Page 108 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
Fluence and Skin Cooling
We discussed skin cooling in Section 3.1, but here we will show the ‘balance’ that should be strived for when considering fluence, and skin cooling.
Figure 59 – Pain and skin damage will result from too much fluence and insufficient cooling
In essence, we are trying to heat the follicle stems cells such that they are cooked, irreversibly, to kill the follicle. This requires a sufficient amount of heat energy to be applied to the stem cells, which, in turn, means that a lot of excess energy is looking to go somewhere!
We must mitigate against this extra heat energy by applying a sufficient level of skin surface cooling. If too much fluence is applied, without the appropriate level of skin cooling, then excess heat will raise the temperatures of the epidermal basal melanin, which will flow towards the thermal pain receptors in the upper dermis.
This will make the treatment painful and may lead to unwanted skin damage. It appears that many laser/IPL operators are unaware of the importance of skin cooling. Given that we are deliberately trying to overheat the skin, it would seem obvious that cooling should always be applied. Quite frankly, if skin surface cooling is not being used then the operator is not doing the job properly! When the correct level of cooling is applied for the fluence being used, the pain sensation is greatly reduced, leading to more comfortable treatments.
We choose the fluence according to the target follicle depth and hair colour. If a sufficient amount of fluence is applied, then the stem cells should be destroyed, leading to permanent removal of that follicle.
To balance the effects of the excess heat energy, which always happens, we must apply a sufficient level of cooling. Doing so with lead to much more comfortable and safe treatments, with good results.
Skin cooling is critical!!
Figure 60 – The correct balance of fluence and cooling will ensure safe and comfortable treatments
________________________________________________________________________ 108 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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