LASER

Question 1

Light Amplification by Stimulated Emission of Radiation

Answer 1

Photon that hits atom that is already excited

This creates radiation effect

Question 2

History of LASER: 1917

Answer 2

1917 Einstein - concept of stimulated emission of radiation

Question 3

Biophysical father of LASER

Answer 3

Albert Einstein

Question 4

History of LASER: 1954

Answer 4

Shawlow, Townes, Basoc and Prochorov
MASER
1st stimulated emission device

Question 5

History of LASER: 1960`

Answer 5

Javan and Maiman
Ruby LASER - maiman
He-Ne LASER - javan
Visible portion of em spectrum

Question 6

History of LASER: 1962

Answer 6

White et al
Cold LASER
Indigoviolet portion of roygbiv of light

Question 7

History of LASER: 1960-1970

Answer 7

endre mester
Low level LASER diode type
Non thermal effects of LASER
Therapeutic father of LLLT
Was only used by doctors

Question 8

History of LASER: 2002

Answer 8

low intensity laser in rehabilitation

Question 9

On EM spectrum, it is close to —- and ——

Answer 9

infrared and visible

Question 10

properties of laser

Answer 10

Monochromatic : single frequency and wavelength making one color
Coherent : moves in one direction
Collimated : multiple wavelengths of radiation move parallel to each other

Question 11

LASER produces —- intensity light in —- area/s

Answer 11

high, one

Question 12

LASER physical components (gaseous and photodiode)

Answer 12

active medium (lasing agent); helium-neon; gallium arsenide, gallium-aluminum arsenide;

resonance chamber; sealed glass cylinder; diode p=n junction gap

power source; electrical; electrical

Question 13

spontaneous emission

Answer 13

Absorption: When you plug the machine, the electrons move to higher energy shells

Emission: moves inwards to lower energy shell, creates radiation

Made of various wavelengths, therefore not monochromatic

Question 14

stimulated emission is made of — wavelengths, therefore you make a —–

Answer 14

Made of similar wavelengths, therefore you make a laser

Question 15

longer wavelength = —- frequency = —— penetration

Answer 15

lower frequency, deeper penetration

Question 16

red light vs violet light

Answer 16

violet = shorter wavelength

red = longer wavelength

Question 17

red light penetration

Answer 17

600-700 nm

Question 18

Helium-neon LASER penetration

Answer 18

632.8 nm

Question 19

Ruby LASER penetration

Answer 19

694.3 nm

Question 20

gallium aluminum arsenide LASER penetration

Answer 20

860-780 nm

Question 21

gallium arsenide laser penetration

Answer 21

904-910 nm

Question 22

power (mW)

Answer 22

rate of energy flow

Question 23

power density (mW/cm2)

Answer 23

amount of power per unit area

maximum of 100 mW/cm2

Question 24

class 1

Answer 24

power: <0.5 mW

no hazard

Question 25

class 1M

Answer 25

power: <0.5 mW

no hazard because of large diameter beam or less-divergent beam

Question 26

class 2

Answer 26

power: < 1 mW

safe for momentary viewing

provokes blink reflex

Question 27

class 3A

Answer 27

<5 mW

Laser pointers; eye hazard with prolonged exposure

Question 28

class 3B

Answer 28

<500 mW

for therapy; permanent eye damage with brief exposure, viewing of siffused beam reflected from skin is safe; minor burns with long exposure

Question 29

class 4

Answer 29

> 500 mW

surgical and industrial cutting laser

permanent eye damage

serious skin burns

burns clothing

Question 30

photobiomodulation

Answer 30

light modulates biological processes

enhances cellular function

Question 31

energy=

Answer 31

power x time

Question 32

energy density

Answer 32

energy / area of irradiation

Question 33

therapeutic range of energy density

Answer 33

0.5 to 20 j/cm2

Question 34

process of photobiomodulation

Answer 34

light => chromophore activation => mitochondrial cytochrome oxidative metabolism => photobiomodulation => analgesia, alter NCV, anti-inflammation, inc. collagen and protein synthesis, enhanced cell metabolism (ATP & RNA)

Question 35

indications of laser

Answer 35

pain control, inflammation control, wound healing

wounds, tendinopathies, trigger points, RA, OA, TMJ, carpal tunnel

Question 36

first laser for inhibiting bacterial growth of P. aeruginosa and S. aureus

Answer 36

red laser (632.8 or 670 nm)

Question 37

Laser for inhibiting bacterial growth of P. aeruginosa, S. aureus & e. coli

Answer 37

HeNe Laser (630 nm) at 1-20 J/cm2

Question 38

another laser for inhibiting bacterial growth of P. aeruginosa and S. aureus

Answer 38

blue light (405 nm) at 10-20 j/cm2

Question 39

laser for vasodilation

Answer 39

red Laser

Question 40

contraindications

Answer 40

Over eyes
Malignancy
Within 4-6 months of radiotherapy
Hemorrhage
Over the thyroid
Low back/abdomen of pregnant patient
Epilepsy
Pacemakers (for clinics)

Question 41

precaution

Answer 41

Metal implants
Epiphyseal plates in children
Impaired sensation
Impaired mentation
Photophobia (you can proceed with proper patient education)

Question 42

energy density for soft tissue healing

Answer 42

5-16 j/cm2

Question 43

energy density for fracture healing

Answer 43

5-16 j/cm2

Question 44

energy density acute arthritis

Answer 44

2-4 j/cm2

Question 45

energy density lymphedema

Answer 45

1-5 j/cm2

Question 46

energy density neuropathy

Answer 46

10-12 j/cm2

Question 47

energy density acute soft tissue inflammation

Answer 47

2-8 j/cm2

Question 48

energy density chronic soft tissue inflammation

Answer 48

10-20 j/cm2

Question 49

energy density chronic arthritis

Answer 49

4-8 j/cm2

Question 50

techniques of application

Answer 50

Stationary with contact
Stationary with non-contact (open wounds and infection)
Gridding (point by point)
Scanning => Like ultrasound, For larger areas

Question 51

documentation

Answer 51

May indicate specific type of LASER in very first part

LASER x power x energy density on body area to rationale