> Maybe a wearable ultrasound instead?
If one is concerned about the potentially damaging effects of radiation, and the relative safety of ultrasound technology springs to mind, then one may be also interested in reading more about the apparently forbidden topic of ultrasound safety studies, if such a person can get past the cognitive dissonance from having been told the consensus opinion on how safe ultrasound is, e.g.:
https://www.amazon.com/Studies-Conducted-Indicate-Prenatal-U...
https://www.westonaprice.org/book-reviews/50-human-studies-j...
http://whale.to/c/50_human_studies.html
https://harvoa.substack.com/p/dbr
The jury may still be out?
All of those links are for the same book from 2015 (the fourth isn't direct to the relevant article but it's easy to find on the page). Has there been any new information since then?
I personally prefer to approach the topic of "safety" by considering the trade-offs. The knowledge gained through ultrasound significantly outweighs potential risks associated with it.
People still continue to play the lotto thinking they will win, and they reject statistically low risks in lieu of a greater risk created by avoidance. See: any vaccination topic.
When shifting into the topic of a wearable though, the extreme amount of time alone amplifies the risks into outright dangerous levels. I did not seriously believe ultrasound to be safe to that level.