Re: cellphones (L3)

[Bemmzim]

In a message dated 6/20/2002 5:26:26 AM Eastern Standard Time, [EMAIL PROTECTED] writes:

> Why is power unimportant?  Are you suggesting that people could be
harmed
> by picowatts of power at just the right frequency?

Resonance.  It's what brought down that famous suspension bridge.

MR scanning utilizes the sensitivity of magnitized hydrogen protons to produce medical images.

When placed in  strong magnetic field protons can be excited by electro-magnetic radiation within a relatively narrow range. The actual energy of the    EM is relatively low (when we put our first MR scanner at the hospital in 1983 the rf   frequency used was the same as that used to broadcast papal radio. This was one  of the first superconducting magnets in the country with a powerful field strength of .3T. Our newest magnet is 3T (one of the first in the country for clinical use)and 7 and 8T magnets are being built for research. With these ultra-high field systems SAR (Specific Absorption Rates) become important. You really can get a bit cooked in these scanners but cancer; I don't think so.