Higher frequency ultrasound (3 MHz) will...

Higher frequency ultrasound (3 MHz) will...

• A. Be absorbed sooner
• B. Penetrate deeper
• C. Produce no heat
• D. Travel faster

Answer: (A)

Higher frequency ultrasound is attenuated more rapidly in tissue, so its energy is deposited over a shorter distance. The energy is absorbed more readily, meaning the ultrasound doesn’t travel as deep as a lower-frequency beam. The speed of sound in tissue is not determined by frequency, so travel speed doesn’t increase with frequency. Because the energy is absorbed, some heating occurs in the tissues, which tends to be greater with higher frequencies. So the correct idea is that a higher frequency beam will be absorbed sooner.

Higher frequency ultrasound is attenuated more rapidly in tissue, so its energy is deposited over a shorter distance. The energy is absorbed more readily, meaning the ultrasound doesn’t travel as deep as a lower-frequency beam. The speed of sound in tissue is not determined by frequency, so travel speed doesn’t increase with frequency. Because the energy is absorbed, some heating occurs in the tissues, which tends to be greater with higher frequencies. So the correct idea is that a higher frequency beam will be absorbed sooner.