Physical Mechanisms In Radiation Biology

The fundamental understanding of the production of biological effects by ionizing radiation may well be one of the most important scientific objectives of mankind; such understanding could lead to the effective and safe utilization of the nuclear energy option. In addition, this knowledge will be of immense value in such diverse fields as radiation therapy and diagnosis and in the space program. To achieve the above stated objective, the U. S. Department of Energy (DOE) and its predecessors embarked upon a fundamental interdisciplinary research program some 35 years ago. A critical component of this program is the Radiological and Chemical Physics Program (RCPP). When the RCPP was established, there was very little basic knowledge in the fields of physics, chemistry, and biology that could be directly applied to understanding the effects of radiation on biological systems. Progress of the RCPP program in its first 15 years was documented in the proceedings of a conference held at Airlie, Virginia, in 1972. At this conference, it was clear that considerable progr:ess had been made in research on the physical and chemical processes in well-characterized systems that could be used to understand biological effects. During this period of time, most physical knowledge was obtained for the gas phase because the technology and instru mentation had not progressed to the point that measurements could be made in liquids more characteristic of biological materials.

Physical Processes in Radiation Biology covers the proceedings of an International Symposium on Physical Processes in Radiation Biology, held at the Kellogg Center for Continuing Education, Michigan State University on May 6-8, 1963, sponsored by the U.S. Atomic Energy Commission. The symposium aims to address the core problems of radiation biology concerning the absorption, distribution, and utilization of high energy packets in biological systems. This book is composed of 21 chapters, and begins with an introduction to the absorption, excitation, and transfer processes in molecular solids. The subsequent chapters discuss the nature of exciton processes; the mechanisms of charge transport in biological materials; the interactions of fast and slow electrons with model systems; the importance of liquid structures in determining the development of radiation damage; and the nature of the metastable species formed. The concluding chapters explore the importance of charge migration in energy transfer processes in different biological systems and the significance of higher excited levels in charge migration and energy transfer. These chapters also describe the nature of the hydration of electrons and protons in aqueous systems. This book will be of great value to radiation biologists, biophysicists, physical chemists, and physicists.

Mechanisms in Radiobiology, Volume II: Multicellular Organisms presents the development of radiobiology, which has run parallel with the advancement of biology. This book discusses the fundamental aspects of radiobiology in connection with the therapeutic use of X-rays in medicine. Organized into five chapters, this book begins with an overview of radiation effects on embryonic and adult organisms, particularly in mammals. This text then discusses the immunological processes in irradiated organisms. Other chapters consider the mechanisms of action of protective and sensitizing agents and examine the primary or secondary effects of the irradiation on the various organs. This book discusses as well the experimental possibilities of improving the recovery of irradiated mammals. The final chapter deals with the reactions of living organisms after a damaging dose of ionizing radiation, which is determined by a variety of biological and physical factors. This book is a valuable resource for radiobiologists, pathologists, scientists, physicists, clinicians, and research workers.

Advances in Radiation Biology, Volume 14: Relative Radiation Sensitivities of Human Organ Systems, Part II focuses on radiation sensitivities of particular human organ systems. The sensitivities are then assessed based on the severity and the rapidity in which the effects of radiation manifest. The opening chapter surveys the clinical and experimental data on approaches toward the prevention of bladder complications in clinical radiotherapy. A discussion on HeLa cells, which are of special importance in human cervical cancer therapy, is then presented. In presenting this topic, this book emphasizes radiation sensitivity and radiobiology of tumors of the cervix of the female genital tract. Chapter 3 briefly covers imaging techniques for hypothalamic-pituitary dysfunction diagnosis and introduces hormonal therapy for remarkable improvements in both physical and mental status of patients. The subsequent chapters discuss basic radiobiology of the thyroid in experimental animal and the late effects of therapeutic and low-level radiation in humans. The radiation damages in bone and cartilage and the changes occurring in the various types of vessels during radiation therapy are also discussed. Chapter 7 presents the basic biology of spermatogenesis, as it applies to the understanding of radiation effects. This chapter also explains the studies of rodents, as it applies to subhuman primates and to man. Moreover, it considers as well the mechanisms of radiation damage to the testis, as elucidated by experimental studies of rodents and subhuman primates. Finally, it presents the limited data available on man and discusses these data in terms of the biology of the system known from experimental studies. The concluding chapter describes the features of radiation-induced hepatic injury, ranging from asymptomatic biochemical or a radiographic abnormality to fulminant, fatal hepatic failure. Radiation biologists will greatly benefit from this book, especially those who are involved in dose fractionation in radiation therapy.

Advances in Radiation Biology, Volume 2, reflects a continuing effort to provide wide-ranging analyses of progress in various phases of radiation research. The articles cover a spectrum of topics varying from the initial physical events which allow us to discriminate color, to the chemical and biological processes which determine the extent and permanence of radiation damage, and finally to the role of genetic control and damage in determining the fate of irradiated cells. The basic emphasis of the articles also varies. In some, the main attempt is to review extensively the available data so as to evaluate the possible contributions of various mechanisms to a given phenomenon. One article is devoted an evaluation of one physical approach which appears to be a promising way of understanding color perception. These different treatments should be of value not only to the researcher but also to the student, inasmuch as each approach is invariably dictated by the state of the art in the area being covered.