Totally agree regarding not extrapolating to 10 MHz.

I had went down a huge rabbit hole to find the source for the 22 dB/cm/MHz paper that everyone quoted. People reference the Diagnostic Ultrasound textbook; that textbook references an old nondigital ultrasound reference book, which finally references a Fry paper from 1977 [1].

It's funny because the Fry paper never explicitly mentions the number 22 dB/cm/MHz. But there was one figure (Figure 12), where if you fit a line through the data in that figure, you get a slope of 23.5 dB/cm/MHz.

Here's a spreadsheet of me fitting the data: https://docs.google.com/spreadsheets/d/1a70svm-zrzp1SQT5v2m_...

But yes, you're totally right that even the Fry paper Figure 12 was only up to 2 MHz, so it's totally not fair to extrapolate to 10 MHz.

[1] https://pubmed.ncbi.nlm.nih.gov/690336/