Patient safety and the medical physicist.

Overexposures in computed tomography: In several institutions, overexposures have occurred during use of x-ray computed tomography (CT) for brain perfusion studies to identify 10 the neurological consequences of strokes and other events. In some cases, patients received exposures that were several times greater than necessary. The overexposures were caused by use of inappropriate CT protocols for brain perfusion studies, and by the desire to achieve appealing low-noise images rather than images acquired at the lowest dose consistent with adequate diagnostic information. Another contributing factor was the cacophony of terms used to describe 15 CT parameters across makes and models of CT scanners.