1. بسم الله الرحمن الرحیم مهرداد کفاشی 8533051

2. The application of laser in medical

3. What is Laser? L ight A mplification by S timulated E mission of R adiation 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.

4. 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.

5. How a laser works?

6. 1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of Cr 3+ in the ruby crystal to higher energy levels. 2. At a specific energy level, some Cr 3+ emit photons. At first the photons are emitted in all directions. Photons from one Cr 3+ stimulate emission of photons from other Cr 3+ and the light intensity is rapidly amplified.

7. 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.

8. Laser s ystem components

9. Directionality divergence angle (  )

10. Basic concepts for a laser Absorption Spontaneous Emission Stimulated Emission Population inversion

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

12. 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.

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

14. 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

15. Common used Laser lights Laser mediaColorWavelength (nm) Carbon dioxideFar infrared10,600 Ruby Red 694 KTP:YAGGreen 532 Argon Green 514 Xenon fluorideUltraviolet 351

16. Lasers vs. Conventional Light Sources LED (Light Emitting Diode) Nd:YAG Laser Source: Google

17. 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

18. 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

19. Laser interaction with tissue  Used as scalpels and electrocoagulators  Precise microsurgery  Relative “dry”  Less damage to adjunct tissue  Less postoperative pain and edema

20. 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

21. 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

22. Beam Hazards Eye Hazard Cornea/lens hazard: 290-400 nm and 1400-10,600 nm Retinal 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

23. Lasers vs. Conventional Light Sources ( a Apparent visual angle laser source A collimated beam can be focused to a small spot on the retina Conventional light source

24. Eye Injury Nd:YAG (1064 nm) - Permanent damage Individual saw a white flash, heard a click, then immediately a dark spot in visual field

25. 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

26. 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..

27. What conditions can be treated with ThermaScan: Wrinkles Aging Skin Hypertrophic scars Acne scars

28. 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.

31. 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

32. 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

33. Hair removal The laser sufficiently heats the pigment to destroy the hair follicles without damaging the delicate pores and structures of the skin.