Page 42 - An Introduction to Laser Tattoo Removal

Chapter 2 – Fundamentals of Laser Tattoo Removal v1.0
This process generates a raft of fibroblasts, macrophages and mast cells, which ‘attack’ the ink particles. The macrophages will attempt to remove the ink from the skin and deposit them in the lymph nodes around the body, where they remain until death.
However, the fibroblasts and mast cells do not remove the ink – they merely ‘engorge’ it and stay in the dermis. During this process, the ink particles are ‘collected’ and form aggregates or ‘clumps’ of ink within the dermis. Studies have shown that fibroblasts, in particular, are essentially fixed within the connective tissue of the dermis, which explains the longevity and resilience of tattoos.
When tattoo ink is introduced into the skin, it is essentially ‘pushed’ into the dermis using needles. These needles create small pockets of trauma in the skin with some disruption to the collagen matrix. As a result, the skin’s repair processes kick in and fix the damage caused by the tattooing.
Inevitably, this results in the creation of scar tissue around the damaged sites, which can be seen under a microscope (using biopsies).
So, a tattoo is actually a damaged piece of skin laden with ink particles.
The repair process can take months following the introduction of the ink. During this time any ink in the epidermis will slough off (flake away) from the surface. This reduces the ‘intensity’ of the tattoo and many owners will confirm this.
Figure 18: A fairly typical tattoo of an old flame...
If the tattoo artist has done their job properly, all of the ink should be in the dermis. (Lousy artists will push ink into the fatty tissue which results in a lousy tattoo!)
Each time a tattoo is hit with laser energy, some of that energy is absorbed by the ink particles which causes them to heat up. Most of this thermal energy is used in the subsequent photomechanical reaction. However, a small fraction of the thermal energy conducts from the ink as heat, raising the local temperatures significantly. This results in thermal damage in the collagen surrounding the ink particles which eventually induces scar formation, especially if too much energy has been applied.
This has been seen many times in histological examination of post-treatment tattoos. What this means, in reality, is that every laser treatment creates a little more scar tissue, EVERY TIME!
For this reason, we should always endeavour to minimise the total energy used in the treatments - i.e. only use sufficient energy to generate the desired response in the ink.
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Chapter 2 LEVEL A Laser Tattoo Removal
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