Protection against ultraviolet and visible radiation used in medical therapy

There is an increasing number of applications for UV and visible radiation in medical therapy and diagnosis, and in areas related to cosmetology. All these applications pose risks of unwanted exposure of the staff executing the treatment and the patients. A new survey in Norwegian hospitals accounting for the status of radiation protection in phototherapy will be presented. The survey concludes that the occupational dose limits recommended by ICNIRP are not exceeded under normal use of UV therapy in departments of dermatology. The selection of spectra and patient doses are mostly based on experience as well as on information from the suppliers of equipment, who also normally deliver the radiometers used for dose control. The quality of the equipment used for blue-light phototherapy of newborns has improved since 1992. Compared to the previous survey, more suitable light sources are used, and the irradiance of the equipment is higher today than 12 years ago. A standard for phototherapy of newborns (IEC 60601-2-50, Medical electrical equipment-Part 2-50) is poorly known among the hospital departments. Particularly is the required dosimetry seldom performed and the permitted UV content of the therapy lamps is not routinely assayed (an effective UV irradiance of 10 -5 mW/cm is the limit). Blue light may cause photochemical damage to various organs. The eyes of the patients are routinely protected in order to avoid blue light-induced photochemical damage to the retina. Photodynamic treatment (PDT) of cancer and other diseases is performed by combining a photosensitizer and intense red or infrared radiation. Little is known about the potential side effects of the various sensitizers, but eyes and skin have been identified as critical organs. Standardized light regimens do not exist at the moment except for recommendations from the manufacturers of photosensitizers and light sources.