Laser Lecture - Lecture 2 (modalities) Flashcards
Using electromagnetic waves to heat human tissue from microwaves and radiofrequencies
Diathermy
From visible radiation levels
Laser
What kind of electromagnetic waves are felt - infrared rays or UV?
UV rays
KNOW: Xrays / Gamma rays are the most powerful
Visible light has much less wavelengths
Are most electromagnetic waves sensed by the body?
Nope
Laser therapy is part of light therapy
Light Amplification by Stimulated Emission of Raidtion is what?
Laser
What can be used to cauterize wounds in surgery?
High power lasers
KNOW: Low level lasers can be used for healing, pain, inflammatory neuromuculoskeletal conditions
KNOW: Theres two kinds of lasers - low level lasers and high level lasers (strength differs)
KNOW: Low level laser therapy can be used for carpal tunnel
KNOW: High level laser gets that tissue and icnreased theraml effects (warms it up more to get those thermal effects)
KNOW: How a laser works
A power source produces energy which in turn excites the electrons
When those electrons get excited they emit photons (or light energy)
Within the laser itself there are little mirriors and the photons continue to bounce off of those and eventaully they run into electrons which excites them even more to release more photons (positive feedback loop)
This gives us a very consintrated light energy
Then we have this small opening in the front of the laser that allows this highly condinced light energy to escape
The depth of the tissue able to absorb energy from the laser depends on what?
The wavelength (deeper tissue needs different wavelengths to absorb)
623nm laser is what color and transmits how deep
red/orange 2-3cm
830nm is what kind of laser and transmits how deep
infrared
2-4cm
1064nm is what kind of laser and transmits how deep?
Infrared from HILT
4-7cm
Photosensitive molecules in membranes of cells and organelles that are sensitive to specific wavelengths of light
Chromophores
For example if you should a wavelength into skin which is a wavelength of 7000-1200 nm thats goign to stimulate mitochondrial chromophores which will stimulate the mitochondrial and cause increased ATP synthesis / cellular repair /repdodruction / increased production of mRNA for procollagen
Mitochondrial chromophores are what wavelength. What effects do you get (3)
700-1200nm
Increased ATP synthesis
Cellular repair/reproduction
Increased production of mRNA for procollagen
Myoglobin and hemoglobin chromophores are stimulated at what wavelength
400-700nm
We get increased tissue healing from laser due to these chromophores
Why is inflammation decreased w/ laser
Increased histamine and nitric oxide = increased vasodilation = improved BF
KNOW: laser decreases pain
* reduction in bradykinin
Increased levels of beta endorphine
Supression of C-fiber afferent pain nerves
Decreased nerve conduction and amplitude
KNOW: Laser causes increased tissue healing increased osteoblastic proliferation
improved diabetic / neuropathic foot ulcers
increased BF
increased blood vessel permeability
cell metabolism/anti-inflammatory mechanisms
Indications from laser
* TMD
* Lumbar/cervical dysfunction
* Shoulder pain / dysfunction
* Fibromyalgia, myofascial dirsoders
* Lateral elbow epicondylitits
* Knee degenerative joint disease
* Carapl tunnel syndrome
* Achilles tendonitis
* Wounds
However - lots of studies found that this wasnt true
So you have to weigh the pros and cons of actucally purchasing
* generally evidence is not strong for laser utilization and they’re expensive so lots of clinics dont buy them
Determines depth of energy absorption and what kind of tissues are most affected (deep vs non deep) in a laser
Wavelength
Low Level Laser Therapy (LLLT) peak output
Less than 500mW
High Intensity Laser therapy peak output
> 500mW
KNOW: Power is measured in mW
Rate of pulses of laser emission is known as
Frequency
Why should pulses of be utulized w/ HILT? What are the benefits of it being pulsed?
Because of the increased power
Reduces the excessive thermal effects and tissue damage
Total energy develered is measured in
Joules
The amount of joules of energy delevered is based on what (4)
Power
Frequency
Treatment size
Treatment time
How is total energy calculated?
Peak power x pulse frequency x pulse duration x time applied to pt / total treatment area
30mW=0.03W; continuous; 30 sec treatment time
0.03W * 30 sec /1cm2= 0.9J/cm2 for single probe 1 cm2
For cluster with 6 probes 0.9J/cm2 * 6 = 5.4J/cm2
30mW with pulse rate of 1,000Hz and pulse duration of 300μsec
(0.03W * 1,000Hz * 0.0003 sec) = mean power = 9mW
0.009W * 30 sec /1cm2 = 0.27J/cm2
dont really know what this means - but her audio didnt work
KNOW: For carpal tunnel we use low laser
for latearl epicondylitis / trigger points we use low and high intensity
KNOW: part of the problem w/ lasers it that we need them coming in 5 times a week for several weeks which isnt doable for lots of pts
Joules = treatment time * power
2/.3 = 3.5sec??????????
Single diode has how much power
300mW
Cluster has how much power?
540mW
GRID method is 1cm squares holding laser there for a second or 2 then moving on and going down your grid
in contact w/ pts skin
So you’re only holding it in each box for about a second
if I was doing single diode 1J i would hold it for 1 second 3-4 times
W/ scan method for laser you’re hovering over pts skin and doing sweeps
hard to gage the amount of E going into the pt
Point stimulation
for one point were trying to hit really hard
1 J = 3.5 secofons remove and do it over and over again
going to have to relearn all this shit
Contraindications for laser
* direct eye exposure
* Prgnancy
* Active malignancy
* Active hemorrhage
* Ope/Active growth plate (not yet ossified) (age 22)
* Endocrine system - thyroid gland - can alter hormone release
Precuations
* Impaired sensation (can generate heating effects)
* Indirect eye exposure (risk of retinal damage - wear protective goggles)
* Skin color - darker skin color may lead to greater laser enegery absorption - increased superficial tissue injury release - dosage should be less than 9 joules for darker skin color
Clinical procedure for laser:
* Select appropriate laser (class 3b or 4) - we use 3b LLLT
* Describe purpose and benefits to pt
* Clear patient of contraindications, skin inspection, sensation check
* Take pre-measures (girth etc…)
* Position patient in appropriate and comfortable position (treatment area exposed / patient weaing protective eyewear)
* Set appropraite parameters on device
* Don protective eyewear
Position laser applicator in contact w/ skin
* prependicular to skin surface
* if sweep mode is used, hover over skin
* HILT will require a specer (make sure theres space between laser applicator and pts skin)
Begin treatment
* Point to treatment area for time
* Move (point and move)
Inform patient of open communication for adverse effects
Following reatment:
* Turn off machine before removing eyewear
* Remove protective eyewear
* Wipe off applicator w/ alc wipe
Assess pt response
* Skin check
* Post- measures
Documentation
* Type of laser
* Duration
* Total Energy Delivered
* Frequency if pulsed (pulsed duration)
* Power
* Treatment area
Patient response
* Test, treat, re-test
* Adverse effects (this is a yes or no)
Recommended outcome measures
* AROM/PROM
* MMT Grip dynamometry (especialy w/ eipcondylitits)
* Pain
* Pressure algometry
* Sensory testing
* Nerve conduction
* Functional measures
