Specific absorption rates induced in head tissues by microwave radiation from cell phones

The wireless telephone industry is concerned about how the public may use the SARs, because, according to one industry source, "SARs by themselves may be misleading and variations in SARs do not represent a variation in safety." Indeed, SAR values can vary as a function of carrier frequency (for example, 850 or 1,900 MHz, used to transmit the telephone message) or how the handset is held. The author gives some insights into SAR, what it is, how is it determined, and what it means.