I don't think you mean radiation poisoning, which would be caused by ingesting radio-active particles. But you are right to be concerned about radiation damage to brains etc by the radio waves that a cell phone uses, which are particularly strong on 'talk'.
Fact is, I don't think anybody knows for sure. So far there has been no strong evidence of it made public. But if there were evidence, it may be suppressed because of the money involved, until it became too strong to be suppressed.
It is probably much safer to use a WIRED remote microphone/speaker in your ear - that's a good thing to do if you're concerned. Bluetooth remote may be unsafe also. Nobody knows.