Contents Preface 1. Introduction and Recommendations

Transcription

1 Contents Preface iii 1. Introduction and Recommendations Purpose and Scope Quantities and Units Controlled and Uncontrolled Areas Shielding Design Goals for Medical X-Ray Imaging Facilities and Effective Dose Controlled Areas Uncontrolled Areas Shielding Design Assumptions Air-Kerma Limits for Radiographic Films General Concepts Fundamentals of Shielding for Medical X-Ray Imaging Facilities Basic Principles Types of Medical X-Ray Imaging Facilities Radiographic Installations Fluoroscopic Installations Interventional Facilities Dedicated Chest Installations Mammographic Installations (Permanent and Mobile) Computed Tomography Installations Mobile Radiography and Fluoroscopy X-Ray Units Dental X-Ray Facilities Bone Mineral Measurement Equipment Veterinary X-Ray Facilities Other X-Ray Imaging Systems Shielding Design Elements Interior Walls Sheet Lead Gypsum Wallboard Other Materials vii

2 viii / CONTENTS Exterior Building Walls Doors Lead-Lined Doors Wooden Doors Door Interlocks, Warning Lights, and Warning Signs Windows Lead Glass Plate Glass Lead Acrylic Floors and Ceilings Standard-Weight Concrete Light-Weight Concrete Floor Slab Construction Floor-to-Floor Heights Interstitial Space Shielding Design Considerations Penetrations in Protective Barriers Joints Construction Standards Dimensions and Tolerances Elements of Shielding Design Strategic Shielding Planning Project Development Process Strategic Planning and Budgeting Programming Schematic (Preliminary) Design Design Development Construction Document Preparation Documentation Requirements Computation of Medical X-Ray Imaging Shielding Requirements Concepts and Terminology Shielding Design Goals Distance to the Occupied Area Occupancy Factors Workload and Workload Distribution Use Factor

3 CONTENTS / ix Primary Barriers Unshielded Primary Air Kerma Preshielding Secondary Barriers Leakage Radiation Scattered Radiation Total Contribution from Secondary Radiation Shielding Calculation Methods General Shielding Concepts Shielding for Primary Barriers Shielding for Secondary Barriers Additional Method for Representative Radiographic Rooms, and Radiographic and Fluoroscopic Rooms Uncertainties Examples of Shielding Calculations Cardiac Angiography Dedicated Chest Unit The Radiographic Room The Floor of the Radiographic Room Primary Barrier Calculation for Floor Beneath the Radiographic Table Secondary Barrier Calculation for Floor The Ceiling of a Radiographic Room Wall Containing the Chest Image Receptor in the Radiographic Room Wall Containing the Chest Image Receptor in the Radiographic Room Secondary Barrier: Chest Image- Receptor Wall Darkroom Wall in the Radiographic Room The Cross-Table Wall in the Radiographic Room Control Wall in the Radiographic Room Radiographic and Fluoroscopic Room Secondary Barrier Calculation for the Floor in the Radiographic and Fluoroscopic Room

4 x / CONTENTS Primary Barrier Calculation for the Floor in the Radiographic and Fluoroscopic Room Mammography Computed Tomography Dose-Length Product Method The Isodose Map Method Cautionary Notes Bone Mineral Density Units (Dual Energy X-Ray Absorption Scanners) Shielding Design Report Radiation Protection Surveys Introduction Inspection for Voids Evaluation of Shielding Adequacy Visual Inspection to Determine the Presence and Thickness of Radiation Barriers Before the Structure Has Been Completed Transmission Measurements to Determine the Presence and Thickness of Radiation Barriers Determination of the Adequacy of Radiation Barriers Primary Barrier: Chest-Buck Wall Secondary Barrier: Chest-Bucky Wall, Area Beyond Chest Bucky Cross-Table Wall Secondary Barrier at Which it is Impossible to Aim Primary Beam Floor Summary Computed Tomography Scanner Survey Survey Report Problem Abatement Documentation Appendix A. Transmission Data Appendix B. Computation of Primary Barrier Thickness Appendix C. Computation of Secondary Barrier Thickness C.1 Scattered Radiation

5 CONTENTS / xi C.2 Leakage Radiation C.3 Total Secondary Barrier and Secondary Transmission C.4 The General Case Appendix D. Instrumentation for Performing Radiation Protection Surveys Glossary Symbols References The NCRP NCRP Publications Index