Laser Safety Issues Research Articles

Sigurna primjena lasera u stomatologiji

Safety, mainly patient safety, has become the foundation upon which all other aspects of quality health care are built. Since lasers are progressively used in various fi elds of dentistry, laser safety issues have recently become of great importance. Lasers are considered effective but potentially hazardous to the patients, due to their improper use and lack of laser safety awareness. Assuming that use of lasers in dental practice will gradually increase, the aim of this study is to introduce the basics on laser safety in dentistry. Study also serves as a reminder for colleagues, who are or will be laser users, on potential laser hazards, laser safety measures and ways to ensure and improve patient safety in laser dentistry.

Super-Resolution Scanning Laser Microscopy Based on Virtually Structured Detection.

Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches-including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy-have been established to achieve super-resolution imaging. However, none of these methods is suitable for the super-resolution ophthalmoscopy of retinal structures because of laser safety issues and inevitable eye movements. We recently experimentally validated virtually structured detection (VSD) as an alternative strategy to extend the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost, and phase artifact-free strategy to achieve super-resolution in scanning laser microscopy. In this article we summarize the basic principles of the VSD method, review our demonstrated single-point and line-scan super-resolution systems, and discuss both technical challenges and the potential of VSD-based instrumentation for super-resolution ophthalmoscopy of the retina.

Extracting Picosecond Time Constants from Steady-State Spectroscopy: A Physical Chemistry Experiment

Femtosecond spectroscopy is a key technique in modern physical chemistry research. Thus, femtosecond techniques, as well as molecular processes occurring on femto- to picosecond time scales, should be included in a physical chemistry curriculum. Usually, experiments covering the topic are challenging due to costly equipment and laser safety issues. A laboratory experiment is described that allows students to trace picosecond kinetics with safe and affordable equipment. The students record temperature-dependent IR spectra of an iron carbonyl complex, tricarbonyl(η4-1,5-cyclooctadiene)iron. Due to “turnstile” motion of the ligands a coalescence of IR bands is observed. By simulating the spectra, the picosecond time constants of the motion and further spectroscopic parameters may be extracted. An Arrhenius analysis yields the barrier for the turnstile motion.

Laser-based displays: a review

After the invention of lasers, in the past 50 years progress made in laser-based display technology has been very promising, with commercial products awaiting release to the mass market. Compact laser systems, such as edge-emitting diodes, vertical-cavity surface-emitting lasers, and optically pumped semiconductor lasers, are suitable candidates for laser-based displays. Laser speckle is an important concern, as it degrades image quality. Typically, one or multiple speckle reduction techniques are employed in laser displays to reduce speckle contrast. Likewise, laser safety issues need to be carefully evaluated in designing laser displays under different usage scenarios. Laser beam shaping using refractive and diffractive components is an integral part of laser displays, and the requirements depend on the source specifications, modulation technique, and the scanning method being employed in the display. A variety of laser-based displays have been reported, and many products such as pico projectors and laser televisions are commercially available already.

Overview of the Board of Laser Safety's professional certification programs for Laser Safety Officers

Abstract Laser technology has evolved as an important tool for many applications, including a variety of medical uses. The study of laser safety has similarly grown and evolved. For many advanced laser operations, ensuring the safety of people in the area of the laser requires an advanced knowledge of the arcane principles involved. The complexity of the hazards associated with many laser systems, and the unique skill set needed to effectively evaluate and implement control measures for those hazards, have created the need for organizations to clearly identify those individuals with the proficiency necessary to manage such advanced laser safety issues. To meet this need, the Board of Laser Safety (BLS) was established as a nonprofit organization affiliated with the Laser Institute of America to develop and sustain a program for safety professionals to establish and maintain recognizable competence and expertise in the area of laser safety. The BLS developed a Certified Laser Safety Officer (CLSO) program, by which individuals who have demonstrated comprehensive knowledge in the area of laser safety may designate themselves a CLSO. Shortly thereafter, the BLS created the Certified Medical Laser Safety Officer (CMLSO) program, to recognize individuals with the knowledge and expertise necessary to evaluate and control laser hazards under the special conditions that exist in the medical arena. This paper provides an introduction to the CLSO and CMLSO programs.

High Power Density Laser Build-Up Welding with CNC Precision

The use of laser energy in material processing for boring, cutting and welding has been state of the art for many years [1]. The good focussing ability of the laser allows power densities that are hardly possible with conventional welding processes. Thus, the desired component processing can be carried out on a limited area with low overall power where component and material are subjected to minimum thermal loading. The laser build-up welding process which is particularly suited for low distortion applications, as well as materials that are difficult to weld using conventional methods, is explained in detail. Co2 laser, nd:yag laser and diode laser as established beam sources in laser material processing are compared with newer, innovative beam sources like the fiber laser and disk laser that have been developed in the recent years. Where the possible spectrum of use ranges from small parts to large components weighing tons, the need for a universal handling system is discussed together with laser safety issues. Several industrial applications for laser build-up welding are presented.

Stereoscopic PIV on multiple color-coded light sheets and its application to axial flow in flapping robotic insect wings

Non-scanning volume flow measurement techniques such as 3D-PTV, holographic and tomographic particle image velocimetry (PIV) permit reconstructions of all three components (3C) of velocity and vorticity vectors in a fluid volume (3D). In this study, we present a novel 3D3C technique termed Multiple-Color-Plane Stereo Particle-Image-Velocimetry (color PIV), which allows instantaneous measurements of 3C velocity vectors in six parallel, colored light sheets. We generated the light sheets by passing white light of two strobes through dichroic color filters and imaged the slices by two 3CCD color cameras in Stereo-PIV configuration. The stereo-color images were processed by custom software routines that sorted each colored fluid particle into one of six gray-scale images according to its hue, saturation, and luminance. We used conventional Stereo PIV cross-correlation algorithms to compute a 3D planar vector field for each light sheet and subsequently interpolated a volume flow map from the six vector fields. As a first application, we quantified the wake and axial flow in the vortical structures of a robotic insect (fruit fly) model wing. In contrast to previous findings, the measured data indicate strong axial flow components on the upper wing surface, including axial flow in the leading-edge vortex core. Collectively, color PIV is robust against mechanical misalignments, avoids laser safety issues, and computes instantaneous 3D vector fields in a fraction of the time typical for other 3D systems. Color PIV might thus be of value for volume measurements of highly unsteady flows.

Retinal Evaluation After 810 nm Dioderm Laser Removal of Eyelashes

BACKGROUND When operating hair removal lasers on the face or in the periorbital region, even with an ocular shield in place, patients often report seeing “flashing lights” each time the laser is fired. This phenomenon suggests stimulation of retinal photoreceptors and raises laser safety issues. OBJECTIVE To perform retinal electrophysiologic studies to evaluate the safety of hair removal lasers in the periorbital region. METHODS Five patients with severe trichiasis secondary to trachoma were studied. The 810 nm Dioderm laser (Cynosure, Inc., Chelmsford, MA) was used to treat the eyelash follicles on the lower eyelid of each patient. Cox III metal eye shields (Oculo-Plastik, Inc., Montreal, Canada) were placed behind the eyelids of both eyes during the laser procedure. Prior to irradiation, a comprehensive ophthalmic evaluation including pupillary and slit-lamp examination, funduscopy, and full-field electroretinograms (ERGs) was performed. A comprehensive ophthalmic evaluation including ERG testing was repeated 30 minutes and 3–6 months after completion of treatment. An independent blinded assessor evaluated the ERG studies. Subjective reports of laser light sensation, pain, and discomfort during and after the laser procedure were also assessed. RESULTS There was no detectable change in slit-lamp, pupillary, or funduscopic evaluations after periorbital laser irradiation. Similarly the pre- and posttreatment ERGs were unchanged. Three patients reported seeing flashing lights during the procedure. CONCLUSION We found no ERG evidence of retinal damage after laser hair removal in the periorbital region, with Cox III-type ocular shields over the eyes, even when patients subjectively reported “flashing lights” during laser irradiation.

Survey and evaluation of the education and training needs in laser safety

This paper presents the results from a survey undertaken to assess levels of safety awareness and to identify the education and training needs of the laser community in the UK. Results show that 75% of appointed Laser Safety Officers in the UK have a responsibility for teaching laser safety; disturbingly only 54% of these people have received some form of laser safety training themselves. Opinions regarding current training provision show that theoretical issues are well covered but that calculations and practical laser safety issues are topics not well taught. Results from questions regarding topics that should be included on training courses are presented. The survey results show a reliance upon administrative controls and personal protective equipment within the laser community. These findings are compounded by the conclusion that current training provision places an over-emphasis upon theoretical laser safety issues at the expense of practical safety advice and information. The need for a more flexible and targeted approach to laser safety training is demonstrated.

Exposure to “lessons learned”: A tool for laser safety

This article outlines the value and steps to follow for establishing a “lessons learned program”, with specific application to a laser safety program. As a communication tool and preventive measure for laser safety issues, the program is an effective means of turning accident investigation into a proactive rather than a reactive exercise by emphasizing corrective rather than disciplinary (looking for someone to blame) actions.

Laser safety hazard assessment — A generic model

The status of laser safety amongst UK manufacturers is reported. A disturbing proportion feel the need for practical guidance on laser safety issues. Furthermore no improvements in laser safety protocols in the past 5 years are evident. Closer studies of the much larger laser user community and also the HSE Inspectorate has revealed a matrix of issues pertinent to users and their laser application. A need to support the user with practical information is demonstrated. Laser safety research activities have investigated the task of hazard assessment and a novel ‘Loughborough Laser Hazard Assessment Model’ has been defined and tested. The model provides a general methodology for hazard assessment and, furthermore, is the kernel of an advisory software system. The methodical approach to hazard assessment can be extended to risk assessment processes in laser and non-laser related activities.

Laser safety hazard assessment — A generic model

Abstract The status of laser safety amongst UK manufacturers is reported. A disturbing proportion feel the need for practical guidance on laser safety issues. Furthermore no improvements in laser safety protocols in the past 5 years are evident. Closer studies of the much larger laser user community and also the HSE Inspectorate has revealed a matrix of issues pertinent to users and their laser application. A need to support the user with practical information is demonstrated. Laser safety research activities have investigated the task of hazard assessment and a novel ‘Loughborough Laser Hazard Assessment Model’ has been defined and tested. The model provides a general methodology for hazard assessment and, furthermore, is the kernel of an advisory software system. The methodical approach to hazard assessment can be extended to risk assessment processes in laser and non-laser related activities.

Nursing Perspective: Clinical Laser Safety Issues Survey

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