Page 60 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
● However, what is not so obvious is that the effective treatment spot size may be smaller than you imagine.
 Figure 30: 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 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 31: Three handpiece tips used with typical Chinese table-top lasers.
● However, in some systems the end of the spacer is not the ‘best’ position to locate the skin (see diagram below). This may be due to the manufacturer designing the spacer wrongly (which we have seen in some systems!) or the wrong lens being placed in the handpiece.
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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