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However, it is not as simple as this might indicate. The problem is that higher fluences will also induce more potential tissue damage in the dermis. This appears to be even more of an issue following my recent research on these interactions. Up to 90% of all the laser energy we throw into tattooed skin may well be reflected back from the tattoo due to very rapid steam bubble formation, which essentially acts like a mirror. This reflected energy will undoubtedly cause damage to the collagen.
So using higher fluences for poorly absorbing inks might not be a good answer. It may create more problems in the surrounding tissues.
Summary
The Scheibner and Choi reports give us a better understanding of the effects of laser energy in tattoo inks. They also indicate how strongly those coloured inks absorb those wavelengths. Extrapolating from their data we can see, approximately, the ratios of absorptions and how they compare. The physics of these interactions tells us that poor absorbers merely need more energy (fluence) to achieve the same reactions as strong absorbers.
But, the clinical application of higher fluences is fraught with danger – if you do choose to apply higher fluences, be very careful and use lots of cooling post-treatment to extract as much thermal energy as possible.
Huh?!?!
Finally – an interesting point - Choi stated that they believe that the reactions are more dependent on the wavelength than the pulse duration. They state that “wavelength is more influential than pulse duration for the removal of each coloured ink. Regardless of the pulse duration, the 532nm laser was the most effective in clearing red, orange and yellow coloured inks and was mildly effective in removing green and black coloured inks.”
It appears that the Q-switched, nano-second 532nm pulses were very useful...
Hope this helps, Mike.
You can find a lot more information about laser tattoo removal in our book:
https://thelaserguysblog.wordpress.com/our-book/
Mike’s Blog Posts 135