The two laws of laser therapy that we will discuss in this article may sound self-evident. However, very few therapists spend time to think this over. The first law of phototherapy states that light must be absorbed for any photoreaction to occur. In a previous article, Laser beam interaction with the skin, we’ve looked at […]
Why you cannot do laser hair removal on light blond, white and red hair.
We are constantly bombarded by manufacturers and sales people telling us that their laser or light-based equipment can do permanent hair removal on all hair colours. But as those of us with a bit of experience know by now, this is not the full truth. So why can’t we treat some lighter hair colour?Let’s start […]
Laser beam interaction with the skin
Marketing brochures for lasers and other light-based devices usually paints a picture of a light beam that enters the skin and hit the target molecule perfectly, it is then absorbed in its totality and providing the greatest result very time. But is this really true? No. The reality is that the moment a light beam […]
How to buy a laser
Looking at what is important when buying equipment. How do I buy a laser? Is a frequently recurring question we get at LaserCollege. Although there is no standard short answer for this question, we have tried to create a simplified process that will enable anybody to buy the best suited equipment for his or her […]
Photoreactions
Photoreactions are the interactions between light and biological matter. What happens when the light energy is absorbed by biological matter? The four most common types of reactions you will encounter during aesthetic treatments are: photothermal-, photoablative-, photochemical- and photoacoustic reaction. A photothermal reaction is when the light energy is converted to heat. For the aesthetic […]
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Thus, the number of times you laser can pulse in one second. The formula for frequency is f = 1/time, and is given in hertz (Hz).This may seem theoretical and not really worth knowing, but it does have a significant influence […]
Spot size
Spot size is the treatment surface you have which each pulse. The spot size of a machine can be fixed or adjustable and can come in a variety of shapes. Although a treatment parameter on its own, it is only meaningful when viewed in combination with other treatment parameters, like power or energy. Important to […]
Energy density (radiant exposure) and power density (irradiance).
Irradiance is the power received by a surface per unit area, W/cm2. Radiant exposure (fluence) is the energy received by a surface per unit area, J/cm2. We already know that energy is power multiplied with a unit time. Fluence is the most common adjustable treatment parameter you will encounter in photothermal laser therapy. The question […]
Energy and power
Energy and power: The difference between a $5000 and a $80000 machine. We will discuss the treatment parameters, energy and power, together since they are closely related. Keep in mind that this article is written from a perspective of lasers causing a photothermal reaction. With low-level lasers and LED devices the energy and power are […]
Pulse length
If you think of the wavelength as the active ingredient of your machine, the combination of the remaining treatment parameters makes for the dose. The first of these parameters is the pulse length. The pulse length can be adjustable or fixed, depending on the system you may use. As the name says, it is the […]