Impact of TOF PET on whole-body oncologic studies: A human observer detection and localization study

Objectives Phantom studies have shown improved lesion detection with TOF PET. For the first time we now evaluate the benefit of fully-3D, TOF PET in clinical whole-body oncology using human observers to localize and detect lesions in realistic patient anatomic backgrounds.

Methods 100 patient studies with normal FDG uptake were chosen. 1-cm spheres were imaged in air at variable locations in the scanner FOV corresponding to lung and liver locations within each patient (4:1 local uptake). Sphere data were appropriately attenuated and merged with patient data to produce fused list data files. All list files were iteratively reconstructed with full corrections and with or without the TOF kernel. The images were presented to 4 clinicians to localize and report with a confidence level the presence/absence of a lesion. The data will be analyzed to calculate the probability of correct localization and detection, and the area under the LROC curve.

Results Initial results from a related study using a channelized hotelling observer (CHO SNR) show improved lesion detection for low uptake lesions and large patients (up to 14% gain). The human observer study is ongoing and will quantify the clinical impact of TOF PET on lesion detection and localization.

Conclusions In this study we evaluate the impact of TOF PET on lesion detection and localization by human observers in realistic human imaging settings. The conclusions will be derived for different BMI patients, varying scan times, and lesion locations.

Research Support This work was supported by National Institutes of Health grant No. R01-CA113941.