Transcription
Radiation Oncology Physics:A Handbook for Teachers and StudentsE.B. PodgorsakTechnical EditorSponsored by the IAEA and endorsed by the COMP/CCPM, EFOMP, ESTRO, IOMP, PAHO and WHO
Cover photograph courtesy of E. Izewski
RADIATION ONCOLOGY PHYSICS:A HANDBOOK FOR TEACHERS AND STUDENTS
The following States are Members of the International Atomic Energy GIUMBENINBOLIVIABOSNIA AND HERZEGOVINABOTSWANABRAZILBULGARIABURKINA FASOCAMEROONCANADACENTRAL AFRICANREPUBLICCHILECHINACOLOMBIACOSTA RICACÔTE D’IVOIRECROATIACUBACYPRUSCZECH REPUBLICDEMOCRATIC REPUBLICOF THE CONGODENMARKDOMINICAN REPUBLICECUADOREGYPTEL ORGIAGERMANYGHANAGREECEGUATEMALAHAITIHOLY SEEHONDURASHUNGARYICELANDINDIAINDONESIAIRAN, ISLAMIC REPUBLIC ANKENYAKOREA, REPUBLIC OFKUWAITKYRGYZSTANLATVIALEBANONLIBERIALIBYAN ARAB ARMALAYSIAMALIMALTAMARSHALL CCOMYANMARNAMIBIANETHERLANDSNEW RAGUAYPERUPHILIPPINESPOLANDPORTUGALQATARREPUBLIC OF MOLDOVAROMANIARUSSIAN FEDERATIONSAUDI ARABIASENEGALSERBIA AND MONTENEGROSEYCHELLESSIERRA LEONESINGAPORESLOVAKIASLOVENIASOUTH AFRICASPAINSRI LANKASUDANSWEDENSWITZERLANDSYRIAN ARAB REPUBLICTAJIKISTANTHAILANDTHE FORMER YUGOSLAVREPUBLIC OF MACEDONIATUNISIATURKEYUGANDAUKRAINEUNITED ARAB EMIRATESUNITED KINGDOM OFGREAT BRITAIN ANDNORTHERN IRELANDUNITED REPUBLICOF TANZANIAUNITED STATES OF AZIMBABWEThe Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute ofthe IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957.The Headquarters of the Agency are situated in Vienna. Its principal objective is “to accelerate andenlarge the contribution of atomic energy to peace, health and prosperity throughout the world’’.
RADIATION ONCOLOGYPHYSICS: A HANDBOOK FORTEACHERS AND STUDENTSINTERNATIONAL ATOMIC ENERGY AGENCYVIENNA, 2005
COPYRIGHT NOTICEAll IAEA scientific and technical publications are protected by the termsof the Universal Copyright Convention as adopted in 1952 (Berne) and asrevised in 1972 (Paris). The copyright has since been extended by the WorldIntellectual Property Organization (Geneva) to include electronic and virtualintellectual property. Permission to use whole or parts of texts contained inIAEA publications in printed or electronic form must be obtained and isusually subject to royalty agreements. Proposals for non-commercialreproductions and translations are welcomed and will be considered on acase by case basis. Enquiries should be addressed by email to the PublishingSection, IAEA, at sales.publications@iaea.org or by post to:Sales and Promotion Unit, Publishing SectionInternational Atomic Energy AgencyWagramer Strasse 5P.O. Box 100A-1400 ViennaAustriafax: 43 1 2600 29302tel.: 43 1 2600 22417http://www.iaea.org/books IAEA, 2005Printed by the IAEA in AustriaJuly 2005STI/PUB/1196IAEA Library Cataloguing in Publication DataRadiation oncology physics : a handbook for teachers and students / editorE. B. Podgorsak ; sponsored by IAEA [et al.]. — Vienna : International Atomic Energy Agency, 2005.p.; 24 cm.STI/PUB/1196ISBN 92–0–107304–6Includes bibliographical references.1. Radiation dosimetry — Handbooks, manuals, etc. 2. Dosimeters— Handbooks, manuals, etc. 3. Radiation — Measurement —Handbooks, manuals, etc. 4. Radiation — Dosage — Handbooks,manuals, etc. 5. Radiotherapy — Handbooks, manuals, etc. 6. Photonbeams. 7. Electron beams. 8. Radioisotope scanning. I. Podgorsak,E. B., ed. II. International Atomic Energy Agency.IAEAL05–00402
FOREWORDIn the late 1990s the IAEA initiated for its Member States a systematicand comprehensive plan to support the development of teaching programmesin medical radiation physics. Multiple projects were initiated at various levelsthat, together with the well known short term training courses andspecialization fellowships funded by the IAEA Technical Cooperationprogramme, aimed at supporting countries to develop their own universitybased master of science programmes in medical radiation physics.One of the early activities of the IAEA in this period was thedevelopment of a syllabus in radiotherapy physics, which had the goal ofharmonizing the various levels of training that the IAEA provided. This wascarried out during 1997–1998, and the result of this work was released as areport used for designing IAEA training courses. In 1999–2000 a more detailedteachers’ guide was developed, in which the various topics in the syllabus wereexpanded to form a detailed ‘bullet list’ containing the basic guidelines of thematerial to be included in each topic so that lectures to students could beprepared accordingly. During the period 2001–2002 E.B. Podgorsak (Canada)was appointed editor of the project and redesigned the contents so that thebook became a comprehensive handbook for teachers and students, withcoverage deeper than a simple teachers’ guide. The initial list of topics wasexpanded considerably by engaging an enhanced list of internationalcontributors. The handbook was published as working material in 2003 andplaced on the Internet in order to seek comments, corrections and feedback.This handbook aims at providing the basis for the education of medicalphysicists initiating their university studies in the field. It includes the recentadvances in radiotherapy techniques; however, it is not designed to replace thelarge number of textbooks available on radiotherapy physics, which will still benecessary to deepen knowledge in the specific topics reviewed here. It isexpected that this handbook will successfully fill a gap in the teaching materialfor medical radiation physics, providing in a single manageable volume thelargest possible coverage available today. Its wide dissemination by the IAEAwill contribute to the harmonization of education in the field and will be ofvalue to newcomers as well as to those preparing for their certification asmedical physicists, radiation oncologists, medical dosimetrists and radiotherapytechnologists.Endorsement of this handbook has been granted by the followinginternational organizations and professional bodies: the InternationalOrganization for Medical Physics (IOMP), the European Society forTherapeutic Radiology and Oncology (ESTRO), the European Federation ofOrganisations for Medical Physics (EFOMP), the World Health Organization
(WHO), the Pan American Health Organization (PAHO), the CanadianOrganization of Medical Physicists (COMP) and the Canadian College ofPhysicists in Medicine (CCPM).The following international experts are gratefully acknowledged formaking major contributions to the development of an early version of thesyllabus: B. Nilsson (Sweden), B. Planskoy (United Kingdom) andJ.C. Rosenwald (France). The following made major contributions to thishandbook: R. Alfonso (Cuba), G. Rajan (India), W. Strydom (South Africa)and N. Suntharalingam (United States of America). The IAEA scientificofficers responsible for the project were (in chronological order) P. Andreo,J. Izewska and K.R. Shortt.EDITORIAL NOTEAlthough great care has been taken to maintain the accuracy of informationcontained in this publication, neither the IAEA nor its Member States assume anyresponsibility for consequences which may arise from its use.The use of particular designations of countries or territories does not imply anyjudgement by the publisher, the IAEA, as to the legal status of such countries or territories,of their authorities and institutions or of the delimitation of their boundaries.The mention of names of specific companies or products (whether or not indicatedas registered) does not imply any intention to infringe proprietary rights, nor should it beconstrued as an endorsement or recommendation on the part of the IAEA.The authors are responsible for having obtained the necessary permission for theIAEA to reproduce, translate or use material from sources already protected bycopyrights.
PREFACERadiotherapy, also referred to as radiation therapy, radiation oncology ortherapeutic radiology, is one of the three principal modalities used in thetreatment of malignant disease (cancer), the other two being surgery andchemotherapy. In contrast to other medical specialties that rely mainly on theclinical knowledge and experience of medical specialists, radiotherapy, with itsuse of ionizing radiation in the treatment of cancer, relies heavily on moderntechnology and the collaborative efforts of several professionals whosecoordinated team approach greatly influences the outcome of the treatment.The radiotherapy team consists of radiation oncologists, medicalphysicists, dosimetrists and radiation therapy technologists: all professionalscharacterized by widely differing educational backgrounds and one commonlink — the need to understand the basic elements of radiation physics, and theinteraction of ionizing radiation with human tissue in particular. Thisspecialized area of physics is referred to as radiation oncology physics, andproficiency in this branch of physics is an absolute necessity for anyone whoaspires to achieve excellence in any of the four professions constituting theradiotherapy team. Current advances in radiation oncology are driven mainlyby technological development of equipment for radiotherapy procedures andimaging; however, as in the past, these advances rely heavily on the underlyingphysics.This book is dedicated to students and teachers involved in programmesthat train professionals for work in radiation oncology. It provides acompilation of facts on the physics as applied to radiation oncology and as suchwill be useful to graduate students and residents in medical physicsprogrammes, to residents in radiation oncology, and to students in dosimetryand radiotherapy technology programmes. The level of understanding of thematerial covered will, of course, be different for the various student groups;however, the basic language and knowledge for all student groups will be thesame. The text will also be of use to candidates preparing for professionalcertification examinations, whether in radiation oncology, medical physics,dosimetry or radiotherapy technology.The intent of the text is to serve as a factual supplement to the varioustextbooks on medical physics and to provide basic radiation oncology physicsknowledge in the form of a syllabus covering all modern aspects of radiationoncology physics. While the text is mainly aimed at radiation oncologyprofessionals, certain parts of it may also be of interest in other branches ofmedicine that use ionizing radiation not for the treatment of disease but for thediagnosis of disease (diagnostic radiology and nuclear medicine). The contents
may also be useful for physicists who are involved in studies of radiationhazards and radiation protection (health physics).This book represents a collaborative effort by professionals from manydifferent countries who share a common goal of disseminating their radiationoncology physics knowledge and experience to a broad international audienceof teachers and students. Special thanks are due to J. Denton-MacLennan forcritically reading and editing the text and improving its syntax.E.B. Podgorsak
CONTRIBUTORSAndreo, P.University of Stockholm, Karolinska Institute,SwedenEvans, M.D.C.McGill University Health Centre, CanadaHendry, J.H.International Atomic Energy AgencyHorton, J.L.University of Texas MD Anderson Cancer Center,United States of AmericaIzewska, J.International Atomic Energy AgencyMijnheer, B.J.Netherlands Cancer Institute, NetherlandsMills, J.A.Walsgrave Hospital, United KingdomOlivares, M.McGill University Health Centre, CanadaOrtiz López, P.International Atomic Energy AgencyParker, W.McGill University Health Centre, CanadaPatrocinio, H.McGill University Health Centre, CanadaPodgorsak, E.B.McGill University Health Centre, CanadaPodgorsak, M.B.Roswell Park Cancer Institute, United States ofAmericaRajan, G.Bhabha Atomic Research Centre, IndiaSeuntjens, J.P.McGill University Health Centre, CanadaShortt, K.R.International Atomic Energy AgencyStrydom, W.Medical University of Southern Africa,South AfricaSuntharalingam, N.Thomas Jefferson University Hospital, UnitedStates of AmericaThwaites, D.I.University of Edinburgh, United KingdomTolli, H.International Atomic Energy Agency
BLANK
CONTENTSCHAPTER 1.1.1.BASIC RADIATION PHYSICS . . . . . . . . . . . . . . . . . . .1INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1.1.Fundamental physical constants (rounded off to foursignificant figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1.2.Important derived physical constants and relationships . .1.1.3.Physical quantities and units . . . . . . . . . . . . . . . . . . . . . . . .1.1.4.Classification of forces in nature . . . . . . . . . . . . . . . . . . . . .1.1.5.Classification of fundamental particles . . . . . . . . . . . . . . . .1.1.6.Classification of radiation . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1.7.Classification of ionizing photon radiation . . . . . . . . . . . . .1.1.8.Einstein’s relativistic mass, energy and momentumrelationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1.9.Radiation quantities and units . . . . . . . . . . . . . . . . . . . . . . .11134456671.2.ATOMIC AND NUCLEAR STRUCTURE . . . . . . . . . . . . . . . . . .1.2.1.Basic definitions for atomic structure . . . . . . . . . . . . . . . .1.2.2.Rutherford’s model of the atom . . . . . . . . . . . . . . . . . . . . .1.2.3.Bohr’s model of the hydrogen atom . . . . . . . . . . . . . . . . . .1.2.4.Multielectron atoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.5.Nuclear structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.6.Nuclear reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.7.Radioactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.8.Activation of nuclides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.9.Modes of radioactive decay . . . . . . . . . . . . . . . . . . . . . . . .779101214151619201.3.ELECTRON INTERACTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.3.1.Electron–orbital electron interactions . . . . . . . . . . . . . . . .1.3.2.Electron–nucleus interactions . . . . . . . . . . . . . . . . . . . . . . .1.3.3.Stopping power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.3.4.Mass scattering power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22232324251.4.PHOTON INTERACTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.4.1.Types of indirectly ionizing photon radiation . . . . . . . . . . .1.4.2.Photon beam attenuation . . . . . . . . . . . . . . . . . . . . . . . . . .1.4.3.Types of photon interaction . . . . . . . . . . . . . . . . . . . . . . . . .1.4.4.Photoelectric effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.4.5.Coherent (Rayleigh) scattering . . . . . . . . . . . . . . . . . . . . . .262626282829
3.1.4.14.Compton effect (incoherent scattering) . . . . . . . . . . . . . . .Pair production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Photonuclear reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Contributions to attenuation coefficients . . . . . . . . . . . . . .Relative predominance of individual effects . . . . . . . . . . .Effects following photon interactions . . . . . . . . . . . . . . . . .Summary of photon interactions . . . . . . . . . . . . . . . . . . . . .Example of photon attenuation . . . . . . . . . . . . . . . . . . . . .Production of vacancies in atomic shells . . . . . . . . . . . . . . .303234343637384041BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43CHAPTER 2.2.1.2.2.2.3.2.4.2.5.2.6.2.7.2.8.DOSIMETRIC PRINCIPLES,QUANTITIES AND UNITS . . . . . . . . . . . . . . . . . . . . . .45INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PHOTON FLUENCE AND ENERGY FLUENCE . . . . . . . . . . . .KERMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CEMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABSORBED DOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .STOPPING POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RELATIONSHIPS BETWEEN VARIOUS DOSIMETRICQUANTITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.7.1.Energy fluence and kerma (photons) . . . . . . . . . . . . . . . . .2.7.2.Fluence and dose (electrons) . . . . . . . . . . . . . . . . . . . . . . . .2.7.3.Kerma and dose (charged particle equilibrium) . . . . . . . .2.7.4.Collision kerma and exposure . . . . . . . . . . . . . . . . . . . . . . .454548484949CAVITY THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.8.1.Bragg–Gray cavity theory . . . . . . . . . . . . . . . . . . . . . . . . . . .2.8.2.Spencer–Attix cavity theory . . . . . . . . . . . . . . . . . . . . . . . . .2.8.3.Considerations in the application of cavity theory toionization chamber calibration and dosimetry protocols .2.8.4.Large cavities in photon beams . . . . . . . . . . . . . . . . . . . . . .2.8.5.Burlin cavity theory for photon beams . . . . . . . . . . . . . . . .2.8.6.Stopping power ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .616162BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70545456576064666668
CHAPTER 3.RADIATION DOSIMETERS . . . . . . . . . . . . . . . . . . . . .713.1.3.2.INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PROPERTIES OF DOSIMETERS . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.1.Accuracy and precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.1.1. Type A standard uncertainties . . . . . . . . . . . . . .3.2.1.2. Type B standard uncertainties . . . . . . . . . . . . . .3.2.1.3. Combined and expanded uncertainties . . . . . . .3.2.2.Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.3.Dose rate dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.4.Energy dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.5.Directional dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.6.Spatial resolution and physical size . . . . . . . . . . . . . . . . . . .3.2.7.Readout convenience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.2.8.Convenience of use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .717272727373747475767676763.3.IONIZATION CHAMBER DOSIMETRY SYSTEMS . . . . . . . . .3.3.1.Chambers and electrometers . . . . . . . . . . . . . . . . . . . . . . . .3.3.2.Cylindrical (thimble type) ionization chambers . . . . . . . .3.3.3.Parallel-plate (plane-parallel) ionization chambers . . . . .3.3.4.Brachytherapy chambers . . . . . . . . . . . . . . . . . . . . . . . . . . .3.3.5.Extrapolation chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . .7777787979793.4.FILM DOSIMETRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.4.1.Radiographic film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.4.2.Radiochromic film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8181843.5.LUMINESCENCE DOSIMETRY . . . . . . . . . . . . . . . . . . . . . . . . . .3.5.1.Thermoluminescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.5.2.Thermoluminescent dosimeter systems . . . . . . . . . . . . . . .3.5.3.Optically stimulated luminescence systems . . . . . . . . . . . .848586883.6.SEMICONDUCTOR DOSIMETRY . . . . . . . . . . . . . . . . . . . . . . . .3.6.1.Silicon diode dosimetry systems . . . . . . . . . . . . . . . . . . . . .3.6.2.MOSFET dosimetry systems . . . . . . . . . . . . . . . . . . . . . . . .8989903.7.OTHER DOSIMETRY SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . .3.7.1.Alanine/electron paramagnetic resonance dosimetrysystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.7.2.Plastic scintillator dosimetry system . . . . . . . . . . . . . . . . . .3.7.3.Diamond dosimeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91919292
3.7.4.Gel dosimetry systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .933.8.PRIMARY STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.8.1.Primary standard for air kerma in air . . . . . . . . . . . . . . . . .3.8.2.Primary standards for absorbed dose to water . . . . . . . . .3.8.3.Ionometric standard for absorbed dose to water . . . . . . . .3.8.4.Chemical dosimetry standard for absorbed dose to water3.8.5.Calorimetric standard for absorbed dose to water . . . . . .9495959696973.9.SUMMARY OF SOME COMMONLY USED DOSIMETRICSYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9799CHAPTER 4.4.1.4.2.4.3.4.4.RADIATION MONITORING INSTRUMENTS . . . . 101INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OPERATIONAL QUANTITIES FORRADIATION MONITORING . . . . . . . . . . . . . . . . . . . . . . . . . . . . .AREA SURVEY METERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.1.Ionization chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.2.Proportional counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.3.Neutron area survey meters . . . . . . . . . . . . . . . . . . . . . . . . .4.3.4.Geiger–Müller counters . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.5.Scintillator detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.6.Semiconductor detectors . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.7.Commonly available features of area survey meters . . . .4.3.8.Calibration of survey meters . . . . . . . . . . . . . . . . . . . . . . . .4.3.9.Properties of survey meters . . . . . . . . . . . . . . . . . . . . . . . . .4.3.9.1. Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.9.2. Energy dependence . . . . . . . . . . . . . . . . . . . . . . .4.3.9.3. Directional dependence . . . . . . . . . . . . . . . . . . . .4.3.9.4. Dose equivalent range . . . . . . . . . . . . . . . . . . . .4.3.9.5. Response time . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.9.6. Overload characteristics . . . . . . . . . . . . . . . . . . .4.3.9.7. Long term stability . . . . . . . . . . . . . . . . . . . . . . .4.3.9.8. Discrimination between different typesof radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.9.9. Uncertainties in area survey measurements . . 11111112112112INDIVIDUAL MONITORING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134.4.1.Film badge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
ence dosimetry badge . . . . . . . . . . . . . . . .Radiophotoluminescent glass dosimetry systems . . . . . . .Optically stimulated luminescence systems . . . . . . . . . . . .Direct reading personal monitors . . . . . . . . . . . . . . . . . . . .Calibration of personal dosimeters . . . . . . . . . . . . . . . . . . .Properties of personal monitors . . . . . . . . . . . . . . . . . . . . . .4.4.7.1. Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.7.2. Energy dependence . . . . . . . . . . . . . . . . . . . . . . .4.4.7.3. Uncertainties in personal monitoringmeasurements . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.7.4. Equivalent dose range . . . . . . . . . . . . . . . . . . . . .4.4.7.5. Directional dependence . . . . . . . . . . . . . . . . . . .4.4.7.6. Discrimination between different typesof radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115116116117118118118119119119120120BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120CHAPTER 5.TREATMENT MACHINES FOR EXTERNALBEAM RADIOTHERAPY . . . . . . . . . . . . . . . . . . . . . . . 1235.1.5.2.INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X RAY BEAMS AND X RAY UNITS . . . . . . . . . . . . . . . . . . . . . . .5.2.1.Characteristic X rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.2.2.Bremsstrahlung (continuous) X rays . . . . . . . . . . . . . . . . .5.2.3.X ray targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.2.4.Clinical X ray beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.2.5.X ray beam quality specifiers . . . . . . . . . . . . . . . . . . . . . . .5.2.6.X ray machines for radiotherapy . . . . . . . . . . . . . . . . . . . . .1231241241241251261271275.3.GAMMA RAY BEAMS AND GAMMA RAY UNITS . . . . . . . .5.3.1.Basic properties of gamma rays . . . . . . . . . . . . . . . . . . . . . .5.3.2.Teletherapy machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.3.3.Teletherapy sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.3.4.Teletherapy source housing . . . . . . . . . . . . . . . . . . . . . . . . .5.3.5.Dose delivery with teletherapy machines . . . . . . . . . . . . . .5.3.6.Collimator and penumbra . . . . . . . . . . . . . . . . . . . . . . . . .1291291301301311321325.4.PARTICLE ACCELERATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.4.1.Betatron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.4.2.Cyclotron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.4.3.Microtron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132134134135
5.5.LINACS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.1.Linac generations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.2.Safety of linac installations . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.3.Components of modern linacs . . . . . . . . . . . . . . . . . . . . . . .5.5.4.Configuration of modern linacs . . . . . . . . . . . . . . . . . . . . . .5.5.5.Injection system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.6.Radiofrequency power generation system . . . . . . . . . . . . .5.5.7.Accelerating waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.8.Microwave power transmission . . . . . . . . . . . . . . . . . . . . . .5.5.9.Auxiliary system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.10. Electron beam transport . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.11. Linac treatment head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.12. Production of clinical photon beams in a linac . . . . . . . . .5.5.13. Beam collimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5.14. Production of clinical electron beams in a linac . . . . . . . . .5.5.15. Dose monitoring system . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.6.RADIOTHERAPY WITH PROTONS, NEUTRONS ANDHEAVY IONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SHIELDING CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . .COBALT-60 TELETHERAPY UNITS VERSUS LINACS . . . . .SIMULATORS AND COMPUTEDTOMOGRAPHY SIMULATORS . . . . . . . . . . . . . . . . . . . . . . . . . . .5.9.1.Radiotherapy simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.9.2.Computed tomography simulator . . . . . . . . . . . . . . . . . . . 471481491491511521531561571585.10. TRAINING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160CHAPTER 6.EXTERNAL PHOTON BEAMS:PHYSICAL ASPECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 1616.1.6.2.INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .QUANTITIES USED IN DESCRIBING A PHOTON BEAM . .6.2.1.Photon fluence and photon fluence rate . . . . . . . . . . . . . .6.2.2.Energy fluence and energy fluence rate . . . . . . . . . . . . . . .6.2.3.Air kerma in air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.2.4.Exposure in air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.2.5.Dose to small mass of medium in air . . . . . . . . . . . . . . . . . .1611611621621631641646.3.PHOTON BEAM SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
6.4.6.5.INVERSE SQUARE LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PENETRATION OF PHOTON BEAMS INTO APHANTOM OR PATIENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.5.1.Surface dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.5.2.Buildup region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.5.3.Depth of dose maximum zmax . . . . . . . . . . . . . . . . .
physics. This book is dedicated to students and teachers involved in programmes that train professionals for work in radiation oncology. It provides a compilation of facts on the physics as applied to radiation oncology and as such will be useful to graduate s
