MRI maps heat from cellphone radiation in jarred cow brains
Plastic containers of cow brains could help further a consensus on cellphone radiation and brain tumors – with an imaging technique that shows what happens to radiation when absorbed by the brain. IEEE Spectrum reports.
Cellphone radiofrequency energy absorbed by brain tissue is converted into heat. Now, scientists have used nuclear magnetic resonance (NMR) -- the technology behind MRI -- to create high-resolution 3-D images of the heat when absorbed by cow brain tissue and a brain-like gel.
The method could be refined for measurements of human brains in vivo (while the brain is still in your head, that is).
“For the brain, you need a noninvasive technology. Nothing should penetrate the tissue,” says study researcher David Gultekin from Weill Cornell Medical College. “NMR has that capability. It provides a 3-D temperature field with very high spatial and temporal resolution, and it can cover the whole head in less than 10 seconds.”
Since regular cellular handsets can’t be used in the strong magnetic fields generated by MRI systems, the researchers developed an RF-emitting antenna, and they placed sample containers with the antenna next to them in an MRI machine:
- They turned the antenna on for 12 minutes each at output powers of 125, 250, 500, 1000, and 2000 milliwatts -- mimicking the range of typical cellphone outputs from average to peak power.
- At 500 mW, 1 watt, and 2W, the temperature of the sample area closest to the antenna went up by 1, 3.5, and more than 5 degrees C, respectively. These increases showed up as hot spots in the 3-D images generated by the MRI machine.
- At 125 and 250 mW, the temperature changes were less than 1 °C and don’t appear in the images.
The work was published in the Proceedings of the National Academy of Sciences last week.
[Via IEEE Spectrum]
Image: Cushing Center / J. Fang