There have been HUNDREDS of in vitro studies whose aim have been to quantify the ideal energy density (the quantity we call dose) for biostimulation. The optimal range of doses that have been widely accepted in the industry are from 2-15 Joules per square centimeter. So start with a modest value at the bottom of that range…..6 Joules per square centimeter.
Let's consider, for example, the lower lumbar region for chronic back pain. Typically, the pain stems from somewhere between disks L1 through L5. This area spans approximately 10 centimeters wide by 15 centimeters long, for a total treatment area of 150 square centimeters. The total energy (measured in Joules) needed AT THE TARGET region is then straight-forwardly calculated by multiplication of an energy DENSITY of 6 Joules per square centimeter by 150 square centimeters, yielding a total energy needed of 900 Joules.
The target area is NOT the surface of the skin. Our body is a highly TURBID medium. This means the laser's beam is highly attenuated through a combination of scatter AND absorption. So the dose delivered to the TARGET is MUCH less than that which is exposed to the surface. The heart of the ailment, in this example, lies in and around the spinal cord, which is at an average depth of 6 centimeters beneath the surface. So how much radiation is left at this depth inside our bodies??
Our bodies are made up of about 80% water, and so for a first approximation, let us see how much radiation penetrates through 6 cm of water. A series of experiments that measured the three-dimensional dose distribution of an 800 nm and 1064 nm beam in a water phantom. From the figure, which plots percent of transmitted energy vs depth in water, only 29% of the radiation exposed to the surface is actually delivered to a depth of 6 cm. This means that in order to deliver the prescribed energy of 900 Joules to the target depth, you must start with just over three thousand Joules at the surface. So you can see it is NOT the case that you can simply apply 900 Joules in the treatment session. If you did, you would only be left with 260 Joules at the target, which spread over the 150 square centimeter area, would yield a dose of just under 2 Joules per square centimeter, which is an inadequate dose.
Now…what is the treatment length that can deliver this value of dose?? That depends on the power output of the laser. Power (in Watts) tells you the amount of energy (in Joules) you can deliver per unit time (in seconds). Simple multiplication yields the values in the table. For a standard Class IIIb laser of 200 milliWatts (remembering that Class IIIb lasers by definition fall between 5 and 500 milliWatts) you would have to treat for upwards of four and a half hours to deliver such a dose, whereas the RLT can accomplish this dose in under 3 minutes. From a clinical standpoint, this is the definition of feasibility.
Let's consider, for example, the lower lumbar region for chronic back pain. Typically, the pain stems from somewhere between disks L1 through L5. This area spans approximately 10 centimeters wide by 15 centimeters long, for a total treatment area of 150 square centimeters. The total energy (measured in Joules) needed AT THE TARGET region is then straight-forwardly calculated by multiplication of an energy DENSITY of 6 Joules per square centimeter by 150 square centimeters, yielding a total energy needed of 900 Joules.
The target area is NOT the surface of the skin. Our body is a highly TURBID medium. This means the laser's beam is highly attenuated through a combination of scatter AND absorption. So the dose delivered to the TARGET is MUCH less than that which is exposed to the surface. The heart of the ailment, in this example, lies in and around the spinal cord, which is at an average depth of 6 centimeters beneath the surface. So how much radiation is left at this depth inside our bodies??
Our bodies are made up of about 80% water, and so for a first approximation, let us see how much radiation penetrates through 6 cm of water. A series of experiments that measured the three-dimensional dose distribution of an 800 nm and 1064 nm beam in a water phantom. From the figure, which plots percent of transmitted energy vs depth in water, only 29% of the radiation exposed to the surface is actually delivered to a depth of 6 cm. This means that in order to deliver the prescribed energy of 900 Joules to the target depth, you must start with just over three thousand Joules at the surface. So you can see it is NOT the case that you can simply apply 900 Joules in the treatment session. If you did, you would only be left with 260 Joules at the target, which spread over the 150 square centimeter area, would yield a dose of just under 2 Joules per square centimeter, which is an inadequate dose.
Now…what is the treatment length that can deliver this value of dose?? That depends on the power output of the laser. Power (in Watts) tells you the amount of energy (in Joules) you can deliver per unit time (in seconds). Simple multiplication yields the values in the table. For a standard Class IIIb laser of 200 milliWatts (remembering that Class IIIb lasers by definition fall between 5 and 500 milliWatts) you would have to treat for upwards of four and a half hours to deliver such a dose, whereas the RLT can accomplish this dose in under 3 minutes. From a clinical standpoint, this is the definition of feasibility.