Laser transmission through transparent membranes used in cutaneous laser treatment

Background. Some clinicians perform cutaneous laser treatments through tran sparent membranes to protect themselves and the surroundings from contamina tion by ejected tissue particles. Transmissibility of these membranes influ ences the tissue irradiance. Objective: We compared the optical transmissibility of 8 membranes. Methods: In part 1, a Schwartz Electro-Optics Q-switched alexandrite laser (wavelength of 720-800 nm, beam diameter of 3 mm) was directed through 8 me mbranes. A Molectron JD 2000 Joulemeter Ratiometer obtained measurements of percent loss of laser energy (for calculation of percent transmission) thr ough each. To evaluate other wavelengths used in skin treatment, an SLM Ami nco UV-VIS model 2000 spectrophotometer measured variance of transmission o ver a spectral region from 350 to 900 nm in 4 of the membranes. Results: The samples listed in order of increasing amounts of light energy lost across the membrane as compared with control (direct irradiation) were as follows: (1) Handi Wrap plastic wrap: 7% loss, 93% transmission; (2) gl ass slide: 8% loss; (3) Bioclusive transparent dressing: 11% loss; (4) Tega derm transparent dressing: 26% loss; (5) Vigilon dressing without plastic b acking: 34% loss; (6) Vigilon dressing with one layer of plastic backing: 3 7% loss; (7) Acuderm dressing: 41% loss; and (8) OpSite IV 48% loss. Conclusions: Transmissibility of the interposed membranes must be considere d when determining the dosimetry of light energy required by the tat-get ti ssue.