Laser Safety

Question 1

LASER

Answer 1

Light
Amplification of the 
Stimulated 
Emission of 
Radiation

Question 2

Risk of Laser

Answer 2

fire

*esp to pt airway + eye damage (staff/pt)

Question 3

regulates manufacturing/marketing of lasers

Answer 3

US FDA

Question 4

most commonly used laser standard addressing medical laser safety

Answer 4

American National Standards Institute

*compliance is voluntary

Question 5

What does ANSI require?

Answer 5

Laser Safety Officer (LSO) at institutions that use Class IIIB + IV lasers

Question 6

minimal distance in which laser beams can have effects

Answer 6

Nominal hazard zone

Question 7

maximal laser energy that can be absorbed w/o harm

Answer 7

maximum permissible exposure

Question 8

Identified hazards + developed safety standards

Answer 8

OSHA

Question 9

3 features of laser light

Answer 9

1. coherence
2. collimation
3. monochromacity

Question 10

electrons in medium in unstable position – collapse to lower, more stable energy position

Answer 10

spontaneous emission

Question 11

adjacent molecules/atoms absorb released energy, atoms in higher energy phase release energy

Answer 11

stimulated emission

Question 12

laser is produced by

Answer 12

two packets of energy (incident + excitation) combine = amplification

Question 13

energy and wavelength of laser is determined by

Answer 13

medium used

Question 14

lasers exert their effects by

Answer 14

focusing large amount of energy on a discrete area

Question 15

thermal effects of lasers are a result of

Answer 15

burns secondary to energy absorption

Question 16

photochemical effects of lasers are a result of

Answer 16

specific molecules/radiant energy

Question 17

mechanic effects of lasers are a result of

Answer 17

tissue disruption to photoacoustic shock waves

Question 18

toxic release of lasers are a result of

Answer 18

toxic gases, carcinogens, and viable microorganisms within laser plume

Question 19

lasers readily absorbed by H2O, effect most body tissues/pigments

Answer 19

long wavelength lasers

Question 20

lasers strongly absorbed by Hgb, pass thru clear substances easily

Answer 20

short wavelength lasers

Question 21

CO2 laser

Answer 21

WL 10,600 nm
absorbed by all tissue w/ H20
Clear glasses reqd

Question 22

Nd: YAG laser

Answer 22

WL 1064 nm
Neodynium-doped-yttrium-aluminum-garnet
(active medium - crystal + y/a/g w/ neody ions)

Question 23

KTP laser

Answer 23

WL 532 nm
potassium-titanyl-phosphate (Nd:YAG laser thru KTP crystal to shorten WL)
visible emerald green color 
precise focus, good coag
penetrates to depth: 0.5-2mm
used for airway, NS, GYN
Photoblation + photocoag

Question 24

Argon Laser

Answer 24

WL 488-515 nm
Ionized argon (medium) beam is green/blue visible light spectrum
Shallow tissue penetration 
good for eye (esp retina/derm/plastic)
photocoag

Question 25

Helium laser

Answer 25

visible red light incorporated into other lasers to function as aiming beam can be used for acupuncture

Question 26

most common laser injury

Answer 26

perf of organ/vessel

Question 27

most vulnerable injury

Answer 27

eye injury (result from reflected beams)

Question 28

eye injury types

Answer 28

photokeratitis photochemical cataracts thermal retinal injuries corneal burns

Question 29

damage to retina

Answer 29

WL 400-1400 nm | argon, Nd: YAG

Question 30

damage to cornea

Answer 30

WL > 1400 nm

Question 31

extent of eye injury determined by

Answer 31

``` WL pupil size degree of pigmentation size of retinal image pulse duration pule rep rate ```

Question 32

type of eye protection used

Answer 32

depends on laser used

Question 33

Colored glasses required for

Answer 33

short wl

Question 34

clear glasses required for

Answer 34

long wl (CO2)

Question 35

do not use what d/t risk of fire?

Answer 35

petroleum based lubricant

Question 36

if virus suspected

Answer 36

filtration masks should be worn

Question 37

laser plume

Answer 37

vaporization of tissue produces a plume of smoke/fine particles

Question 38

Required for laser plume particles

Answer 38

Special high efficiency masks

Question 39

Ordinary surgical masks can filter

Answer 39

3 microm | *laser plume = 0.31 microm

Question 40

Coherence

Answer 40

All waves are in phase, both in time and in space.

Question 41

Collimation

Answer 41

The waves travel in parallel directions.

Question 42

Monochromaticity

Answer 42

All waves have the same wavelength.