(C kg^-1) of air, formerly* the roentgen (R). This measurement of exposure applies only to ionizing electromagnetic radiation, such as gamma and x rays, not to particulate radiation (e.g., alpha or beta particles). In the field (outside the laboratory), exposure is the quantity that is measured, although for convenience, it is commonly assumed that exposure and absorbed dose (see below) are the same when expressed in traditional units (i.e., I R = 1 rad).

Although beta and alpha radiations can be detected in the field, determination of their contribution to tissue dose is a complex process not reasonably implemented except under laboratory conditions. Exposure to alpha- and beta-emitting radionuclides, expressed in terms of their intake, is related to their concentrations in air, food, and water. The primary dose to persons exposed to these concentrations results from ingestion and inhalation of the radionuclides.

A useful quantity in radiation physics is the energy actually deposited in a certain amount (mass) of tissue. This unit is referred to as absorbed dose. The unit of absorbed dose is the gray (Gy), formerly the rad; the gray is equivalent to the absorption of one Joule of energy per kilogram. One gray equals 100 rad; 1 milligray (mGy) equals 100 millirad (mrad). However, the amount of energy deposited in tissue does not account for differences in the biological effects of different radiation types.

The dosimetric quantity that accounts for the differences in biological effectiveness of various types of radiation and that allows doses from different radiations to be combined, through expressing their health effects on a common basis, is called the equivalent dose. It is calculated by multiplying the absorbed dose by the appropriate radiation weighting factor, "w_R" (ICRP, 1991a). For example, the factor for alpha particles is 20 and that for gamma and beta radiation is 1, indicating that it requires the absorption of about 20 times more energy from gamma or beta radiation than alpha radiation to cause a given biological effect. These weighting factors are approximate and the true value for a given type of radiation, radiation effect, or specific population can vary by up to an order of magnitude. The unit of equivalent dose is the sievert (Sv), formerly the rem. One sievert equals 100 rem; 1 millisievert (mSv) equals 100 millirem (mrem).

Front Matter (R1-R20)

Summary (1-14)

1 Introduction (15-22)

2 Fundamentals of Radiation Safety and Protection (23-41)

3 Standard Practices in Occupational Radiation Protection (42-54)

4 Current Paradigms for Radiation Protection in the U.S. Army (55-63)

5 Army Radiation Protection and Safety Programs in Light of Civilian Standard Practices and Recommendations for Improvement (64-82)

6 Decisionmaking by Commands (83-87)

7 Follow-up of Persons with Known or Suspected Exposure to Ionizing Radiation (88-107)

8 Recommendations (108-112)

References (113-118)

Appendix A: The ACE Directive (119-128)

Appendix B: Participants in Committee Meetings and Workshop (129-132)

Appendix C: Biographical Summaries (133-139)