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الرحمن الله بسمالرحیم
کفاشی 8533051مهرداد
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.