But he cautioned that the exposure levels and durations were far greater than what people typically encounter, and thus cannot “be compared directly to the exposure that humans experience.” Moreover, the rat study examined the effects of a radio frequency associated with an early generation of cellphone technology, one that fell out of routine use years ago. Any concerns arising from the study thus would seem to apply mainly to early adopters who used those bygone devices, not to users of current models.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.