Radiation exposure associated with imaging of the chest: comparison of different radiographic and computed tomography techniques.

Exposure to ionizing radiation due to radiologic examinations is associated with the risk of induction of malignancy. This has to be balanced against the potential benefits of detection of a malignant tumor with radiologic examinations. For comparison of radiation exposure levels from different sources, the concept of effective dose equivalent was developed, which is used to assess an individual's risk of developing malignancy. Effective dose equivalent ranges from 0.06 to 0.25 millisieverts (mSv) with chest radiography in 2 views, 3-27 mSv with computed tomography (CT) using conventional examination parameters, and 0.3-0.55 mSv using low dose CT settings. These values can be compared with radiation exposure levels from natural sources (on average 2.4 mSv per year in Germany). Based on considerations by the International Commission on Radiological Protection, it can be expected that radiation exposure with an effective dose equivalent of 1 mSv would lead to 5 additional malignancies in 100,000 individuals exposed.