Review of Basic PhysicsELECTROSTATICS1.The addition or removal of electrons is called

electrification.2.Likechargesrepel;unlikechargesattract.3.Coulomb’slawofelectrostaticforce:

R4 R3

R1 R2

R1 R2 R3 R4

*v,Initialvelocity;v′,Finalvelocity.

4.Onlynegativechargescanmoveinsolids.5.Electrostaticchargeisdistributedontheoutersurface

ofconductors.6.The concentration of charge is greater when the

radiusofcurvatureissmaller.

ELECTRODYNAMICSOhm’sLaw:V=IRAseriescircuit:

1.Vt=V1+V2+V3+V4

2.Iisthesamethroughallelements.3.Rt=R1+R2+R3+R4

Aparallelcircuit:

1.Visthesameacrosseachcircuitelement.2.It=I1+I2+I3+I4

3. 1 1 1 1 11 2 3 4R R R R Rt = + + +

Electricpower:P=IV=I 2 R[(A)(V)=W]Work:Work=QV[(C)(V)=J]Potential:V=W/Q[J/C=V]Capacitance:C=Q/V[C/V=F]

MAGNETISM1.Everymagnethasanorthpoleandasouthpole.2.Likepolesrepel;unlikepolesattract.3.Gauss’slaw:

ELECROMAGNETISM1.Amagneticfieldisalwayspresentaroundaconduc-

torinwhichacurrentisflowing.2.Changing magnetic fields can produce an electric

field.3.Transformerlaw:

CLASSICAL PHYSICSLinearforce:F=ma[(kg)(m/s2)=N]Momentum:p=mv[(kg)(m/s)]Mechanicalwork(orenergy):Work(orE)=Fs[(N)(m)=J]Kineticenergy:E= 1

2 mv2[(kg)(m2/s2)=J]Mechanicalpower:P=Fs/t[(N)(m)/s=J/s=W]ConservationofmomentumbetweenAandBfn1*:

m v m v m v m vA A B A A A B B+ = ′ = ′

ConservationofkineticenergybetweenAandBfn1*:

12

2 12

2 12

2 12

2m v m v m v m vA A B B A A B B( ) ( ) ( ) ( )+ = ′ = ′

F cQ Q

dA B=

2

F kM M

d= 1 2

2

VV

NN

P

S

P

S

=

Useful Units in Radiology SIPrefixes

Factor Prefix Symbol

1018 Exa E1015 Peta P1012 Tera T109 Giga G106 Mega M103 Kilo k102 Hecto h101 Deca da10−1 Deci d10−2 Centi c10−3 Milli m10−6 Micro µ10−9 Nano n10−12 Pico p10−15 Femto f10−18 Atto a

SIBaseUnits

Quantity Name Symbol

Length Meter mMass Kilogram kgTime Second sElectric current Ampere A

SIDerivedUnitsExpressedinTermsofBaseUnits

SI UNIT

Quantity Name Symbol

Area Square meter m2

Volume Cubic meter m3

Speed, velocity Meter per second m/sAcceleration Meter per second squared m/s2

Density, mass density Kilogram per cubic meter kg/m3

Current density Ampere per square meter A/m2

Concentration (of amount of substance) Mole per cubic meter Mole/m3

Specific volume Cubic meter per kilogram m3/kg

SpecialQuantitiesofRadiologicScienceandTheirAssociatedSpecialUnits

CUSTOMARY UNIT SI UNIT

Quantity Name Symbol Name Symbol

Exposure roentgen R air kerma Gya

Absorbed dose rad rad gray Gy1

Effective dose rem rem sievert SvRadioactivity curie Ci becquerel BqMultiply R by 0.01 to obtain Gya

Multiply rad Gy by 0.01 to obtain Gyt

Multiply rem by 0.01 to obtain SvMultiply Ci by 3.73 × 1010 to obtain BqMultiply R by 2.583 × 10−4 to obtain C/kg

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2015v1.0

Radiologic Science

for TechnologistsPhysics, Biology, and Protection

Eleventh Edition

This page intentionally left blank

Stewart Carlyle Bushong, ScD, FAAPM, FACR

Professor of Radiologic ScienceBaylor College of MedicineHouston, Texas

Radiologic Science

Physics, Biology, and Protection

for Technologists

Eleventh Edition

3251 Riverport LaneSt. Louis, Missouri 63043

RADIOLOGIC SCIENCE FOR TECHNOLOGISTS: PHYSICS, BIOLOGY, AND PROTECTION, ELEVENTH EDITION

ISBN: 978-0-323-35377-9

Copyright © 2017 by Elsevier, Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions.

This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

Previous editions copyrighted 2013, 2008, 2004, 2001, 1997, 1993, 1988, 1984, 1980, and 1975.

Library of Congress Cataloging-in-Publication Data

Names: Bushong, Stewart C., author.Title: Radiologic science for technologists : physics, biology, and protection / Stewart Carlyle Bushong.Description: Eleventh edition. | St. Louis, Missouri : Elsevier, [2017] | Includes bibliographical

references and index.Identifiers: LCCN 2016034345 | ISBN 9780323353779 (hardcover : alk. paper)Subjects: | MESH: Technology, Radiologic | Radiation Protection | Radiography—methodsClassification: LCC R895 | NLM WN 160 | DDC 616.07/57—dc23 LC record available at https://

lccn.loc.gov/2016034345

Executive Content Strategist: Sonya SeigafuseContent Development Manager: Billie SharpContent Development Specialist: Kristen MandavaPublishing Services Manager: Julie EddyProject Manager: Abigail BradberryDesign Direction: Paula Catalano

Printed in Canada

Last digit is the print number: 9 8 7 6 5 4 3 2 1

v

ReviewersAmy Crofts, MHa/Ed; RT (R)(QM)Clinical Teaching FacultyOwens Community CollegeToledo, Ohio

Joy Menser, MSM, RT(R) (T)Radiography Program DirectorOwensboro Community and Technical CollegeOwensboro, Kentucky

Jeffery E. Tillotson, BS RT (R)Clinical CoordinatorNashville General Hospital School of Heath SciencesNashville, Tennessee

This page intentionally left blank

vii

DedicationI wrote the first edition of this textbook in 1974 not expecting anyone to read it much less buy it! I wrote it to get promoted. My academic chairman explained to me that in order to be promoted to full professor at Baylor College of Medicine one had to write a textbook (Bushong, SC. A Book Report. Radiologic Technology pg. 405-409, March/April 2013).

The greatest reward I have received in writing this 11th edition and the previous ten is the many new friends I now have because of this textbook. So I dedicate this edition to you, my friends in radiologic education. Many have contributed to this textbook and many have shared with me the speaking platform at educational meetings. Thank you very much for your friendship and I apologize to those I have left out because I’m late in the fourth quarter and I can’t remember!!!

Kenneth Abramovitch, University of TexasNancy Adams, Louisiana State UniversityArlene M. Adler, Indiana University NorthwestChristian Allard, Universidat de Arica, ChileCarla Allen, University of MissouriFelipe Allende, Universidad Centrale, ChileKelly Angel, Kaiser PermanenteRichard S. Angulo, Pima Medical InstituteSebastian Arancibia, Universidad Centrale, ChileAlex Backus, Gateway Community CollegePhilip Ballinger, Ohio State UniversityStephen Balter, Columbia UniversityEd Barnes, Medical Technology Management InstituteGary Barnes, University of AlabamaMarcy Barnes, Lexington Community CollegeCecilia Munoz Barabino, Universidad Nacional Mayor,

PeruShirley A. Bartley, Hillyard Technical CenterTammy Bauman, Banner Thunderbird Medical CenterRichard Bayless, University of MontanaChris Beaudry, Yakima Valley Community CollegeRochel Becker, Johns Hopkins School of Medical

ImagingAlberto Bello, Jr., Danville Area Community CollegeBobbie Lynnette Biglane, US Air Force

Melanie Billmeier, North Central Texas CollegeNathaniel L. Bishop, Jefferson College of Health

SciencesGeorge Bissett, Texas Children’s HospitalChristie Bolton, Jefferson State CollegeDenise Bowman, Community Hospital of Monterrey

PeninsulaColleen Brady, Minnesota State CollegeJett Brady, The Methodist HospitalJeffrey Brown, Kaiser PermanenteKaren Brown, Gateway Community CollegeNorman L. Burgess, Brookhaven CollegeBarry Burns, University of North CarolinaDeanna Butcher, St. Cloud HospitalPriscilla Butler, American College of RadiologyJames Byrne, Houston Community CollegeCisca Bye, Montgomery County Community CollegeAndres Cabezas Cabrera, Universidad Centrale, ChileRobert Cahalan, Iowa Society of Radiologic

TechnologistsDonna L. Caldwell, Arkansas State UniversityShaun T. Caldwell, UT MD Anderson Cancer CenterWilliam J. Callaway, Lincoln Land Community CollegeRichard R. Carlton, Arkansas State UniversityMary Ellen Carpenter, Essex County College

viii Dedication

Quinn Carroll, Midland CollegeRichard Carson, Oregon Institute of TechnologyChristi Carter, Brookhaven CollegeTimothy C. Chapman, Gateway Community CollegeChristian Chavez, Universidat de Arica, ChileAlexandro Cerda, Clinicas las Condes, ChileJean Christensen, Mercy Medical CenterValerie Christensen, Association of Educators in Imaging

and Radiologic SciencesCarolyn L. Cianciosa, Niagara County Community

CollegeDavid Clayton, UT MD Anderson Cancer CenterBrenda M. Coleman, Columbia State Community

CollegeEdgar Colon, Universidad Central del CarribianJudy Cook, Tarrant County CollegeCathy Cooper, Alabama Society of Radiologic

TechnologistsCharles Coulston, Bluegrass Community and Technical

CollegeAnuja Cox, Dona Ana Community CollegeTracy Crandall, Atlanta Society of Radiologic

TechnologistsRussell Crank, Rockingham Memorial Hospital

HealthcareSuzanne E. Crandall, Iowa Methodist Medical CenterAngela Culliton, Mercy Medical CenterCheryl V. Cunningham, Virginia Western Community

CollegeJacklyn Scott Darling, Morehead State UniversityLynne Davis, Houston Community CollegeDenise DeGennaro, Lone Star CollegeAnn Delaney, University of MontanaJenny Delawalla, Gwinnett Technical CollegeTammy Delker, Indian Hills Community CollegeLois Depouw, Rasmussen CollegeSteve Deutsch, Spencer HospitalRandall D. Dings, Pima Community CollegeMartha Dollar, Columbus Technical CollegeSarajane Doty, Kentucky Community and Technical

CollegeMary Doucette, Great Basin CollegeMarsha Dougherty, Lone Star CollegeEric Douglas, St. Luke’s Episcopal HospitalCheryl DuBose, Arkansas State UniversityPat Duffy, Roxbury Community CollegeAndrea Guillen Dutton, Chaffey CollegeUrsula Dyer, Kilgore CollegeJohn W. Eichinger, Technical College of the Low CountryKaren Emory, Grady Memorial HealthcareMichael A. Enriquez, Merced Community CollegeRodrigo Espinoza, Universidad Centrale, ChileLisa S. Fanning, Massachusetts College of Health

SciencesShanna Farish, Medical RT Board of ExaminersTerri Fauber, Virginia Commonwealth University

Bill Faulkner, University of TennesseeScott Flamm, Texas Heart InstituteKae Brock Fleming, Columbia State Community CollegeSherry Floerchinger, Dixie State College of UtahM. Ella Flores, Blinn CollegeMike Frain, Northern New Mexico CollegeEugene Frank, Riverland Community CollegeRichard Fucillo, Burlington Community CollegeMichael Fugate, University of FloridaRodrigo Antonio Galaz, University of SantiagoMarcelo Galvez, Clinica las Condes, ChileIsmael Garcia, Del Mar CollegeSandra Garcia, Fort Sam HoustonAndrew Gardner, Atlanta Technical CollegeJoe Garza, Lone Star CollegeRudy Garza, Austin Community CollegeCamille Gaudet, Hospital Regional Dr-Georges-L-

DumontPamela Gebhart-Cline, Riverside SchoolDiane George, Jackson State CollegeSusan Giboney, Kaiser PermanenteTim Gienapp, Apollo CollegeJulie A. Gill, ASRTLaci Giroir, Beaumont Baptist HospitalYvonne Grant, Iowa Society of Radiologic

TechnologistsJoel Gray, Medical Physics ConsultingGinger Griffin, Jacksonville, FLLaVern Gurley, Shelby State Community CollegeJennyfer Gutierrez, University of PeruDick Gwilt, Indian Health ServiceJeff Hamzeh, Keiser UniversityLoretta Hanset, Harris County Hospital DistrictNancy Harvey, University of IowaMichael D. Harpin, University of South AlabamaKenya Haugen, Baptist Health SystemArt Haus, Ohio State UniversityNancy Hawking, University of ArkansasJoyce O. Hawkins, Bon Secours Richmond Health

SystemJohn Hazle, UT MD Anderson Cancer CenterClyde R. Hembree, University of TennesseeEd Hendrick, Northwestern UniversityChad Hensley, University of Nevada-Las VegasTracy Herrmann, University of CincinnatiVictoria Holas, Arizona Western CollegePeggy Hoosier, Advanced Health Education CenterMiguel Iglesias, Colegio Technologo Medico del PeruKeith Indeck, Norwalk Radiology CenterJanie Jackson, Tarrant County CollegeDonald Jacobson, Medical College of WisconsinJeniesa Johnson, Tarrant County CollegeNancy Johnson, Gateway Community CollegeStarla Jones, Medical College of GeorgiaLinda Joppe, Rasmussen CollegeHelen Schumpert Kauchak, Ashville MRI

Dedication ix

Dianne M. Kawamura, Weber State UniversityLeslie E. Kendrick, Boise State UniversityCheryl Kerr, San Diego Naval StationApril D. Kidd, USFDA/CDRHJeannie Kilgore, Clovis Community CollegeJeffery B. Killian, Midwestern State UniversityPaul A. Kusber, Mills Peninsula SchoolRuth Kusterer, Virginia Society of Radiologic

TechnologistsKent Lambert, Drexel UniversityTim Lambrecht, Baylor Grapevine Diagnostic ImagingJohn P. Lampignano, Gateway Community CollegePaul Laudicina, College of DuPageGary Leach, Memorial Hermann HospitalLois Lehman, Texas Scottish Rite Hospital for

ChildrenDeborah Leighty, Hillsborough Community CollegePatricia Lenza, Concord’s Community CollegeTheresa Levitsky, St. Francis Medical CenterKurt Loveland, Southern Illinois UniversityMichelle Luciano, UNE Puerto RicoRodrigo Marchant, Universidad Centrale, ChileVictor Ruiz Marquez, University of PeruMark. J. Martone, Massachusetts College of Health

SciencesEileen M. Maloney, American Registry of Radiologic

TechnologistsRon Marker, Wheaton Franciscan HealthcareValerie Martin, Brookhaven CollegeStarla Mason, Laramie County Community CollegeWilliam May, Mississippi State UniversityAllyson Matheaus, Wharton County Junior CollegeChris B. Martin, Oklahoma Health Sciences CenterLeAnn Maupin, Oregon Institute of TechnologyCynthia McCullough, Mayo ClinicDave McLaren, Polk State CollegeFrancisco Mena, Clinicas las Condes, ChileDarrly Mendoza, Mills Peninsula SchoolJoy Menser, Owensboro Community CollegeRobert Meisch, Indiana State UniversityKim Metcalf, George Washington UniversityMassimo Midiri, University of PalermoBecky Miller, Horry-Georgetown Technical CollegeDebbie K. Miller, Spokane Community CollegeRuby Montgomery, Marion County Community CollegeDawn Moore, Atlanta Society of Radiologic

TechnologistsFernando A. Morales, Universidad Diego PortalesJose Rafael Moscoso, Universidad Central del CaribeC. William Mulkey, Midlands Technical CollegeMindy Mutschler, Mercy Medical CenterGlenna Neumann, Atlanta Society of Radiologic

TechnologistsCharles Newell, University of South AlabamaMary Ellen Newton, St. Francis SchoolEdward Nickoloff, Columbia University

Jon Nissenbaum, Massachusetts Eye and Ear Infirmary

Tanya Nolan, Weber State UniversityLarry Norris, Lone Star CollegeSandra Ochoa, Del Mar CollegeCyndee Oliver, Lone Star CollegeLori Oswalt, Covenant School of RadiographyFrancis Ozor, Lone Star CollegeGeorge Pales, University of NevadaPaula Pate-Schloder, Misericordia UniversityBrenda L. Pfeiffer, Loma Linda UniversityRob Posteraro, Covenant School of RadiographyChase Poulsen, Jefferson College of Health SciencesJerilyn J. Powell, Rapid City Regional HospitalValerie J. H. Powell, Robert Morris UniversityKevin Powers, American Society of Radiologic

TechnologistsPerri Preston, University of FloridaRoger A. Preston, Reid Hospital & Health ServicesCheryl Pressly, Grady Health School of Imaging

TechnologyJames Pronovost, Naugatuck Valley Community CollegeBarbara Smith Pruner, Portland Community CollegeJohn Radtke, Louisiana State UniversityEytan Raz, University of RomeRoland Rhymus, Loma Linda UniversityTeresa Rice, Houston Community CollegeJennifer A. Rigsby, Austin Community CollegeCynthia Robertson, Lone Star CollegeTed Robertson, Washoe Medical CenterRita Robinson, Memorial Hermann HospitalJeannean Rollins, Arkansas State UniversityVeronica Rosales, Universidad Austal de ChileDonna Rufsholm, South Peninsula HospitalBonnie Rush, Educational EnterpriseFrancesca Russo, Sant Marcia DilicodiaLoren A. Sachs, Orange Coast CollegeMarilyn Sackett, Advanced Health Education CenterDorothy Saia, Stamford HospitalEhsan Samei, Duke UniversityThomas Sandridge, University of IllinoisJim Sass, Gwinnett Technical CollegeBette Schans, Colorado Mesa UniversityJill Schulz, Covenant Medical CenterEric J. Shepard, Fort Sam HoustonLana Scherer, Covenant HealthMartin Schotten, Yuma Medical CenterEuclid Seeram, British Columbia Institute of

TechnologyKim Seigman, Covenant HealthJoseph Shackelford, Jackson Community CollegeElizabeth Shields, Presbyterian HospitalLinda Shields, El Paso Community CollegeAnthony Siebert, University of California, DavisMarcelo Zenteno Silva, Universidad Austal de ChileMark A. Sime, Mercy Medical Center

x Dedication

Kathryn M. Slagle, University of Alaska-AnchorageDawn Stark, Mississippi State UniversityMike Stewart, New Mexico State UniversityRees Stuteville, Oregon Institute of TechnologyDonald Summers, Lincoln Land Community CollegeRaquel Tapia, Del Mar CollegeChristl Thompson, El Paso Community CollegeKyle Thornton, City College of San FranciscoGina Tice, Gadsden State Community CollegeKimberly Todd, Jackson State Community CollegeRenee Tossell, Pima Community CollegeBrenna Travis, Tarrant County CollegeWilliam Tyler, Savannah Technical InstituteVirginia Vanderford, Portland Community CollegeBeth L. Veale, Midwestern State UniversitySusan Sprinkle Vincent, Advanced Health Education

CenterDonna Vitetta, White Plains CollegeLouis Wagner, University of Texas Medical SchoolJeff Walmsley, Lorain Community CollegeSteven D. Walters, Regional Medical Center of San JoseCheryl Dutton Walton, Huntsville HospitalPatti Ward, Colorado Mesa UniversityBrenda Watson, Camosun CollegeLynette K. Watts, Midwestern State UniversityLaurie Weaver, Casper CollegeStephanie A. Wells, Brookhaven College

Diana S. Werderman, Trinity CollegeAmy D. Westbury, Oregon Technical CollegeMark White, University of NebraskaTracey B. White, Arkansas State UniversityChristine Wiley, North Shore Community CollegeCarla Williams, Carteret Community CollegeJudy Williams, Grady Memorial HospitalBettye G. Wilson, ARRTLeslie F. Winter, JRCERTRay Winters, Arkansas State UniversityKen Wintch, Colorado Mesa UniversityMary E. Wolfe, Catholic Medical CenterAndrew Woodward, Wor-Wic Community CollegeErica K. Wight, University of Alaska-AnchorageRaymond Wilenzek, Tulane UniversityCharles Willis, UT MD Anderson Cancer CenterRobert Wilson, University of TennesseeRay Winters, Arkansas State UniversityMelinda Wren, Del Mar CollegeDonna Lee Wright, Midwestern State UniversityJennifer Yates, Merritt CollegeBrad York, Houston Community CollegeBrian Zawislak, Northwestern University Medical

SchoolXie Nan Zhu, Guangzhou Medical CollegeKelly J. Zuniga, Houston Community College

xi

This Book is also Dedicated to My Friends Here and Gone:

Abby KuramotoArlo Carlyle HopkinsonBaily Schroth (†)Baily SpauldingBandit Davidson (†)Bella BushongBiscuit Carlyle MartinBoef Kuipers (†)Brittney ProminskiBrownie Hindman (†)Brutus Payne (†)Buffy Jackson (†)Butterscotch Bushong (†)Casper Miller (†)Cassie Kronenberger (†)Chandon Davis (†)Chester Chase (†)Choco Walker (†)Clifford Carlyle DevoeCoco WinsorCookie Lake (†)Colonel TravisDesi LohrenzDually JacksonDude Carlyle SchwartzDuke Carlyle McMullin

Duncan Hindman (†)Ebony Bushong (†)Emme Carlyle CouchFlap MalyFonzie Schroth (†)Frank EdlundGeraldine Bushong (†)Ginger Chase (†)Grayton FriedlanderGretchen Scharlach (†)Guadalupe Tortilla HolmbergHeidi Carlyle CouchJemimah Bushong (†)Kate Davidson (†)Kokopelli Carlyle HamesLinus Black (†)Lizzie Carlyle BryanLizzy Carlyle ProminskiLoftus MeadowsLouie Carlyle EdlundLucy Spaulding (†)Lupe Tortilla HolmbergMaddie BushongMaxwell Haus (†) and my lensesMaxwell Carlyle McMullinMidnight Lunsford (†)

Mimi Hana (Indian Princess)Molly Holmberg (†)Muttly Chase (†)Olive Carlyle AswadPancho Villa Holmberg (†)Peanut Schroth (†)Penny Carlyle Friedlander (†)Pepper MillerPercy LohrenzPetra Chase (†)Powers JacksonQueenie Carlyle ReedSadie Carlyle ReedSammie ChaseSapphire Miller (†)Sebastian Miller (†)Sophie Carlyle ArcherSusi BuesoTeddy SchrothTigger Carlyle BriceToby Schroth (†)Toto Walker (†)Travis Chase (†)Tuffy Beman

(†) = R.I.P.

xii

Dedication – Saintly StitchersThis eleventh edition of Radiologic Science for Technologists is dedicated to my new friends at St. Martin’s Episcopal Church, Houston, which is not even my church. I discovered that their project to knit kneelers for their new sanctu-ary needed additional stitchers. They taught me to stitch and that one can stitch while in conversation, while in church, while watching TV, and during many other activities. It is easy to do and easy to multi-task when stitching is one of the activities.

A recent article in the Houston Chronicle included an interview with me, one of two Saintly Stitching males. “It’s a total chick magnet.” When I break out my stitching at the airport or wherever, the chicks, mostly in the fourth quarter, do come flocking with lots of questions and compliments.

More importantly I’ve been promised that when I finish my kneeler I will be a slam-dunk to get into Heaven. I’ve been at it for a year now and plot my progress - that’s my kneeler hanging on the railing below. At the present pace I will finish in March, 2031.

From left:Row 1: Ada Grundy, Barbara Bush, Betty Workman, Ann Thurmond, Lee Hunnell, Marthann Weaber, Susan Rovello, Karen Fast, Nancy Marymee. Row 2: Joyce Jackson, Gerri Utterson, Bette Fryar, Pam Bentley, Clem McIver, Joan Hilley, Shirley Hopkins, Gerry Eversol, Ann Cochran, Fran Smith. Row 3: Shirley Allen Anne McFaddin, Sue Rea, Barbara Svetlik. Row 4: Michele Roberts, Stewart Bushong, Bobbie Adams, Martha Ann Linden, Dorothy Browne, Mary Epps, Kay Handley, Carroll Selander, Betty Ann Graves.

xiii

PrefacePURPOSE AND CONTENTThe purpose of Radiologic Science for Technologists: Physics, Biology, and Protection is threefold: to convey a working knowledge of radiologic physics; to prepare radiography students for the certification examination by the ARRT; and to provide a base of knowledge from which practicing radiographers can make informed decisions about technical factors, diagnostic image quality, and radiation management for both patients and personnel.

This textbook provides a solid presentation of radio-logic science, including the fundamentals of radiologic physics, diagnostic imaging, radiobiology, and radiation management. Special topics include mammography, fluoroscopy, interventional radiology, helical computed tomography, and the various modes of digital imaging.

The fundamentals of radiologic science cannot be removed from mathematics, but this textbook does not assume a mathematics background for the readers. The few mathematical equations presented are always fol-lowed by sample problems with direct clinical applica-tion. As a further aid to learning, all mathematical formulas are highlighted with their own icon.

Likewise, the most important ideas under discussion are presented with their own colorful penguin icon and box. A PENGUIN is a very important fact that you should place on your iceberg.

The eleventh edition improves this popular feature of information bullets by including even more key con-cepts and definitions in each chapter. This textbook also presents learning objectives, chapter overviews, and chapter summaries that encourage students and make the text user-friendly for all. Challenge Questions at the end of each chapter include definition exercises, short-answer questions, and a few calculations. These ques-tions can be used for homework assignments, review sessions, or self-directed testing and practice. Answers

to all questions are provided on the Evolve site at http://evolve.elsevier.com.

HISTORICAL PERSPECTIVEFor seven decades after Roentgen’s discovery of x-rays in 1895, diagnostic radiology remained a relatively stable field of study and practice. Truly great changes during that time can be counted on one hand: the Crookes tube, the radiographic grid, radiographic inten-sifying screens, and image intensification.

Since the publication of the first edition of this text-book in 1975, however, newer systems for diagnostic imaging have come into routine use: multislice helical computed tomography, computed radiography, digital radiography, digital radiographic tomosynthesis, and digital fluoroscopy. Truly spectacular advances in com-puter technology and x-ray tube and image receptor design have made these innovations possible, and they continue to transform diagnostic imaging.

NEW TO THIS EDITIONThe eleventh edition has been reorganized, consoli-dated, and updated to reflect the current imaging envi-ronment. Currently we are essentially engaged in digital imaging. Digital radiography has replaced screen-film radiography rapidly and this requires that radiologic technologists acquire a new and different fund of knowl-edge in addition to what has been required previously—and in the same length of training time! Two new chapters were added on digital imaging, primarily focus-ing on patient dose safety with these newer techniques. Though the trend is to replace film/screen radiography with digital radiography, chapters concerning film/screen radiography were left in this 11th edition for reference purposes and those schools still teaching film/screen radiography.

In addition, the targeted focus on this necessary new content and closer alignment with ASRT core curricu-lum ensures student technologists are prepared to take the ARRT exam and have the background they need to perform well in the clinical environment.

ANCILLARIESStudent WorkbookThis resource has been updated to reflect the changes in the text and the rapid advancements in the field of radiologic science. Part I offers a complete selection of

xiv Preface

worksheets organized by textbook chapter. Part II, the Math Tutor, provides an outstanding refresher for any student. The Laboratory Experiments collect experi-ments designed to demonstrate important concepts in radiologic science. These are now available on the Evolve site at http://evolve.elsevier.com for ease of use.

Evolve ResourcesInstructor ancillaries, including an ExamView Test Bank of over 900 questions, an image collection of all of the images in the text, and a PowerPoint lecture presenta-tion are all available to instructors at http://evolve.else-vier.com.

Students and instructors have access to the textbook challenge questions answer keys, laboratory experi-ments, the workbook math tutor answer key, and the workbook worksheet answer keys.

A NOTE ON THE TEXTAlthough the ARRT has not formally adopted the Inter-national System of Units (SI units), they are presented in this eleventh edition. With this system come the cor-responding units of radiation and radioactivity.

The roentgen and the rad are being replaced by the gray (Gya and Gyt respectively) and the rem by the sievert (Sv). In this edition, the SI units are presented first, followed by the earlier units in parentheses. A summary of special quantities and units in radiologic science can be found on the inside front cover of the text.

Radiation exposure is measured in SI units of C/kg, measured in mGy. Because mGy is also a unit of dose, a measurement of radiation exposure is distinguished from tissue dose by applying a subscript a or t to mGy, according to the recommendations of Archer and Wagner (Minimizing Risk From Fluoroscopic X-rays, PRM, 2007). Therefore radiation exposure is measured in mGya and tissue dose in mGyt.

ACKNOWLEDGMENTSFor the preparation of the eleventh edition, I am indebted to the many readers of the previous editions who

submitted suggestions, criticisms, corrections, and compliments.

I am particularly indebted to the following radiologic science educators, whom I have identified on the Dedi-cation page of this eleventh edition. Their suggestions for change and clarification were always right on target. Many supplied illustrations, and they are additionally acknowledged with the illustration in this eleventh edition.

My friend and colleague, Ben Archer, is the author of the Penguin Tale (Page 3), which for me has become a particularly effective teaching tool. And that, in turn, has led to some 30 Penguintoons suggested by educators and students, which I now show regularly during lec-tures. I’ll never forget the first. Three of Ruby Mont-gomery’s students interrupted me at Judy William’s Atlanta SRT Student and Educators’ Conference in 2002. “Do polar bears eat penguins?” they asked. “Sure they do, they’re carnivorous,” I responded. “No, polar bears live at the North Pole, penguins at the South Pole!” … intense audience laughter.

The drawing of the Penguintoons and the illustra-tions in this book are the work of another close friend and colleague, Kraig Emmert. Thanks, Kraig, for your exceptional time and effort.

When I am in the audience of a lecture and leave with a single Penguin, I consider the lecture successful. Please send me your Penguins!

As you, student or educator, use this text and have questions or comments, I hope you will email me at sbushong@bcm.edu so that together we can strive to make this very difficult material easier to learn. I may not respond immediately, but I promise I will respond.

“Physics is fun” is the motto of my radiologic science courses.

Stewart Carlyle Bushong

xv

ContentsPART IRADIOLOGIC PHYSICS, 1 1 Essential Concepts of Radiologic Science, 2 2 The Structure of Matter, 26 3 Electromagnetic Energy, 44 4 Electricity, Magnetism, and Electromagnetism, 60

PART IIX-RADIATION, 83 5 The X-ray Imaging System, 84 6 The X-ray Tube, 104 7 X-ray Production, 122 8 X-ray Emission, 135 9 X-ray Interaction With Matter, 146

PART IIITHE RADIOGRAPHIC IMAGE, 161 10 Radiographic Image Quality, 162 11 Scatter Radiation, 186 12 Screen-Film Radiography, 207 13 Screen-Film Radiographic Technique, 236

PART IVTHE DIGITAL RADIOGRAPHIC IMAGE, 265 14 Medical Imaging Computer Science, 266 15 Computed Radiography, 283 16 Digital Radiography, 296 17 Digital Radiographic Technique, 306 18 Viewing the Digital Image, 321

PART VIMAGE ARTIFACTS AND QUALITY CONTROL, 335 19 Screen-Film Radiographic Artifacts, 336 20 Screen-Film Radiographic Quality Control, 343

21 Digital Radiographic Artifacts, 354 22 Digital Radiographic Quality Control, 365

PART VIADVANCED X-RAY IMAGING, 373 23 Mammography, 374 24 Mammography Quality Control, 388 25 Fluoroscopy, 404 26 Digital Fluoroscopy, 420 27 Interventional Radiology, 434 28 Computed Tomography, 441

PART VIIRADIOBIOLOGY, 469 29 Human Biology, 470 30 Fundamental Principles of Radiobiology, 483 31 Molecular Radiobiology, 491 32 Cellular Radiobiology, 498 33 Deterministic Effects of Radiation, 507 34 Stochastic Effects of Radiation, 522

PART VIIIRADIATION PROTECTION, 541 35 Health Physics, 542 36 Designing for Radiation Protection, 551 37 Radiography/Fluoroscopy Patient Radiation

Dose, 567 38 Computed Tomography Patient Radiation

Dose, 577 39 Patient Radiation Dose Management, 587 40 Occupational Radiation Dose Management, 598

Glossary, 615 Index, 635

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1

PART

IRADIOLOGIC PHYSICS

2

C H A P T E R

1

Essential Concepts of Radiologic Science

OUTLINE

OBJECTIVESAt the completion of this chapter, the student should be able to do the following:

1. Describethecharacteristicsofmatterandenergy.2. Identifythevariousformsofenergy.3. Defineelectromagneticradiationandionizingradiation.4. Statetherelativeintensityofionizingradiationfromvarious

sources.5. Listtheconceptsofbasicradiationprotection.6. Discussthederivationofscientificsystemsofmeasurement.7. Listanddefineunitsofradiationandradioactivity.

Nature of Our SurroundingsMatter and EnergySources of Ionizing RadiationDiscovery of X-RaysDevelopment of Medical ImagingReports of Radiation InjuryBasic Radiation Protection

FiltrationCollimationProtectiveApparelGonadalShieldingProtectiveBarriers

Standard Units of MeasurementLengthMassTimeUnits

MechanicsVelocityAccelerationNewton’sLawsofMotionWeightMomentumWorkPowerEnergyHeat

Terminology for Radiologic Science

NumericPrefixesRadiologicUnits

The Medical Imaging Team

CHAPTER 1 Essential Concepts of Radiologic Science 3

T HIS CHAPTER explores the basic concepts of

the science and technology of x-ray imaging.

These include the study of matter, energy, the

electromagnetic spectrum, and ionizing radiation. The

production and use of ionizing radiation as a diagnos-

tic tool serve as the basis for radiography. Radiologic

technologists who deal specifically with x-ray imaging

are radiographers. Radiographers have a great respon-

sibility in performing x-ray examinations in accordance

with established radiation protection standards for the

safety of patients and medical personnel.

The instant an x-ray tube produces x-rays, all of the

laws of physics are evident. The projectile electron

from the cathode hits the target of the anode produc-

ing x-rays. Some x-rays interact with tissue, and other

x-rays interact with the image receptor, forming an

image. The physics of radiography deals with the pro-

duction and interaction of x-rays.

Radiography is a career choice with great opportu-

nities in a number of diverse fields. Welcome to the

field of medical imaging!

NATURE OF OUR SURROUNDINGSIn a physical analysis all things can be classified asmatterorenergy.Matterisanythingthatoccupiesspaceand has mass. It is the material substance of whichphysicalobjectsarecomposed.Allmatteriscomposedof fundamental building blocks called atoms, whichare arranged in various complex ways. These atomicarrangements are considered at great length inChapter2.

Aprimary,distinguishingcharacteristicofmatter ismass,thequantityofmattercontainedinanyphysicalobject.Wegenerallyusethetermweightwhendescrib-ingthemassofanobject,andforourpurposeswemayconsidermass andweight tobe the same.Remember,however,thatinthestrictestsensetheyarenotthesame.Whereasmassisactuallydescribedbyitsenergyequiva-lence,weight istheforceexertedonabodyundertheinfluenceofgravity.

Massismeasuredinkilograms(kg).Forexample,onEarth,a200-lb(91-kg)manweighsmorethana120-lb(55-kg) woman. This occurs because of the mutualattraction,calledgravity,betweentheEarth’smassandthemassofthemanorwoman.Onthemoon,themanandthewomanwouldweighonlyaboutone-sixthwhattheyweighonEarthbecause themassof themoon ismuchlessthanthatoftheEarth.However,themassofthemanand thewoman remainsunchangedat91kgand55kg,respectively.

Mass is the quantity of matter as described by its energy equivalence.

MATTER AND ENERGYMatterisanythingthatoccupiesspace.Itisthematerialsubstance having mass of which physical objects arecomposed.The fundamental, complexbuildingblocksofmatterareatomsandmolecules.Thekilogram,the

A PENGUIN TALE BY BENJAMIN RIPLEY ARCHER, PHD

In the vast and beautiful expanse of the Antarctic region, there was once a great, isolated iceberg floating in the serene sea. Because of its location and accessibility, the great iceberg became a Mecca for penguins from the entire area. As more and more penguins flocked to their new home and began to cover the slopes of the ice field, the iceberg began to sink farther and farther into the sea. Penguins kept climbing on, forcing others off the iceberg and back into the ocean. Soon the iceberg became nearly submerged owing to the sheer number of penguins that attempted to take up residence there.

Moral: The PENGUIN represents an important fact or bit of information that we must learn to understand a subject. The brain, similar to the iceberg, can retain only so much information before it becomes overloaded. When this happens, concepts begin to become dislodged, like penguins from the sinking iceberg. So, the key to learning is to reserve space for true “penguins” to fill the valuable and limited confines of our brains. Thus key points in this book are highlighted and referred to as “PENGUINS.”

4 PART I Radiologic Physics

FIGURE1-1 The blade of a guillotine offers a dramatic example of both potential and kinetic energy. When the blade is pulled to its maximum height and is locked into place, it has potential energy. When the blade is allowed to fall, the potential energy is released as kinetic energy.

scientific unit of mass, is unrelated to gravitationaleffects.Theprefixkilostandsfor1000;akilogram(kg)isequalto1000grams(g).

Although mass, the quantity of matter, remainsunchangedregardlessofitsstate,itcanbetransformedfromonesize,shape,andformtoanother.Considera1-kgblockofice,inwhichshapechangesastheblockof ice melts into a puddle of water. If the puddle isallowedtodry,thewaterapparentlydisappearsentirely.Weknow,however, thatthe ice is transformedfromasolidstatetoaliquidstateandthatliquidwaterbecomeswatervaporsuspendedinair.Ifwecouldgatherallthemoleculesthatmakeuptheice,thewater,andthewatervapor and measure their masses, we would find thateachformhasthesamemass.

Similartomatter,energycanexist inseveralforms.In the InternationalSystem (SI) energy ismeasured injoules(J).Inradiologytheunitelectronvolt(eV)isoftenused.

Potential energy is theability todoworkbyvirtueofposition.Aguillotinebladeheldaloftbyaropeandpulleyisanexampleofanobjectthatpossessespoten-tialenergy(Figure1-1).Iftheropeiscut,thebladewilldescendanddoitsghastlytask.Workisrequiredtogetthebladetoitshighposition,andbecauseofthisposi-tion,thebladeissaidtopossesspotentialenergy.Otherexamples of objects that possess potential energy

Energy is the ability to do work.

include a rollercoaster on top of the incline and thestretchedspringofanopenscreendoor.

Kinetic energyistheenergyofmotion.Itispossessedbyallmatterinmotion:amovingautomobile,aturningwindmillwheel,afallingguillotineblade.Thesesystemscanalldoworkbecauseoftheirmotion.

Chemical energyistheenergyreleasedbyachemicalreaction.Animportantexampleofthistypeofenergyisthatwhichisprovidedtoourbodiesthroughchemicalreactionsinvolvingthefoodsweeat.Atthemolecularlevel, this area of science is called biochemistry. Theenergyreleasedwhendynamiteexplodesisamoredra-maticexampleofchemicalenergy.

Electrical energy represents the work that can bedonewhenanelectronmovesthroughanelectricpoten-tialdifference(voltage).Themostfamiliarformofelec-trical energy is normal household electricity, whichinvolves the movement of electrons through a copperwirebyanelectricpotentialdifferenceof110volts(V).All electric apparatus, such as motors, heaters, andblowers,functionthroughtheuseofelectricalenergy.

Thermal energy (heat)istheenergyofmotionatthemolecularlevel.Itisthekineticenergyofmoleculesandis closely related to temperature. The faster the mol-ecules of a substance are vibrating, the more thermalenergy the substance has and the higher is itstemperature.

Nuclear energyistheenergythatiscontainedwithinthenucleusofanatom.Wecontrolthereleaseanduseofthistypeofenergyinelectricnuclearpowerplants.An example of the uncontrolled release of nuclearenergyistheatomicbomb.

Electromagnetic energy isperhaps the least familiarform of energy. It is the most important for our pur-poses,however,becauseit isthetypeofenergythatisusedinx-rayimaging.Inadditiontox-raysandgammarays, electromagnetic energy includes radio waves;microwaves;andultraviolet,infrared,andvisiblelight.Electromagneticenergydoesnotincludesoundordiag-nosticultrasound.

Just as matter can be transformed from one size,shape,andformtoanother,sotoocanenergybetrans-formed from one type to another. In radiology, forexample,electricalenergy in thex-ray imagingsystemisused toproduce electromagnetic energy (thex-ray),whichthenisconvertedtochemicalenergyintheradio-graphic film or an electrical signal in a digital imagereceptor.

Reconsidernowthestatementthatallthingscanbeclassified as matter or energy. Look around you andthink of absolutely anything, and you should be

CHAPTER 1 Essential Concepts of Radiologic Science 5

convincedofthisstatement.Youshouldbeabletoclas-sify anything as matter, energy, or both. Frequently,matter and energy exist side by side—a moving auto-mobilehasmassandkineticenergy;boilingwaterhasmassandthermalenergy;theLeaningTowerofPisahasmassandpotentialenergy.

Perhapsthestrangestpropertyassociatedwithmatterandenergyisthattheyareinterchangeable,acharacter-istic first described by Albert Einstein in his famoustheoryof relativity.Einstein’smass-energy equivalenceequationisacornerstoneofthattheory.

Thismass-energyequivalenceservesasthebasisforthe atomic bomb, nuclear power plants, and certainnuclearmedicineimagingmodalities.

MASS-ENERGY

E = mc2

where E is energy, m is mass, and c is the velocity (speed) of electromagnetic radiation (light) in a vacuum.

Energy emitted and transferred through space iscalledradiation.Whenapianostringvibrates,itissaidto radiate sound; the sound is a form of radiation.Ripplesorwavesradiatefromthepointwhereapebbleis dropped into a still pond. Visible light, a form ofelectromagnetic energy, is radiated by the sun and iselectromagnetic radiation. Electromagnetic energy isusually referred to as electromagnetic radiation or,simply,radiation.

Matterthatinterceptsradiationandabsorbspartorallofitissaidtobeexposedorirradiated.Spendingadayatthebeachexposesyoutoultravioletlight.Ultra-violetlightisthetypeofradiationthatcausessunburn.During a radiographic examination, the patient isexposedtox-rays.Thepatientissaidtobeirradiated.

Radiation is the transfer of energy.

Ionization is the removal of an electron from an atom.

Thusany typeofenergy that iscapableof ionizingmatter isknownas ionizingradiation.X-rays,gammarays,andultravioletlightaretheonlyformsofelectro-magneticradiationwithsufficientenergytoionize.Somefast-movingparticles(particleswithhighkineticenergy)arealsocapableofionization.Examplesofparticle-typeionizing radiation are alpha and beta particles (seeChapter2).Althoughalphaandbetaparticlesaresome-timescalledrays,thisdesignationisincorrect.

SOURCES OF IONIZING RADIATIONManytypesofradiationareharmless,butionizingradi-ation can injure humans. We are exposed to manysourcesofionizingradiation(Figure1-3).Thesesourcescanbedividedintotwomaincategories:natural envi-ronmental radiationandman-made radiation.

Naturalenvironmentalradiationresultsinanannualdoseofapproximately3millisieverts(mSv).Man-maderadiation results in 3.2mSv annually. An mSv is theunit of effective dose. It is used to express radiationexposure of populations and radiation risk in thosepopulations.

Natural environmental radiation consists of fourcomponents: cosmic rays, terrestrial radiation, inter-nally deposited radionuclides, andradon.Cosmicraysareparticulateandelectromagneticradiationemittedbythe sun and stars. On Earth, the intensity of cosmicradiationincreaseswithaltitudeandlatitude.Terrestrialradiation results from deposits of uranium, thorium,and other radionuclides in the Earth. The intensity is

Ionizing radiation isaspecialtypeofradiationthatincludesx-rays.Ionizingradiationisanytypeofradia-tionthatiscapableofremovinganorbitalelectronfromtheatomwithwhichitinteracts(Figure1-2).Thistypeof interaction between radiation and matter is calledionization.Ionizationoccurswhenanx-raypassesclosetoanorbitalelectronofanatomandtransferssufficientenergytotheelectrontoremoveitfromtheatom.Theionizing radiation may interact with and ionize addi-tional atoms. Theorbital electron and the atom fromwhichitwasseparatedarecalledanion pair.Theelec-tronisanegativeion,andtheremainingatomisaposi-tiveion.

FIGURE 1-2 Ionization is the removal of an electron from an atom. The ejected electron and the resulting positively charged atom together are called an ion pair.

Negative ion(free electron)

Positive ion(remaining atom)

Targetatom

e�

Ionizing radiation

Ion pair