Physical and Biological Hazards of the Workplace, 3rd Edition

Chapter 11IONIZING RADIATION

James P. Seward*

Although most physicians and other healthcare professionals do not often encounter individuals injured by ionizing radiation in their practices, they can anticipate questions about radiation exposure and its potential health effects. In the rare event that a patient does present following radiation exposure or contamination with radioactive materials, the following information will be of assistance in the individual’s case management. Important information on resources for emergency information and expert advice are included at the end of this chapter.

BACKGROUND RADIATION

Although this chapter is generally concerned with unusual high exposures to ionizing radiation, routine low-level exposure to radiation is unavoidable. Background radiation is the primary source of most individuals’ exposure during their lifetimes. Background radiation has both a natural and an artificial (“human-made”) component. In the United States the population average for total natural and human-made background is approximately 6.2 mSv/year (620 mrem). Worldwide the range of natural background radiation varies considerably from 1 to 10 mSv with an average of about 2.4 mSv. Radon accounts for about one half of the dose globally. In the United States natural background is typically somewhat higher at about 3.1 mSv due to higher radon levels. Cosmic radiation, terrestrial sources (e.g., thorium and uranium), and internally deposited radionuclides (e.g., potassium-40 ...