Page 175 - Mike Murphy's Blog Posts

D1 - Treating Benign Pigmented Lesions with an IPL and a QS Nd:YAG laser
I often hear laser/IPL operators saying that they “don’t want to burn their patients/clients.” They are wrong!! They DO want to ‘burn’ them, but in a very controlled manner...
Every photothermal treatment (the removal of hair, blood vessels, benign pigmentation etc) requires delivering light energy to generate a thermal (heat) response in the tissues. We are literally trying to ‘burn’ the unwanted cells to kill them.
If we apply the correct energy (fluence) in the correct pulsewidth (cooking time) then we can safely and effectively destroy the unwanted cells, without damaging the surrounding tissues.
My calculations reveal that most of the light energy we fire at the skin does NOT do the job we want it to!! In fact, in some circumstances, less than 1% of the light energy is actually doing the job!! That means that more than 99% of the light energy is generating excess heat in the skin, looking to cook something. This is not good...
To mitigate against this we must apply plenty of cooling to the skin. After all, we are trying to ‘burn’ it, but not all of it!
I carried out a wee test to show the difference between treating a benign pigmented lesions with the Q-switched Nd:YAG laser using the 532nm wavelength and an IPL using the 480nm filter.
So, while the laser will only generate a 532nm beam (which is strongly absorbed in both melanin and blood), the IPL will produce a range of wavelengths from 480 up to 1200 nm. Also, the QS laser is fired in an extremely short pulse – only about 10 nanoseconds long, while the IPL was fired in a 35 millisecond pulse (which is 3.5 million times longer!!)
As a consequence of these pulsewidths, the Nd:YAG laser generates a ‘photomechanical’ response in the melanosomes while the IPL produces a ‘photothermal’ reaction. In addition, the strong absorption by the blood coupled with the very short pulses will cause the capillary vessels to burst apart too.
The following set of photos come from a young lady who had a benign pigmented mark on her calf (many thanks to her for her kind permission to use these photos). She agreed to try both the QS 532nm beam and the IPL beam to see how they differed.
We decided to treat the top half with the QS Nd:YAG laser, and the bottom half with the IPL.
Mike’s Blog Posts 175