This is absolutely my question as well - curious if it's legal to do this, I'm guessing yes as it's an existing ultrasound device? But is there possibility of permanent damage?
It's objectively cool, but very curious about the safety as well.
This is the coolest part! Turns out, the powers you need are actually lower than what is used for imaging babies :) We measured our probe with a hydrophone on a computer-controlled scanner to get the pressure field, and made sure that it's below diagnostic levels (the generally accepted mechanical index limit is 1.9 and ours was 0.4 peak). We also made sure to avoid the eyes and keep thermals in check.
That's reassuring, but not entirely reassuring. Fetuses are a bit further from the emitter. You're focusing the pressure waves, but what about peripheral pressure waves disrupting the brain?
What would make it illegal to do this? Generally anything which hasn't been invented yet is legal, it's rare (but not impossible) for something to be banned before it exists.
9. Does FDA require IRB review and approval of off-label use of a legally marketed device?
...(unrelated for this conversation)...
Yes, when the off-label use of a legally marketed device is part of a research study collecting safety and effectiveness data involving human subjects, IRB review and approval is required (21 CFR 812.2(a)). For additional information on the off-label use of devices, see the FDA Information Sheet guidance, “ ‘Off-label’ and Investigational Use of Marketed Drugs, Biologics and Medical Devices.”
It's objectively cool, but very curious about the safety as well.