SBIR-STTR Award

Laser treatment of vascular skin lesions, such as port wine stains, has been attempted with a myriad of laser systems. Early therapeutic efforts resulted in unacceptable scarring that was attributed to unselective heating of tissue. Understanding the mechanisms of laser-tissue interactions lead to the clinical application of pulsed lasers which selectively target the vasculature and leave the surrounding tissue thermally unaffected. Despite these advancements, the optimum laser pulse duration has yet to be investigated. Modeling predicts that a pulse width of several milliseconds would be ideal. Flashlamp-pumped dye lasers (pulse width = 0.4 ms) create pulses which are short to avoid bruising, or purpura, and are localized to the Irradiated spot. Purpura is a result of vessel disruption and is not a desired clinical or cosmetic endpoint. Continuous wave lasers (exposure time > 30 ms) result in scarring due to overheating the vessel. We will develop a solid state laser capable of generating pulses between the range of one and ten milliseconds. This laser is a modification of a surgical laser we currently manufactured. As part of this study, the laser's effectiveness at coagulating vessels in an animal model will be compared to that of the flashlamp-pumped system.Awardee's statement of the potential commercial applications of the research:This application will produce a Family of Dermatology Laser Products: 1. KTP Laser at 532 nm, pulsed from I to 20 ms with synchronous scanner 2. same Laser, with tunable dye laser from 570 to 630 nm added, and 3. family of scanners with above Lasers for various applications.National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)

Vascular skin lesions have been treated with pulsed dye lasers with pulses as long as 0.5 milliseconds, and mechanically gated continuous lasers with pulses as short as 30 ms. Until recently, the pulsewidth range from 0.5 ms to 30 ms has not been explored. For the Phase I work of the project, Laserscope developed a KTP laser at 532 nm (green) that was pulsed from 1 to >30 ms, and very encouraging animal studies were conducted at Wellman Labs, MGH, showing that this pulsewidth range may be very important to treat vascular lesions, as was previously predicted from theoretical modeling. For Phase II of this project, this KTP laser will be used in clinical evaluation for portwine stains and telangiectasia. A dye laser will be added to this KTP laser to give millisecond pulses tunable from 520 to 630 um. Animal studies and clinical evaluation will follow at Wellman labs for treatment of vascular lesions with this tunable laser. The output of this laser is also Q-switched and can produce pulses at 532 nm with a pulsewidth of 150 ns, as well as pulses at 1064 nm with about 50 ns pulsewidth. These micropulses will be used to treat pigmented lesions and possible tattoos. A mechanical scanner will also be developed to enable very uniform treatment of vascular as well as pigmented lesions. If successful, a single laser will then be able to treat vascular and pigmented lesions as well as tattoos.Proposed Commercial Applications:Family of Dermatology Laser Products from Laserscope:1. Pulsed KTP Laser (532 nm), 1 to 20 ms, with scanner for vascular lesion.2. Same laser, with tunable dye laser from 570 to 630 nm added.3. Same laser, with features to treat pigmented lesions and tattoos added.4. Family of scanners with above lasers.