1. Give reasons why non-invasive techniques are needed for diagnosis. Describe the properties of ultrasound

2. © Pearson Education Ltd 2009 This document may have been altered from the original The arrangement of components in an endoscope and a cross-section view of the tube

3. Describe the piezoelectric effect. Explain how ultrasound transducers can both transmit and receive high- frequency sound. Describe the principles of ultrasound scanning and explain why a gel is required.

4. A crystal with a p.d. across it contracts by a very small amount and the same crystal forced to contract by ultrasound induces a p.d. across the crystal.

5. The structure of an ultrasound transducer

6. (a)A graph showing how the intensity of the transmitted ultrasound wave varies with time, and (b)the corresponding reflected wave.

7. Describe the difference between A-scan and B-scan. Calculate acoustic impedance. Calculate the fraction of intensity reflected. Explain why impedance matching is important.

8. At a boundary, part of the initial intensity is transmitted, and part is reflected.

9. A transducer is sending out ultrasound pulses