MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING potx

Medical Science Series MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING B H Brown, R H Smallwood, D C Barber, P V Lawford and D R Hose Department of Medical Physics and Clinical Engineering, University of Sheffield and Central Sheffield University Hospitals, Sheffield, UK Institute of Physics Publishing Bristol and Philadelphia Copyright © 1999 IOP Publishing Ltd © IOP Publishing Ltd 1999 All 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, photocopying, recording or otherwise, without the prior permission of the publisher. Multiple copying is permitted in accordance with the terms of licences issued by the Copyright Licensing Agency under the terms of its agreement with the Committee of Vice-Chancellors and Principals. Institute of Physics Publishing and the authors have made every possible attempt to find and contact the original copyright holders for any illustrations adapted or reproduced in whole in the work. We apologize to copyright holders if permission to publish in this book has not been obtained. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN 0 7503 0367 0 (hbk) ISBN 0 7503 0368 9 (pbk) Library of Congress Cataloging-in-Publication Data are available Consultant Editor: J G Webster, University of Wisconsin-Madison, USA Series Editors: C G Orton, Karmanos Cancer Institute and Wayne State University, Detroit, USA J A E Spaan, University of Amsterdam, The Netherlands J G Webster, University of Wisconsin-Madison, USA Published by Institute of Physics Publishing, wholly owned by The Institute of Physics, London Institute of Physics Publishing, Dirac House, Temple Back, Bristol BS1 6BE, UK US Office: Institute of Physics Publishing, The Public Ledger Building, Suite 1035, 150 South Independence Mall West, Philadelphia, PA 19106, USA Typeset in L A T E X using the IOP Bookmaker Macros Printed in the UK by Bookcraft Ltd, Bath Copyright © 1999 IOP Publishing Ltd TheMedicalScienceSeriesistheofficialbookseriesoftheInternationalFederationforMedicaland BiologicalEngineering(IFMBE)andtheInternationalOrganizationforMedicalPhysics(IOMP). IFMBE TheIFMBEwasestablishedin1959toprovidemedicalandbiologicalengineeringwithaninternational presence.TheFederationhasalonghistoryofencouragingandpromotinginternationalcooperationand collaborationintheuseoftechnologyforimprovingthehealthandlifequalityofman. TheIFMBEisanorganizationthatismostlyanaffiliationofnationalsocieties.Transnationalorganiza- tionscanalsoobtainmembership.Atpresentthereare42nationalmembers,andonetransnationalmember withatotalmembershipinexcessof15000.Anobservercategoryisprovidedtogivepersonalstatusto groupsororganizationsconsideringformalaffiliation. Objectives •Toreflecttheinterestsandinitiativesoftheaffiliatedorganizations. •Togenerateanddisseminateinformationofinteresttothemedicalandbiologicalengineeringcommunity andinternationalorganizations. •Toprovideaninternationalforumfortheexchangeofideasandconcepts. •Toencourageandfosterresearchandapplicationofmedicalandbiologicalengineeringknowledgeand techniquesinsupportoflifequalityandcost-effectivehealthcare. •Tostimulateinternationalcooperationandcollaborationonmedicalandbiologicalengineeringmatters. •Toencourageeducationalprogrammeswhichdevelopscientificandtechnicalexpertiseinmedicaland biologicalengineering. Activities TheIFMBEhaspublishedthejournalMedicalandBiologicalEngineeringandComputingforover34years. AnewjournalCellularEngineeringwasestablishedin1996inordertostimulatethisemergingfieldin biomedicalengineering.InIFMBENewsmembersarekeptinformedofthedevelopmentsintheFederation. ClinicalEngineeringUpdateisapublicationofourdivisionofClinicalEngineering.TheFederationalso hasadivisionforTechnologyAssessmentinHealthCare. Everythreeyears,theIFMBEholdsaWorldCongressonMedicalPhysicsandBiomedicalEngineering, organizedincooperationwiththeIOMPandtheIUPESM.Inaddition,annual,milestone,regionalconferences areorganizedindifferentregionsoftheworld,suchastheAsiaPacific,Baltic,Mediterranean,Africanand SouthAmericanregions. TheadministrativecounciloftheIFMBEmeetsonceortwiceayearandisthesteeringbodyforthe IFMBE.ThecouncilissubjecttotherulingsoftheGeneralAssemblywhichmeetseverythreeyears. ForfurtherinformationontheactivitiesoftheIFMBE,pleasecontactJosAESpaan,ProfessorofMedical Physics,AcademicMedicalCentre,UniversityofAmsterdam,POBox22660,Meibergdreef9,1105AZ,Am- sterdam,TheNetherlands.Tel:31(0)205665200.Fax:31(0)206917233.E-mail:IFMBE@amc.uva.nl. WWW:http://vub.vub.ac.be/∼ifmbe. IOMP The IOMP was founded in 1963. The membership includes 64 national societies, two international organiza- tions and 12 000 individuals. Membership of IOMP consists of individual members of the Adhering National Organizations. Two other forms of membership are available, namely Affiliated Regional Organization and Corporate Members. The IOMP is administered by a Council, which consists of delegates from each of the Adhering National Organization; regular meetings of Council are held every three years at the International Copyright © 1999 IOP Publishing Ltd Conference on Medical Physics (ICMP). The Officers of the Council are the President, the Vice-President and the Secretary-General. IOMP committees include: developing countries, education and training; nominating; and publications. Objectives •To organize international cooperation in medical physics in all its aspects, especially in developing countries. • To encourage and advise on the formation of national organizations of medical physics in those countries which lack such organizations. Activities Official publications of the IOMP are Physiological Measurement, Physics in Medicine and Biology and the Medical Science Series, all published by Institute of Physics Publishing. The IOMP publishes a bulletin Medical Physics World twice a year. Two Council meetings and one General Assembly are held every three years at the ICMP. The most recent ICMPs were held in Kyoto, Japan (1991), Rio de Janeiro, Brazil (1994) and Nice, France (1997). The next conference is scheduled for Chicago, USA (2000). These conferences are normally held in collaboration with the IFMBE to form the World Congress on Medical Physics and Biomedical Engineering. The IOMP also sponsors occasional international conferences, workshops and courses. For further information contact: Hans Svensson, PhD, DSc, Professor, Radiation Physics Department, University Hospital, 90185 Umeå, Sweden. Tel: (46) 90 785 3891. Fax: (46) 90 785 1588. E-mail: Hans.Svensson@radfys.umu.se. Copyright © 1999 IOP Publishing Ltd CONTENTS PREFACE PREFACETO‘MEDICALPHYSICSANDPHYSIOLOGICALMEASUREMENT’ NOTESTOREADERS ACKNOWLEDGMENTS 1BIOMECHANICS 1.1Introductionandobjectives 1.2Propertiesofmaterials 1.2.1Stress/strainrelationships:theconstitutiveequation 1.2.2Bone 1.2.3Tissue 1.2.4Viscoelasticity 1.3Theprinciplesofequilibrium 1.3.1Forces,momentsandcouples 1.3.2Equationsofstaticequilibrium 1.3.3Structuralidealizations 1.3.4Applicationsinbiomechanics 1.4Stressanalysis 1.4.1Tensionandcompression 1.4.2Bending 1.4.3Shearstressesandtorsion 1.5Structuralinstability 1.5.1Definitionofstructuralinstability 1.5.2Whereinstabilityoccurs 1.5.3Bucklingofcolumns:Eulertheory 1.5.4Compressivefailureofthelongbones 1.6Mechanicalworkandenergy 1.6.1Work,potentialenergy,kineticenergyandstrainenergy 1.6.2Applicationsoftheprincipleofconservationofenergy 1.7Kinematicsandkinetics 1.7.1Kinematicsoftheknee 1.7.2Walkingandrunning 1.8Dimensionalanalysis:thescalingprocessinbiomechanics 1.8.1Geometricsimilarityandanimalperformance 1.8.2Elasticsimilarity 1.9Problems 1.9.1Shortquestions Copyright © 1999 IOP Publishing Ltd 1.9.2Longerquestions 2BIOFLUIDMECHANICS 2.1Introductionandobjectives 2.2Pressuresinthebody 2.2.1Pressureinthecardiovascularsystem 2.2.2Hydrostaticpressure 2.2.3Bladderpressure 2.2.4Respiratorypressures 2.2.5Footpressures 2.2.6Eyeandearpressures 2.3Propertiesoffluidsinmotion:theconstitutiveequations 2.3.1Newtonianfluid 2.3.2Otherviscositymodels 2.3.3Rheologyofblood 2.3.4Virchow’striad,haemolysisandthrombosis 2.4Fundamentalsoffluiddynamics 2.4.1Thegoverningequations 2.4.2Classificationofflows 2.5Flowofviscousfluidsintubes 2.5.1Steadylaminarflow 2.5.2Turbulentandpulsatileflows 2.5.3Branchingtubes 2.6Flowthroughanorifice 2.6.1Steadyflow:Bernoulli’sequationandthecontinuityequation 2.7Influenceofelasticwalls 2.7.1Windkesseltheory 2.7.2Propagationofthepressurepulse:theMoens–Kortewegequation 2.8Numericalmethodsinbiofluidmechanics 2.8.1Thedifferentialequations 2.8.2Discretizationoftheequations:finitedifferenceversusfiniteelement 2.9Problems 2.9.1Shortquestions 2.9.2Longerquestions 3PHYSICSOFTHESENSES 3.1Introductionandobjectives 3.2Cutaneoussensation 3.2.1Mechanoreceptors 3.2.2Thermoreceptors 3.2.3Nociceptors 3.3Thechemicalsenses 3.3.1Gustation(taste) 3.3.2Olfaction(smell) 3.4Audition 3.4.1Physicsofsound 3.4.2Normalsoundlevels 3.4.3Anatomyandphysiologyoftheear 3.4.4Theoriesofhearing Copyright © 1999 IOP Publishing Ltd 3.4.5Measurementofhearing 3.5Vision 3.5.1Physicsoflight 3.5.2Anatomyandphysiologyoftheeye 3.5.3Intensityoflight 3.5.4Limitsofvision 3.5.5Colourvision 3.6Psychophysics 3.6.1WeberandFechnerlaws 3.6.2Powerlaw 3.7Problems 3.7.1Shortquestions 3.7.2Longerquestions 4BIOCOMPATIBILITYANDTISSUEDAMAGE 4.1Introductionandobjectives 4.1.1Basiccellstructure 4.2Biomaterialsandbiocompatibility 4.2.1Usesofbiomaterials 4.2.2Selectionofmaterials 4.2.3Typesofbiomaterialsandtheirproperties 4.3Materialresponsetothebiologicalenvironment 4.3.1Metals 4.3.2Polymersandceramics 4.4Tissueresponsetothebiomaterial 4.4.1Thelocaltissueresponse 4.4.2Immunologicaleffects 4.4.3Carcinogenicity 4.4.4Biomechanicalcompatibility 4.5Assessmentofbiocompatibility 4.5.1Invitromodels 4.5.2Invivomodelsandclinicaltrials 4.6Problems 4.6.1Shortquestions 4.6.2Longerquestions 5IONIZINGRADIATION:DOSEANDEXPOSURE—MEASUREMENTS,STANDARDSAND PROTECTION 5.1Introductionandobjectives 5.2Absorption,scatteringandattenuationofgamma-rays 5.2.1Photoelectricabsorption 5.2.2Comptoneffect 5.2.3Pairproduction 5.2.4Energyspectra 5.2.5Inversesquarelawattenuation 5.3Biologicaleffectsandprotectionfromthem Copyright © 1999 IOP Publishing Ltd 5.4Doseandexposuremeasurement 5.4.1Absorbeddose 5.4.2Doseequivalent 5.5Maximumpermissiblelevels 5.5.1Environmentaldose 5.5.2Whole-bodydose 5.5.3Organdose 5.6Measurementmethods 5.6.1Ionizationchambers 5.6.2G-Mcounters 5.6.3Scintillationcounters 5.6.4Filmdosimeters 5.6.5Thermoluminescentdosimetry(TLD) 5.7Practicalexperiment 5.7.1Dosemeasurementduringradiography 5.8Problems 5.8.1Shortquestions 5.8.2Longerquestions 6RADIOISOTOPESANDNUCLEARMEDICINE 6.1Introductionandobjectives 6.1.1Diagnosiswithradioisotopes 6.2Atomicstructure 6.2.1Isotopes 6.2.2Half-life 6.2.3Nuclearradiations 6.2.4Energyofnuclearradiations 6.3Productionofisotopes 6.3.1Naturallyoccurringradioactivity 6.3.2Man-madebackgroundradiation 6.3.3Inducedbackgroundradiation 6.3.4Neutronreactionsandman-maderadioisotopes 6.3.5Unitsofactivity 6.3.6Isotopegenerators 6.4Principlesofmeasurement 6.4.1Countingstatistics 6.4.2Samplecounting 6.4.3Liquidscintillationcounting 6.5Non-imaginginvestigation:principles 6.5.1Volumemeasurements:thedilutionprinciple 6.5.2Clearancemeasurements 6.5.3Surfacecounting 6.5.4Whole-bodycounting 6.6Non-imagingexamples 6.6.1Haematologicalmeasurements 6.6.2Glomerularfiltrationrate 6.7Radionuclideimaging 6.7.1Boneimaging Copyright © 1999 IOP Publishing Ltd 6.7.2Dynamicrenalfunction 6.7.3Myocardialperfusion 6.7.4Qualityassuranceforgammacameras 6.8Tableofapplications 6.9Problems 6.9.1Shortproblems 6.9.2Longerproblems 7ULTRASOUND 7.1Introductionandobjectives 7.2Wavefundamentals 7.3Generationofultrasound 7.3.1Radiationfromaplanecircularpiston 7.3.2Ultrasoundtransducers 7.4Interactionofultrasoundwithmaterials 7.4.1Reflectionandrefraction 7.4.2Absorptionandscattering 7.5Problems 7.5.1Shortquestions 7.5.2Longerquestions 8NON-IONIZINGELECTROMAGNETICRADIATION:TISSUEABSORPTIONANDSAFETY ISSUES 8.1Introductionandobjectives 8.2Tissueasaleakydielectric 8.3Relaxationprocesses 8.3.1Debyemodel 8.3.2Cole–Colemodel 8.4Overviewofnon-ionizingradiationeffects 8.5Low-frequencyeffects:0.1Hz–100kHz 8.5.1Propertiesoftissue 8.5.2Neuraleffects 8.5.3Cardiacstimulation:fibrillation 8.6Higherfrequencies:>100kHz 8.6.1Surgicaldiathermy/electrosurgery 8.6.2Heatingeffects 8.7Ultraviolet 8.8Electromedicalequipmentsafetystandards 8.8.1Physiologicaleffectsofelectricity 8.8.2Leakagecurrent 8.8.3Classificationofequipment 8.8.4Acceptanceandroutinetestingofequipment 8.9Practicalexperiments 8.9.1Themeasurementofearthleakagecurrent 8.9.2Measurementoftissueanisotropy 8.10Problems 8.10.1Shortquestions 8.10.2Longerquestions Copyright © 1999 IOP Publishing Ltd 9GAININGACCESSTOPHYSIOLOGICALSIGNALS 9.1Introductionandobjectives 9.2Electrodes 9.2.1Contactandpolarizationpotentials 9.2.2Electrodeequivalentcircuits 9.2.3Typesofelectrode 9.2.4Artefactsandfloatingelectrodes 9.2.5Referenceelectrodes 9.3Thermalnoiseandamplifiers 9.3.1Electricpotentialspresentwithinthebody 9.3.2Johnsonnoise 9.3.3Bioelectricamplifiers 9.4Biomagnetism 9.4.1Magneticfieldsproducedbycurrentflow 9.4.2Magnetocardiogram(MCG)signals 9.4.3Coildetectors 9.4.4Interferenceandgradiometers 9.4.5Othermagnetometers 9.5Transducers 9.5.1Temperaturetransducers 9.5.2Displacementtransducers 9.5.3Gas-sensitiveprobes 9.5.4pHelectrodes 9.6Problems 9.6.1Shortquestions 9.6.2Longerquestionsandassignments 10EVOKEDRESPONSES 10.1Testingsystemsbyevokingaresponse 10.1.1Testingalinearsystem 10.2Stimuli 10.2.1Nervestimulation 10.2.2Currentsandvoltages 10.2.3Auditoryandvisualstimuli 10.3Detectionofsmallsignals 10.3.1Bandwidthandsignal-to-noiseratios 10.3.2Choiceofamplifiers 10.3.3Differentialamplifiers 10.3.4Principleofaveraging 10.4Electricalinterference 10.4.1Electricfields 10.4.2Magneticfields 10.4.3Radio-frequencyfields 10.4.4Acceptablelevelsofinterference 10.4.5Screeningandinterferencereduction 10.5Applicationsandsignalinterpretation 10.5.1Nerveactionpotentials 10.5.2EEGevokedresponses Copyright © 1999 IOP Publishing Ltd [...]... material in both physics and engineering courses at Bachelor’s and Master’s degree levels At the postgraduate level the target reader is a new graduate in physics or engineering who is starting postgraduate studies in the application of these disciplines to healthcare The book is intended as a broad introductory text that will place the uses of physics and engineering in their medical, social and historical... material at a higher level, appropriate for postgraduates and for those entering a research programme in medical physics and biomedical engineering Some sections of the book do assume a degree level background in the mathematics needed in physics and engineering The introduction to each chapter describes the level of material to be presented and readers should use this in deciding which sections are... Miller who, during his years as Professor of Medical Physics in Sheffield until his retirement in 1975, and indeed since that time, gave both of us the enthusiasm for our subject without which our lives would be much less interesting Brian Brown and Rod Smallwood Sheffield, 1981 Copyright © 1999 IOP Publishing Ltd NOTES TO READERS Medical physics and biomedical engineering covers a very wide range of subjects,... graduates in physics and engineering as well as serving the needs of our technical staff Whilst this new book is based upon the earlier text, it has a much wider intended readership We have still included much of the practical information for technical staff but, in addition, a considerably greater depth of material is included for graduate students of both medical physics and biomedical engineering. .. enthusiasm for the subject without which this book would never have been written Brian Brown and Rod Smallwood Sheffield, 1998 Copyright © 1999 IOP Publishing Ltd PREFACE TO MEDICAL PHYSICS AND PHYSIOLOGICAL MEASUREMENT’ This book grew from a booklet which is used in the Sheffield Department of Medical Physics and Clinical Engineering for the training of our technical staff The intention behind our writing... descriptive, so that these parts should be accessible to medical students with an interest in the technological aspects of medicine The applications of physics and engineering in medicine have continued to expand both in number and complexity since 1981 and we have tried to increase our coverage accordingly The expansion in intended readership and subject coverage gave us a problem in terms of the size... source of inspiration and we have used some of his lecture material in Chapter 13 However, we start with a recognition of the encouragement given by Professor Martin Black Our thanks must also go to all our colleagues who tolerated our hours given to the book but lost to them Sheffield has for many years enjoyed joint University and Hospital activities in medical physics and biomedical engineering The result... used as part of Sheffield University courses in medical physics and biomedical engineering, we have included problems at the end of each chapter The intention of the short questions is that readers can test their understanding of the main principles of each chapter Longer questions are also given, but answers are only given to about half of them Both the short and longer questions should be useful to students... the very wide range of physiological measurement and treatment techniques which are often grouped under the umbrella title of medical physics and physiological measurement However, it is more fulfilling to treat a subject in depth rather than at a purely practical level and we have therefore included much of the background physics, electronics, anatomy and physiology which is necessary for the student... wide range of physiological measurement and treatment techniques which are often grouped under the umbrella titles of medical physics, clinical engineering and physiological measurement However, it was more fulfilling to treat a subject in a little depth rather than at a purely practical level so we included much of the background physics, electronics, anatomy and physiology relevant to the various procedures . Ltd PREFACE ThisbookisbaseduponMedicalPhysicsandPhysiologicalMeasurementwhichwewrotein1981.That bookhadgrowninturnoutofabookletwhichhadbeenusedintheSheffieldDepartmentofMedicalPhysics andClinicalEngineeringforthetrainingofourtechnicalstaff.Theintentionbehindourwritinghadbeen togivepracticalinformationwhichwouldenablethereadertocarryoutaverywiderangeofphysiological measurementandtreatmenttechniqueswhichareoftengroupedundertheumbrellatitlesofmedicalphysics, clinicalengineeringandphysiologicalmeasurement.However,itwasmorefulfillingtotreatasubjectina littledepthratherthanatapurelypracticallevelsoweincludedmuchofthebackgroundphysics,electronics, anatomyandphysiologyrelevanttothevariousprocedures.Ourhopewasthatthebookwouldserveasan introductorytexttograduatesinphysicsandengineeringaswellasservingtheneedsofourtechnicalstaff. Whilstthisnewbookisbasedupontheearliertext,ithasamuchwiderintendedreadership.Wehave stillincludedmuchofthepracticalinformationfortechnicalstaffbut,inaddition,aconsiderablygreaterdepth ofmaterialisincludedforgraduatestudentsofbothmedicalphysicsandbiomedicalengineering.AtSheffield weofferthismaterialinbothphysicsandengineeringcoursesatBachelor’sandMaster’sdegreelevels.Atthe postgraduatelevelthetargetreaderisanewgraduateinphysicsorengineeringwhoisstartingpostgraduate studiesintheapplicationofthesedisciplinestohealthcare.Thebookisintendedasabroadintroductory textthatwillplacetheusesofphysicsandengineeringintheirmedical,socialandhistoricalcontext.Much ofthetextisdescriptive,sothatthesepartsshouldbeaccessibletomedicalstudentswithaninterestinthe technologicalaspectsofmedicine.Theapplicationsofphysicsandengineeringinmedicinehavecontinued toexpandbothinnumberandcomplexitysince1981andwehavetriedtoincreaseourcoverageaccordingly. Theexpansioninintendedreadershipandsubjectcoveragegaveusaproblemintermsofthesizeofthe book.Asaresultwedecidedtoomitsomeoftheintroductorymaterialfromtheearlierbook.Wenolonger includethebasicelectronics,andsomeoftheanatomyandphysiology,aswellasthebasicstatistics,have beenremoved.Itseemedtousthattherearenowmanyothertextsavailabletostudentsintheseareas,sowe havesimplyincludedtherelevantreferences. Therangeoftopicswecoverisverywideandwecouldnothopetowritewithauthorityonallofthem. Wehavepickedbrainsasrequired,butwehavealsoexpandedthenumberofauthorstofive.RodandIvery muchthankRodHose,PatLawfordandDavidBarberwhohavejoinedusasco-authorsofthenewbook. Wehavereceivedhelpfrommanypeople,manyofwhomwereacknowledgedintheprefacetothe originalbook(seepagexxiii).NowaddedtothatlistareJohnConway,LisaWilliams,AdrianWilson, ChristineSegasby,JohnFennerandTonyTrowbridge.Tonydiedin1997,buthewasasourceofinspiration andwehaveusedsomeofhislecturematerialinChapter13.However,westartwitharecognitionofthe encouragement. Medical Science Series MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING B H Brown, R H Smallwood, D C Barber, P V Lawford and D R Hose Department of Medical