Lasers

Question 1

When laser light hits the skin, it is reflected, transmitted, and ultimately ________.

Answer 1

absorbed

Question 2

Once transmitted into the tissues, the laser undergoes what 3 things?

Answer 2

1. refraction
2. divergence
3. reflection

Question 3

What are the 3 essential characteristics of laser light?

Answer 3

1. monochromatic
2. coherent
3. collimated

Question 4

Evidence suggests that _______ may be the only clinically important feature of laser light.

Answer 4

monochromaticity

Question 5

Photo-biomodulation can be broken down further into what two categories?

Answer 5

1. photo-biostimulation

2. photo-bioinhibition

Question 6

Laser photons are absorbed by photosensitive organic molecules called _______.

Answer 6

chromophores

Question 7

What are the 3 proposed therapeutic effects of laser?

Answer 7

1. tissue healing
2. pain management
3. reduction of inflammation

Question 8

With laser light there is an increase in what three things, via the mitochrondrial respiratory chain enzyme cytochrome c oxidase acting as a photoreceptor?

Answer 8

1. ATP production
2. ROS
3. NO

Question 9

Too much ROS signalling causes cell _______.

Answer 9

apoptosis

Question 10

ROS signalling at slightly above physiological levels may do what 3 things?

Answer 10

1. stem cell differentiation
2. ion channel interference
3. cellular growth

Question 11

LLLT ______ ROS in oxidative stressed cells and tissues.

Answer 11

reduces

Question 12

LLLT ________ levels of pro-inflammatory cytokines in activated inflammatory cells

Answer 12

reduces

Question 13

The Ca2+ response to LLLT changes gene expression and causes secretion of what 4 factors?

Answer 13

1. growth factors
2. interleukins
3. inflammatory cytokines
4. small molecules

Question 14

Light in the green to red/near IR wavelengths catalyzes the ability of cytochrome C oxidase to generate NO, leading to what 4 things?

Answer 14

1. vasodilation
2. modulation of inflammatory and immune response
3. regulation of pro and anti-inflammatory responses
4. modulation of angiogenesis

Question 15

The modulation of inflammatory and immune response due to NO is generated by inhibiting __ and __ cell diversification and leukocyte recruitment

Answer 15

T and B

Question 16

Laser reduces levels of proinflammatory cytokines in ______ inflammatory cells

Answer 16

activated

Question 17

Laser changes _______ of activated monocytes and macrophages

Answer 17

phenotype

Question 18

Laser _______ wound healing

Answer 18

accelerates

Question 19

The local effect of laser for pain = reduced pain by reducing local ________

Answer 19

inflammation

Question 20

The central effect of laser for pain = release of ______ and _____ is used over specific acupuncture points

Answer 20

enkephalins; endorphins

Question 21

There is better evidence for use of laser for management of ______ MSK pain than ____ pain

Answer 21

chronic; acute

Question 22

LLLT produces mW of power which is _______ for each instrument

Answer 22

fixed

Question 23

Therapeutic lasers go up to what mW?

Answer 23

500

Question 24

Treatment does is given as J/__.

Answer 24

point

Question 25

_____ density is usually fixed for each device.

Answer 25

power

Question 26

Laser dosage is commonly given in J per ____

Answer 26

point

Question 27

You need to take into account the ____ of the laser beam for power density calculations

Answer 27

area

Question 28

J/point is a more accurate way of determining _____ energy

Answer 28

total

Question 29

_______ ______ is important in determining response to laser

Answer 29

total energy

Question 30

What is the penetration depth (in mm) of red to near-infrared light?

Answer 30

1-5 mm

Question 31

What is the penetration depth of near to mid-infrared light?

Answer 31

5-10 mm

Question 32

Research suggests that radiant exposures of ____ J/cm^2 can alter cellular processes

Answer 32

0.01

Question 33

What determines the depth of penetration ?

Answer 33

colour!

Question 34

There is evidence to suggest a _______ dose response to laser therapy

Answer 34

bi-phasic

Question 35

Frequency for an acute injury? For a chronic?

Answer 35

< 1kHz for acute; > 1 kHz for chronic

Question 36

Is contact or a non-contact technique preferred?

Answer 36

contact (with some pressure)

Question 37

What are 8 CI's for LLLT?

Answer 37

1. treatment of the eye 2. known or suspected malignancy 3. low back or abdomen of pregnant women 4. hemorrhage or severe vascular disease 5. tissues infected with TB / virulent bacteria 6. actively bleeding tissue or untreated haemorrhagic disorders 7. active DVT or thrombophlebitis 8. reproductive tissues

Question 38

What are 6 precautions for LLLT?

Answer 38

1. recently radiated tissues 2. infected regions (with compromised immune function) 3. epiphyseal plates in children 4. anterior neck/ carotid sinus 5. photosensitive areas on patients with light hypersensitivity 6. cognitive impairment

Question 39

What is absolutely required with using LLLT?

Answer 39

EYE PROTECTION