Lasers Flashcards
When laser light hits the skin, it is reflected, transmitted, and ultimately ________.
absorbed
Once transmitted into the tissues, the laser undergoes what 3 things?
- refraction
- divergence
- reflection
What are the 3 essential characteristics of laser light?
- monochromatic
- coherent
- collimated
Evidence suggests that _______ may be the only clinically important feature of laser light.
monochromaticity
Photo-biomodulation can be broken down further into what two categories?
- photo-biostimulation
2. photo-bioinhibition
Laser photons are absorbed by photosensitive organic molecules called _______.
chromophores
What are the 3 proposed therapeutic effects of laser?
- tissue healing
- pain management
- reduction of inflammation
With laser light there is an increase in what three things, via the mitochrondrial respiratory chain enzyme cytochrome c oxidase acting as a photoreceptor?
- ATP production
- ROS
- NO
Too much ROS signalling causes cell _______.
apoptosis
ROS signalling at slightly above physiological levels may do what 3 things?
- stem cell differentiation
- ion channel interference
- cellular growth
LLLT ______ ROS in oxidative stressed cells and tissues.
reduces
LLLT ________ levels of pro-inflammatory cytokines in activated inflammatory cells
reduces
The Ca2+ response to LLLT changes gene expression and causes secretion of what 4 factors?
- growth factors
- interleukins
- inflammatory cytokines
- small molecules
Light in the green to red/near IR wavelengths catalyzes the ability of cytochrome C oxidase to generate NO, leading to what 4 things?
- vasodilation
- modulation of inflammatory and immune response
- regulation of pro and anti-inflammatory responses
- modulation of angiogenesis
The modulation of inflammatory and immune response due to NO is generated by inhibiting __ and __ cell diversification and leukocyte recruitment
T and B
Laser reduces levels of proinflammatory cytokines in ______ inflammatory cells
activated
Laser changes _______ of activated monocytes and macrophages
phenotype
Laser _______ wound healing
accelerates
The local effect of laser for pain = reduced pain by reducing local ________
inflammation
The central effect of laser for pain = release of ______ and _____ is used over specific acupuncture points
enkephalins; endorphins
There is better evidence for use of laser for management of ______ MSK pain than ____ pain
chronic; acute
LLLT produces mW of power which is _______ for each instrument
fixed
Therapeutic lasers go up to what mW?
500
Treatment does is given as J/__.
point
_____ density is usually fixed for each device.
power
Laser dosage is commonly given in J per ____
point
You need to take into account the ____ of the laser beam for power density calculations
area
J/point is a more accurate way of determining _____ energy
total
_______ ______ is important in determining response to laser
total energy
What is the penetration depth (in mm) of red to near-infrared light?
1-5 mm
What is the penetration depth of near to mid-infrared light?
5-10 mm
Research suggests that radiant exposures of ____ J/cm^2 can alter cellular processes
0.01
What determines the depth of penetration ?
colour!
There is evidence to suggest a _______ dose response to laser therapy
bi-phasic
Frequency for an acute injury? For a chronic?
< 1kHz for acute; > 1 kHz for chronic
Is contact or a non-contact technique preferred?
contact (with some pressure)
What are 8 CI’s for LLLT?
- treatment of the eye
- known or suspected malignancy
- low back or abdomen of pregnant women
- hemorrhage or severe vascular disease
- tissues infected with TB / virulent bacteria
- actively bleeding tissue or untreated haemorrhagic disorders
- active DVT or thrombophlebitis
- reproductive tissues
What are 6 precautions for LLLT?
- recently radiated tissues
- infected regions (with compromised immune function)
- epiphyseal plates in children
- anterior neck/ carotid sinus
- photosensitive areas on patients with light hypersensitivity
- cognitive impairment
What is absolutely required with using LLLT?
EYE PROTECTION
