5 ms·

ultrasounds are done on people all the time, especially during pregnancy on relatively fragile fetuses. we'd likely know of any serious risks by now. ultrasound

ultrasounds are done on people all the time, especially during pregnancy on relatively fragile fetuses. we'd likely know of any serious risks by now. ultrasound is more akin to microscopic shaking than a mysterious flux of (highly potent) energy. also consider that the cov2 virus is particularly fragile, for instance, requiring the external support of water to remain intact. it's why you don't need masks in most common situations (just distance), because the virus disintegrates so easily. some viruses, on the other hand, can essentially hibernate and revive themselves once inside a host. those are the ones that would require enough excess energy that damage to other cells and organelles might be a genuine concern.

brodouevencode 6y ago
Great point. If you've never had an ultrasound, it's safe enough that the technician doing them (who may see dozens of patients in a day) isn't even wearing any shielding or protection.
- UncleOxidant 6y ago
  Ultrasound is highly directed. The practitioner isn't getting exposed to a significant amount of ultrasound energy.
  - brodouevencode 6y ago
    Good point, and a fair one. I would imagine though if there were any chance though they would have to be shielded.
  - InitialLastName 6y ago
    Not only is it highly directed, ultrasonic acoustical frequencies disperse very quickly in air. At 1MHz, the energy absorption in air is ~160dB/meter, so a person sitting at arm's length away from the emitter (even if it weren't highly directed) would receive ~6*10^-17 of the power (if that weren't far below any possible noise floor, which it is).
_Microft 6y ago
The proposed ultrasound frequencies are 10-100 times as high as the ones usually used for imaging purposes, so the conclusion that it must be harmless does not naturally follow.
- clairity 6y ago
  i haven't delved into the specifics here, but note that a higher frequency doesn't necessarily mean a higher flux of energy, so that conclusion doesn't necessarily follow either.
  - _Microft 6y ago
    It does not need a "higher flux of energy" to do damage. Exciting a system at its resonance frequency can increase the amplitude of its vibrations to the point that it gets damaged. This does not take lots of energy, it does not take large amplitudes, just periodic input of power at the right frequency. Knowing that a system is fine at one frequency does not say (that) much about other frequencies.
    - clairity 6y ago
      yes, resonance can be significant, but that still doesn't necessarily mean that the energies here are significant, nor that the frequencies applied are the right frequencies, and resonant enough, for damage. the underlying point is that unless we're capable of doing the relevant experiments ourselves, we need to trust that people in the field are cognizant enough to realize these obvious issues, test them, and report their findings. it's unlikely that lay people like us are going to find and gotcha the researchers in the field. that's not to say that, in aggregate, we can't give researchers ideas about what to be researching. that, we can--and should--do, via conversations like this.
      - deleted 6y ago
        [deleted]
      - _Microft 6y ago

brodouevencode 6y ago

Great point. If you've never had an ultrasound, it's safe enough that the technician doing them (who may see dozens of patients in a day) isn't even wearing any shielding or protection.

UncleOxidant 6y ago
Ultrasound is highly directed. The practitioner isn't getting exposed to a significant amount of ultrasound energy.
- brodouevencode 6y ago
  Good point, and a fair one. I would imagine though if there were any chance though they would have to be shielded.
- InitialLastName 6y ago
  Not only is it highly directed, ultrasonic acoustical frequencies disperse very quickly in air. At 1MHz, the energy absorption in air is ~160dB/meter, so a person sitting at arm's length away from the emitter (even if it weren't highly directed) would receive ~6*10^-17 of the power (if that weren't far below any possible noise floor, which it is).

_Microft 6y ago

The proposed ultrasound frequencies are 10-100 times as high as the ones usually used for imaging purposes, so the conclusion that it must be harmless does not naturally follow.

clairity 6y ago
i haven't delved into the specifics here, but note that a higher frequency doesn't necessarily mean a higher flux of energy, so that conclusion doesn't necessarily follow either.
- _Microft 6y ago
  It does not need a "higher flux of energy" to do damage. Exciting a system at its resonance frequency can increase the amplitude of its vibrations to the point that it gets damaged. This does not take lots of energy, it does not take large amplitudes, just periodic input of power at the right frequency. Knowing that a system is fine at one frequency does not say (that) much about other frequencies.
  - clairity 6y ago
    yes, resonance can be significant, but that still doesn't necessarily mean that the energies here are significant, nor that the frequencies applied are the right frequencies, and resonant enough, for damage. the underlying point is that unless we're capable of doing the relevant experiments ourselves, we need to trust that people in the field are cognizant enough to realize these obvious issues, test them, and report their findings. it's unlikely that lay people like us are going to find and gotcha the researchers in the field. that's not to say that, in aggregate, we can't give researchers ideas about what to be researching. that, we can--and should--do, via conversations like this.
    - deleted 6y ago
      [deleted]
    - _Microft 6y ago