http://www.sypris.com/stm/content.asp?page_id=667 Dave,
This is link that shows the F.W. Bell 6010 meter that we have at work. As I suspected, its frequency response is DC to 20kHz. I think that I would have to go along with WFO in this matter. I would suspect RF heating as the culprit. Having someone with a brain tumor AND one on the hip where a cellphone is carried is pretty compelling. The hip matter is particularly disturbing because you don't think of a phone as transmitting from there. There is always the concept of local oscillator leakage during reception. I never really tried to become an expert on cellphones so I don't know what kind of transmissions occur during on-hook (so to speak) operation.
Should she worry about EMF from her wiring? I doubt it. It probably doesn't cause heating like uW leakage does. Is she willing to use standard telephones with corded handsets and cellphones only in emergencies? Anyway, a spectrum analyzer with a broadband antenna might be better used to track down emissions more harmful than the EMF from the wiring.
Dimmers do mess up the AM talk radio experience, especially at low brightness levels, because of the fast rise times, but I doubt they have ever caused a tumor. Hardening of the eardrum, maybe.
Joe