Human exposure to naturally occurring radionuclides in the environment varies depending on daily activities and location with regard to natural radioactive sources [1]. Studies conducted in municipalities of the metropolitan region of Recife verified the presence of radionuclides, such as radon, in food, soil, atmosphere, and water from wells in these locations [2, 3]. However, there is still a need to carry out a human biomonitoring study on the population living in this region. Therefore, it is necessary to verify the suitability of biodosimetric techniques, which aim to assess the frequency of damage caused by ionizing radiation to the body, measuring, when possible, the level of exposure to which they were subjected [4, 5]. Given the above, this work aims to evaluate in vitro the suitability of different biodosimetric techniques to be applied in regions of NORM occurrence with proven existence of radon gas (Rn²²²) and to verify whether it is possible to establish a dose-response correlation between biological damage to DNA and low concentrations of Rn²²² activity. In this work, two biodosimetric techniques were evaluated, Dicentric Chromosome Technique and Micronucleus Technique, and a genotoxicity technique, Comet Assay [6, 7]. The work proposed the in vitro exposure of peripheral human blood samples to Rn²²² gas at four different activity concentrations, namely 93.3, 66.1, 26.0 and 19.4 KBq/m³, and a group of unexposed control samples. The samples were processed and the lymphocytes obtained were evaluated for each of the techniques, namely metaphases for the dicentric technique, binucleated cells (BN) for the micronucleus technique, and individual mononucleated cells for the comet assay. In the dicentric technique, there was a significant increase (p < 0.05) in dicentric frequency in the irradiated samples compared to the control. However, although there was an absolute increase in this frequency among the exposed groups, which was proportional to the concentrations used, it was not statistically significant (p > 0.05). An overdispersion was also observed by Poisson's u ratio (u < 1.96) at the activity concentration of 93.3KBq/m³. For the micronucleus technique, there was also a statistical difference between the irradiated samples and the control samples (p < 0.05) but not between the groups of irradiated samples, which remained on average at 35 MN/ 3000 BN. An expected overdispersion was observed due to cellular distribution, with cells with up to 3 MN being recorded. The comet assay proved the genotoxic effect of radon on the cells, since they showed a reduced number of nucleoids at level 0 and the occurrence of damage comets 3 and 4 in the irradiated samples, demonstrating greater DNA fragmentation in these groups compared to the control group. The damage index analysis revealed a statistical difference in genotoxicity between exposed and control groups. However, no statistical difference was found when comparing the exposed groups. The three techniques evaluated are suitable for demonstrating radiation exposure and differentiating between exposed and unexposed samples, potentially useful in screening exposed individuals. However, the dicentric technique showed higher sensitivity and increased changes with higher concentrations, making it promising for assessing exposure levels and serving as a basis for future studies.