Which of the following methods can be used to remove random events in PET imaging?

In positron emission tomography (PET) imaging, random events refer to counts that are registered when two photons, emitted from separate annihilation events, are mistakenly interpreted as coming from the same event. This can contribute to image noise and distort the results.

Narrowing the coincidence timing window is a method used to mitigate random events by tightening the time window within which the two photons are detected. A stricter coincidence timing window means that only those photon pairs detected within a shorter time frame are considered coincident events. This reduces the likelihood that unrelated photons from different annihilation events are counted together, effectively decreasing the number of random coincidences included in the data. As a result, the signal-to-noise ratio in the resulting images is improved, leading to better image quality and reliability in interpretations.

The other options, while they may have roles in enhancing PET imaging quality to some extent, do not specifically target the reduction of random events in the same focused manner.