Page 81 - Chapter 3 - Fundamentals of Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
There is an indicator known as ‘Omega’ which is a measure of how many cells, in a volume, are irreversibly denatured. As long as Omega exceeds 1, those cells cannot regrow.
We ran a lot of simulations looking at different sized hairs from 50 up to 200 microns in diameter, with a wide range of fluences and pulsewidths. We chose the wavelengths associated with modern day lasers and IPLs.
Figure 29 – The heat conducts (diffuse) outwards towards the germ cells over time
Our model revealed a lot of interesting information about the heating and heat transfer processes which occur in laser/IPL treatments. These included:
1. The choice of wavelength is not very important except when considering darker skin colours – SC5 and SC6;
2. The pulsewidth is not as important as we all thought it was;
3. The fluence is – by far – the most important parameter (setting) in terms of successful
outcomes;
4. Raising the background dermal temperature by a few degrees makes a BIG difference!
This is important when considering the SHR/in-motion technique.
We will be carrying out more research using this model and others, over the next few decades...
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