Radiology Rounds - February 2008 - Minimizing CT Radiation Dose

The fine anatomical detail visible in computed tomography (CT) images has revolutionized diagnosis of both acute and chronic diseases and often provides information critical to the management and planning of treatment for both adults and children. As technological advances have increased, the range of examinations CT utilization has steadily increased and has recently been reported to be as high as 17% of the total radiology workload. However, the x-ray exposure from each CT scan is substantially higher (2-15 mSv) than plain film radiography (0.05-2 mSv) and, therefore, CT accounts for about 70-75% of the total ionizing radiation from diagnostic imaging. While these levels of radiation are well below those that cause deterministic effects (for example, cell death), there is concern that they may be associated with a risk of stochastic effects (such as cancer), albeit small.