DOCSLIB.ORG

Basic Radiation Interactions, Definition of Dosimetric Quantities, and Data Sources

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Basic Radiation Interactions, Definition of Dosimetric Quantities, and Data Sources Basic Radiation Interactions, Definition of Dosimetric Quantities, and Data Sources J.V. Siebers Virginia Commonwealth University Richmond, Virginia USA 2009 AAPM Summer School Learninggj Objectives 1. To review and describ e the bas ics of radiation interactions for understanding radiation dosimetry 2. To review definitions of quantities required for understanding radiation dosimetry ©JVS: 2009 AAPM SS Constants Units Conversions ©JVS: 2009 AAPM SS ©JVS: 2009 AAPM SS Scope Radiation Types Ionizing Interactions can remove atomic orbital electrons Non-Ionizing Particulate Electromagnetic -electron -positron -proton -neutron -alpha -etc. ©JVS: 2009 AAPM SS Types of ionizin g radiation Direc tltly ion iz ing radia tion Direct interactions via the Coulomb force along a particles track Charged particles electrons positrons protons heavy charged particles ©JVS: 2009 AAPM SS Direct Ionization Coulombic Interaction e- A charged particle exerts electromagnetic forces on atomic Energy transfer can electrons result in the ejection of an electron (ionization) ©JVS: 2009 AAPM SS Indirectlyyg Ionizing Radiation Uncharged particles that must first transfer energy to a charged particle which can then further ionize matter Two step process Examples Elec tromagne tic radia tions: x- or γ-rays Neutrons ©JVS: 2009 AAPM SS Indirectly Ionizing Radiation Pho toe lec tr ic Effec t e- Ejec te d h electrons further ionize matter ©JVS: 2009 AAPM SS Radiant Energy R R – Total energy, excluding rest mass, carried by particles Photons: E = hν = hc/λ Electrons + other CPs: kinetic energy T ©JVS: 2009 AAPM SS Energy imparted ε ε - Energy imparted RRin out Q Q mass to energy conversion resulilting from interactions or radioactive decay if(m→E), Q>0 e- e- h Rin h Rout if(E→m), Q<0 R RR R Q ©JVS: 2009 AAPM SS incu in out c out u Dose d D Gy dm Energy deposited per unit mass 1 Gy = 1 J/kg Knowledge of D is the object of dosimetry ©JVS: 2009 AAPM SS Equilibrium Part 1: Radi a tion Equ ilibr ium h e- h RRin out e- e- h h e- RE dQ d RE RRinQ out D Q dm dm ©JVS: 2009 AAPM SS Radiation Sources Radioactive decay Alpha-decay Beta-decay Electron capture Isomeric transitions Accelerated charged particles Direct X-ray generators Atomic energy transitions Characteristic X-rays Auger electrons Interaction products ©JVS: 2009 AAPM SS Radioactive Decay General balance equations AP AA RRDR A Q ZZZZ RR QMP MDR M ©JVS: 2009 AAPM SS Q ©JVS: 2009 AAPM SS Radioactive Decay Activity dN AN dt t AAet 0 ln 2 t 1 2 ©JVS: 2009 AAPM SS Radioactive Decay α AA44 ZZP 22DHeQ α ‘s have short range / AA0 ZZP 11DQ AA0 ZZP 11DQ Neutrino ( , ))p results in spectrum of energies Emax and E are tabulated ( , ) are non-ionizing Electron Capture AA0 ZZPDQP 11e D v Q Can occur when energetically prohibited Followed by characteristic x-rays or Auger electron Isosoecmeric Tra asnsiti on AA*0 ZZP PQ0 decay from meta-stable state Internal Conversion AA* 00 ZZPPQP 11e P e Q Competes with isomeric transition Results in ejection of atomic electron ©JVS: 2009 AAPM SS ©JVS: 2009 AAPM SS β+ 15 15 0 0 8710ON 17321.732 MVMeV Electron 15Oe 0 15 N 0 1.732 MeV Capture 8170 ©JVS: 2009 AAPM SS ©JVS: 2009 AAPM SS Accelerated Charged Particles Direct use Electrons, protons, … Indirect via production of electromagnetic radiation Synchrotron radiation Bremmstrahlung ©JVS: 2009 AAPM SS Synchrotron Radiation h Magnetic Field e- Synchrotron image courtesy of http://www-project.slac.stanford.edu/ssrltxrf/spear.htm ©JVS: 2009 AAPM SS Bremmstrahlung h brems e- ©JVS: 2009 AAPM SS Atomic Energy Transition Characteristic x-ray xray h ©JVS: 2009 AAPM SS Atomic Energy Transition Auger Electron e- ©JVS: 2009 AAPM SS QQyguantifying Radiation Fields Thus far R ε D ©JVS: 2009 AAPM SS Radiation Fluence dN particles N is number of particles crossing sphere 2 da m surrounding P with cross- sectional area da Integrated over all directions and energies Single particle type ©JVS: 2009 AAPM SS Equivalent definition of fluence l nTracks l = particle track length through a V volume l need not be straight Volume can be irregular UflUseful for MtMonte Carlo applications ©JVS: 2009 AAPM SS Energy Fluence Definition dR J da m2 Poly-energetic Mono-energetic E EdE E E Differenti al energy fluence E EddE ©JVS: 2009 AAPM SS Attenuation dndlt l 1 l 0e nt m ©JVS: 2009 AAPM SS el l 0 Attenuation coefficient µ represents the in terac tion (remova l) of primaries from the beam No consideration is given to what occurs as a result of the interaction Secondary particles Energy-to-mass conversion … To remove density dependence, tabulated as µ/ρ [cm2/]/g] ©JVS: 2009 AAPM SS TERMA Total Energy Release per unit MAss J * TERMA kg Describes loss of radiant energy from uncharged primaries as they interact in material Energy lost can be absorbed locally or at a distance For poly-energetic spectra * E J TERMA E dE E ©JVS: 2009 AAPM SS E kg Aside: Photon Interactions To understand what happens with the radiant energy removed, understand the interactions (e.g. γ interactions) ©JVS: 2009 AAPM SS Photon interactions contributing to µ -1 Rayleigh m σ = Rayleigh + Compton scattering τ = photo-electric κ = pair production η = photo-nuclear ©JVS: 2009 AAPM SS RayygSleigh Scatterin g Elastic coherent scattering of the photon by an atom Important for low energy photons Cont tibtributes < 20% to ttltotal attenua tion coefficient ©JVS: 2009 AAPM SS Compton Scattering e- h h 2 NZA cm e A g ©JVS: 2009 AAPM SS Compton ©JVS: 2009 AAPM SS Photoelectric Effect e- ThEThET h e bbA ©JVS: 2009 AAPM SS Photo-electric 34 Z Au 23 h τ increases when shell can participate in reaction ©JVS: 2009 AAPM SS Pair Production e- h pair e+ T 2 avail TTee h 2 mce mc2 o radian T ©JVS: 2009 AAPM SS Triplet Production 2 Thmcavail 2 e e- h e- triplet e+ h 2mc2 T e 3 ©JVS: 2009 AAPM SS Photo-nuclear interactions (γ,n), (γ,Xn), (γ,p), … BE (Binding Energies) result in thresholds >~ 10 MeV Cross-section is small (η<0.1µ) Neutrons are ppgenetrating ©JVS: 2009 AAPM SS ©JVS: 2009 AAPM SS Pb attenuation coefficient ©JVS: 2009 AAPM SS Relative importance of interactions ©JVS: 2009 AAPM SS Summary photon interactions ©JVS: 2009 AAPM SS Energy transferred to charged particles per-itinterac tion nonr generalR RQ tr inuu out photo = compton = pair = Average n tr i tr ni ©JVS: 2009 AAPM SS el l 0 Recall Attenuation coefficient µ represents the interaction (removal) of primaries from the beam No consideration is given to what occurs as a result of the interaction Secondary particles Energy-to-mass conversion … To remove density dependence, tabulated as µ/ρ [cm2/g] ©JVS: 2009 AAPM SS Mass-energy transfer coefficient Describes the transfer of energy to charged partic les tr tr h ©JVS: 2009 AAPM SS KERMA Kinetic Energy Release per unit MAss d KERMA K tr dm * tr J kg The transfer of radiant energy from uncharged primaries to charged particles as they interact in a material Energy transferred can be absorbed locally or at a distance ©JVS: 2009 AAPM SS *Mono-energetic, integrate for poly-energetic Net energy transfer netnetRRRRR rr Rnonr nonr R r R r Q Q trtr tr tr out uuu in inuu out out u u out u Accounts for portion of kerma is radiated away T’Te- hvbrems Compton example T net Thv h e- tre brems h ©JVS: 2009 AAPM SS Mass-energy absorption coefficient RditiRadiative loss frac tion g net g 1 tr tr Mass-energy absorp tion coeffic ien t en 1 g tr ©JVS: 2009 AAPM SS Kerma Components K KKcr Colli s ion Kerma net * dtr en K Kc c dm Portion of kerma that remains collisional energy losses (non-radiative) Radiative Kerma Portion of kerma (transported elsewhere) by radiative losses ©JVS: 2009 AAPM SS Exposure and W Exposure Hist ori cal radia tion unit dQ C X Ionization density in air dm kg Related to air collision kerma by mean energy required to produce an ion pair e C XK c air W air kg WevJeVipJ1.602 1019 ( ) 1 33.97 33.97 e ip16021.602 1019 ( C electron ) electron C air ©JVS: 2009 AAPM SS Aside Indirectly ionizing radiation How many ionization events can be initiated by a 10 keV photo-electron? 3 1 ip ?ip 10 10 eV 294 ip 33.97 eV ©JVS: 2009 AAPM SS Equilibrium Part 2: Charged Particle Equilibrium h e- e- e- e- RR h inc out c e- R RR R Q incu in out c out u CPE RR QCPE ... CPE net inuu out tr net d CPE d DKtr dm dm c ©JVS: 2009 AAPM SS Charggpe particles e-, e+, p, α, … Sources Accelerated beams Radioactive decay Reaction products (e,γ) , … (n,p), … (()e,e), … Coulomb force interaction Inverse square dependence Semi-continuous rather than discrete interactions Results in energy loss and directional change Interaction can be classified by impact parameter ©JVS: 2009 AAPM SS CP interactions undisturbed incident trajectory b = impact parameter a = atitomic radius n = nuclear radius b b>>a Soft, atomic interaction b~a Hard, knock-on interaction a b<<a Nuclear interactions possible ©JVS: 2009 AAPM SS SSppgptopping power Energy loss per unit path-lthlength dE MeV SdEMeV cm2 S dx cm dx g StSeparate components bby iittinteraction S SS col rad ©JVS: 2009 AAPM SS SSppgptopping power formulations BdBased on BthBethe-Bloch , Heitl er, … Electrons: ICRU 37 2 2 SZ22 1 2ln rmcNee A 2 F 2 2 Collisional A 2 Imc e v Tmc2 2 e c Srrad e N A 22 Z EmcBr e 2 2 137 A F 11 21ln2 8 Material dependent terms ©JVS: 2009 AAPM
Load more

Recommended publications
  • Neutron Interactions and Dosimetry Outline Introduction Tissue
    Outline • Neutron dosimetry Neutron Interactions and – Thermal neutrons Dosimetry – Intermediate-energy neutrons – Fast neutrons Chapter 16 • Sources of neutrons • Mixed field dosimetry, paired dosimeters F.A. Attix, Introduction to Radiological • Rem meters Physics and Radiation Dosimetry Introduction Tissue composition • Consider neutron interactions with the majority tissue elements H, O, C, and N, and the resulting absorbed dose • Because of the short ranges of the secondary charged particles that are produced in such interactions, CPE is usually well approximated • Since no bremsstrahlung x-rays are generated, the • The ICRU composition for muscle has been assumed in absorbed dose can be assumed to be equal to the most cases for neutron-dose calculations, lumping the kerma at any point in neutron fields at least up to 1.1% of “other” minor elements together with oxygen to an energy E ~ 20 MeV make a simple four-element (H, O, C, N) composition Neutron kinetic energy Neutron kinetic energy • Neutron fields are divided into three • Thermal neutrons, by definition, have the most probable categories based on their kinetic energy: kinetic energy E=kT=0.025eV at T=20C – Thermal (E<0.5 eV) • Neutrons up to 0.5eV are considered “thermal” due to simplicity of experimental test after they emerge from – Intermediate-energy (0.5 eV<E<10 keV) moderator material – Fast (E>10 keV) • Cadmium ratio test: • Differ by their primary interactions in tissue – Gold foil can be activated through 197Au(n,)198Au interaction and resulting biological effects
    [Show full text]
  • 7. Gamma and X-Ray Interactions in Matter
    Photon interactions in matter Gamma- and X-Ray • Compton effect • Photoelectric effect Interactions in Matter • Pair production • Rayleigh (coherent) scattering Chapter 7 • Photonuclear interactions F.A. Attix, Introduction to Radiological Kinematics Physics and Radiation Dosimetry Interaction cross sections Energy-transfer cross sections Mass attenuation coefficients 1 2 Compton interaction A.H. Compton • Inelastic photon scattering by an electron • Arthur Holly Compton (September 10, 1892 – March 15, 1962) • Main assumption: the electron struck by the • Received Nobel prize in physics 1927 for incoming photon is unbound and stationary his discovery of the Compton effect – The largest contribution from binding is under • Was a key figure in the Manhattan Project, condition of high Z, low energy and creation of first nuclear reactor, which went critical in December 1942 – Under these conditions photoelectric effect is dominant Born and buried in • Consider two aspects: kinematics and cross Wooster, OH http://en.wikipedia.org/wiki/Arthur_Compton sections http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=22551 3 4 Compton interaction: Kinematics Compton interaction: Kinematics • An earlier theory of -ray scattering by Thomson, based on observations only at low energies, predicted that the scattered photon should always have the same energy as the incident one, regardless of h or • The failure of the Thomson theory to describe high-energy photon scattering necessitated the • Inelastic collision • After the collision the electron departs
    [Show full text]
  • TUTORIAL on NEUTRON PHYSICS in DOSIMETRY S. Pomp1
    TUTORIAL ON NEUTRON PHYSICS IN DOSIMETRY S. Pomp1,* 1 Department of physics and astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden. *Corresponding author. E‐mail address: [email protected] (S.Pomp) Abstract: Almost since the time of the discovery of the neutron more than 70 years ago, efforts have been made to understand the effects of neutron radiation on tissue and, eventually, to use neutrons for cancer treatment. In contrast to charged particle or photon radiations which directly lead to release of electrons, neutrons interact with the nucleus and induce emission of several different types of charged particles such as protons, alpha particles or heavier ions. Therefore, a fundamental understanding of the neutron‐nucleus interaction is necessary for dose calculations and treatment planning with the needed accuracy. We will discuss the concepts of dose and kerma, neutron‐nucleus interactions and have a brief look at nuclear data needs and experimental facilities and set‐ups where such data are measured. Keywords: Neutron physics; nuclear reactions; kerma coefficients; neutron beams; Introduction Dosimetry is concerned with the ability to determine the absorbed dose in matter and tissue resulting from exposure to directly and indirectly ionizing radiation. The absorbed dose is a measure of the energy deposited per unit mass in the medium by ionizing radiation and is measured in Gray, Gy, where 1 Gy = 1 J/kg. Radiobiology then uses information about dose to assess the risks and gains. A risk is increased probability to develop cancer due to exposure to a certain dose. A gain is exposure of a cancer tumour to a certain dose in order to cure it.
    [Show full text]
  • Meeting the Joint Commission's Fluoroscopy Training Requirements
    Meeting The Joint Commission’s Outline Fluoroscopy Training Requirements • Overview of TJC’s recent fluoroscopy requirements Part I: Image Gently, Image Wisely and Dose Optimization • Basics of radiation units, terminology and regulatory limits • Radiation risks in fluoroscopy, their prevalence and probabilities • Physical and operational aspects of fluoroscopes Satish Nair Ph.D, CHP, DABMP Certified Health Physicist • Best practices in fluoroscopy: for patients and operators Certified Medical Physicist F. X. Massé Associates, Inc. Health and Medical Physics Consultants Gloucester, MA fxmasse.com 20th Annual SRPE Educational Conference, Las Vegas, NV April 2019 1 January 2019 Terminology Convert to Equivalent dose (mrem, mSv) X-ray , Gamma, Beta = 1 Alpha = 20 Proton = 2 Head CT Neutron = 5 to 20 Cardiac Exposure Stress Test KUB Image Gently: ‘Pause and Pulse’ resources X Ray 1 January 2019 • Annual Medical Physics evaluation of fluoroscopes • Designated Radiation Safety Officer (RSO) Measure Exposure Extremity X Ray • Dose indices stored in retrievable format: CAK or KAP - if displayed Roentgen Compare to NB Convert to R, mR, mR/h If not displayed: cumulative fluoro time and # of digital spot images Calculate Radiation Effective Dose (Whole Body Dose) • Establish radiation exposure and skin dose thresholds for adverse effects Absorbed dose to organ • Perform evaluation if exceeded these thresholds are exceeded Roentgen equivalent man Roentgen absorbed dose rem, mrem, mrem/year rad, mrad 1 July 2018 Sievert: Sv, mSv • Use of shielding
    [Show full text]
  • Chapter 3. Fundamentals of Dosimetry
    Chapter 3. Fundamentals of Dosimetry Slide series of 44 slides based on the Chapter authored by E. Yoshimura of the IAEA publication (ISBN 978-92-0-131010-1): Diagnostic Radiology Physics: A Handbook for Teachers and Students Objective: To familiarize students with quantities and units used for describing the interaction of ionizing radiation with matter Slide set prepared by E.Okuno (S. Paulo, Brazil, Institute of Physics of S. Paulo University) IAEA International Atomic Energy Agency Chapter 3. TABLE OF CONTENTS 3.1. Introduction 3.2. Quantities and units used for describing the interaction of ionizing radiation with matter 3.3. Charged particle equilibrium in dosimetry 3.4. Cavity theory 3.5. Practical dosimetry with ion chambers IAEA Diagnostic Radiology Physics: a Handbook for Teachers and Students – chapter 3, 2 3.1. INTRODUCTION Subject of dosimetry : determination of the energy imparted by radiation to matter. This energy is responsible for the effects that radiation causes in matter, for instance: • a rise in temperature • chemical or physical changes in the material properties • biological modifications Several of the changes produced in matter by radiation are proportional to absorbed dose , giving rise to the possibility of using the material as the sensitive part of a dosimeter There are simple relations between dosimetric and field description quantities IAEA Diagnostic Radiology Physics: a Handbook for Teachers and Students – chapter 3, 3 3.2. QUANTITIES AND UNITS USED FOR DESCRIBING THE INTERACTION OF IONIZING RADIATION
    [Show full text]
  • Survivor Dosimetry
    Chapter 12 SURVIVOR DOSIMETRY Part A. Fluence-to-Kerma Conversion Coefficients George D. Kerr, Joseph V. Pace III, Stephen D. Egbert Introduction An important step in the dosimetry evaluation is to relate the radiation passing through a unit volume of a material of interest (fluence) to the energy release (kerma) in the material, which determines the absorbed dose. The fluence-to-kerma conversion coefficients or “kerma coefficients” used in the Dosimetry System 1986 (DS86) are taken from Kerr (1982). These kerma coefficients are based on body tissue compositions for Reference Man from the International Commission on Radiological Protection (1975) and Kerr (1982), the mass energy- absorption coefficients for photons from Hubbell (1982), and the elemental kerma coefficients for neutrons from Caswell et al. (1980). Hence, the kerma coefficients used in DS86 are approximately 20 years old. In order to provide an updated set of kerma coefficients for use in the Dosimetry System 2002 (DS02), a new evaluation has been completed. This new evaluation considered recently suggested changes in the composition of soft tissues of the body in ICRU Report 44 (International Commission on Radiation Units and Measurements 1989), the mass energy- absorption coefficients for photons by Hubbell and Seltzer (1996), and the elemental kerma coefficients for neutrons in ICRU Report 63 (International Commission on Radiation Units and Measurements 2000). The new DS02 kerma coefficients for soft tissue are presented as both point-wise data for use in Monte Carlo radiation transport calculations and multigroup data for use in discrete ordinates radiation transport calculations. Elemental Composition of Soft Tissue Various approximations to the elemental composition of the tissues and organs of the human body have been used in both kerma and dose calculations for photons and neutrons.
    [Show full text]
  • Chapter 2: Dosimetric Principles, Quantities and Units
    Chapter 2: Dosimetric Principles, Quantities and Units Set of 131 slides based on the chapter authored by J.P. Seuntjens, W. Strydom, and K.R. Shortt of the IAEA publication: Review of Radiation Oncology Physics: A Handbook for Teachers and Students Objective: To familiarize the student with the basic principles of the quantities used in dosimetry for ionizing radiation. Slide set prepared in 2006 by G.H. Hartmann (Heidelberg, DKFZ) Comments to S. Vatnitsky: [email protected] IAEA International Atomic Energy Agency CHAPTER 2. TABLE OF CONTENTS 2.1 Introduction 2.2 Radiation field quantities (also denoted as Radiometric quantities) 2.3 Dosimetrical quantities: fundamentals 2.4 Dosimetrical quantities 2.5 Interaction coefficients: electrons 2.6 Interaction coefficients: photons 2.7 Relation between radiation field and dosimetric quantities 2.8 Cavity theory IAEA Review of Radiation Oncology Physics: A Handbook for Teachers and Students - 2.Slide 1 1 2.1 INTRODUCTION Radiation dosimetry has its origin in the medical application of ionizing radiation starting with the discovery of x-rays by Röntgen in 1895. In particular • the need of protection against ionizing radiation, • the application in medicine required quantitative methods to determine a "dose of radiation". The purpose of a quantitative concept of a dose of radiation is: • to predict associated radiation effects (radiation detriments) • to reproduce clinical outcomes. IAEA Review of Radiation Oncology Physics: A Handbook for Teachers and Students - 2.1. Slide 1 2.1 INTRODUCTION The connection to the medical profession is obvious. The term dose of radiation was initially used in a pharmacological sense, that means: analogously to its meaning when used in prescribing a dose of medicine.
    [Show full text]
  • Measurement of Air Kerma Rate for Cs-137 Using Different Ionization Chambers
    Sudan Academy of Science (SAS) Atomic Energy Council Measurement Of Air Kerma Rate For Cs-137 Using Different Ionization Chambers By Khalid TagElsir Ahmed Mohammed B. Sc. (Honors) in biomedical physics Elneelain University (2008) A Thesis Submitted to the Sudan Academy of Science in partial of the requirement for the Degree of M.Sc. In radiation protection Supervisor: Dr. El tayeb Abdalla Hag Musa July 2013 Sudan Academy of Sciences (SAS) Atomic Energy Council Measurement of Air Kerma Rate for Cs-137 Using Different Ionizing Chambers By Khalid TagElsir Ahmed Mohammed Examination committcc ______ Title_____________________ Name______________ Supervisor_________ Dr. Eltayeb Abdalla Hag Musa External examiner Prof.Dr. Mohamed Osman Sid Ahmed DEDICATION To my parents To my brother and sister To all my friends To ail whom I love ACKNOWLEDGEMENTS Most of all thanks are due to Allah the most helper and most merciful. I would like to express my sincere gratitude to my supervisor Dr. El tayeb Abdalla Hag Musa for his invaluable guidance and continuous support and encouragement. 1 would like also, to express my gratitude and thanks to the staff of SSDL lab for hospitality and co-operation special thanks to Mr. Ayman Abd elsafy, Ali Mohamed Ali and Bodour Emam for their help , valuable advices encouragement and support in the laboratory work. Iwould like to express my gratitude and sincere appreciation to Miss.Mona Siddig Mohammed Numairy (UMST) for her invaluable guidance and continuous support and encouragement, without her help this work have never been accomplished. 1 would like to express my deep thanks to Mr. Abubaker Bashir Ahmed for his great help in data analysis.
    [Show full text]
  • Specification of Brachytherapy Source Strength
    AAPM REPORT NO. 21 SPECIFICATION OF BRACHYTHERAPY SOURCE STRENGTH Published for the American Association of Physicists in Medicine by the American institute of Physics AAPM REPORT NO. 21 SPECIFICATION OF BRACHYTHERAPY SOURCE STRENGTH REPORT OF AAPM Task Group No. 32* Members Ravinder Nath, Yale University, Chairman Lowell Anderson, Memorial Sloan-Kettering Institute Douglas Jones, Northwest Medical Physics Center Clifton Ling, University of California at San Francisco Robert Loevinger, National Bureau of Standards Jeffrey Williamson, University of Arizona William Hanson, Radiological Physics Center Consultant *The Task Group is part of the AAPM Radiation Therapy Committee, Faiz M. Khan, Chairman. June 1987 Published for the American Association of Physicists in Medicine by the American Institute of Physics Further copies of this report may be obtained from Executive Officer American Association of Physicists in Medicine 335 E. 45 Street New York, NY 10017 Library of Congress Catalog Card Number: 87-72124 International Standard Book Number: 0-88318-545-8 International Standard Serial Number: 0271-7344 Copyright © 1987 by the American Association of Physicists in Medicine 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 written permission of the publisher. Published by the American Institute of Physics, Inc., 335 East 45 Street, New York, New York 10017 Printed in the United States of America Table of Contents I. Introduction................................................ 3 II. U.S. Standards for Brachytherapy Sources ................. ...4 III. Source Specification Methods Currently in Use ............ ...6 A. Activity of the Radionuclide ...........................
    [Show full text]
  • Radiation Biology: Cell Biology
    Agenda Radiologic Units: • Greys, Sieverts, Coulombs per kg, & What You Need to Becquerel's Know • Conventional Units TODD VAN AUKEN M.ED. RT (R)(MR) • Other Concepts (LET, Q-Factor, Effective Dose, NCRP Report # 116) • Crazy Happenings with Radiation Coulomb per kg or C/kg-Exposure (X) Erythema Dose • A Coulomb (C) is the basic unit of electric charge • Measurement of positive and negative particles created when radiation ionizes atoms in dry air (Radiation intensity in the air) • Unit of Exposure for X-rays and Gamma Rays (Restricted to Photons only) • Used for x-ray equipment calibration (X-ray tube output) • Conventional Unit: Roentgen (R) Air Kerma Gray (Gy)-Absorbed Dose (D) • Kinetic energy is transferred from the primary beam • Amount of energy per unit mass absorbed by an (photons) to the patient (e-) irradiated object • SI quantity that can be used to measure radiation • 1 joule (J) of energy absorbed concentration transferred to a point at the surface of a in 1 g of absorbing material patient’s or radiographer’s body • Absorption of energy may • The energy transfer is called the kinetic energy result in biological damage released in the material or kerma (air kerma) • As the Z# of the object • Dose Area Product (DAP)- sum total of Air Kerma increases the absorbed dose over the exposed area of the patient’s surface (entire increases amount of energy delivered to the patient) • Conventional Unit: RAD (Radiation Absorbed Dose) Linear Energy Transfer Linear Energy Transfer Low LET Low LET High LET High LET LET= Rate at which energy
    [Show full text]
  • Interaction of Radiation with Matter in Radiology and Nuclear Medicine Which Is/Are True? the Energy of a Photon Is: • Particle Interactions – A
    11/19/2014 2014-2015 Residents' Core Physics Lectures Mondays 7:00-8:00 am in VA Radiology and UCSDMC Lasser Conference Rooms Nuclide Families Topic Chapters Date Faculty 1 Introduction and Basic Physics 1, 2 M 11/17 Andre 2 Interaction of Radiation and Matter 3 M 11/24 Andre RSNA Week No Lecture M 12/01 Family Nuclides with Same: Example 3 Computers 4 M 12/08 Hall 4 X-Ray Production 5 M 12/15 Andre 131 125 Christmas and New Year’s Holiday M 12/22, Isotopes Atomic number (Z) I , I : Z=53 12/29 5 Generators 5 M Andre 99 99 01/05/2015 Isobars Mass number (A) Mo , Tc : A=99 131 Isotones Neutron number (A-Z) 53I : 131-53=78 Isomers A and Z same but different Tc99m and Tc99: energy state Z=43, A=99, ΔE=142 keV Textbook: The Essential Physics of Medical Imaging, Bushberg, et al., Philadelphia: Lippincott Williams & Wilkins, 2002, 2nd Edition X = element symbol A Course Web Site??: http://3dviz.ucsd.edu/~radiology_residents/Home.html ZX Z = number of protons A = number of protons + neutrons 2 • Stable isotopes found Chapter 3: Interaction of Radiation with Matter along line N/Z = 1 at The Basis of X-Ray Imaging low Z Next time • Stable isotopes found we address along line N/Z = 1.5 at these high Z devices • Odd N and odd Z tend to be unstable “Huge relevance • Odd Z elements offer to a Resident” potential for NMR (unpaired p+) A ZX X = element symbol Z = number of protons A = number of protons + neutrons or digital detector AAPM/ABR Syllabus Chapter 3: Interaction of Radiation with Matter Module 4: Interactions of Ionizing Radiation with Matter After completing this module, the resident should be able to apply the “Fundamental Knowledge” and “Clinical in Radiology and Nuclear Medicine Applications” learned from the module to example tasks, such as those found in “Clinical Problem-Solving.” Fundamental Knowledge: • Particle Interactions 1.
    [Show full text]
  • Chapter 13 BRACHYTHERAPY
    Chapter 13 BRACHYTHERAPY: PHYSICAL AND CLINICAL ASPECTS N. SUNTHARALINGAM Department of Radiation Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, United States of America E.B. PODGORSAK Department of Medical Physics, McGill University Health Centre, Montreal, Quebec, Canada H. TÖLLI Division of Human Health, International Atomic Energy Agency, Vienna 13.1. INTRODUCTION Brachytherapy (sometimes referred to as curietherapy or endocurie therapy) is a term used to describe the short distance treatment of cancer with radiation from small, encapsulated radionuclide sources. This type of treatment is given by placing sources directly into or near the volume to be treated. The dose is then delivered continuously, either over a short period of time (temporary implants) or over the lifetime of the source to a complete decay (permanent implants). Most common brachytherapy sources emit photons; however, in a few specialized situations b or neutron emitting sources are used. There are two main types of brachytherapy treatment: ● Intracavitary, in which the sources are placed in body cavities close to the tumour volume; ● Interstitial, in which the sources are implanted within the tumour volume. 451 CHAPTER 13 Intracavitary treatments are always temporary, of short duration, while interstitial treatments may be temporary or permanent. Temporary implants are inserted using either manual or remote afterloading procedures. Other, less common forms of brachytherapy treatments include surface plaque, intra- luminal, intraoperative and intravascular source applications; for these treatments either g or b emitting sources are used. The physical advantage of brachytherapy treatments compared with external beam radiotherapy is the improved localized delivery of dose to the target volume of interest.
    [Show full text]