Diagram illustrating the ON and OFF timings relative to the trail start time t_Start and end time t_Stop. To account for any possible interference, as well as the larger FoV of CT1-CT4, these timings are separated by 60 s. If possible, the OFF timing consists of two time periods prior and post trail as shown above, each taking half the duration of the length of the trail T_Trail. If not, only a single OFF region is used, either before or after the trail (depending on when the trail occurs in the run).