Exam 2- Low-Level Laser Therapy

Visible light wavelengths

400-700nm

A higher frequency means?

Higher energy

Light is transmitted as______ and packaged in______

Waves

Photons

Adding energy to electrons causes them to ?

Move to a higher energy orbit

-atom is an an "excited state"

If the electron gives up energy it?

Moves to a lower energy orbit

-"ground state"

What are the steps for the production of a laser?

Pumping of active medium

Population inversion

Spontaneous emission

Stimulated emission

Amplification

What step is the application of an external source of power to the lasting medium?

Pumping Step (1)

What does the pumping step cause?

Population inversion

What step is it when the number of excited atoms outweighs the number at ground state?

Population Inversion (step 2)

What makes laser different from other type of light?

Both photons have identical frequency, direction and phase

What is it called when 2 photons continue to cause the release of other identical photons as long as excited atoms are present?

Chain reaction= stimulated emission

Excited atoms will_________ release a photon of light. What will this do?

Spontaneously

Return it to ground state

What is it called when photons travel back and forth in the resonance chamber?

Amplification

When is the beam of light emitted from a laser?

Amplification process is maximal

What is it when it when the same wavelength and all in phase?

Coherence

-light is emitted in an organized fashion

What is it when the laser is a single color?

Monochromatic (same wavelength)

What is it when the photons move in a parallel fashion, and don't diverge?

Collimation

When the wavelength is longer (lower frequency) there is?

Deeper penetration

How are most lasers produces now?

Semiconductor (or diode)

Describe the set up of a semiconductor (or diode) laser)

Two laters of material in a silicon matrix

Layer interface is reflective

What is it called when the laser can penetrate well but isn't absorbed by a lot of stuff?

Therapeutic window

What is the values for the therapeutic window?

632.8 to 905nm

What are things that can absorb the laser beam?

Water

Hemoglobin

Melanin

Absorption of melanin drops off at?

600 to 780 nm

Water absorbing increases at what values?

1000-2000 nm

Visible red is what wavelength

600-700 nm

Near infrared values

700-905 nm

As the concentration of melanin or hemoglobin increases what happens?

The depth of penetration of the light decrease

What will determine the overall depth of penetration the photons will attain?

Wavelength

The longer wavelength means the __________ penetration

Deeper

Means more therapeutic effect

In an LED light the light that is produces is __________. What does this mean?

No coherent

-there're the same wavelength but not lined up together leading to more scatter= less penetration

What are the different techniques of application of laser?

Gridding technique

Scanning technique (non-contact)

Scanning technique (contact)

Describe the scanning technique (non-contact)

Laser held 5-10 mm from skin

Energy level decreases with distance

Describe the scanning technique (contact)

Move laser emitter while in contact (like ultrasound is applied)

The effect of laser is from?

Absorption of photons by light cels

What is lower doses of laser called?

Photobiostimulation

What is higher doses of laser called?

Photbioinihibition

What are molecules that accept energy from photons called?

Chromophores

What are the chromophoes in our body called? Where are they located?

Cytrochromes

In mitochondria

Chemistry of healing is stimulated by?

Light

-produce ATP increasing membrane transport=more healing

What is the process where a chain of chemical reactions is triggered by exposure to light?

photostimulation or photobiomodulation

What is a primary effect of laser?

Direct interaction of photons with cytochromes

What is a secondary effect of laser?

Something that happens in the same cell in which photons produced the primary effects

-induced by primary effects

What are tertiary effects of laser?

Indirect responses of distant cells to changes in other cells that have been interacted directly with photons

Indications of using laser in inflammatory phase

Decrease pain

Decrease inflammation

Indications of laser in proliferation phase

Enhance angiogenesis

Enhance the formation of granular tissue

Enhance collagen synthesis

What are the different classes of laser?

Class I

Class 1M

Class II

Class III (IIIa and IIIb)

Class IV

What class laser is invisible lasers

Class I

What class laser do we use?

Class 1M

Do we need to use eye protection with our lasers in lab?

No

-cause they're Class 1M

What class lasers are visible lasers and hazardous if directed continually into the eye (laser pointers)?

Class II

At what class level laser should you start wearing eyeware?

Class III

What class laser has a moderate risk to the retina but not to the skin or tissues and eye protection must be worn?

Class III

What is class IIIa lasers?

1mW to less than 5mW output (laser pointers)

What is class IIIb lasers?

5mW to 500 mW

What class are most therapeutic lasers? Except ours in lab is not this class

Most are class IIIb

What class laser can cause damage to the eyes, skin burns and fire hazard? (Causes heat)

Class IV

Protective eyeware is required for what class lasers?

Class IIIb and Class IV

-both patient and doctor

Contraindications to laser

Cancer

Pregnancy

Avoid direct exposure to eyes

Over areas of active hemorrhage

Over the thyroid gland

Directly over open wounds, unless covered with a clear protective barrier

Epileptic patients

Precautions of laser

Infection

Testicles

Sympathetic ganglia, vagus nerve, cardiac regions in those with heart disease

Open growth plates

Bruises

Photosensitive skin

Dosage of laser takes what into consideration?

Duty cycle (can be continuous or pulsed)

Dosage of laser depends on?

Output of laser

Number of diodes

Explore time

Beam surface area of the laser

What laser has bursts of energy with higher peak power and less thermal effects? They are more directed energy deliver to target tissue

Super pulsed laser

A lower frequency laser is good for what?

Repair and regeneration of tissue

Immune response

Anti-inflammatory effects

Lower range of frequencies for lasers are considered?

Bio-stimulatory

Frequency of lasers for acute injures

5-3000 Hz

You can do what with acute injures with laser?

Stimulate (heal)

Inability (pain relief)

TRUE or FALSE

A smaller more frequent and localized doses are generally more advantageous than larger, systemic does

True

Treatment time of laser for acute injuries

Around 3 min

Using laser on chronic injuries, what may be noted?

Temporary increase in pain

_______ does may be necessary to achieve treatment responses in chronic injuries

Larger

Acute conditions usually show results in how many treatments?

1 to 2

Chronic conditions usually need how many treatments prior to produce significant responses?

3-4 treatments