Page 109 - Chapter 3 - An Introduction to Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
The curves in Figure 54 show how the fluence behaves in the skin for three wavelengths, 532nm, 755nm and 1064nm; plus an ‘averaged’ data set representing the average of 755 and 1064nm data. The horizontal dotted line shows the fluence incident at the skin surface.
Figure 54 – Change of fluence with depth for three wavelengths, due to back-scattering
Back-scattering, combined with incoming photons increases the total fluence available in the region between the surface and a depth of around 1.4mm. As a consequence, any fluence applied at the skin surface will be increased in the top layer of the dermis – which may be beneficial in our treatments.
Conclusion
The importance of back-scattering has been overlooked in laser/IPL skin treatments. Yet, it is clear from the above, that is it very important since it can have a significant effect on the fluences in the skin.
Understanding these processes will help to make proper choices about fluence settings, and, therefore, lead to better clinical results.
________________________________________________________________________ 109 Chapter 3 Laser/IPL Hair Removal
© The Laser-IPL Guys, 2022
Relative fluence
2 50 2 40 2 30 2 20 2 10 2 00 1 90 1 80 1 70 1 60 1 50 1 40 1 30 1 20 1 10 1 00
90 80 70 60 50 40 30 20 10
7 55 nm Ave rage d 1064nm 5 32 nm
Fluence vs depth
Epid
ermi
D
ermi
s
s
Fluenc
e applied
at skin surface
Blood
Blood
Blood
plexus 2%
plexus
1%
plexus 0.5%
0.085 0.3 0
Skin surface
Basal layer
0.6 0.9
1.2 1.5 1.8 2.1
Depth into the skin (mm)
2.4 2.7 3.0