The Physics & Technology of Radiation Therapy
Author: Patrick McDermott and Colin OrtonISBN: 9781930524323
Published: 2010 | 856 pp. | Hardcover
Price: $ 125.00
International Journal of Radiation Oncology Biology Physics, Vol. 80, No. 2 | 2011
This
introduction to the physics and technology of radiation therapy developed from
years of classroom lecture notes taken by radiation oncology residents is
designed to take the reader from elementary mathematic concepts through the
basic physics of radiation to applications in clinical medical physics. It
presents a wide range of information in a simple yet concise manner, omitting
detailed explanations for clarity but using clinical examples for emphasis.
The
authors state that the book is for ‘‘the rest of the radiation therapy
community’’—radiation technologists, dosimetrists, and
radiation oncologists—so the text is suitable for radiation physics trainees
and radiation oncology residents and represents a useful introductory
self-study tool for physicists not trained in therapeutic radiation physics planning
to enter this field.
The
book is laid out in 20 chapters. Because radiation physics depends heavily on
math, the book begins by reviewing mathematic principles, followed by basic
physics and applied radiation therapy physics, and ending with novel treatment delivery
modalities in the final chapter. Numeric examples are provided where necessary,
with colored pictorial illustrations, and practice questions, chapter
summaries, and bibliographic references are provided at the end of each
chapter. Although the book does not cover treatment planning, it does cover
most of the fundamental information relevant to radiation therapy practice.
Radiation technologists with limited or no college math would benefit from the
earlier chapters. Physics students and junior physicists would find the beginning
chapters to be basic but would appreciate the later chapters. Radiation
oncology residents would benefit from the entire book. An appendix is dedicated
to technologists and radiation oncologists preparing for certification
examinations and points them to the relevant book sections.
As
the authors state in the preface, the book assumes that the majority of the
readers are not expert in math or physics and shies away from mathematic
equations. It achieves this at the expense of leaving the reader with many
questions about the derivation of some of those equations. Thus, a more
advanced physics or math reader may find that mathematic symbols used in the
earlier chapters of the book are not defined. For example, it would be helpful
to mention that dot (.) represents multiplication to avoid
confusion with scalar product. Also, r
is introduced as the exponent, but n appears
on the equations as the exponent (e.g., equations 1.1 and 1.5). The authors
define scalar and vector quantities in Chapter 2 and mention that arrows are
used to represent a vector, but this convention is not followed consistently
throughout the chapter. A few examples: in equation 2.2, V needs an arrow; in
equation 2.6, g needs an arrow; and
in equation 2.7, W and F need arrows.
Force
plays an important role in describing the interaction between two bodies or
particles (e.g., electrons interacting with atoms in the human body). The
authors’ casual dismissal of a further definition of force in Chapter 2 is
disappointing.
The
authors have given gravitational acceleration a fixed value of 9.8 m/s2.
They should have pointed out that this value varies with location and can
affect quantities like atmospheric pressure, used in machine calibration.
Equation 2.6 (weight = m x g) should have mentioned that g is gravitational acceleration, not
just another constant value.
Chapter
3 presents radioactivity, including basic properties of nuclei, nuclear forces
and transformations, radioactivity equations, heavy particles and particle accelerators,
and commonly used radioactive materials and their half-lives. Decay processes,
including positron emission and electron capture, are mentioned, though not in
detail. A physician reader needs to understand the importance of these
processes in brachytherapy, especially for 125I,
which decays through electron capture only, vs. 103Pd,
which decays through both processes.
In
Chapter 4, to avoid confusion, it would be better to have used Vp for peak voltage rather than kVp. In Figure 6.4, Ey’ is not shown,
and the figure caption is confusing. Chapter 8 discusses film dosimetry but does not mention radiochromic
dosimetry, a topic of increased interest. It would
also have helped to discuss the use of thermoluminescent
dosimeters in detail for in vivo dosimetry and verification of external agency machine
output calibration. The authors state that there exist only three linac manufacturers, whereas there are actually three major
linac manufacturers. Also, although the text refers
to a Mevalac machine, there exists no such linac or manufacturer.
This
book represents a useful resource for technologists and radiation oncologists
and a good starting point for junior physicists involved in radiation therapy.
The text is more concise and often easier to understand than other books on radiation
therapy physics, like, for example, Khan’s The
Physics of Radiation Therapy, the leading physics reference text book in
this field.
Dan
Odero, Ph.D.
Raleigh
Regional Cancer Center
Beckley,
WV