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The key is knowing exactly where to aim. While the MRI machine took readings, Elias ran a test at a low intensity to see if he could gently heat up the spot on Doby’s thalamus he was targeting. Satisfied with the result, he then proceeded to blast an area millimeters wide with 6,000 joules of focused sound energy for a few seconds. A graph on his monitor showed the temperature jumping to about 60C (140F). Everything around it stayed at a normal 37C. Other than a brief sensation of heat inside his head, Doby said he didn’t feel a thing. Elias repeated the process three more times, checking the tremor after each. By the fourth, it was gone.Leaving it at "knowing where to aim" is severely underselling the problem, because then the next step is how to aim.
Back in 2003 when I still studied physics I attended a talk back by a Dutch biomedical researcher who worked on shock wave lithotripsy - a procedure where ultrasound is used to break kidney stones. So same idea as this, except kidney stone
So what he pointed out was that the human body is not a medium of uniform density, so the way the sound waves propagate is hard to calculate.
Worse, the human body tends to move, even when the patient is under anesthetics. Even if you sedate someone enough to lie perfectly still, the heartbeat means blood vessels grow and shrink, breathing causes miniscule motions that can throw off the ultrasound beams.
Maybe this is specific to kidney stones though, maybe kidneys are just a lot more "floppy" organs and maybe kidney stones move a lot. Maybe the brain is a lot more "stable" in the skull. And I suppose the method of destruction is different (kidney stones need to be shattered by ultrasound waves, whereas this method uses heat), so that might also be an influence.
I'm not being critical of this technology btw, just trying to point out that the engineering problems involved are likely a lot more interesting than that this article is suggesting.
[0] https://en.wikipedia.org/wiki/Lithotripsy
Leaving it at "knowing where to aim" is severely underselling the problem, because then the next step is how to aim.
Back in 2003 when I still studied physics I attended a talk back by a Dutch biomedical researcher who worked on shock wave lithotripsy - a procedure where ultrasound is used to break kidney stones. So same idea as this, except kidney stone
So what he pointed out was that the human body is not a medium of uniform density, so the way the sound waves propagate is hard to calculate.
Worse, the human body tends to move, even when the patient is under anesthetics. Even if you sedate someone enough to lie perfectly still, the heartbeat means blood vessels grow and shrink, breathing causes miniscule motions that can throw off the ultrasound beams.
Maybe this is specific to kidney stones though, maybe kidneys are just a lot more "floppy" organs and maybe kidney stones move a lot. Maybe the brain is a lot more "stable" in the skull. And I suppose the method of destruction is different (kidney stones need to be shattered by ultrasound waves, whereas this method uses heat), so that might also be an influence.
I'm not being critical of this technology btw, just trying to point out that the engineering problems involved are likely a lot more interesting than that this article is suggesting.
[0] https://en.wikipedia.org/wiki/Lithotripsy