Lecture on LASER

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Presentation Transcript

LASERRoma Rosas D. Veron, MPH, PTRP : 

LASERRoma Rosas D. Veron, MPH, PTRP 1

Topic Objectives : 

Topic Objectives Classify the different types of low power lasers according to their frequency and effects to body tissues Compare LPL from other physical agents with regards to pain and wound management Discuss the unique qualities of LPL and how it differs from ordinary light Operate LPL machine and giving proper treatment parameters 2

Definition : 

Definition Light Amplification by Stimulated Emission of Radiation

History : 

History Albert Einstein (1917) Theodore Maiman (1960) Medical lasers – 1960 -1963 Ga-As lasers - 2002 4

How the first ruby laser works : 

How the first ruby laser works 5

Unique Qualities of LASER : 

Unique Qualities of LASER Single-colored with majority of the radiation emitted by the device being clustered around a single wL with a very narrow band width 6

Unique Qualities of LASER : 

Unique Qualities of LASER Aka NON-DIVERGENCE “straightness” of the directed radiation 7

Unique Qualities of LASER : 

Unique Qualities of LASER Parallel waves that propagate with a high degree of order approximating the same phase (temporal) and same direction (spatial) 8

Incandescent vs. Laser Light : 

9 Incandescent vs. Laser Light Many wavelengths Multidirectional Incoherent Monochromatic Unidirectional Coherent

Common Components of all Lasers : 

Common Components of all Lasers 10 Active Medium The active medium may be solid crystals such as ruby or Nd:YAG, liquid dyes, gases like CO2 or Helium/Neon, or semiconductors such as GaAs. Active mediums contain atoms whose electrons may be excited to a metastable energy level by an energy source. Excitation Mechanism Excitation mechanisms pump energy into the active medium by one or more of three basic methods; optical, electrical or chemical. High Reflectance Mirror A mirror which reflects essentially 100% of the laser light. Partially Transmissive Mirror A mirror which reflects less than 100% of the laser light and transmits the remainder.

Fundamentals of Laser Operation : 

Fundamentals of Laser Operation 11

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12

Lasing Action Diagram : 

Lasing Action Diagram 13 Energy Introduction Ground State Excited State Metastable State Spontaneous Energy Emission

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14

Common Lasers and Their Wavelengths : 

Common Lasers and Their Wavelengths TYPE wL Uses Ar-Fl 193 LASIK, lithography He-Cd 325 - 442 printing, typsetting GaAs 910 nm biostimulation He-Ne 543,594,612 & 632.8 spectroscopy, bar code scan Krypton 647.1 - 676.4 white light laser Ruby 694.3 holography, tattoo removal Nd:YAG 1064 surgery, CO2 10600 surgery, cutting/welding Nitrogen 337.1 measures air pollution

Factors Affecting the Effect of Laser Beam on Biological Tissues : 

Factors Affecting the Effect of Laser Beam on Biological Tissues Wavelength Depth of penetration – 1-4 mm Dosage Pain: 16-20 seconds Wound healing: 20-30 seconds Number of treatment

Method of Application : 

Method of Application “Gridding” technique Pain: 16-20 sec Wound: 20-30 sec “Surround” technique HeNe – 30 sec/ 2 cm2 GaAs – 20 sec/ 2 cm2

HeNe Laser : 

HeNe Laser Most commonly used Red laser DOP: 0.8 mm – 15 mm

Diode Laser : 

Diode Laser Active medium is a semiconductor wherein an electric potential is applied to the medium leading to stimulated emission Ga-As laser 19

Types of Laser : 

Types of Laser HIGH POWER LASER Hot/hard laser > 60 mW Thermal responses and cause tissue damage Used in surgery CO2, Argon, YAG LOW POWER LASER Soft/cold laser < 60 mW Minimal or no thermal response Used in PT: 1 mW HeNe, GaAs

Effects of Cold Lasers : 

Effects of Cold Lasers Cellular effects Increased ATP and nucleic acid production Stimulation of macrophages Stimulation of fibroblasts to increase collagen production Altered nerve conduction and regeneration Vasodilation 21

Physiological Effects of LPL : 

Physiological Effects of LPL Pain reduction Accelerated tissue healing Decrease skin impedance after low laser stimulation

Indications : 

Indications Open lesions Decubitus ulcers Diabetic ulcers Incisions Lacerations Burns Degenerative articular Tendinitis TMJ dysfunction Back pains CTS Rheumatic d/o

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24

Contraindications : 

Contraindications Do not radiate the eye directly Pregnant woman Fontanelles of babies Photosensitivity Cancerous lesions Endocrine glands Hemorrhaging lesions

Precautions : 

Precautions Tx of patients with pins, metal plates and plastics Tx of patients with cardiac pacemakers Extreme age Under heavy medication With thick eschar With scar tissue With dry skin With infection

ANSI Classifications : 

ANSI Classifications 27 Class 1: Do not pose a hazard. Class 2: Capable of creating eye damage through chronic exposure. Class 3a: Not hazardous if viewed momentarily w/ naked eye but hazardous if viewed w/ optical instruments Class 3b: Cause injury upon direct viewing of the beam and specular reflections Class 4: Pose eye, skin and fire hazard

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The End

Endolaser 476 : 

Endolaser 476 Class IIIB Solid state: Ga-AS-Al wL: 780/830 nm Power of probe: 10 mW Beam diam: 4 mm Precautions: Never look directly into the probe Always wear goggles Place the laser unit 2 m away from SWD/MWD 29

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30 1 3 2 6 8 4 5 7 9 10

Endolaser 476 : 

Endolaser 476 On/off switch Charger indicator lamp Battery status lamp Selector for pulsed/ continuous therapy Selector for percentage of power Tx time selector Tx time display Dose selector Dose display Stop button Start button Laser indicator lamp Laser test lightmeter Laser test selector Dose indicator lamp Power indicator lamp Laser tip Start/stop contact switch 31

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