An Exposure System for Long-Term and Large-Scale Animal Bioassay of 1.5-GHz Digital Cellular Phones

We developed an exposure system for an animal bioassay to evaluate possible health effects by the exposure with 1.5-GHz-band personal digital cellular system used in Japanese telecommunications. For large-scale and long-term study, i.e., 500 rats were employed for two years, the exposure system was designed to simultaneously expose 100 rats and to easily maintain. The specific absorption rate (SAR) inside the rat was evaluated with numerical simulation using anatomical rat models and was validated by comparing it with experimental dosimetry using phantom models. Variation and uncertainty of the SAR in the rat for each exposure was also statistically investigated using logged data, which had been acquired in the exposure system during the animal bioassay. We confirmed that the desired exposure (a SAR averaged over a brain of 2 W/kg for the high-dose group and 0.67 W/kg for the low-dose group and a SAR average over a whole body of less than 0.4 W/kg) had been fairly achieved during the exposure period of two years. A relatively large variation of the SAR was found in the male high-dose group