LASER

Question 1

What does LASER stand for?

Answer 1

Light Amplification by Stimulated Emission of Radiation

Question 2

What is a LASER?

Answer 2

An electromagnetic modality with a wavelength in the ultraviolet, visible light and infrared spectrum

Question 3

What range are the wavelengths?

Answer 3

Between 400 nm (ultraviolet) and 70 nm (infrared)

Question 4

What are hot LASERS’s?

Answer 4

Emit an energy measured in watts that result in a thermal effect in the tissue

Question 5

What are hot LASER’s used for?

Answer 5

Can cause tissue destruction and are used for surgical purposes (ex. eye surgery)

Question 6

What are cold LASER’s?

Answer 6

Emit an energy measured in milli-watts that have no thermal effects

Question 7

What are cold LASER’s used for?

Answer 7

To stimulate a photochemical effect in the cell

Question 8

What is low level laser therapy?

Answer 8

The accepted terminology for the use of therapeutic LASER technology

Question 9

What is polychromatic?

Answer 9

A combination of light waves of varying lengths and colour combined to result in white light

Question 10

What does a prism do?

Answer 10

Separates light waves of differing lengths resulting in light beams of varying colours (ROY G BIV)

Question 11

What are some LASER beam characteristics?

Answer 11

• Monochromatic
• Coherent
• Collimated
• Low power (measured in milli-watts)
• High density (focused light beam)

Question 12

What are the different types of beam shapes?

Answer 12

• Collimated
• Diverging
• Converging

Question 13

What are some characteristics of light?

Answer 13

• Dual nature: both a wave and a particle
• Light energy is transmitted through space as particles that contain tiny ‘energy packets’ called photons
• Each photon has a unique wavelength and frequency
• If a photon of adequate energy level collides with an electron of an atom it causes the atom to be in an excited state

Question 14

What is the physics of LASER?

Answer 14

• Energy stimulation is at the atomic level of a cell
• Causes the electron to jump to a higher orbit ‘energizing’ the atom
• The atom wants to return to its normal state and releases the energy in the form of a photon
• All the photons are all identical in wavelength

Question 15

What is spontaneous emissions?

Answer 15

Atoms release energy photons randomly in different orders and different directions; naturally occurring

Question 16

What is stimulates emissions?

Answer 16

Occurs when a photon of specific energy is introduced and absorbed by the atom

Question 17

How does stimulated emission occur?

Answer 17

An environment must exist with unlimited excited atoms; this is called population inversion

Question 18

What is a LASER generator?

Answer 18

Comprised of a tube with mirrors at either end, one being semi-permeable

Question 19

What are some different types of lasing mediums between the mirrors?

Answer 19

• Gas: HeNE (helium/neon)
• Semiconductor: GaAs (galium arsenide)
• Synthetic ruby (crystal lasers)
• Neodymium, aluminum, garnet (crystal laser)
• Organic dyes (liquid laser)
• Chemical lasers

Question 20

What depth can a gas lasing medium penetrate?

Answer 20

Superficial penetration (0.5-1.0 cm)

Question 21

What are the effects of the different wavelengths?

Answer 21

• Ultraviolet: photochemical changes (ex. suntan)
• Infrared: Deep penetration (5-8 cm), thermal effects
• Visible (red) light: superficial penetration (.5-1.0 cm), both photochemical and thermal effects

Question 22

What is dosage reported in?

Answer 22

Joules per square centimetre

Question 23

What is dosage dependent on?

Answer 23

• Output of the laser in milli-watts
• Time of exposure in seconds
• Beam surface area of laser in cm2

Question 24

What is the formula for the treatment time for a given area?

Answer 24

Ta = (E/Pav) X A

• Ta: treatment time for a given area
• E: millijoules of energy per cm2
• Pav: avergae laser power in milliwatts
• A: beam area in cm2

Question 25

What are the different types of application techniques?

Answer 25

• Sequential: each square cm is lased
• Non-sequential: alternate grids are lased with overlap
• Scanning: no contact between probe and skin

Question 26

What are the different frequencies and what are they used for?

Answer 26

• 2.5 Hz: for acute injuries
• 20 Hz: for wound healing
• 150 Hz: for pain relief
• 5 Khz: for chronic injuries and non-healing or infected wounds

Question 27

What are some different treatment areas?

Answer 27

• Trigger points
• Acupuncture points
• Painful areas
• Open wounds, cuts, ulcers

Question 28

What does LASER depth of penetration depend on?

Answer 28

The type of laser energy delivered

Question 29

What does direct effect of depth penetration mean?

Answer 29

The response that occurs from absorption

Question 30

What does indirect effect of depth penetration mean?

Answer 30

A lessened response that occurs deeper in the tissues; upper layers effected, affect the deeper layers

Question 31

What is the depth penetration of HeNe?

Answer 31

Occurs within first 2-5 mm with an indirect effect of up to 8-10 mm

Question 32

What is the depth penetration of GaAs?

Answer 32

1-2 cm with an indirect effect up to 5 cm

Question 33

What are the indications of LASER?

Answer 33

• Wound healing: increased collagen synthesis
• Edema inflammation reduction: inhibiting inflammatory mediators
• Pain reduction: decreased sensory conduction, inflammation and increased healing
• Scar tissue: increased epithelialization and decreased exudate material
• Immunologic response: increased phagocytosis
• Bone response: increased consolidation
• Peripheral nerve regeneration

Question 34

What are some precautions/contraindications for LASER?

Answer 34

• Safety goggles must be worn by both therapist and patient
• Do not use in pregnancy
• Do not treat eyes, over the heart
• Cancer, tumors