(a)[6]
Explain the key principles of using ultrasound to collect diagnostic information about internal body structures.
(b)[2]
State and explain one advantage of high frequency ultrasound over low frequency ultrasound for medical diagnosis.
(c(i))[3]
The absorption (attenuation) coefficient for ultrasound in muscle is $23\,\text{m}^{-1}$. A parallel beam of ultrasound is sent through a muscle of thickness $6.4\,\text{cm}$. Calculate the ratio $$\frac{\text{intensity of transmitted beam}}{\text{intensity of incident beam}}.$
(c(ii))[2]
An ultrasound transmitter sends out a pulse. Suggest why, when the pulse signal is processed, any signal received later at the detector is usually amplified more than one received earlier.