Hendee's Radiation Therapy Physics (eBook)

Todd Pawlicki, Daniel J. Scanderbeg, George Starkschall (Autoren)

eBook Download: EPUB

2016 | 4. Auflage
John Wiley & Sons (Verlag)
978-1-118-57527-7 (ISBN)

Infos

The publication of this fourth edition, more than ten years on from the publication of Radiation Therapy Physics third edition, provides a comprehensive and valuable update to the educational offerings in this field. Led by a new team of highly esteemed authors, building on Dr Hendee's tradition, Hendee's Radiation Therapy Physics offers a succinctly written, fully modernised update.

Radiation physics has undergone many changes in the past ten years: intensity-modulated radiation therapy (IMRT) has become a routine method of radiation treatment delivery, digital imaging has replaced film-screen imaging for localization and verification, image-guided radiation therapy (IGRT) is frequently used, in many centers proton therapy has become a viable mode of radiation therapy, new approaches have been introduced to radiation therapy quality assurance and safety that focus more on process analysis rather than specific performance testing, and the explosion in patient-and machine-related data has necessitated an increased awareness of the role of informatics in radiation therapy. As such, this edition reflects the huge advances made over the last ten years. This book:

• Provides state of the art content throughout
• Contains four brand new chapters; image-guided therapy, proton radiation therapy, radiation therapy informatics, and quality and safety improvement
• Fully revised and expanded imaging chapter discusses the increased role of digital imaging and computed tomography (CT) simulation
• The chapter on quality and safety contains content in support of new residency training requirements
• Includes problem and answer sets for self-test

This edition is essential reading for radiation oncologists in training, students of medical physics, medical dosimetry, and anyone interested in radiation therapy physics, quality, and safety.

Todd Pawlicki, PhD, FAAPM
Professor and Vice-Chair of Medical Physics
Department of Radiation Medicine and Applied Sciences
University of California, San Diego, CA, USA

Daniel J. Scanderbeg PhD
Associate Professor
Department of Radiation Medicine and Applied Sciences
University of California, San Diego, CA, USA

George Starkschall PhD, FACMP, FAAPM, FACR
Research Professor,
Department of Radiation Physics,
Division of Radiation Oncology,
The University of Texas MD Anderson Cancer Center,
Houston, TX, USA

Inhalt

Preface to the Fourth Edition, vi

Preface to the Third Edition, vii

Preface to the Second Edition, viii

Preface to the First Edition, ix

1 Atomic Structure and Radioactive Decay, 1

2 Interactions of X Rays and Gamma Rays, 16

3 Interactions of Particulate Radiation with Matter, 29

4 Machines for Producing Radiation, 35

5 Measurement of Ionizing Radiation, 57

6 Calibration of Megavoltage Beams of X Rays and Electrons, 77

7 Central-axis Point Dose Calculations, 96

8 External Beam Dose Calculations, 110

9 External Beam Treatment Planning and Delivery, 123

10 The Basics of Medical Imaging, 146

11 Diagnostic Imaging and Applications to Radiation Therapy, 154

12 Tumor Targeting: Image-guided and Adaptive Radiation Therapy, 170

13 Computer Systems, 182

14 Radiation Oncology Informatics, 197

15 Physics of Proton Radiation Therapy, 204

16 Sources for Implant Therapy and Dose Calculation, 215

17 Brachytherapy Treatment Planning, 231

18 Radiation Protection, 248

19 Quality Assurance, 267

20 Patient Safety and Quality Improvement, 294

Appendix: Answers to Selected Problems, 310

Index, 317

Rezensionen

"The book is well structured and gives an excellent overview on all practical aspects of modern radiotherapy and the physics involved. The many examples and problems allow for immediate check of the understanding of the text and make it fun to read. The new editors certainly did a very good job in carrying on the tradition of the original book" Physica Medica, Feb 2017. Full review available here

"The newly published fourth edition of Hendee's Radiation Therapy Physics (Authors: Todd Pawlicki, Daniel J. Scanderbeg, George Starkschall) provides an updated overview, analysis and practical guidance of the various aspects of the radiation therapy physics. Published ten years after the publication of the third edition, this book reviews all newly introduced modalities and approaches in
Radiation therapy - intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), digital imaging, CT simulation, proton therapy, radiation therapy informatics. An important part of the book is the focus on the professional approaches in radiation protection, patient safety, quality assurance, quality improvement and even training for residents. The book is written by experts in the field - all three authors are well known professionals working in the field of Radiation Physics and Radiation Medicine. Throughout this book the reader finds scientific, educational and practical information from the very basics of radiation physics to the latest achievements in the field of Radiation Therapy. Each chapter is well structured, giving a good balance between the theoretical and practical aspects. The appendix is dedicated to solving practical problems and provides professional advice, as well as self-tests......This book is both an excellent reference which will be useful in all medical physics departments and at the same time a perfect guidance material for professionals in related specialties. It continues very well the line set by Prof. William Hendee (past IOMP ExCom member). The Content and Structure of the book are excellent. These are really necessary for a book with such coverage and volume. Thefourth edition of Hendee's Radiation Therapy Physics is yet another fundamental book that will be very useful reference for various specialists for many years
ahead" - Medical Physics World 2016

Textauszug

CHAPTER 1
ATOMIC STRUCTURE AND RADIOACTIVE DECAY

1. Objectives
2. Introduction
3. Atomic and nuclear structure
   1. Atomic units
   2. Mass defect and binding energy
   3. Electron energy levels
   4. Nuclear stability
4. Radioactive decay
5. Types of radioactive decay
   1. Alpha decay
   2. Beta decay
   3. Gamma emission and internal conversion
6. Radioactive equilibrium
7. Natural radioactivity and decay series
8. Artificial production of radionuclides
9. Summary
10. Problems
11. References

Objectives

After studying this chapter, the reader should be able to:

• Understand the relationship between nuclear instability and radioactive decay.
• Describe the different modes of radioactive decay and the conditions in which they occur.
• Interpret decay schemes.
• State and use the fundamental equations of radioactive decay.
• Perform elementary computations for sample activities.
• Describe the principles of transient and secular equilibrium.
• Discuss the principles of the artificial production of radionuclides.

Introduction

The composition of matter has puzzled philosophers and scientists for centuries. Even today, the mystery continues as strange new particles are detected in high-energy accelerators. Various models proposed to explain the composition and mechanics of matter are useful in certain applications, but invariably fall short in others. One of the oldest models, the atomic theory of matter devised by early Greek philosophers,1 remains a useful approach to understanding many physical processes, including those important to the study of the physics of radiation therapy. The atomic model is used in this text, but it is important to remember that it is only a model, and that the true composition of matter remains an enigma.

Atomic and nuclear structure

The atom is the smallest unit of matter that possesses the physical and chemical properties characteristic of one of the 118 elements, 92 of which occur naturally and the others are produced artificially. The atom consists of a central positive core, termed the nucleus, surrounded by a cloud of electrons moving in orbits around the nucleus. The nucleus is composed of protons and neutrons, collectively termed nucleons, with a diameter on the order of 10−14 meters (m). Protons are subatomic particles with a mass of 1.6734 × 10−27 kilograms (kg) and a positive charge of +1.6 × 10−19 Coulombs. Neutrons are subatomic particles with a mass of 1.6747 × 10−27 kg and no electrical charge. The electron cloud surrounding the nucleus has a diameter of about 10−10 m.

Electrons have a mass of 9.108 × 10−31 kg and a negative charge of –1.6 × 10−19 Coulombs. In the neutral atom, the number of protons in the nucleus is balanced by an equal number of electrons in the surrounding orbits. An atom with a greater or lesser number of electrons than the number of protons is termed a negative or positive ion.

An atom is characterized by the symbolAZX, in which A is the number of nucleons in the nucleus, Z is the number of protons in the nucleus (or the number of electrons in the neutral atom), and X represents the chemical symbol for the particular element to which the atom belongs. The number of nucleons, A, is termed the mass number of the atom and Z is called the atomic number of the atom. The difference A – Z is the number of neutrons in the nucleus, termed the neutron number, N. Each element has a characteristic atomic number but can have several mass numbers depending on the number of neutrons in the nucleus. For example, the element hydrogen has the unique atomic number of 1, signifying the solitary proton that constitutes the hydrogen nucleus, but can have zero (11H), one (21H), or two (31H) neutrons. The atomic forms 1H, 2H, and 3H (the subscript 1 can be omitted because it is redundant with the chemical symbol) are said to be isotopes of hydrogen because they contain different numbers of neutrons combined with the single proton characteristic of hydrogen. Isotopes of an element have the same Z but different values of A, reflecting a different neutron number, N. Isotones have the same N but different values of Z and A. 3H, 4He, and 5Li are isotones because each nucleus contains two neutrons (N = 2). Isobars have the same A, but different values of Z and N.  3H and  3He are isobars (A = 3). Isomers are different energy states of the same atom and therefore have identical values of Z, N, and A. For example 99mTc and 99Tc are isomers because they are two distinct energy states of the same atom. The m in 99mTc signifies a metastable energy state that exists for a finite time (6 hours half-life) before changing to 99Tc. The term nuclide refers to an atomic nucleus in any form.

Atomic units

Units employed to describe dimensions in the macroscopic world, such as kilograms, Joules, meters, and Coulombs, are too large to use at the atomic level. Units more appropriate for the atomic scale include the atomic mass unit (amu) for mass, electron volt (eV) for energy, nanometer (nm) for distance, and electron charge (e) for electrical charge.

The amu is defined as 1/12 of the mass of an atom of the most common form of carbon, 12C, which has 6 protons, 6 neutrons, and 6 electrons. One amu = 1.66 × 10−27 kg. By definition, the atomic mass of an atom of 12C is 12.00000 amu. In units of amu, the masses of atomic particles are as follows:

Every atom has a characteristic atomic mass, Am. The gram-atomic mass of an isotope is an amount of the isotope in grams that is numerically equivalent to the isotope's atomic mass. For example, one gram-atomic mass of 12C is exactly 12 grams. One gram-atomic mass of any isotope contains 6.0228 × 1023 atoms, which is a constant value that is known as Avogadro's number NA. With these expressions, the following quantities can be computed:

Example 1-1

Compare the number of electrons/g for 12C to the number of electrons/g for 40Ar.

For 12C, the atomic number is 6 and the atomic mass is 12.000. Consequently, the number of electrons/g is 6.0228 × 1023 × 6/12.000 = 3.0114×1023 electrons/g.

For 40Ar, the atomic number is 18 and the atomic mass is 39.948. Consequently, the number of electrons/g is 6.0228 × 1023 × 18/39.948 = 2.714 × 1023 electrons/g.

Note that, although the atomic masses and atomic numbers of carbon and argon are widely different from one another, the electron densities are within 10% of each other. Because for most materials the mass number is approximately twice the atomic number, the electron densities will be relatively constant.

The electron volt (eV) is a unit of energy equal to the kinetic energy of a single electron accelerated through a potential difference (voltage) of 1 volt. One keV = 103 eV and 1 MeV = 106 eV. One nanometer (nm) is 10−9 meters. The electron unit of electrical charge = 1.6 × 10−19 Coulombs. One eV is equal to 1.6 × 10−19 Joules of energy.

Example 1-2

What is the kinetic energy (Ek) of an electron accelerated through a potential difference of 400,000 volts [400 kilovolts (kV)]?

Mass defect and binding energy

The neutral 12C atom contains 6 protons, 6 neutrons, and 6 electrons. The mass of the components of this atom can be computed as:

The mass of an atom of 12C, however, is 12.00000 amu by definition. That is, the sum of the masses of the components of the 12C atom exceeds the actual mass of the atom. There is a mass defect of 0.09888 amu in the 12C atom. The difference in mass must be supplied to separate the 12C atom into its constituents. The mass defect can be described in terms of energy according to Einstein's expression E = mc2, for the equivalence of mass and energy. In this expression, E is energy, m is mass, and c is the speed of light in a vacuum (3 × 108 m/sec). From the formula for mass-energy equivalence, 1 amu of mass is equivalent to 931 MeV of energy. For example, the energy equivalent to the mass of the electron is (0.00055 amu) (931 MeV/amu) = 0.511 MeV.

The energy associated with the mass defect of 12C is (0.09888 amu)(931 MeV/amu) = 92.0 MeV. The energy equivalent to the mass defect of an atom is known as the binding energy of the atom and is the energy required to separate the atom into its constituent parts. Almost all of the binding energy of an atom is associated with the nucleus and reflects the influence of the strong nuclear force that binds particles together in the nucleus. For 12C, the average binding energy per nucleon is 92.0 MeV/12 = 7.67 MeV/nucleon. When computing the average binding energy per nucleon as the...

Produkt-Details

• Erscheint lt. Verlag: 21.1.2016
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie ► Gesundheitsfachberufe
• Themenwelt: Medizinische Fachgebiete ► Radiologie / Bildgebende Verfahren ► Radiologie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Schlagworte: Bill Hendee • Computed tomography (CT) • Daniel J. Scanderbeg • Digital Imaging • FMEA • George Starkschall • Hendee's Radiation Therapy Physics • IGRT • image-guided radiation therapy • IMRT • Informatics • intensity-modulated radiation therapy • Medical & Health Physics • medical physics • Medical Science • Medizin • Oncology & Radiotherapy • Onkologie • Onkologie u. Strahlentherapie • Physics • Physik • Physik in Medizin u. Gesundheitswesen • Process Map • proton radiation therapy • Protons • Quality and Safety • radiation oncology • Radiation oncology Resident • radiation therapy informatics • radiation therapy physics • radiation treatment • Radiologie • Radiologie u. Bildgebende Verfahren • Radiology & Imaging • rca • real-time imaging • SPC • Strahlentherapie • Todd Pawlicki • William Hendee
• ISBN-10: 1-118-57527-X / 111857527X
• ISBN-13: 978-1-118-57527-7 / 9781118575277