The Safe Use of Ultrasound in Medical Diagnosis 3Rd Edition Edited by Gail Ter Haar

The Safe Use of Ultrasound in Medical Diagnosis 3rd Edition Edited by Gail ter Haar We should like to acknowledge the support of the British Medical Ultrasound Society, the European Federation of Societies for Ultrasound in Medicine and Biology, and the National Physical Laboratory (UK). Without their generosity this revision would not have been possible. The British Institute of Radiology 36 Portland Place, London W1B 1AT, UK www.bir.org.uk Published in the United Kingdom by The British Institute of Radiology © 1991 The British Institute of Radiology © 2000 The British Medical Ultrasound Society & The British Institute of Radiology © 2012 The Authors This book is licensed under a Creative Commons Attribution-NonCommercial- NoDerivs 3.0 Unported License Some rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical or photocopying, recording, or otherwise for commercial purposes, or altered, transformed, or built upon, without the prior written permission of the British Institute of Radiology First published 1991 (978-0-905749-28-0) Second edition 2000 (978-0-905749-42-6) Third edition 2012 (978-0-905749-78-5) British Library Cataloguing-in Publication data A cataloguing in record of the publication is available from the British Library ISBN 978-0-905749-78-5 (print) ISBN 978-0-905749-79-2 (eBook) A print version of this book can be purchased from the BIR website The British Institute of Radiology has no responsibility for the persistence or accuracy of URLs for external or third- party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate All opinions expressed in this publication are those of the respective authors and not the publishers. The publishers have taken the utmost care to ensure that the information and data contained in this publication are as accurate as possible at the time of going to press. Nevertheless the publishers cannot accept any responsibility for errors, omissions or misrepresentations howsoever caused. All liability for loss, disappointment or damage caused by reliance on the information contained in this publication or the negligence of the publishers is hereby excluded Contents Contributors iv Preface v Chapter 1 Introduction 1 Gail ter Haar Chapter 2 The propagation of ultrasound through tissue 4 Francis A. Duck Chapter 3 The acoustic output of diagnostic ultrasound scanners 18 Adam Shaw and Kevin Martin Chapter 4 Ultrasound-induced heating and its biological consequences 46 Charles C. Church and Stanley B. Barnett Chapter 5 Non-thermal effects of diagnostic ultrasound 69 J. Brian Fowlkes Chapter 6 Radiation force and its possible biological effects 81 Hazel C. Starritt Chapter 7 Bio-effects—cells and tissues 91 Gail ter Haar Chapter 8 The safe use of contrast-enhanced diagnostic ultrasound 105 Douglas L. Miller Chapter 9 Epidemiological prenatal ultrasound studies 125 Kjell Å. Salvesen Chapter 10 Safety standards and regulations: the manufacturers’ 134 responsibilities Francis A. Duck Chapter 11 Guidelines and recommendations for the safe use of diagnostic 142 ultrasound: the user’s responsibilities Gail ter Haar Glossary 159 Index 163 iii Contributors Dr Stanley B. Barnett, MSc, PhD 11/147 Darley St. West, Mona Vale, NSW 2103, Australia E-mail: [email protected] Dr Charles C. Church, MSc, PhD National Center for Physical Acoustics, University of Mississippi, MS 38655, USA E-mail: [email protected] Professor Francis A. Duck, PhD, DSc 3 Evelyn Rd, Bath BA1 3QF, UK E-mail: [email protected] Professor J. Brian Fowlkes, PhD Department of Radiology, University of Michigan, Medical Science I, 1301 Catherine, Room 3226C, Ann Arbor, MI 48109-5667, USA Department of Biomedical Engineering, University of Michigan, 3315 Kresge Research Building III, 204 Zina Pitcher Place, Ann Arbor, MI 48109-0552, USA E-mail: [email protected] Dr Kevin Martin, BSc, PhD, FIPEM Department of Medical Physics, University Hospitals of Leicester, Inﬁ rmary Square, Leicester LE1 5WW, UK E-mail: [email protected] Dr Douglas L. Miller, PhD Basic Radiological Sciences Division, Department of Radiology, University of Michigan SPC 5667, 3240A Medical Science Building I, 1301 Catherine Street, Ann Arbor, MI 48109, USA E-mail: [email protected] Dr Kjell Å. Salvesen, MD, PhD Department of Obstetrics and Gynaecology, Clinical Sciences, Lund University, Box 117, SE-221 00 Lund, Sweden E-mail: [email protected] Mr Adam Shaw, BA, MA (Cantab) Acoustics and Ionizing Radiation Division, National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK E-mail: [email protected] Dr Hazel C. Starritt, PhD Medical Physics and Bioengineering, Royal United Hospital, Combe Park, Bath BA1 3NG, UK E-mail: [email protected] Dr Gail ter Haar, MA, PhD, DSc Institute of Cancer Research, 15 Cotswold Road, Belmont, Sutton SM2 5NG, UK E-mail: [email protected] iv The Safe Use of Ultrasound in Medical Diagnosis Preface It is an oft observed fact that safety sessions at congresses are seldom well attended, and that the sneaky insertion of a lecture on a safety-related topic into a specialist session may be regarded by some as the opportunity for a coffee break, but the fact remains that the safe use of diagnostic ultrasound is the responsibility of the person conducting the scan. In order for appropriate judgements to be made, the practitioner must be knowledgeable about the hazards and risks involved in performing an ultrasound examination, and this book aims to provide this basic knowledge. Leading world experts in the fields of ultrasound physics, biology, standards and epidemiology have contributed chapters, written at a level that is intended to be accessible to everyone, whatever their background. Each chapter is extensively referenced to allow readers to delve deeper into a topic of interest if they so wish. Ultrasound has an unprecedented safety record, but that does not mean that we can be cavalier about its use. What is evident from the information presented in this book is that there are many gaps in our knowledge about ultrasound safety. Many of the studies on which we base our information and recommendations have been carried out in animal models whose relevance to the human is not fully understood, ultrasound exposure conditions which have little relevance to diagnostic ultrasound pulses, or on scanners that are no longer in common clinical use. While this is useful information, it must always be interpreted with care. It must be remembered that “absence of evidence of harm is not the same as absence of harm” (Salvesen et al., 2011). It is never possible to prove a negative, all we can do is to use increasingly more sensitive tests and assays. It is for these reasons that professional societies continue to support committees whose remit is to inform and educate users about the safe of ultrasound, so that ultrasound imaging can continue to enjoy its reputation as a technique whose benefits far outweigh any potential risk. The publication of the third edition of this book would not have been possible without the generous support of the British Medical Ultrasound Society, European Federation of Societies for Medical Ultrasound and the National Physical Laboratories to whom I am extremely grateful. Gail ter Haar London, November 2012 Reference Salvesen KÅ, Lees C, Abramowicz J, Brezinka C, ter Haar G, Maršál K. 2011. Safe use of Doppler ultrasound during the 11 to 13 + 6-week scan: is it possible? Ultrasound Obstet Gynecol, 37, 625–628. v The Safe Use of Ultrasound in Medical Diagnosis Chapter 1 Introduction Gail ter Haar Institute of Cancer Research, Sutton, UK The decision by the British Medical Ultrasound Society (BMUS), the European Federation of Societies for Ultrasound in Medicine & Biology (EFSUMB) and the UK National Physical Laboratory (NPL) to sponsor the revision of this publication on the topic of the safety of diagnostic ultrasound in medical practice at this time is entirely appropriate. In England alone, over two and a half million obstetric ultrasound scans (about four for every live birth) are performed every year (Department of Health, 2012). Many of these are carried out using the new generations of ultrasound scanners, which have the potential to produce significantly higher acoustic outputs than their predecessors (see Chapter 3). Ultrasound imaging has become more sophisticated and new techniques such as tissue harmonic imaging, pulse coding and contrast-enhanced imaging are becoming more common, bringing with them not only increased diagnostic capabilities, but also uncharted waters as far as safety considerations are concerned. This is not unusual; we have a track record of safety studies lagging behind clinical applications—there are, for example, no epidemiological studies concerned with the use of pulsed Doppler techniques. This state of affairs is not to be condoned, and there is now considerable effort being put into understanding the way in which an ultrasonic beam interacts with tissue in terms of its heating potential, and the probability of inducing mechanical effects such as acoustic cavitation, so that there is more chance of predicting and preventing the occurrence of an unwanted bio-effect. During the early 1990s a change was made by the Food and Drug Administration (FDA) in the USA that has affected all those using ultrasound for medical diagnosis. Output levels had been set in the 1980s simply on the basis that such conditions had been in use before, with no evidence of hazard. The change allowed intensities previously reserved only for peripheral vascular studies to be used for all studies, including first- trimester scanning. No epidemiological or other evidence was then, or is now, available to support the assertion of safety at these higher exposures. The FDA change resulted in the widespread availability of high specification pulsed Doppler and Doppler imaging modes for uses in addition to cardiovascular applications, including obstetrics.

Load more