{"id":651,"date":"2011-04-18T21:02:21","date_gmt":"2011-04-19T01:02:21","guid":{"rendered":"http:\/\/blogs.vassar.edu\/ltt\/?p=651"},"modified":"2011-05-05T14:27:38","modified_gmt":"2011-05-05T18:27:38","slug":"651","status":"publish","type":"post","link":"https:\/\/pages.vassar.edu\/ltt\/?p=651","title":{"rendered":"Project Research and Data- Laser Safety and Precautions"},"content":{"rendered":"<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">From Title 21, Volume 8 of the Code of Federal Regulations<\/span><\/span><\/span><span style=\"color: #23238e\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">.<\/span><\/span><\/span><\/p>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Part 1040 &#8212; Performance Standards for Light-emitting Products<\/span><\/span><\/span><\/p>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Sec. 1040.10 Laser Products<\/span><\/span><\/span><\/p>\n<p><span style=\"color: #000099\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\"><span style=\"text-decoration: underline\">(http:\/\/www.accessdata.fda.gov\/scripts\/cdrh\/cfdocs\/cfcfr\/cfrsearch.cfm?fr=1040.10)<\/span><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">The following information will be used:<\/span><\/span><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Detailed \tdescriptions of Class Levels<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Definitions \t(Collateral radiation, human access, integrated radiance, safety \tinterlock, etc.)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Federal \tregulations\/guidelines for laser use\/operation<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Several \tCautions<\/span><\/span><\/span><\/li>\n<\/ul>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">J. Marshall, Br. J. Ophthalmol. <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\"><strong>82<\/strong><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">, 1335 (1998).<\/span><\/span><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Why \tthe eye is of primary interest in laser safety<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">The \t\tthree primary damage mechanisms of over(eye)exposure to laser light<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">This \t\tis dependent on wavelength, pulse duration, and energy<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">The \thistory of laser safety and when codes of practice entered the laser \trealm <\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">This \t\tbegan within 5 years of the first demonstration of a laser, 1960<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Definitions<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Median \t\tEffective Dose (ED)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Dose \t\t\twhich results in irreversible retinal damage<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Maximum \t\tPermissible Exposure Levels (MPE)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Maximum \t\t\texposure length that results in no damage<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Layman \tdescriptions of laser classes <\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">International \t\tconcerns<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">World \t\t\tHealth Organisation (WHO)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">International \t\t\tCommittee for Non-ionising Radiation Protection (ICNRP)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">International \t\t\tElectro-technical Comission (IEC)<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">The \t\tdevelopment of laser pointers<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Beginning \t\t\twith early laser pointers: <\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">class \t\t\t\t2 systems that used helium-neon laser sources with and emission \t\t\t\twavelength at 632.8 nm<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Original \tintent of lasers for the public<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">For \t\tuse in lecture theaters or boardrooms<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">The \tvisual effect of making eye-contact with laser light<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">In \t\torder of increasing brightness:<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Dazzle<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\">\u201c<span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">After \t\t\timage\u201d formation<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Flash \t\t\tblindness<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Irreversible \t\t\tdamage<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Dan Vergano. &#8220;Powerful laser pointers create risks: Lights deliver strong beams that can damage \t\teyes.&#8221; <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\"><em>USA TODAY<\/em><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\"> 18  Nov. 2010<\/span><\/span><\/span><\/p>\n<p><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">This article discusses the dangers of laser pointers sold via the internet. Points made are:<\/span><\/span><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">These \tlaser pointers contain greater strength than what is FDA approved, \tand the FDA only has jurisdiction over our producers and not our \tbuyers<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Possible \tretinal damage (they cite the <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\"><em>New \tEngland Journal of Medicine<\/em><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: small\">Dangers \tof green colored laser pointers<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Times New Roman,serif\"><span style=\"font-size: x-small\">* \tthis article is somewhat dramatized and contributes as a supporting \telement to the article by John Marshall<\/span><\/span><\/span><\/li>\n<\/ul>\n<p><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">W. M. Steen and J. Mazumder, <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\"><em>Laser Material Processing<\/em><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">, 4th ed. (Springer, London, 2010). <\/span><\/span><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Chapter \t13 of main interest<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Page \t519 outlines main danger of lasers- damage to the eye, damage to the \tskin, electrical hazards, and fume hazards<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Danger \tto eye<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Damage \t\tto retina in back of eye and damage to cornea in front<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Radiation \t\ton retina focused by eye\u2019s lens to amplify power by about 10^5 \t\t(100,000)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser \t\t\tat the visible or near-visible waveband are much more dangerous \t\t\tcompared to outside the band<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Eye \t\tdamaged through explosive evaporation (cooking and boiling)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Safe \t\texposure limit indicated by maximum permissible exposure (MPE) \t\tlevels<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Levels \t\t\tvery low, especially as lasers become more powerful<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Danger \tto skin<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser \t\tclasses 3R, 3B, and 4 are dangerous to the skin, with 3R least \t\tdangerous and 4 most dangerous<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Safety \t\tarrangements<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">1) \t\t\tBeam terminated with material able to withstand beam for several \t\t\tminutes<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">2) \t\t\tStray reflections minimized<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">3) \t\t\tAll personnel must wear goggles<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">4) \t\t\tMust seek approval for entry<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">5) \t\t\tWarning lights and hazard notices<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">6) \t\t\tCare taken in beam alignment<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">7) \t\t\tLaser safety officer to check on guidelines<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Electrical \tdanger<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"> \u201c<span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">A \t\ttypical CO2 laser may have a power supply capable of firing the \t\ttubes with 30,000V with 400mA\u201d (W. M. Steen and J. Mazumder \t\t2010:525)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Fatal \t\t\tdischarge possible at this level<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Earthing \t\tsystem must be present<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Fume \tdanger<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"> <span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">High \t\ttemperature of laser able to volatilise most materials, creating \t\tpotentially dangerous fume<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Organic \t\tmaterials particularly dangerous; laser might create radical groups \t\thighly dangerous to people<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">A. L. McKenzie, <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\"><em>J. Radiol. Prot<\/em><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">. <\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\"><strong>8<\/strong><\/span><\/span><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">, 209 (1988)<\/span><\/span><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\">\u201c<span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">It \twould seem that no organ of the body is immune from incision, \tresection, coagulation or ablation by laser\u201d (McKenzie 1988:209)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser \ttypes and characteristics<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Carbon \t\tdioxide laser<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">20-100 \t\t\tW of far-infrared (wavelength of 10.6 \u03bcm)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Usually \t\t\tcontinuous, sometimes pulsed between several hundred and several \t\t\tthousand hertz<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Radiation \t\t\t\tat this level easily absorbed in water- explosive disruption of \t\t\t\tcells as water becomes steam (tissue ablation by vaporisation)<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Heat \t\t\tdamage under the ablated surface is minimal<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Because \t\t\tof tissue coagulation between 60-80 degrees Celsius, tissue is \t\t\tdenatured and blood vessels are constricted; bloodless operation<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Used \t\t\t\tin gynaecology procedures, especially treatment of cervical \t\t\t\tintra-epithelial neoplasia<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Argon \t\tlasers<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">3-6 \t\t\tW of blue-green light (usually several wavelengths at one time, \t\t\tusually 488 nm and 514.5 nm most common)<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Highly \t\t\tscattered, diffuses a few hundred microns below tissue; good for \t\t\tsurface use such as coagulation<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Nd:YAG \t\tlasers<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Neodymium-doped \t\t\tyttrium aluminium garnet<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Nd:Y3Al5O12<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Near-infrared \t\t\tradiation (wavelength of 1.06 \u03bcm)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Either \t\t\t\tcontinuous at 60-100 W or pulses at tens of nanoseconds at \t\t\t\tseveral mJ per pulse.<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">When \t\t\t\t\tpulsed, known as Q switched lasers as opposed to continously \t\t\t\t\tworking (cw) mode<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Beam \t\t\tscatters less than argon laser light, and absorbed less than \t\t\tcarbon dioxide laser radiation<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Can \t\t\t\tcoagulate more volume (several mm of soft tissue) than both argon \t\t\t\tand carbon dioxide lasers<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Other \t\tlasers<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Krypton \t\t\tlaser<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">647 \t\t\t\tnm or 568 nm; can be tuned to any wavelength in visible spectrum<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Eye \thazard<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Sight \t\timpairment through retina, cornea, and\/or lens damage<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Cataract \t\tinduced by absorption of near-infrared or ultraviolet radiation<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Thermal \t\t\tdamage present long before cataract, however<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Cornea \t\taffected by heat like egg white- will \u201ccook\u201d the cornea and \t\tcreate opaque patch where laser impacts<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Visible \t\tand near-infrared radiation at 1.06 \u03bcm can travel through ocular \t\tmedia to retina<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">~ \t\t\t40% of Nd:YAG laser radiation hits retina; \u00be will be transmitted \t\t\tor reflected (only ~10% absorbed in retina)<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">MPE<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Carbon \t\t\tdioxide- 560 t<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-0.75 <\/span><\/span><\/sup><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">mW \t\t\tcm<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-2<\/span><\/span><\/sup><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Argon- \t\t\t9 t<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-0.25 <\/span><\/span><\/sup><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">mW \t\t\tcm<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-2<\/span><\/span><\/sup><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Nd:YAG- \t\t\t1.8 t<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-0.25 <\/span><\/span><\/sup><\/span><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">mW \t\t\tcm<\/span><\/span><\/span><span style=\"color: #000000\"><sup><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">-2<\/span><\/span><\/sup><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Eye \t\t\tblink reflex time is usually cited as 0.25s<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Eye \tprotection<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Different \t\ttypes of eye protection are needed for different types of lasers in \t\tmedicine<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Other \thazards<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Skin \t\tburns<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Maximum \t\t\tpermissible exposure tables are also calculated for skin contact, \t\t\tlike for eye contact<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser-proof \t\t\tprotection is impractical to wear, however<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Safety \t\t\t\tcontrolled by prevention of skin contact instead<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Smoke<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\">\u201c<span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Smoke \t\t\tis produced when cell water has been removed from soft tissue, \t\t\tleaving the dried framework to char and burn\u201d (McKenzie \t\t\t1988:217)<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Fire<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Cited \t\t\tby Fisher as a greater hazard than eye injury (McKenzie 1988:217)<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser \ttheatre<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Windows \t\tneed to be shielded according to power of laser<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">Laser \tProtection Adviser and Laser Protection Supervisor (LPA and LPS)<\/span><\/span><\/span>\n<ul>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">LPA \t\tin control of installation, training, and usage<\/span><\/span><\/span><\/li>\n<li><span style=\"color: #000000\"><span style=\"font-family: Arial,sans-serif\"><span style=\"font-size: x-small\">LPS \t\ta subordinate of LPA; in charge of supervision and observation of \t\tthe rules<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>From Title 21, Volume 8 of the Code of Federal Regulations. Part 1040 &#8212; Performance Standards for Light-emitting Products Sec. 1040.10 Laser Products (http:\/\/www.accessdata.fda.gov\/scripts\/cdrh\/cfdocs\/cfcfr\/cfrsearch.cfm?fr=1040.10) The following information will be used: Detailed descriptions of Class Levels Definitions (Collateral radiation, human access, integrated radiance, safety interlock, etc.) Federal regulations\/guidelines for laser use\/operation Several Cautions J. Marshall, Br. [&hellip;]<\/p>\n","protected":false},"author":862,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[992],"tags":[],"class_list":["post-651","post","type-post","status-publish","format-standard","hentry","category-group-5"],"_links":{"self":[{"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/posts\/651","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/users\/862"}],"replies":[{"embeddable":true,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=651"}],"version-history":[{"count":7,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/posts\/651\/revisions"}],"predecessor-version":[{"id":1276,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=\/wp\/v2\/posts\/651\/revisions\/1276"}],"wp:attachment":[{"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pages.vassar.edu\/ltt\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}