7 X-Ray Safety A. Introduction Radiation producing devices (RPD) have long been used as important tools in research and teaching. Concern over health risks associated with radiation exposure from such devices has led to occupational exposure limits and strict regulatory controls governing the possession and use of all sources of ionizing radiation. Current limits for radiation exposure are based upon the conservative assumption that there is no completely safe level of exposure. This assumption has led to the general philosophy and regulatory requirement of not only keeping exposures below recommended levels or regulatory limits, but of also maintaining all exposures As Low As Reasonably Achievable (ALARA). This is a fundamental tenet of current radiation safety practice. In order to ensure that all users of ionizing radiation at Iowa State University (ISU) are in compliance with existing regulatory requirements, and that radiation exposures are maintained ALARA, the Department of Environmental Health and Safety (EH&S) has implemented the policies and procedures contained in this X-Ray Safety Manual. This manual is intended to provide sufficient information to ensure that radiation safety practices at ISU are of the highest quality. It is the responsibility of each person working with RPDs to become familiar with the contents of this manual and to observe those procedures and requirements contained herein that are applicable to their particular work. This manual is also intended to supplement the requirements found in the ISU Laboratory Safety Manual. In accordance with Iowa law, RPDs are registered with the Iowa Department of Public Health (IDPH). RPDs are surveyed by EH&S annually, following major repairs, and as otherwise required. Principal investigators (PIs) and departments are required to inform EH&S if x-ray systems, x-ray components, or other RPDs are purchased, transferred to campus, moved between laboratories, or disposed. X-Ray and Radiation-Producing Devices The three major types of x-ray equipment used at ISU are: • medical and veterinary diagnostic x-ray devices • diagnostic x-ray units used in healing arts screening • analytical x-ray units The use of medical diagnostic and therapy radiation devices are restricted to physicians, radiologists, and radiology technicians.