Page 84 - An Introduction to Laser Tattoo Removal

Chapter 2 – Fundamentals of Laser Tattoo Removal v1.0
Spot diameter
Spot size is pretty obvious! The spot size is the area over which the light energy is deposited on the skin surface. It is an area and is measured in mm2 or cm2. However, what is not so obvious is that the effective treatment spot size may be smaller than you imagine.
Figure 39: Laser Spot Size – how do you measure this?
Most lasers use a lensing system to focus the beam at the point of interaction (usually the skin surface). In the vast majority of cases these spots tend to be roughly circular. By doing so we are able to concentrate the light energy into the desired spot areas. This is very important as you will see in the section describing energy density/fluence. Some laser systems will use a ‘spacer’ device attached to the handpiece. This usually indicates the best position to locate the skin surface relative to the beam aperture.
Figure 40: On the left - three handpiece tips used with typical Chinese table-top lasers. On the right – a spot diameter adjustable handpiece tip, typically used in larger, floor-mounted lasers.
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Chapter 2 LEVEL A Laser Tattoo Removal
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