Page 249 - Blog Posts v1

They made their choice of a pulsewidth of one TRT based on minimising the heat transfer to adjacent tissues. They DID NOT consider the heat energy required to actually denature the target tissue. Their original calculations were based on achieving some desired temperature in the target tissue, sufficient to irreversibly denature that tissue's proteins.
However, the flaw in their argument was that they did not consider the time necessary to achieve irreversible denaturation. We all know that if we try to boil an egg then it must go into a pot of boiling water for around three minutes or so. If the egg is removed at two minutes then it will be too runny!
The first egg (above) was removed too early - hence its runny, undercooked consistency. The second egg was removed after 3.5 minutes - my personal favourite. The last egg shows the best way to enjoy boiled eggs - with soldiers....
A longer cooking time (pulsewidth) will denature more of the egg's proteins, for the same temperature.
Exactly the same happens with laser treatments of vessels and hair follicles. Applying the heat energy for too short a time will result in partial denaturation of the target's proteins - this may lead to insufficient damage and, hence, regrowth of that tissue. This explains why some treatments end up with poor results - usually due to a low energy input or short pulsewidths.
Heat Conduction from a Vessel or Follicle
Imagine a 'hot' blood vessel or hair follicle in the dermis, following the absorption of some laser energy. Within that absorbing volume the absorbed energy will generate a rise in local temperature. That temperature rise is dependent on the absorption coefficient and the mass of the absorbing volume, which, in turn, is dependent on the physical size of the absorbing volume.
Hence, the temperature rise is dependent on the square of the radius of the vessel/follicle (since the volume depends likewise).
Mike’s Blog Posts 249