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The Safe Use of Lasers

The Safe Use of Lasers. in Clinical Practice. John Saunderson Laser Protection Adviser Hull & East Yorkshire Hospitals. Content. Welcome Nature of laser radiation Laser classes & hazards Local safety systems Operational safety Q & As. L ight A mplification by the S timulated

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The Safe Use of Lasers

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  1. The Safe Use of Lasers in Clinical Practice John Saunderson Laser Protection Adviser Hull & East Yorkshire Hospitals

  2. Content • Welcome • Nature of laser radiation • Laser classes & hazards • Local safety systems • Operational safety • Q & As.

  3. Light Amplification by the Stimulated Emission of Radiation

  4. 40 W bulb - 5% efficient • 2,000 x light energy from 1 mW laser pointer At 1 metre • 40 W bulb = 3.2 W/mm2 • 1mW laser pointer = • 1 mW/mm2 (300 x bulb), or • 0 W/mm2 • 40 W surgical laser • 40,000 x laser pointer

  5. 1 mm beam focussed to 20 microns  (1000/20)2 = 2500 power density

  6. Visible Green 532 nm Red 633 nm Invisible Nd:YAG 1064 nm CO2 10600 nm

  7. __________________________ • Continuous beam __ • Single pulse __ __ __ __ __ __ __ • Interrupted pulses

  8. Laser Device Classes & Hazards • Class 1 • Class 1M • Class 2 • Class 2M • Class 3R • Class 3B • Class 4 • Applies to device as a whole.

  9. Video

  10. Class 1 • no risk to eyes (including using optical viewing instruments) • no risk to skin • (either low power device or totally encased)

  11. Class 1M • no risk to the naked eye • no risk to skin

  12. Class 2 • no risk to eyes for short term exposure (including using optical viewing instruments) • no risk to skin • (visible, so blink response protects) • (may cause dazzle or flash blindness)

  13. Class 2M • no risk to naked eye for short time exposure • no risk to skin

  14. Class 3R • low risk to eyes • no risk to skin • (risk for intentional intrabeam viewing only) • (may be a dazzle hazard)

  15. Class 3B • medium to high risk to eyes • low risk to skin • (aversion response protects skin, or must be focussed to such a small spot that pin-prick effect only)

  16. Class 4 • high risk to eyes and skin • low risk to skin • (diffuse reflection may be hazardous) • (possible fire hazard)

  17. HEYH Trust CP137Health & Safety at Work Policy- Lasers - • Includes safety of class 3B and class 4 lasers

  18. Laser Safety Structure • Risk assessment • Controlled Area • Local Rules • Laser Protection Supervisor • Laser Protection Adviser • Authorised Operators and Assistants

  19. Risk Assessments

  20. Risk Assessments

  21. Local Rules(How to work safely) • Specific to each laser • What are hazards? • Controlled area - limit area of hazard - signs • Users & Laser Protection Supervisor • Safety precautions (e.g. eyewear, blinds) • Methods of safe working, etc. • Adverse incident procedure, LPA, etc.

  22. Laser Protection Supervisor

  23. Laser Protection Adviser

  24. Authorised Users

  25. Authorised Users

  26. Incidents

  27. Example

  28. MDA “One Liners” - Eye risk? August 2002 (Issue 17) MDA has become aware of the use of inappropriate filters for lasers used in ophthalmic surgery. This can lead to permanent eye damage for the operator. When connecting a laser to a protective system with filters,ensurethat the wavelengths of laser radiation for which thefilteroffer protection match the output wavelength of thelaser. If a fault is suspected with the filters, the procedure should be discontinued and the filters examined by a trained engineer.

  29. Example • Laser • 520-575 nm Green, 2 W • 568-575 nm Yellow, 1 W • 670 nm Red (aim), < 5 mW • Goggles labelled • 560-570 nm OD>4 • 570-580 nm OD>5 • 580-650 nm OD>6

  30. Example • Laser • 520-575 nm Green, 2 W • 568-575 nm Yellow, 1 W • 670 nm Red (aim), < 5 mW • Goggles labelled • 560-570 nm OD>4 • 570-580 nm OD>5 • 580-650 nm OD>6

  31. MDA “One Liners” - Hind Sight? March 2000 (Issue 8) Two separate incidents reported to MDA involving faulty laser equipment resulted in permanent retinal damage (one to a patient and one to the operator). In both cases, the operator had noticed that the equipment was behaving unusually but carried on with the procedure. Abnormal performance of any equipment should be questioned immediately.

  32. Laser Eyewear Labelling • DI 1060 L7 X Z • 620 TO 700 nm OD 2 • CARBON DIOXIDE, O.D. 10 @ 10600 NM • DIR 690 - 1290 L4 • D 1064 L7, IR 1064 L8, DIR 1350 - 1400 L7, DIR > 1400 - 1580 L5, DI 2090 - 2100 L5, DI 2900 - 2940 L5 D = continuous wave laser, I = pulsed laser (0.1 ms - 100 ms) R = giant pulsed laser (1 ns - 10 s), M = mode-coupled pulse laser (< 1 ns)

  33. Wavelength • Number before the L in nanometres • “Colour” of beam • May be single number (e.g. 10600) or a range (e.g. 2090 – 2100) • Wavelength on laser should fall within range on eyewear

  34. Optical Density • Number after the L • Strength of filter • OD 1 – only 1/10th of laser light transmitted • OD2 - 1/100th, • OD3 - 1/1000th, etc. • Local rules should say strength required. • Note – higher ODs may be very dark

  35. Other Hazards • Fire • Anaesthetic gas ignition • Plumes

  36. f i n

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