a. Explain what is meant by acoustic impedance and outline its role in the use of ultrasound scans.
b. Brain tissue has a density of 1.04 × 10³ kg m⁻³ and ultrasound travels at 1.58 × 10³ m s⁻¹ through it. Calculate the acoustic impedance of brain tissue.
c. This is the trace formed on the screen of an oscilloscope when ultrasound is reflected from the front and rear surfaces of the head of a fetus. The time-base of the oscilloscope is set at 10 μs div⁻¹.

i. Explain why the second peak is lower than the fetus.
ii. Calculate the diameter of the head of the fetus.

Transcribed Image Text:

Figure 30.26