Biological effects of excimer laser radiation

Excimer laser radiation at 193 nm (ArF) and 308 nm (XeCl) is being used for medical applications. Because ultraviolet radiation is absorbed by DNA and causes cell killing, mutagenesis, and carcinogenesis, the effects of 193- and 308-nm excimer laser radiation on biological material have been studied. Radiation at 193 nm causes less cell killing than conventional 254 nm germicidal light per incident photon. Radiation at 193 nm showed very low potential for causing mutation because proteins absorb strongly at 193 nm, thereby reducing the photon flux reaching the nuclear DNA. In addition, the quantum yield of a cytotoxic and mutagenic photoproduct of DNA is lower for 193 nm than for 254 nm. Radiation at 308 nm is cytotoxic and mutagenic. Results of in vitro assays indicate that the relative ability of excimer laser radiation to cause DNA damage decreases in the order 248 nm>308 nm>193 nm