Photodamage in deep tissue two-photon optical biopsy of human skin

J Biophotonics. 2015 Oct;8(10):816-25. doi: 10.1002/jbio.201400083. Epub 2014 Dec 18.


Photodamage, induced by femtosecond laser radiation, was studied in thick samples of human skin tissue (healthy skin and neoplastic lesions). Photobleaching, photoionization, and thermomechanical damage effects were characterized comparatively. The laser power dependence of the damage rates allowed to connect macroscopic effects to underlying molecular processes. Optical effects were correlated to histopathological changes. Tissue alterations were found only from thermomechanical cavitation and limited to superficial layers of the epidermis. From the depth-dependencies of all damage thresholds a depth-dependent power-compensation scheme was defined allowing for damage-free deep tissue optical biopsy. Damage-induced luminescence pattern for different excitation powers and a corresponding threshold analysis.

Keywords: biomedical imaging; multiphoton processes; nonlinear microscopy; photodamage; skin imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomechanical Phenomena / radiation effects
  • Biopsy / adverse effects
  • Humans
  • Molecular Imaging
  • Optical Phenomena*
  • Photobleaching
  • Photons / adverse effects*
  • Skin / metabolism
  • Skin / pathology*
  • Skin / radiation effects*
  • Temperature