Laser Therapy PDF

LASER Therapy Prepared by: Dr/ Ahmed Sayed Aly Lecturer of Physical Therapy – Modern University for Technology & Information in Cairo (MTI) PHD of P.T- Faculty of Physical Therapy - Cairo University - LASER is an electromagnetic modality. - T...

LASER Therapy Prepared by: Dr/ Ahmed Sayed Aly Lecturer of Physical Therapy – Modern University for Technology & Information in Cairo (MTI) PHD of P.T- Faculty of Physical Therapy - Cairo University - LASER is an electromagnetic modality. - The word LASER is an acronym or abbreviation for Light Amplification by Stimulated Emission of Radiation. LASER differs from other sources of light as it emits light that is : - Monochromatic: single wavelength & single color - Coherent: travels I a straight line - Polarized & Collimated (parallel): concentrates its beam into a defined spot Atom  Energy orbits Atom structure Resting state of the atom ( ground state) -Electron will stay in its lowest energy level (ground state) unless it absorbs an adequate amount of energy (photons) to move it to one of its higher orbital levels, equal the amount of energy between 2 energy orbits. -When this occurs, the atom is said to be in an (excited state).  The atom stays in this excited state only momentarily and releases an identical photon which returns it to a ground state. This process is called spontaneous emission.  -A photon released from an excited atom would stimulate another similarly excited atom releasing an identical photon. These two photons would promote the release of additional identical photons as long as other excited atoms were present. This process is called stimulated emissions.  Production of LASER: A large number of atoms with the electrons in the excited state can lead to amplification since one photon releases a second and these two can release more and so on. Components of laser unit: 1. The energy source ( may be electrical , light & thermal) 2. Lasing medium (materials that generates the laser light may be gas, solid , liquid or semiconductor) 3. Resonating cavity (mirrored chamber contains the lasing medium)  Energy source Lasing medium Laser beam Full reflective mirror 100 % Partial reflective mirror 90-95 % Resonating chamber Laser unit Properties of LASER: 1. Monochromaticity: (one color) lasers are of a single specific wavelength 2. Coherence: ( similarity ) - Temporarily - spatially 3. Directional: (Collimation) parallel fashion  Keep on your mind that LASER is wavelength dependent for penetration and absorption  Helium neon laser Helium neon laser give radiation in the red visible region at 632.8 nm. Helium neon laser penetrates 0.5 - 1mm before losing 37% of its intensity. Semiconductor diode lasers (gallium arsenide (Ga-As)) Ga-As laser give radiation in the infrared region at 904 nm. Infrared radiation will penetrate > 2mm before losing 37% of its intensity.  Keep on your mind -There is a direct relationship between wavelength and LASER penetration through body tissues. -There is an inverse relationship between wavelength and LASER absorption by the skin. -So: Lasers with wavelength in the near infrared such as 904 nm (Ga-As) are chosen to treat subcutaneous structures whereas skin lesions or superficial wounds surfaces are appropriately treated by one of the (He Ne) lasers which will be absorbed largely in the skin.  Classification of Laser: - According to the nature of the lasing medium utilized into: a- Solid state lasers (Ruby crystal) b- Gas lasers ( He Ne) c- Semiconductor or diode lasers (Ga As): d-Liquid lasers: are also known as dye lasers because they use organic dyes as the lasing medium. e- Chemical lasers: are usually extremely high powered and frequently used for military purposes.  - According to Potential hazardous posed to the exposed skin and to the un accommodated eye into 4 classes: Laser tissue interaction  When laser radiations interact with matter the effects are the same as any other equivalent electromagnetic radiation – ( reflection, refraction, absorption ). Laser tissue interaction Photothermal Photomechanical Photochemical theory Physiological Effects of Laser: 1- Stimulation of tissues healing (wound healing, soft tissues healing and nervous tissue regeneration). 2- Anti-inflammatory effect (stimulate phagocytosis). 3- Pain control. 4- Enhance nerve conduction velocity. 5- Increase angiogenesis (formation of new blood vessels) and improve of micro-circulation. Indications of Laser Therapy: 1. Non- infected and infected skin wound and ulcers. 2. Non-united fracture. 3. Acute and chronic inflammation of musculoskeletal system as OA and RA. 4. Acute and chronic soft tissues injuries. 5. Neurogenic pain. 6. Trigger point and acupuncture point stimulation. Contraindication of Laser Therapy: 1. Direct irradiation of the eyes. 2. Hemorrhaging regions. 3. Locally to the endocrine glands. 4. Pregnancy.