LASER Definition Light Amplification by Stimulated Emission of Radiation History In 1967 a few years after the first working laser was invented, Endre Mester from Hungary wanted to find out if laser might cause cancer. He took some mice, shaved the hair off their backs, divided them into two groups and gave a laser treatment with a low powered ruby laser to one group.
The mice did not get cancer and to his surprise the hair on the treated group grew back more quickly than the untreated group. That was how "laser biostimulation" was discovered. Laser Light A typical laser emits light in a narrow, low-divergence monochromatic = single-colored beam with a well-defined wavelength. Laser Light Although the word light is typically used in the expansive sense, as photons of any energy; it is not limited to photons in the visible spectrum. So there are infrared lasers, ultraviolet lasers, X-ray lasers, etc
Low-level laser light is compressed light of a wavelength from the cold, red part of the spectrum of electromagnetic radiation. It is different from natural light in that it is one precise color; it is coherent =it travels in a straight line, monochromatic = a single wavelength and polarized = it concentrates its beam in a defined location or spot. These properties allow laser light to penetrate the surface of the skin with no heating effect, no damage to the skin and no known side effects. Rather, laser light directs biostimulative light energy to the body's cells which the cells then convert into chemical energy to promote natural healing and pain relief Continuous - Pulsed A laser may either be built to emit a continuous beam or a train of short pulses. This makes fundamental differences in construction, usable laser media, and applications. In the continuous wave (CW) mode of operation, the output of a laser is relatively consistent with respect to time.
Continuous - Pulsed In the pulsed mode of operation, the output of a laser varies with respect to time, typically taking the form of alternating 'on' and 'off' periods. In many applications one aims to deposit as much energy as possible at a given place in as short time as possible. Laser Output Power Power Density Mechanism certain wavelengths of light certain intensities delivered for a certain amount of time will aid tissue regeneration resolve inflammation relieve pain boost the immune system
Biostimulation Improved metabolism Increase of cell metabolism Analgesic effect Anti-inflammatory and anti-edematous effects Stimulation of wound healing Effects Mechanism The exact mechanism is still being explored and debated but it is agreed that the mechanism is photochemical. LLLT is not a heat therapy. Mechanism Observed biological and physiological changes include cell membrane permeability up- and down-regulation of ATP and NOS
ATP- Adenosine 5'- triphosphate is a multifunctional nucleotide primarily known in biochemistry as the molecular currency" of intracellular energy transfer transports chemical energy within cells is produced as an energy source during the processes of photosynthesis and cellular respiration Nitric oxide generated by macrophages as part of the immune response. Nitric oxide is toxic to bacteria and other pathogens. Many bacterial pathogens have evolved mechanisms for nitric oxide resistance. It is a signaling molecule Acts mainly against oxidative stress So the answer to all our questions is Low Level Laser Therapy???
"best" wavelength dose dose-rate effects beam penetration the role of coherence and pulses peak power repetition rates Not so sure about Dose The energy (E) of the light directed at a given unit of area (A) during a given session of therapy. The energy is measured in J (joules), the area in cm2, and, consequently, the dose in J/cm2. Dose Mathematically, this may be expressed as follows: E D = ---- A [J/cm2]
Dose Assuming that the power (P) output of the laser probe remains constant during treatment, the energy (E) of the light will be equal to the power multiplied by the time (t) during which the light is emitted. The dose may then be calculated as follows: P t D = ---- [J/cm2] A Dose Recommendati ons Treatment on the affected area with 0,5 to max. 4 J/cm2, for good results in the beginning once daily, if possible. 0.5-2 J per acupuncture point 1-4 J per trigger point Power density Power in W X irradiation time in seconds Irradiation surface in cm2 = J/cm2 1Watt = 1 Joule/sec
Calculation Power : 50 mw oder 0,05 W Surface of Area: 10 cm2 Dose 2 J Irradiation Time? Irradiation Time = Dose(J) x Area(cm2) / Power (W) X= 2 x 10/0,05 X= 400sek X= 6,6 min Irradiation Time : 6.6 min Calculation for Laseracupunctu re Power : A: 50 mw oder 0,05 W B: 400mW Dose 2 J Irradiation Time? Irradiation Time = Dose(J) / Power (W) X= 2 /0,05 Irradiation Time = 40sek X= 2/0,4 Irradiation Time : 5 sec. Wavelenght
Wavelength Material Helium Neon Laser 632.8 nm recommended for non healing wounds Gallium Arsenide Laser 780nm -904 nm recommended for tendons and joints Infrared Laser recommended for laser acupuncture Laser Pen Laser Comb Laser Shower.. Different Kinds of Soft Lasers
Which laser model? for small animals: 22 up to 50 mw, for big animals: with 50 to 200 mw. soft tissue injuries chronic pain wound healing nerve regeneration Clinical applications resolve of viral and bacterial infections How to
Contraindications Irradiation of eyes Irradiation of tumors Irradiation of pregnant uterus Irradiation of non closed fontanels Studies There is an uncountable number of studies in the field of Low Level Laser therapy The conclusions differ from Helpful Useless Great Have a look!
Author Joint (s) Result Reason for exclusion Gallachi 1981 Cervical and lumbar No significant differences Acupuncture and trigger point exposure only Lewith 1981 Knee LLLT significantly better Trigger point than placebo exposure only Walker 1983 Not stated LLLT significantly better Peripheral nerve than placebo exposure only, randomisation doubtful Waylonis 1988 Low back No significant differences Trigger point exposure only Snyder-Mackler 1989 Lumbar and cervical LLLT significantly better Trigger point than placebo exposure only Rogvi-Hansen 1991 Knee No significant differences Did not irradiate joint, but peripheral nerves and top of patella only Bjordal et al: A systematic review of low level laser therapy with location-specific doses for pain from joint disorders The results of this review were surprisingly unequivocal in favour of active LLLT when dosage was titrated above the suggested lower dose limit for reduction of inflammation. In our opinion, many trial authors and reviewers have investigated clinical effects without having a hypothesis of which biological action they expect from LLLT. They have often disregarded the fact that LLLT dose is affected by physical and anatomical penetration characteristics. Although we have tried to cater for these factors, it must be remembered that our estimate range of laser penetration is hypothetical. We currently lack hard data on what biological effects laser causes at certain depths and tissues in the body.
Laser Safety