TE Enriched Sample (E)

Non-ionizing Medical Imaging 2 78 C Endoscope The capability of guiding light by optical fibres implies the feasibility of transmitting images. This eventually becomes a useful application in medical imaging — endoscope . Structure In an endoscope, a large number of optical fibres are put together to form a bundle. There are two kinds of bundles in an endoscope: coherent and incoherent. The coherent fibre bundle is used to transmit images while the incoherent (also called non- coherent) one is used for illumination (guiding light). Apart from channels containing optical fibres, an endoscope usually contains two more channels. One is used to pass down tools such as forceps for cutting tissues. The other is used to pass down air or water for inflating and flushing organs, or cleaning the tip. When the endoscope is being used, the tube is inserted into the patient’s body. The front end is movable to allow the user to look around inside an organ. As the tube is flexible, such an endoscope is also called a flexible endoscope . Teaching notes Ss should be able to describe how a fibre optic endoscope works. Basic components of a fibre optic endoscope such as lighting, lens system (objective & eyepiece) and imaging system are required. ( MC: DSE 2022 Q4.2) In other words, the incoherent one is for sending light to the area under examination, and the coherent one is for sending reflected light back from that area. (See DSE 2014 Q4.4) endoscope 內窺鏡 coherent fibre bundle 相干光纖束 flexible endoscope 可彎式內窺鏡 Fig. 2.32 An endoscope control to remove body fluids movable section tip grasping forceps water/air control locking control to fix tip position tool channel magnifying eyepiece light for illumination tool channel (DSE 2022 Q4.2) 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.