What affects the sensitivity of a detection system?

The sensitivity of a detection system in nuclear medicine is significantly influenced by the properly set pulse height analyzer (PHA) and the window width. The PHA is crucial in differentiating between photons of interest (those originating from the radionuclide being imaged) and background noise or scatter. By setting the PHA correctly, the system can selectively allow only the desired energy range of photons to contribute to the detected signal. This enhances the overall detection efficiency for the specific radionuclide, improving the sensitivity of the system.

The width of the window determines how broad or narrow the energy range is for accepted signals. A well-defined energy window ensures that the system captures the relevant emissions while rejecting those that fall outside this range, effectively filtering out unwanted signals. If the window is too wide, it may introduce noise and decrease sensitivity; if too narrow, it may exclude valid signals, thereby decreasing the total count rate.

Other components, such as the thickness of the camera crystal and collimator design, also influence sensitivity but are not as directly related to the specific energy detection as the PHA settings. Instrument deadtime can affect the ability to detect signals during the intervals immediately following a detected event, potentially leading to missed counts, but this aspect addresses timing rather than