Real-time photothermal imaging and response in pulsed dye laser treatment for port wine stain patients.

BACKGROUND This study was performed to assess the photothermal response of highly focused laser energy using infrared thermal imaging instrument to detect and assess the actual temperature distribution during flash lamp pumped pulsed dye laser (FLPPDL) treatment for port wine stain (PWS) patients and avoiding its complications. METHODS A retrospective review of 40 patients with PWS birthmark treated with FLPPDL (l = 585 nm, tp = 1500 ms, 7 mm spot) was conducted over a 2-year period. Subjects' ages ranged between 28 and 46 years (mean 29 years); there were 24 females and 16 males. Twenty patients received non-cooling laser treatment (NC-LT) using light dosages of 5-12 J/cm 2 . Another 20 patients received cryogen spray cooling laser treatment (CSC-LT) using light dosages of 5-12 J/cm 2 . A real-time infrared thermal imaging and the thermal wave equation were used for assessment. The results of temperature distributions related to the energy change were analyzed. RESULTS Proper temperature measurement using infrared thermal imaging instrument and thermal wave equation in non-cooled PWS patients showed that the energy density of pulsed dye laser (PDL) higher than 7 J/cm 2 can reach >44°C and result in burn injury. However, when energy densities beyond 10 J/cm 2 were administered, along with using CSC, thermal damage was could still be minimized without the risk of damage to the treated area. CONCLUSION Using infrared thermal imaging instrument and thermal wave equation, we can predict the skin temperature distribution in FLPPDL for PWS patients during the treatment. In conjunction with CSC, the complications can be minimized.