Chapter 12, Problem 79PP

For cranial ultrasound, why is it advantageous to use frequencies in the kHZ range rather than in the MHz range?

1. A.    The antinodes of the standing waves will be closer together at the lower frequencies than at the higher frequencies.
2. B.     There will be no standing waves at the lower frequencies.
3. C.     Cranial bones will attenuate the ultrasound more at the lower frequencies than at the higher frequencies.
4. D.    Cranial bones will attenuate the ultrasound less at the lower frequencies than at the higher frequencies.