To perform effective treatments, the wavelengths used need to correspond to the absorption spectrum for the target chromophore. Since the various wavelengths have different energies, light of a certain wavelength can travel only a certain distance into the skin; this is called the penetration depth.
Unlike laser, the light generated from Intense Pulsed Light Systems is broad waveband. The waveband of light emitted from the Ellipse System is chosen so that it both has the correct penetration depth and the optimal absorption by the target chromophore, with minimal absorption by the competing chromophores. The short flashes of light are timed to heat up the target to the correct temperature without damaging surrounding tissues.
The raw light from the flash-lamp used in Intense Pulsed Light systems includes invisible ultraviolet and infrared light, as well as visible white light. First-generation Intense Pulsed Light systems filter out the ultraviolet light, but allow the infrared light through.
The Ellipse second generation (I2PL ) system has an extra filter to remove the infrared light (which is not absorbed by the target chromophores, melanin and haemoglobin but which is absorbed by the interstitial fluid). This ensures that the light that is directed to the skin contains only the wavelengths that are required to perform the treatment. Treatment with I²PL is thereby more effective, since it uses much less energy and does not require artificial cooling. The risk of side effects is also reduced.
Use of the correct waveband of light and selective photothermolysis means that the natural pigments haemoglobin and/or melanin absorb the light transmitted into the skin. An optical coupling gel is used to enhance the light penetration. Both the energy and the timing of the pulse are computer-controlled so that the target is heated to 70º C for 1 ms. This is sufficient time to ensure that the target is selectively destroyed – the surrounding skin and the water in the skin are not harmed.
The light that is absorbed by melanin and haemoglobin is absorbed in the epidermis. Fortunately, this distance allows the Ellipse I²PL system to treat many of the most common and most annoying skin problems:
Further treatments are in preparation, and will be released as they are clinically documented to be safe and effective.
The amount of energy is important; to ensure that the target receives the energy required getting the desired result without damaging the surrounding tissue.
The pulse time is important because it controls how quickly the energy is delivered. This is determined by the Thermal Relaxation Time (TRT) of the target. For fine adjustment these can be altered by the user.
As well as the pulse duration, the shape of the pulse is also important. Because the energy is measured over the full length of the pulse, it is important that the pulse shape is as square as possible. That is to say the intensity of the pulse should be consistent throughout its life.
An inconsistent pulse will mean that the skin receives different levels of energy throughout the pulse. It also means that the spectrum of the light will change from the theoretical values during the pulse (similar the effect seen when a dimmer switch is used).
Unlike many other products on the market, Ellipse carefully controls both the amount of energy and the pulse so that the best possible result is obtained.