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The application of laser in medical

What is Laser?

Light Amplification by Stimulated

Emission of Radiation

A device produces a coherent beam of optical radiation by stimulating electronic, ionic, or molecular transitions to higher energy levels

When they return to lower energy levels by stimulated emission, they emit energy.

Properties of Laser

Monochromatic Concentrate in a narrow range of wavelengths (one

specific colour).

Coherent All the emitted photons bear a constant phase

relationship with each other in both time and phase

Directional A very tight beam which is very strong and

concentrated.

How a laser works?

1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of Cr3+ in the ruby crystal to higher energy levels.

2. At a specific energy level, some Cr3+ emit photons. At first the photons are emitted in all directions. Photons from one Cr3+ stimulate emission of photons from other Cr3+ and the light intensity is rapidly amplified.

3. Mirrors at each end reflect the photons back and forth, continuing this process of stimulated emission and amplification.

4. The photons leave through the partially silvered mirror at one end. This is laser light.

Laser s ystem components

Directionality

divergence angle ()

Basic concepts for a laser

Absorption

Spontaneous Emission

Stimulated Emission

Population inversion

Absorption

Energy is absorbed by an atom, the electrons are excited into vacant energy shells.

Spontaneous Emission

The atom decays from level 2 to level 1 through the emission of a photon with the energy hv. It is a completely random process.

Stimulated Emission

atoms in an upper energy level can be triggered or stimulated in phase by an incoming photon of a specific energy.

The stimulated photons have unique properties:

In phase with the incident photon

Same wavelength as the incident photon

Travel in same direction as incident photon

Common used Laser lights

Laser media Color Wavelength (nm)

Carbon dioxide Far infrared 10,600

Ruby Red 694

KTP:YAG Green 532

Argon Green 514

Xenon fluoride Ultraviolet 351

Lasers vs. Conventional Light Sources

LED (Light Emitting Diode)

Nd:YAG Laser

Source: Google

A laser is used for many medical purposes. Because of:

the laser beam is so small the laser beam is precise it enables medicine to safely treat specific

tissue without injuring surrounding tissue

Tissue & Cellular Response Magnitude of tissue’s reaction are based on

physical characteristics of: Output wavelength/frequency Density of power Duration of treatment Vascularity of target tissues Indirect effect – produced by chemical events

caused by interaction of photons emitted from laser & the tissues

Laser interaction with tissue

Used as scalpels and

electrocoagulators

Precise microsurgery

Relative “dry”

Less damage to

adjunct tissue

Less postoperative

pain and edema

Laser Hazard Classification Accessible Emission Limit (AEL)

Lasers and laser systems are classified on the basis of the laser radiation accessible outside the laser during the intended use

and to which the human eye or skin is possible to be exposed

Laser Hazard Classification

Class 1 laser:

Low power; Considered safe Class 2 laser:

Eye protection afforded by the eye blink response Class 3 laser:

Medium power; Hazard to the eye from direct exposure

Class 4 laser:

High power; Hazard to the eye and skin from direct and reflected exposure; Fire hazard

Beam HazardsEye Hazard

Cornea/lens hazard: 290-400 nm and 1400-10,600 nmRetinal hazard region: 400 - 1400nm

Eye entering the eye is focused. The irradiance on the retina can be increased as much as 100,000

One central fovea laser hit can cause blindness

Lasers vs. Conventional Light Sources

(a

Apparent visual angle

laser sourcelaser sourceA collimated beam can be focused to aA collimated beam can be focused to asmall spot on the retinasmall spot on the retina

Conventional light sourceConventional light source

Eye Injury

Nd:YAG (1064 nm) - Permanent damageNd:YAG (1064 nm) - Permanent damageIndividual saw a white flash, heard a click, then immediately a Individual saw a white flash, heard a click, then immediately a dark spot in visual fielddark spot in visual field

Misdirected laser energy may perforate a viscus or a large blood vessel

Perforation may occur several days later when edema and necrosis are maximal

Perforation

Laser Skin Rejuvenation

For Wrinkle Reduction and restoring your skin to its natural beauty

The PROFILE ThermaScan laser brings a whole new approach to

wrinkle treatment

What is ThermaScan? THERMASCAN's innovative technology sets new standards

for the treatment of wrinkles and several other skin conditions.

THERMASCAN is a special pulsed infrared laser that can selectively target the

region in your skin responsible for improving collagen. .

What conditions can be treated with ThermaScan:

Wrinkles

Aging Skin

Hypertrophic scars

Acne scars

How does ThermaScan work?  THERMASCAN treatment uses an infrared laser to

rejuvenate your skin from the inside out. The laser energy delivered by the THERMASCAN penetrates into the upper layers of your skin.The energy absorbed by the targeted areas stimulates the fibroblast cells in your skin to begin generating collagen. Collagen and elastin fibers continue to multiply after your treatment, and you will see improving results over the months ahead. This treatment helps restore your skin to its natural beauty, making it softer, smoother and more vibrant.

Laser surgery

Laser surgery can be used to: Remove tumors (brain, liver)

With minimal damage to surrounding healthy tissue With minimal scarring

Seal small blood vessels to reduce blood loss Seal nerve endings to reduce postoperative pain Remove warts, moles, and tattoos Reduce the appearance of skin wrinkles, scars, and

other skin blemishes Remove hair

LASER SKIN CARE

The lasers produce an intense but gentle burst of laser light that passes harmlessly through the skin and is selectively absorbed by the vessel or legion.

The light produced by the laser generates heat within the vessel or legion, destroying it without causing thermal injury to any of the surrounding tissue

Hair removalThe laser sufficiently heats the pigment to destroy the hair

follicles without damaging the delicate pores and structures of

the skin.