[Chromosome mutagenicity of a 193 nm Excimer laser]

Considering the fundamental role somatic mutations play in carcinogenesis, inducing mutations by any form of therapy should be avoided as far as possible. The mutagenicity of UV irradiation in the wavelength range of 248 to 310 nm is well established. The data on shorter wavelengths, e.g. 193 nm, however, are so far not clear-cut. Therefore, the potential chromosome-damaging effect of a 193 nm excimer laser was examined in the present study. Cultures of primary human fibroblasts and the Chinese hamster cell line CHO were the object of examinations. The in situ preparation technique used allowed detection of a locally limited clastogenic (chromosome damaging) effect in the neighborhood of the irradiated area. A slight increase in the frequency of chromosome aberrations could be observed in the area close to the laser-exposed field, which was attributed to the fluorescence generated by the laser under the given experimental conditions. Quantitative comparison with the data obtained from experiments with 254 nm irradiation from a UV lamp or exposure to 248 nm excimer laser-pulse irradiation, however, made the former activity appear somewhat insignificant. If one considers the practical aspects of the new laser surgery, the chromosome-damaging effect of the 193 nm pulse laser seems to be negligible.