Selective Photothermolysis Definition

A more precise form of laser hair and tattoo removal

Doctors performing laparoscopic surgery in operating theater. Credit: Caiaimage/Martin Barraud / Getty Images

Definition: Selective photothermolysis (fō'tō-thĕrm-ol'i-sis) is a precise microsurgery technique used to target tissue in a specific area. It matches the specific wavelength of light and heats the tissue and destroys it with a laser without affecting or damaging surrounding tissue. The targeted cells are destroyed by the absorption of light and transfer of energy.

Decreasing a lasers pulse time allows surgeons to provide short bursts of energy to the tissue.

The pulse limits peripheral damage yet creates enough power to affect the targeted area.

The target of the laser is determined by its color. For instance, when selective photothermolysis is used in laser tattoo removal, the laser targets specific colors. Different lasers, or different settings on the same laser, are then used to break up different colors of the ink of the tattoo.

Selective photothermolysis was first developed for the process of laser hair removal but has since been used in the treatment of the following conditions:

  • Enlarged sebaceous glands for the treatment of acne
  • Laser hair removal
  • Tattoo removal
  • Port wine stains
  • Warts
  • Spider veins

The light energy that is emitted by the laser is absorbed by the molecules responsible for its color. For hair removal, the molecules would be melanin. For port wine stains, the molecules would be hemoglobin. The laser’s wavelength and the length of its pulse will determine the effectiveness of treatment.

Selective photothermolysis is the reason why a pale-skinned patient with a black tattoo will achieve better and fastest results. The laser breaks down the dark ink leaving the pale skin around it intact. It also explains why ink colors which are closer to skin colors, such as brown, yellow, or pink, are more challenging to remove.

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