title: TRASER: acute phase vascular and follicular changes.
abstract: OBJECTIVE
  A TRASER (Total Reflection Amplification of Spontaneous Emission of Radiation) is a novel device that utilizes the energy from a flashlamp to induce the spontaneous emission of photons from a fluorescent medium. This study was designed to observe clinical and histological changes of skin treated with two different fluorescent media selected for their peak emissions tuned for vascular and hair follicle targets.
  
  
  METHODS
  A purpuric clinical response for the vascular target was assessed with a TRASER using the fluorescent medium Pyrromethene 556 producing a narrow spectrum peaking at 544 nm. Using a 12 mm spot and pulse duration of 1 ms, treatment pulses with fluences of 6.0-9.5 J/cm2 were given along the forearm of subject with photo type II skin. Follicular structures were targeted with the dye cell switched to Sulforhodamine 640 Chloride, producing a narrow peak at 654 nm. Using a 12 mm spot, single 20 ms pulses with fluencies from 14.0 to 20.0 J/cm2 were delivered with 5 °C contact cooling to the shaved chest of a subject with photo type II skin with brown hair. Clinical observations were photographed and assessed by two physicians. A 4 mm punch skin biopsy was taken at approximately 60 and 30 minutes respectively for both the vascular and hair regions. The paraffin embedded H&E stained vertical sections were analyzed by a dermatopathologist.
  
  
  RESULTS
  A characteristic threshold purpuric response was noted at 7.2 J/cm2 . The histological changes consistently showed intravascular thrombosis of the small sub-dermal plexus of capillaries down to larger vessels approaching the subcutaneous fat. There were no extravasated red blood cells. Clinical hair follicle target changes of perifollicular edema and transient erythema, similar to those described with standard hair removal lasers, were noted. Histologically these were shown to be limited to the target structures.
  
  
  CONCLUSIONS
  This is the first demonstration of clinical and histological acute phase changes associated with use of a TRASER with wavelengths optimized for vascular and follicular targets. The findings of this observational study support the notion that the TRASER can be used as an effective vascular and hair removal device.
authors.affiliation: Department of Dermatology, University of California Irvine, Irvine, California.
authors.forename: Katharine
authors.initials: K
authors.lastname: Ball
authors.forename: Morgan
authors.initials: M
authors.lastname: Gustavsson
authors.forename: Ronald
authors.initials: R
authors.lastname: Harris
authors.forename: Leo
authors.initials: L
authors.lastname: Berganza
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Zachary
mesh_terms: D001706:Biopsy; D001808:Blood Vessels / Q000473:pathology / Q000528:radiation effects*; D004487:Edema / Q000209:etiology; D004890:Erythema / Q000209:etiology; D005456:Fluorescent Dyes / Q000627:therapeutic use; D005542:Forearm; D018859:Hair Follicle / Q000473:pathology / Q000528:radiation effects*; D006204:Hair Removal / Q000009:adverse effects / Q000295:instrumentation*; D006801:Humans; D007834:Lasers / Q000009:adverse effects; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000627:therapeutic use; D011693:Purpura / Q000209:etiology; D013909:Thorax
chemical_list: D005456:Fluorescent Dyes; C504196:pyrromethene 546; D011162:Porphobilinogen
keywords: TRASER; hair removal; histology; vascular lesion