Radiation Oncology: A Physicist’s-Eye View , Michael Goitein , Springer, New York, 2008. $129.00 (330 pp.). ISBN 978-0-387-72644-1
The title of Michael Goitein’s book Radiation Oncology: A Physicist’s-Eye View is a play on words. The concept of “beam’s-eye view” in radiation-therapy treatment planning was developed by Goitein himself to describe the radiographic view of a patient’s anatomy, as seen from the radiation source. His stated intention for the book is to describe as simply as possible from a physicist’s perspective the use of radiation in the treatment of cancer. In the attempt, he succeeds admirably but his account does not cover clinical issues; also, it exclusively embraces high-energy x-ray and proton-beam therapies, a focus that reflects the author’s main interests in radiation oncology and major contributions to the field. For three decades Goitein was involved in unique developments in those two treatment modalities at Massachusetts General Hospital in Boston, and he is now a professor emeritus of radiation oncology at Harvard University Medical School.
Treatment planning in radiation oncology essentially involves designing a set of radiation beams to maximize the therapeutic ratio, the ratio between tumor-control probability (TCP) and normal-tissue complication probability (NTCP). Until the 1970s it was only possible to do such calculations by hand, although some computer programs were available to enhance the process. The treatment plan essentially involved a set of isodose contours superimposed on a hand drawing of a transverse cross section of a patient’s anatomy. The invention of whole-body computed x-ray tomography (CT), for which physicists Allan Cormack and Godfrey Houns-field shared the 1979 Nobel Prize in Physiology or Medicine, and rapid advances in computer technology changed all of that.
Goitein realized the potential of the new technology and led the development of three-dimensional treatment planning using CT images. Today 97% of radiation-therapy treatments in the US involve CT imaging. Goitein is also well known for his development and practical use of a variety of other tools, such as digitally reconstructed radiographs (DRRs), which are radiographs from any direction computed from a set of CT images of the patient (a beam’s-eye view is an example of a DRR); biophysical models for assessing TCPs and NTCPs; and dose-volume histograms for assessing treatment plans and deriving relevant dose statistics for a specific plan.
Until the 1990s a goal of radiation therapy was to provide a uniform dose distribution in the target volume. Treatment plans to accomplish that objective were constructed from individual beams, each with uniform intensity, with some exceptions usually involving wedges or compensating filters. In the late 1980s, Cormack and others developed the concept of intensity-modulated radiation therapy (IMRT), in which individual beams of nonuniform intensity could be used to provide either uniform or nonuniform dose distributions in the target volume. The advantage of that technique compared with uniform-intensity radiation therapy is better conformation of the dose to complex target volumes, specifically concave ones, and improved sparing of surrounding normal tissues. The technique is now routine in x-ray therapy and will find increasing application in proton therapy.
Radiation Oncology gives detailed discussions of the topics mentioned above. Also covered are interactions of radiation with matter; uncertainty in radiation oncology quantities, a topic that in Goitein’s view is often not adequately addressed; delineation of anatomy; radiobiological issues; motion management; optimization in IMRT treatment planning; and confidence and quality assurance.
The rationale for using protons for radiation therapy lies in their physical properties, which result in near-zero dose beyond the target volume and thus provide the ability to conform the planned dose more closely to the specified target volume than is feasible by photon techniques. The author was also responsible for developing and implementing new techniques for proton therapy at the Harvard Cyclotron Laboratory, where nearly 10 000 patients were treated. Furthermore, he was instrumental in establishing the Francis H. Burr Proton Therapy Center at Massachusetts General Hospital. Proton therapy is a rapidly proliferating field and is now firmly established in radiation oncologists’ armamentarium. Goitein’s treatment of the topic is clear and easy to follow, and he highlights the differences between proton and x-ray therapies. He divides the subject into two separate chapters that make up about 25% of the book: chapter 10, “Proton Therapy in Water,” for the ideal situation, and chapter 11, “Proton Therapy in the Patient,” for the clinical and far more complex scenario. The book contains full descriptions of all other relevant topics, including the production and delivery of passively scattered and scanned beams, dose distributions, treatment planning, and assessment of the effects of tissue inhomogeneities. That last topic is critically important in proton and other charged-particle therapies, because unlike the case with neutral beams, the beam range is affected rather than the intensity.
Radiation Oncology is neither a textbook nor an autobiography: It provides a lucid account of some of the modern technologies and methods in radiation therapy in which the author has been a leader. Although I am not aware of any other texts quite like it, Goitein’s book does have some similarities to People and Particles (San Francisco Press, 1997), a largely autobiographical account written by biophysicist Cornelius Tobias and his wife, Ida. Goitein’s avoidance of mathematical formulas makes his treatise easily readable. The footnotes that elaborate concepts and definitions are useful, and the author explains concepts clearly and provides extensive illustrations and understandable diagrams. I found some of the figures to be rather small, but they do not really detract from the quality of the work. Goitein’s book presents excellent background and is an invaluable resource not only for the experienced practitioner but also for the radiation oncologist, medical physicist, or dosimetrist who is new to the field.
