Page 54 - Chapter 3 - Fundamentals of Laser/IPL Hair Removal
P. 54
Spot size
Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
Figure 20 – Scattering in the skin - anisotropy
Again, more on this topic can be found in Chapter 1.
Spot size is pretty obvious! It is usually the diameter of the spot of light energy when applied to the skin surface. Combined with the applied energy, it determines the fluence – which is critical in achieving good clinical results.
However, the spot size changes as soon as the light hits the skin due to scattering. This causes the beam to expand as the light penetrates deeper into the skin, resulting in a loss of fluence. But, just to confuse things, the back-scattered fluence ‘combines’ with the forward-scattering fluence and adds up (see Chapter 1 for a detailed description on this subject).
________________________________________________________________________ 54 Chapter 3 Laser/IPL Hair Removal
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