Continuous Wave (CW) (P)Power X (D)Duration/(A)Area = J/CM²
For example, let’s assume that the power is 10Watts, the duration of treatment is 600 seconds (10 minutes), and the treatment area is 100 cm², or about 5 ½” X 5½” which gives us the following equation: 10W(P) X 600 (D) = 6,000(J) / 100(A) = 60J/cm²
Pulsing J/CM² X T-on T-off ratio - J/CM² = average peak power
For example, let’s assume T-on is 25ms (microseconds) and T-off is 5ms - to determine the ratio (duty cycle) divide T-on by T-off, which gives us a ratio of 20% (5/25 - in other words, at a duty cycle of 20%), which is multiplied by energy density (60J/cm²) then subtracted from the same number (60J/cm² X 20% = 12), yielding the following equation: 60J/cm² (energy density) -12 (energy density minus duty cycle ratio) = Average Peak Power 48J/cm²
1/(T-on +T-off) = frequency; 1 sec. for T-on and T-off; Example: T-on 300ms and T-off 20ms, frequency = 3Hz 300ms is 0.3s, 20ms is 0.02s, 1/(0.3+0.02)=3Hz
For treatment settings, use the following basic formulas:
HIGHER dosage, increase Watts, Time, & DECREASE treatment AREA Smaller treatment area means GREATER energy density
LOWER dosage, decrease Watts, Time, increase treatment AREA Larger treatment area means LOWER energy density
DENSER tissues require HIGHER DOSAGE, PERMEABLE tissues allow for LOWER DOSAGE
SHALLOW tissues are better treated with CW (continuous wave) output, tissues that are DEEPER in the body respond better to fractional, pulsed, or phased energy; the DEEPER and DENSER the tissues, the HIGHER the Hz rate (DUTY CYCLE) and WAVELENGTH for deeper penetration and more optimal clinical outcomes.
All values in determining dosage should be included on a patient’s medical records. When marking a patient’s chart, it is always prudent to be as detailed as possible:
Dosage (Joules) = Watts (power) X Time (duration of treatment in seconds) divided by treatment area (in centimeters)
Energy Density = Joules/Area Typical treatment area 100cm2 (about the size of a playing card) To calculate energy density, simply divide the energy in joules by the area in square centimeters
DOSE is affected by wavelength, power density, tissue type, tissue condition, chronic or acute, pigmentation
1. Icing/cooling surface tissues for a short time before treatment will inhibit absorption by surface tissues and allow the energy to penetrate more deeply to reach the targeted tissues in the muscles, nerves, connective tissues, collagenous tissues, bone tissues, etc., especially while providing a pulsed, or phased treatment modality.
2. Icing/cooling tissues for a short time before treatment offers two benefits: first, it desensitizes the skin and subcutaneous tissues to thermal increase, allowing for longer treatment times over a smaller treatment area; second, it reduces or inhibits metabolic function in surface and subcutaneous tissues, allowing energy to flow more freely to underlying targeted tissues.
In laser therapy, the terms pulsed, phased, fractional, or gated all mean the same thing. In this mode, the laser output is interrupted at regular or preset intervals do enhance the biological effects of the wave energy. Pulsing is beneficial because it allows for more intense micro absorption of energy with less possibility of damage from excess heat or other effects.
The following statements are true when pigmentation is not a primary factor:
1. Continuous wave energy is absorbed more rapidly in surface tissues, and therefore is considered to be most appropriate for more superficial conditions and more permeable tissues.
2. Pulsing is absorbed less rapidly with progression through surface tissues and can therefore be more effective at greater depth and denser tissues.
A laser can be classified as operating in either continuous or fractional mode, depending on whether the power output is continuous over time or whether its output takes the form of pulses of energy at regular intervals scale:
1: Continuous Wave
2: Modulated Continuous Wave (Phased, Pulsed, Gated, Fractional)
3: Modulated Continuous Wave (Phased, Pulsed, Gated, Fractional)
4: Nanosecond Pulses
Continuous Wave Operation Continuous wave emission has no interruption during the delivery of their energy Some applications of lasers depend on a beam whose output power is constant over time; such an output is known as continuous wave mode.
Pulsed, or Phased Operation
Pulsed operation of lasers refers to any laser output not classified as continuous wave, so that the optical power appears in pulses of some duration at some repetition rate. This encompasses a wide range of technologies addressing a number of different motivations. Some lasers are pulsed simply because they are unable to operate in continuous wave mode due to the weak output of their diodes. In other cases, laser therapy application requires the production of pulses having as large an energy as possible. Since the pulse energy is equal to the average power divided by the repetition rate, this goal can sometimes be satisfied by lowering the rate of pulses so that more energy can be built up in between pulses. Other applications rely on the peak pulse power (rather than the energy in the pulse), especially in order to obtain nonlinear optical effects. For a given pulse energy, this requires creating pulses of the shortest possible duration utilizing techniques super pulsing. Typical peak power is in the order of many Watts; however, the necessary high current in this mode will quickly destroy a laser diode unless the time of current conduction is extremely short. Super-pulsed diode lasers cannot work continuously - the maximal pulse time for this laser is in nanoseconds and after each such pulse a long cooling time is needed, usually about a thousand times longer than the pulse time, therefore a so-called super-pulsed laser will transfer an exceedingly small volume of energy. As stimulatory as well as inhibitory therapy laser treatment outcomes depend on volume of energy transferred for optimal clinical outcomes - typically, this type of treatment alone (super-pulsing) usually does not yield desired results.
Therapeutic laser beam energy is best directed toward the targeted tissues when the handpiece is held at a 90-degree angle to the skin with the handpiece emitter resting on the skin. The energy beam is delivered in such a way that it focuses at a distance away from the end of the emitter, according to where the lens is located in the handpiece.
When to Treat in Contact Mode
With the handpiece resting on the skin, the energy beam is usually focused at depth and closer to the vicinity of targeted tissues. When treating in this manner, less energy is left on the surface of the skin and more energy is delivered below the skin to the region of tissues being targeted. This can be observed by holding the hand piece two inches away from the skin and initiating treatment, then doing the same with the hand piece directly on the skin. With the hand piece two inches away from the skin, the sensation of heat is much higher than when it is resting directly on the skin. The majority of therapy laser treatments should be done in this manner. This mode of application is especially relevant when treating in pulse mode, which would typically comprise most treatments being administered.
When to Treat in Non-Contact Mode
When treating in non-contact mode, laser energy should be delivered in a continuous wave beam in the targeted tissue is generally very shallow or right on the skin. This is true when treating dermatological issues, or very shallow nerves such as cranial nerves. this mode of treatment is also done when there is minimal subcutaneous tissue over joints including the hands and fingers, wrists and elbows, knees and ankles, and feet.
When utilizing the 810nm wavelength, the energy of the laser is best applied with the handpiece resting on the skin. The 810nm wavelength should be primarily used when treating large muscle groups or areas of the body that are suffused with hemoglobin or red adipose tissue. When treating with the 980nm or 1064nm wavelengths as joints, nerves, or bone tissue is targeted, treatment can be on or off the skin depending on the depth of tissue being targeted. For example, when treating shallow nerves such as cranial nerves, treatment can be provided with the handpiece on or just off the skin.
GUIDELINES USED TO DETERMINE TREATMENT PARAMETERS:
• CW-continuous wave
• Pulse, phased, or gated mode
• Duty cycle
GENERAL TISSUE DEPTH:
GENERAL TISSUE TYPE:
When treating with multiple wavelengths, it is best to treat with the hand piece gently gliding on the skin for optimal treatment outcomes.
The preset protocols in the laser are designed for a treatment area of one hundred centimeters squared (around the size of a playing card). When needing to treat a larger area, it is best to multiply the treatment duration by the number of areas to be treated. For example, if the treatment area is four hundred centimeters squared, then the whole treatment area can be treated at one time, but the duration of treatment needs to be four times longer. Another treatment option is to increase laser output power rather than extend treatment time to achieve the same dosage (joules per centimeter squared).
Many treatment protocol guidelines are axiomatic, but need to be considered in a different light (no pun intended) when more modern and effective lasers like those by Medray are utilized. For example, setting the Hertz rate, which in-vitro studies at exceptionally low power levels have always indicated should always be lower than 100Hz, may be more effective when set higher when using more appropriate higher power settings. Although this was axiomatic in past years, modern in-vivo treatments at power levels higher than the previous standard “low-level’ settings will prove that this necessarily isn’t the case anymore.