Due to new technological possibilities to sense and visualize processes at a nanoscale, a new experimental field of bionanophysics has developed. One of its directions deals with nanodosimetry. Since the primary targets of interaction of radiation with biological tissue are DNA and other biomolecular structures which have nanoscale dimensions, it is important to have a sensor of corresponding nanovolume. One approach offers to use a thin film dosimeter, which consists of nanodots embedded in a solid thin film matrix. The nanodots are supposed to be a radiation-sensitive substance. This experimental research studies the effects of ultraviolet radiation on zirconia films doped with PbS nanodots (ZrO2:PbS films). The films were fabricated using sol-gel technique. ZrO2:PbS films were irradiated with UV light with wavelengths 250 – 400 nm during 50 minutes. Photoelectron emission from the surface of the films was studied and band structure of the films was calculated. It was found that quantity of localized states decreased after UV irradiation while density of localized states was dependent on concentration of PbS nanodots. The observed changes in band structure of ZrO2:PbS films after UV irradiation allow to suggest that the films may be considered as an effective material for UV radiation dosimetry, PbS nanodots being the UV sensitive substance of such a dosimeter.