[IshKebab]

> My understanding is that sound with a frequency greater than about 150Khz dissipates after passing through 5cms of air; it must dissipate faster in flesh.

Flesh is basically water. Water transmits sound extremely well.

Ultrasonic imaging typically uses frequencies in the low MHz. Like 1-10 MHz.

[denton-scratch]

> Ultrasonic imaging typically uses frequencies in the low MHz. Like 1-10 MHz.

Oh, thank you! So the dissipation is low (because it's water), and the theoretical resolution is 500x greater than my ignorant estimate. I now consider myself better-informed.

[Edit] Now I guess I'm off to see if I can find out what a MHz-grade ultrasound transducer looks like...

[enslavedrobot]

All I know is they charge a lot for them. Ultrasound imaging at home would be amazing, but the transducers are hella expensive.

[IshKebab]

You can actually get quite cheap ones now. They make integrated scanners that work with a phone app. Easily under £1k second hand. Maybe close to that new if you shop around.

I wouldn't recommend it though. The only reason we use ultrasound imaging is because it's cheap, easy and completely harmless. As an actual imaging method it's terrible. There's so much speckle you can barely see anything, except in some situations like pregnancy where you have a convenient bag of water around the thing you're looking it.

There's a reason ultrasonographers are well paid - it's really really hard to read an ultrasound.