title: Dose response of combination photorejuvenation using intense pulsed light-activated photodynamic therapy and radiofrequency energy.
abstract: OBJECTIVE
  To report the results of a dose-response study using a novel photorejuvenation regimen consisting of intense pulsed light-activated photodynamic therapy and radiofrequency energy in patients with Fitzpatrick skin types I through III.
  
  
  METHODS
  A combination intense pulsed light and radiofrequency device (Syneron Medical Ltd, Yokneam, Israel) was used in combination with the topical photosensitizer aminolevulinic acid (ALA) (Levulan Kerastick; DUSA Pharmaceuticals Inc, Wilmington, Mass). Duplicate titration trials were performed on the dorsal forearm skin of 3 patients with Fitzpatrick skin types I through III. Multiple treatments, with varying times of application of ALA (30 minutes and 1, 2, and 3 hours) and intense pulsed light fluence (24-30 J/cm(2)), were completed to determine a minimal erythema dose and a maximal tolerated dose based on epidermal reaction (erythema and crusting) and patient discomfort. Radiofrequency energy levels were constant in all treatment groups.
  
  
  RESULTS
  The ALA application time of 1 to 2 hours for all skin types and fluence levels of 26 to 28 and 24 to 26 J/cm(2) for Fitzpatrick skin types I/II and III, respectively, were determined to be the minimal erythema dose. The ALA application times of 2 to 3 hours and fluence levels of 28 to 30 and 26 to 28 J/cm(2) for skin types I/II and III, respectively, were determined to be the maximal tolerated dose and resulted in severe erythema and crusting. The presence of severe erythema and discomfort precluded longer ALA exposure and higher fluence levels. No epithelial breakdown was observed at any treatment levels.
  
  
  CONCLUSIONS
  The dose-response results defining the minimal erythema dose and the maximal tolerated dose of intense pulsed light-activated photodynamic therapy and radiofrequency energy have led to the development of 2 photorejuvenation protocols based on skin type and severity of photodamage.
authors.affiliation: Division of Facial Plastic and Reconstructive Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hall
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Keller
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Keller
mesh_terms: D003357:Cosmetic Techniques; D004307:Dose-Response Relationship, Radiation; D004598:Electrosurgery; D006801:Humans; D010778:Photochemotherapy; D012060:Rejuvenation; D015595:Skin Aging