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.
"Ultrasound frequencies in diagnostic radiology range from 2 MHz to approximately 15 MHz" https://radiopaedia.org/articles/ultrasound-frequencies?lang...
So 10-50 times as high, but yeah.
1: https://en.wikipedia.org/wiki/High-intensity_focused_ultraso...
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.
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.
I did not claim that the proposed method has to be harmful. I stated that ultrasound imaging gives little to no insight in what happens at frequencies that are an order of magnitude or two higher than that. The second reply was an attempt to do away with the misconception that "higher flux of energy" was necessary for damage.