What is the primary consequence of dead time in positron emission tomography?

In positron emission tomography, dead time refers to the period following the detection of an event during which the system cannot record additional events. This occurs because the detectors need time to reset before they can register another signal. The primary consequence of dead time is the loss of count data, which means that some events that occur in quick succession may not be captured.

As the rate of detected events increases, the effect of dead time becomes more pronounced—leading to a decrease in the total number of counts recorded for a given scanning duration. This results in poorer statistical quality of the images produced, as fewer counts can lead to a lower signal-to-noise ratio and can potentially affect the accuracy of quantitative measurements in a scan. Thus, understanding and managing dead time is critical for optimizing the performance of a PET system.