The biological effects of microwaves on living organisms remain highly controversial. Although some reports have suggested that microwaves may be directly or indirectly genotoxic, a direct action is unlikely because the low energy of microwave photons makes them unable to cause single-strand breaks in DNA. In this work, we examined the possible clastogenic properties of microwaves (2.5 and 10.5 GHz) on blood lymphocytes in vitro by monitoring the frequency of chromosomal aberrations. We also investigated whether blood cells showed increased radiosensitivity or radioresistance when pretreated with the microwaves and then irradiated with gamma radiation. There was no significant difference in the frequency of chromosomal aberrations between cells which had or had not been treated with microwaves. Control cells had a mean frequency of 0.013 aberrations per cell compared to 0.010 and 0.011 aberrations per cell in the microwave-exposed samples. Nor was there any alteration in the radiosensitivity of cells pretreated with microwaves. Gamma irradiated cells showed a mean frequency of 0.279 aberrations per cell compared to 0.343 and 0.310 aberrations per cell in samples pretreated with microwaves. However, cell mortality increased markedly after exposure to microwaves. The results suggest that microwaves do not interact directly or indirectly with chromosomes, although they may target other cell structures, such as cell membranes.

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An approach for half-life determination using gamma spectrometry with Ge detector is presented. This measurement reduces the contribution of the type B component on the total uncertainty. The independence of the method with respect to the instrumental interferences or radiochemical impurities was evidenced. The method shows no limitations for the measurements of samples containing a genetically related impurity of concentrations below than 3% with the same energy or very close to the one of the radionuclide to be measured, e.g., 99 Mo in a 99mTc sample. The results of half-lives are in good agreement with the literature and the associated uncertainties lower than 0.1 %.