LROC analysis of human detection performance in PET and time-of-flight PET

Previous investigations into time-of-flight positron emission tomography (TOFPET) have shown that stochastic noise in images can be reduced when the reconstruction process accounts for the differences in detection times of coincidence photons. Among the factors that influence this reduction are the sensitivity and the spatial and temporal resolutions of the TOFPET detectors. Within the framework of a simplified time-of-flight imaging model, we have considered the effect of these factors on task performance for human observers. The task was detection of mediastinal "hot" tumors in simulated images of the chest. There were 14 simulated TOFPET systems and 2 simulated PET systems considered. Image reconstruction was performed using filtered backprojection (FBP) for PET and a modified FBP for TOFPET. Localization receiver operating characteristic (LROC) methodology, in which the observers must detect and locate the tumors, was used. The LROC study gives insight into how TOFPET detector characteristics might improve in order to make possible observer task performance on a par with PET. A comparison of our results to a theoretical result from the literature was also conducted.