TE Enriched Sample (E)

Summary 87 Keywords A-scan A 掃描 acoustic impedance 聲阻抗 attenuation 衰減 axial resolution 軸向分辨率 B-scan B 掃描 coherent fibre bundle 相干光纖管束 coupling gel 耦合凝膠 endoscope 內窺鏡 endoscopy 內窺鏡檢查 flexible endoscope 可彎式內窺鏡 intensity reflection coefficient 反射聲強係數 lateral resolution 橫向分辨率 optical fibre 光纖 piezoelectric effect 壓電效應 pulse-echo technique 脈衝回聲測距術 resolution 分辨率 transducer 換能器 ultrasound 超聲波 ultrasound scan 超聲波掃描 Common Mistakes • Ö fewer waves are reflected P is bright Ö more waves are reflected Q is dark Ö more waves must have been absorbed P Q B-scan image A dark area in a B-scan image represents the area that reflects a smaller amount of ultrasound waves. This area does not necessarily absorb more waves. (DSE 2012 Q4.4) • higher resolution, brighter image higher resolution, but brightness depends on cross section two bundles of optical fibre The brightness of an image as seen through an optical fibre bundle depends on the total cross-sectional area of the fibre. A higher fibre density does not ensure a brighter image. (DSE 2013 Q4.3) 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.