TE Enriched Sample (E)

Non-ionizing Medical Imaging 2 88 Chapter Exercise Multiple-choice Questions 1. Which of the following statements about the acoustic impedance of a medium is/are incorrect? (1) It depends on the density of the medium. (2) It depends on the sound speed in the medium. (3) It depends on the thickness of the medium. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 2. Given that the intensity reflection coefficient between fat and liver is 1%. Estimate the acoustic impedance of liver if the acoustic impedance of fat is 1.38 × 10 6 kg m −2 s −1 . A. 1.6 × 10 6 kg m −2 s −1 B. 1.7 × 10 6 kg m −2 s −1 C. 1.8 × 10 6 kg m −2 s −1 D. 1.9 × 10 6 kg m −2 s −1 3. Which of the following diagrams best illustrates how an ultrasound scan is carried out? A. B. ultrasound detector ultrasound detector C. D. ultrasound detector ultrasound detector (inside the body) 4. An acoustic shadow may sometimes be seen on an ultrasound image. Shown below is a photo of a salivary stone (pointed by the arrow) found around a salivary gland. An acoustic shadow appears beneath the salivary stone. Given that the transducer is located at the top of the photo. (2.2) A (2.2) Modified from DSE 2012 Q4.5 B (2.2) B (2.2) Which of the following statements about the shadow must be correct? (1) The acoustic impedance of the region in the shadow is very high. (2) Ultrasound of a very low intensity is transmitted into the shadow. (3) Most ultrasound is reflected by the front surface of the object that creates the shadow. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 5. The figure below shows an ultrasound image of a foetus of 12 weeks. Which of the following statements about the image is/are correct? (1) It is an A-scan image. (2) The brightest areas are regions where ultrasound is most attenuated. (3) The transducer is placed above the top of the image. A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only 6. Which of the following combinations best describes the frequencies of ultrasound used for medical imaging of the breast and the kidney? breast kidney A. 100 kHz 400 kHz B. 400 kHz 100 kHz C. 4 MHz 10 MHz D. 10 MHz 4 MHz 7. The refractive index of the cladding of an optical fibre is 1.46. It is known that the critical angle at the core–cladding boundary is 75.5°. What is the refractive index of the core? A. 1.41 B. 1.43 C. 1.51 D. 1.53 C (2.2) B (2.2) D (2.3) C DSE Level-up Companion For more chapter-end questions (mock DSE type), see Level-up Task 92B . Sample © United Prime Educational Publishing (HK) Limited, Pearson Education Asia Limited 2023 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publishers.