ASSESSMENT OF THE GENETIC TOXICITY OF LOW INTENSITY 248 nm AND 308 nm EXCIMER LASER IRRADIATION

Abstract

The potential genetic toxicity of ultraviolet (UV) laser energy was examined using excimer lasers at wavelengths of 248 nm (UVC, krypton fluoride laser) and 308 nm (UVB, xenon chloride laser) with an incident energy per pulse of 1 mJ per unit area of 25 cm2 (0.04 J/cm2). Dosage was controlled by the number of pulses delivered. The Ames screening test for potential carcinogenesis was applied to the specimens irradiated with both wavelengths, in addition to any induced chromosome aberrations in peripheral human lymphocytes. The Ames test and examination of irradiated chromosomes indicated that the 248 nm beam was capable of attacking DNA and had carcinogenic potential with genetic toxicity. The 308 nm beam on the other hand appeared to have no adverse effects on DNA and had no genetic toxicity potential at the parameters of the present study. It can therefore be concluded that cells have high wavelength specificity as far as the action potential of incident UV energy is concerned, which will have obvious implications on choice of laser wavelengths in the UV waveband.