Most textbooks on radiological physics present a broad field which includes physics of 
radiation therapy, diagnosis, and nuclear medicine. The emphasis is on the basic physical 
principles which form a common foundation for these areas. Consequently, the topics of 
practical interest are discussed only sparingly or completely left out. The need is felt for a 
book solely dedicated to radiation therapy physics with emphasis on the practical details. 
This book is written primarily with the needs of residents and clinical physicists in 
mind. Therefore, greater emphasis is given to the practice of physics in the clinic. For the 
residents, the book provides both basic radiation physics and physical aspects of treatment 
planning, using photon beam;, electron beams, and brachytherapy sources. For the clinical 
physicist, additionally, current information is provided on dosimetry. 
Except for some sections in the book dealing with the theory of absorbed dose measurements, the book should also appeal to the radiotherapy technologists. Of particular 
interest to them are the sections on treatment techniques, patient setups, and dosimetric 
calculations. 
Since the book is designed for a mixed audience, a careful balance had to be maintained 
between theory and practical details. A conscious effort was made to make the subject 
palatable to those noiformally trained in physics (e.g., residents and technicians) without 
diminishing the value of the book to the physicist. This object was hopefully achieved by 
a careful selection of the topics, simplification of the mathematical formalisms, and ample 
references to the relevant literature.