1	LASER SAFETY TRAINING William Robeson, Laser Safety Officer North Shore University Hospital Radiology/Radiation Safety Office (516) 562- 3895 Presentation created by: Miyuki Yoshida-Hay
2	Objectives Discuss the properties of laser energy and relate them to the safe use of laser equipment in the peri-operative suite.
3	Introduction LASER is an acronym, which stands for: Light Amplification by Stimulated Emission of Radiation
4	What is a laser and how does it work ? Laser light is a form of electromagnetic (EM) radiation Lasers produce light by a process which involves changes in energy states within the atoms of certain materials. Atoms promoted to higher energy states release this energy in a form of light by a processed called stimulated emission. The laser light is amplified by reflecting it back and forth in a lasing medium with a pair of mirrors
5	What is a laser and how does it work ? (continued) The laser light is then released in a stream or pulse through the partially transmitting mirror at one end of the cavity. The color of laser light is expressed in terms of the laser’s wavelength (e.g., nanometer (nm)).
6	Basic Laser Components
7	Different Types of Lasers Based on its pumping scheme a laser can be classified as Optically pumped laser Electrically pumped laser On the basis of the operation mode, laser fall into classes of Continuous Wave Lasers Pulsed Lasers According to the materials used to produce laser light, lasers can be divided into the following categories : Solid State Gas Excimer
8	Lasing Materials SOLID STATE lasers have lasing materials in a solid matrix, e.g., the ruby or neodymium (Nd)-YAG (yttrium aluminum garnet) lasers. The Nd-YAG lasers emits infrared light at 1,064 nm. GAS lasers (helium and helium-neon, HeNe) have a primary output of a visible red light (633 nm). CO₂ lasers emit energy in the far-infrared 10,600 nm and are used for cutting hard materials. EXCIMER lasers (derived from the terms excited and dimers) use reactive gases, e.g., chlorine and fluorine mixed with inert gases such as argon, krypton or xenon. When electrically stimulated, a pseudomolecule or dimer is produced and when lased, produces light in the ultraviolet range (150 – 350 nm range). DYE lasers use complex organic dyes like rhodamine 6G in liquid solution or suspensions lasing media. They are tunable over a broad range of wavelengths. SEMICONDUCTOR lasers (diode lasers) are not solid state lasers. These electronic devices are generally very small and use low power. They may be built into larger arrays such as the writing source in some laser printers or compact disk players.
9	Common Medical Lasers
10	Laser Fundamentals
11	Reflection Hazards Specular Reflections: Are mirror-like reflection that can reflect close to 100 % of incident light
12	Laser Output
13	Laser Exposure Limits Maximum Permissible Exposure (MPE) is defined as the level of laser radiation to which a person may be exposed without hazardous effect or adverse biological changes in the eye or skin. The MPE of a specific laser is determined based on the wavelength and exposure duration. Nominal Hazard Zone (NHZ) is the space within which the level of direct, reflected, or scattered radiation during normal operation exceeds the applicable MPE. The purpose of a NHZ is to define an area in which control measures are required.
14	LASER HAZARD CLASSES Lasers and laser systems are assigned one of the four broad classes (1 to 4) depending on the potential for causing damage. (American National Standards Institute’s (ANSI) Z136.1 Safe Use of Lasers.)
15	Laser Hazards Beam Hazards Eye Injuries Skin Injuries Non-beam hazards Electrical Fire / Combustion Explosion Chemical Laser Generated Air Contaminants
16	Biological Effects
17	Laser Bioeffects of the Eye Photokeratitis: A burn of the cornea (by UV rays.) Photochemical Cataract / Retinal Injuries: Interaction with tissue cells resulting in changes in the cell chemistry causing damage or change to the tissue. (Damage is cumulative over a working day.) Thermal Retinal Injuries: Effects caused by rise in temperature after laser energy absorption. (Not cumulative as long as the retina cools down between exposures.) Aqueous Flare: Build-up of fluid in the eye. Acoustic Shock: Damage caused when laser pulses induce a shockwave in the retinal tissue causing the rupture of the tissue.
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19	Retinal Hazard Region The wavelength range of light that can enter the eye is 400 to 1,400 nm though we can actually see only 400 -760 nm. The eye can focus a collimated beam of light to a spot 20 microns in diameter on the retina (focal point).
20	Common Clinical Lasers and Associated Eye Injuries
21	Symptoms of Laser Eye Injuries Exposure to the invisible carbon dioxide laser beam (10,600 nm) can be detected by a burning pain at the site of exposure on the cornea or sclera. Exposure to a visible laser beam can be detected by a bright color flash of the emitted wavelength and an after-image of its complementary color (e.g., a green 532 nm laser light would produce a green flash followed by a red after-image). The site of damage depends on the wavelength of the incident or reflected laser beam: When the retina is affected, there may be difficulty in detecting blue or green colors secondary to cone damage, and pigmentation of the retina may be detected. Exposure to the Q-switched Nd:YAG laser beam (1,064 nm) is especially hazardous and may initially go undetected because the beam is invisible and the retina lacks pain sensory nerves.
22	Laser Generate Air Contaminants (LGAC) Air contaminants may be generated when certain Class 3b and Class 4 lasers interact with matter. LGAC may be gaseous or particulate and can under certain conditions pose occupational concern. Patients and health care workers should be protected from inhaling LGAC associated with laser use. LGAC content may include: Metallic fumes Bloodborne Pathogens Bacteria Tissue cell particles Viruses Hydrocarbons Chemical fumes Gaseous vapors
23	Control Measures There are several measures that can be taken to prevent injury from lasers. These measures include: Engineering controls Administrative controls Personnel Protective Equipment
24	Engineering Controls Engineering controls are design features or devices that are applied to a laser or its environment for the purpose of reducing laser hazards. Engineering controls are considered to be the most effective types of control: Protective housing Interlocks Service access panels Key control master switch (Class 3b & Class 4) Beam stop or attenuator (Class 3b & Class 4) Remote interlock connectors (Class 3b & Class 4) Activation warning systems: audible sound, warning light
25	Administrative Controls Administrative controls consist of procedures and information provided to personnel for the purpose of reducing laser hazards. They are: Warning signs and labels Standard Operating Procedures (SOPs) Training
26	Warning Signs All rooms with Class 3b and Class 4 lasers must have appropriate signs posted at all entrances. Signs must: Have posted safety instructions Indicate laser class Indicate type of laser, emitted wavelength, pulse duration and maximum output. Indicate precautions needed such as PPE requirements for eyewear, etc.
27	“DANGER” Warning Sign Safety instructions may include: Eyewear required Invisible laser radiation Knock Before Entering Do Not Enter When Light is “ON” Restricted Area
28	Laser Protective Eyewear Requirements Laser Protective eyewear is available and must be worn by all personnel within the Nominal Hazard Zone (NHZ) of Class 3 b and Class 4 lasers where exposures above the Maximum Permissible Exposure (MPE) can occur. The attenuation factor (OD - optical density) of the laser protective eyewear at each laser wavelength should be specified by the Laser Safety Officer (LSO). All laser protective eyewear shall be clearly labeled with the optical density and the wavelength for which protection is afforded. This is especially important in areas where multiple lasers are housed. Laser protective eyewear shall be inspected for damage prior to use.
29	Laser Protective Eyewear
30	Use of Laser in a Medical Environment
31	Laser Surgery Benefits Decreased pain Decreased blood loss Decreased post surgical edema Reduced risk of infections
32	Laser Safety Practices Laser Protective Eyewear: must be worn even if the fiberoptic delivery system is used within a body cavity. must match the type of laser in use and should be labeled with the optical density and wavelength for which protection is afforded use must be enforced must be kept available near laser warning signs Window coverings that absorb the laser wavelength in use must be used.
33	Laser Safety Practices (cont.) Always put laser in “standby” mode when not in use. NOTE: The RN has the discretion to put the laser in standby mode when not in use. Protect exposed tissue with saturated materials and re-moisten periodically. Use dull, ebonized, or non-reflective anodized instruments. Use backstops or guards as applicable. To avoid inhalation of laser-generated air contaminants (LGAC) wear high filtration (0.1 microns) masks.
34	Laser Safety Practices (cont.) Use a smoke evacuating system according to the manufacturer’s instructions Do not use flammable or combustible materials near the laser application site Allow flammable prep solutions to dry before draping Drape the operative site with flame-resistant drapes and moisten reusable fabrics. Keep a basin of water/saline readily available on the sterile field. Keep a fire extinguisher in the operating room.
35	Laser Safety Practices (cont.) Use “laser-safe” (non PVC) endotracheal tubes during laser surgery in the aerodisgestive tract. An RN will be available at the laser and have the primary responsibility, when the laser is activated, to place it in “standby” mode at the physician’s request or RN’s discretion. Patients and health care workers should be protected from electrical hazards associated with laser use. Keep liquids away from the laser unit and foot pedal. ONLY THE SURGEON SHOULD OPERATE THE LASER FOOT PEDAL Assign a laser team member to all laser procedures.
36	Fiber Optics Lasers
37	Handling of Laser Fiber Delivery Systems 1. Only personnel who have completed appropriate education and equipment in-service training will operate the laser delivery systems. 2. All policies and procedures will be followed when lasers are used. 3. Lasers will be positioned in the room and checked prior to use. 4. Appropriate eye safety filters will be used with endomicroscopes. 5. Windows will be covered completely with appropriate filters. 6. Position laser, fibers, smoke evacuator, foot pedals, hoses, and cords to allow for safe traffic patterns in the room.
38	Handling of Laser Fiber Delivery Systems (cont.) 7. Examine the fiber for breaks or damage of the distal tip, the proximal connector, and the catheter sheath. If damaged, another fiber must be obtained. 8. Do not use clamps or other instruments to secure fiber in the operative site. 9. If required by the manufacturer, calibrate the fiber. 10. When applicable, use coaxial cooling that is appropriate to the procedure. NEVER USE GAS TO PURGE A FIBER IN THE INTRAUTERINE CAVITY. 11. Never fire the laser unless you see the aiming beam and the distal tip of the fiber beyond the end of the microscope. 12. Monitor the patient, the equipment, and the environment for safety. 13. Monitor the fiber for distortion of the beam, decreased power transmission, and accumulation of debris on the tip.
39	Handling of Laser Fiber Delivery Systems (cont.) 14. Never place a hot fiber directly on paper drapes. Wait until the tip is cool before contact with potentially flammable materials. 15. Never use alcohol or alcohol-based products in the operative field. Fibers may be rinsed in hydrogen peroxide or saline intra-operatively. 16. Always put the laser in standby when not aimed at target. 17. Never reuse a disposable fiber - without manufacturer's directions. 18. Never touch the laser fiber to the surface of the target material in the open beam configuration. [TO DO SO PROMOTES CARBONIZATION AND SPARKING WHICH RESULTS IN SURROUNDING TISSUE DAMAGE AS WELL AS A FIRE HAZARD.] A contact tip may be used to touch the target.
40	"REMEMBER" REMEMBER - SAFETY FIRST !!!
41	References The OSHA Laser Hazards website: (http://www.osha.gov/SLTC/laserhazards/index.html) The ANSI Z136.3 - Safe Use of Lasers in Health Care Facilities Laser Safety Training, Indiana University-Purdue University EH & S Laser Safety Training, University of North Carolina – Chapel Hill Basic Laser Safety Training, University of South Florida
42	Laser Safety Quiz Click here to go to the Laser Safety Quiz Complete the quiz to get your certification!