requires an interdisciplinary approach focusing on aspects of safety, efficacy, effectiveness, quality of life, costs, and the ethical issues of treatment. Results Assessment of the FPDL in PWS treatment of children did not follow the model of medical innovation and evaluation. Most assessments have been focused on laser applications that were already in clinical use. Efficacy and effectiveness of laser treatment have been the major concern in most assessments. Only a few studies have looked at costs and ethical aspects of treating children. Conclusions The introduction and diffusion of the use of the FPDL in the treatment of PWS in childhood were uncontrolled, and the field was not prepared to use this technique properly. We believe that this nonadherence to the iterative HCTA model reflects the gradual way by which innovations find their way into clinical practice. Lasers Surg. Med. 28:182,189, 2001. © 2001 Wiley-Liss, Inc. [source] Longterm follow-up of diode laser transscleral cyclophotocoagulation in the treatment of refractory glaucomaACTA OPHTHALMOLOGICA, Issue 1 2010Paolo Frezzotti Abstract. Purpose:, This prospective study was conducted to evaluate the efficacy and safety of transscleral diode laser cyclophotocoagulation (TDLCP) in advanced refractory glaucoma. Methods:, A total of 124 eyes in 121 patients with advanced glaucoma refractory to medical treatment were treated consecutively with TDLCP. Success was defined as final intraocular pressure (IOP) of 5,21 mmHg in eyes with visual acuity (VA) of more than hand movements (HM) and relief of pain in eyes with VA of HM or less, including blind eyes. Results:, Mean patient age was 65.6 ± 17.1 years (range 14,91 years). Mean follow-up was 17 ± 14.6 months (range 3,42 months). Mean pretreatment IOP was 29.9 ± 8.4 mmHg (range 17,58 mmHg) and IOP at last follow-up was 20.8 ± 8 mmHg (range 6,45 mmHg) (p < 0.001). The number of laser applications (mean 9.2 ± 2.8, range 4,15) and maximal laser power (mean 2.01 ± 0.22 mW, range 1.3,3.0 mW) were not associated with lower postoperative IOP. Intraocular pressure of , 21 mmHg was recorded in 63.0% of eyes at the last follow-up visit. Overall, 28 (21.7%) eyes required at least one retreatment. No phthisis bulbi or persistent hypotonia developed. Conclusions:, TDLCP is an effective and safe method for the treatment of advanced refractory glaucoma, although repeated treatments are often necessary. [source] | ||||||||||||||||