What ER radiologists need to know about radiation risks.

The annual per capita medical dose in the US is currently 3 mSv, and has increased by about 600% since the early 1980s. Medical doses now account for approximately 50% of the total US population dose, and will likely continue to increase for the foreseeable future. An average patient at a Level 1 trauma center, with an Injury Severity Score of 14, is expected to undergo imaging procedures that will result in an effective dose of approximately 40 mSv. The median age of a trauma patient in the ER setting is about 30 years, and the male cancer incidence from this amount of radiation is estimated to be approximately 0.3%, with the female risk being approximately 55% higher. For radiation protection purposes, scientific radiation protection authorities consider that the available evidence shows the linear no threshold (LNT) model to be the most prudent one for radiation protection purposes. Accepting that diagnostic examinations are associated with finite radiation risks requires policies that protect patients from unnecessary radiation. Clinical practice should therefore ensure that: (a) tests should only be ordered when the results are expected to affect patient management; (b) non-ionizing alternatives (i.e., US and MR) be considered, particularly for pediatric patients; (c) only indicated exams should be performed where the patient benefit is judged to exceed any radiation risk; and (d) for indicated examinations, all radiation exposures are kept As Low As Reasonably Achievable (ALARA).