Page 179 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
skin surface, the pain receptors’ temperature may drop by 10oC – creating an 18oC ‘window’. More cooling may reduce the receptors’ temperature to 17oC, meaning that there is now a 28oC window before pain is triggered.
Apart from feeling less discomfort during the treatment, this allows the laser/IPL operator to use higher fluences, which ensure a higher probability of success.
The temperatures achieved in the epidermis can only be calculated by numerically solving the heat equation since it involves simultaneous heating and cooling, which we did in our model. The important conclusion here is that sufficient skin surface cooling must be applied to mitigate for the temperature increase in the epidermis to minimise the pain sensations and reduce the likelihood of epidermal and upper dermal damage.
The importance of surface cooling cannot be overstated. Without it, patients will probably be ‘burned’ by the laser/IPL outputs. To ensure a good level of clinical success requires the proper incident energy densities (fluences) coupled with sufficient surface cooling.
Skin surface
Figure 100 – A model of the skin in cross-section. When applying a 5oC cooling tip to the skin surface, the depth of cooling varies with the applied cooling time.
What is the risk of burning the skin with a laser or IPL?
Many people are worried about ‘burning’ the skin during laser/IPL treatment of hair, tattoos, blood vessels etc. But, what is the actual risk?
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