The Progress in Medical Radiation Physics series presents in-depth reviews of many of the significant developments resulting from the application of physics to medicine. This series is intended to span the gap between research papers published in scientific journals, which tend to lack details, and complete textbooks or theses, which are usually far more detailed than necessary to provide a working knowledge of the subject. Each chapter in this series is designed to provide just enough information to enable readers to both fully understand the development described and apply the technique or concept, if they so desire. Thorough references are provided for those who wish to consider the original literature. In this way, it is hoped that the Progress in Medical Radiation Physics series will be a catalyst encouraging medical physicists to apply new techniques and developments in their daily practice. Colin G. Orton ix Contents 1-1. The Tracking Cobalt Project: From Moving-Beam Therapy to Three-Dimensional Programmed Irradiation W. A. Jennings 1. Introduction 2. Establishing Moving-Beam Techniques at the Royal Northern Hospital, 1945-1955 4 2.1. Alternative Moving-Beam Techniques 4 2.2.

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1-I. The Tracking Cobalt Project: From Moving-Beam Therapy to Three-Dimensional Programmed Irradiation.- 1. Introduction.- 2. Establishing Moving-Beam Techniques at the Royal Northern Hospital, 1945-1955.- 2.1. Alternative Moving-Beam Techniques.- 2.2. Conical-Rotation Therapy.- 2.3. Rotating-Chair Therapy.- 2.4. Arc or Pendulum Therapy.- 2.5. Relative Percentage Depth Doses Achieved.- 3. The Tracking Concept and the Operation of the Mark I Tracking Machine, 1957-1959.- 3.1. The Spread of Malignant Disease.- 3.2. Realization of the Tracking Principle.- 3.3. Achieving Uniform Dosage along the Track.- 3.4. Practical Application of the Tracking Technique.- 4. Steps Toward an Improved Tracking Machine, 1960-1965.- 4.1. The Need for Penetrating Radiation.- 4.2. Developing an Improved Control System.- 4.3. An Appeal for Funds for the Tracking Cobalt Project.- 4.4. Consultations and Study Tour.- 4.5. The Need for Elliptical Dose Contours.- 5. Dosimetry and Treatment Planning for the Mark II Tracking Machine.- 5.1. Achieving Elliptical Dose Contours-the Approach Adopted.- 5.2. Sectional Dose Computations.- 5.3. Sectional and Track Dose Measurements.- 5.4. Track Dosage.- 6. Alternative Approaches to Conformation Therapy under Parallel Development Elsewhere-Synchronous Beam-Shaping and Shielding.- 7. Constructing and Installing the Mark II Tracking Machine, 1965-1970.- 8. Commissioning and Using the Mark II Tracking Machine, 1970-1975.- 8.1. The Tracking Cobalt Unit.- 8.2. Commissioning the TCU.- 8.3. Examples of Treatment Applications.- 9. Developing and Commissioning the Mark III Tracking Cobalt Machine, 1975-1980.- 9.1. Limitations of the Mark II Machine.- 9.2. Developing the Mark III Tracking Machine.- 9.3. Treatment Planning by Computer.- 9.4. Funding, Constructing, Installing, and Commissioning the CCTCU.- 9.5. Clinical Indications of Conformation Therapy.- 9.6. Examples of Dose Distributions Achieved with the CCTCU.- 9.7. Recent Developments.- 10. Alternative Approaches to Computer-Controlled Radiotherapy.- References.- 1-II. Physical Aspects of Conformation Therapy Using Computer-Controlled Tracking Units.- 1. Introduction.- 2. Methods for Achieving Conformation Therapy Using Photon Beams.- 2.1. Basic Requirements for Controlling Dose Distributions in Three Dimensions.- 2.2. A Brief Comparison of Conformation Therapy Systems.- 3. Representing Three-Dimensional Treatment Parameters.- 3.1. The "Ideal" Beam.- 3.2. Exposure-Time Profiles, Exposure-Dose Profiles, and Absorbed-Dose Profiles.- 3.3. Radial Time and Exposure-Weighting Diagrams.- 3.4. Combining Axial Exposure-Time Profiles.- 3.5. Combining Tracks Using Exposure-Time Profiles.- 3.6. Combining Axial Exposure-Time Profiles and Transverse-Plane Exposure-Time Profiles.- 4. Controlling Radiotherapy Dose Distributions in Three Dimensions Using a Computer-Controlled Tracking Unit.- 4.1. Slice-by-Slice or Field-by-Field Treatment and Planning.- 4.2. Controlling the Shape of the High-Dose Volume.- 4.3. Controlling the Dose Distribution along the Tumor Axis.- 4.4. The End-of-Track Technique.- 5. A Note on Treatment-Planning Strategy.- 5.1. Thin-Slice and Thick-Slice Planning.- 5.2. Slice-by-Slice Treatment Planning.- 5.3. Field-by-Field Treatment Planning.- 6. Basic Treatment Methods.- 6.1. Machine Operational Modes.- 6.2. Some Basic Treatment Techniques.- 7. Some Examples of Physics Planning Procedures.- 7.1. Planning an Arc Track.- 7.2. Planning a Multitrack Treatment.- 7.3. Planning a Bifurcated Track.- 7.4. A Note on the Transverse-Plane Track.- 8. Tumor (Target) Localization.- 8.1. General Considerations.- 8.2. Tumor Localization for Treatment Planning Using a CT Scanner.- 8.3. Treatment Simulation.- 9. The Experimental Verification of Treatment Plans.- 9.1. Objectives.- 9.2. Choice of Test Phantoms and Dosimeters.- 9.3. Current Measurement Procedures.- 9.4. Dose Measurements Using a Simple Phantom.- References.- 1-III. Computer Systems for the Control of Teletherapy Units.- 1. The Teletherapy Unit.- 1.1. The Royal Free Hospital's Tracking Cobalt Unit.- 1.2. Other Computer-Controlled Teletherapy Units.- 2. Interface with the Computer.- 2.1. The Royal Free Hospital's System.- 2.2. Other Data Transfer Methods.- 2.3. Data Format and Codes.- 2.4. Noise Detection and Elimination.- 3. Programming the Therapy Unit.- 3.1. Basic Methods.- 3.2. Modifications to the Basic Method.- 3.3. Base Position and Safe Starting Poisitions.- 4. The Computer System.- 4.1. Hardware.- 4.2. Software.- 5. Safety and Control Monitoring.- 5.1. Introduction.- 5.2. Computer Hardware Errors.- 5.3. Computer Software Errors.- 5.4. Treatment Unit Errors.- 5.5. Communication Link Errors.- 5.6. Operator Errors.- 6. Future Developments.- References.- 2. Measurement of Human Body Composition in Vivo.- 1. Introduction.- 2. Aims of Studies of Human Body Composition.- 3. Selection of Aspects of Body Composition to be Measured.- 4. Determination of the Elementary Composition of the Body.- 4.1. Analysis of Tissues at Biopsy or Postmortem.- 4.2. Isotopic Dilution.- 4.3. Measurement of Natural or Induced Radioactivity.- 5. Estimation of the Masses of Fat and Fat-Free Tissue.- 5.1. Estimation from Body Density.- 5.2. Estimation by Anthropometry.- 5.3. Estimation from Total Body Water.- 5.4. Estimation from Total Body Potassium.- 5.5. Estimation of Total Body Fat by Dilution.- 5.6. Estimation of Body Fat from Total Body Carbon, Nitrogen, and Calcium.- 6. Analysis of the Fat-Free Mass into Water, Protein, and Minerals.- 7. Estimation of the Masses of Individual Tissues.- 7.1. The Skeleton.- 7.2. Skeletal Muscle.- 8. Future Developments.- 8.1. Techniques of Measurement.- 8.2. Evaluation of Techniques.- 8.3. Interpretation of Data.- References.- 3. Medical Applications of Elemental Analysis Using Fluorescence Techniques.- 1. Introduction.- 2. Principles of Fluorescence X-Ray Emission.- 2.1. Review of Atomic Structure and Characteristic X Rays.- 2.2. Auger Electrons and Coster-Kronig Transitions.- 2.3. Matrix Effect.- 3. Detection and Analysis of Fluorescence X Rays.- 3.1. Overview.- 3.2. Solid-State Detectors.- 3.3. Pulse Processors.- 4. Excitation Modes.- 4.1. Photon Excitation.- 4.2. Particle-Induced X-Ray Emission (PIXE).- 4.3. Electron Excitation.- 5. Summary.- References.- 4. Basic Imaging Properties of Radiographic Systems and Their Measurement.- 1. Introduction.- 2. X-Ray Sensitometry.- 2.1. Methods of Measurement.- 2.2. Inverse-Square X-Ray Sensitometry.- 2.3. Application of a Curve-Smoothing Technique to the Determination of H and D Curves and Their Gradients.- 3. Resolution Properties of Radiographic Imaging Systems.- 3.1. Methods of Measuring MTFs.- 3.2. MTF of a Screen-Film System.- 3.3. MTF of an X-Ray Tube Focal Spot.- 4. Radiographic …