Two-dimensional vs three-dimensional imaging in whole body oncologic PET/CT: a Discovery-STE phantom and patient study

Abstract

Aim: To evaluate the performance of the positron emission tomography (PET)/computed tomography (CT) Discovery-STE (D-STE) scanner for lesion detectability in two-dimensional (2D) and three-dimensional (3D) acquisition.

Methods: A NEMA 2001 Image-Quality phantom with 11 lesions (7-37 mm in diameter) filled with a solution of 18F (lesion/background concentration ratio: 4.4) was studied. 2D and 3D PET scans were sequentially acquired (10 min each) in list mode (LM). Each scan was unlisted into 4, 3 and 2-min scans. Ten [18F]FDG PET oncological patient studies were also evaluated. Each patient underwent a 3D PET/CT whole body scan, followed by a 2D PET scan (4 min LM) and a 3D PET scan (4 min LM) over a single field of view. Both 2D and 3D scans were unlisted in 3 and 2-min scans. Data were evaluated quantitatively by calculating quality measurements and qualitatively by two physicians who judged lesion detectability compared to statistical variations in background activity.

Results: Quantitative and qualitative evaluations showed the superiority of 3D over 2D across all measures of quality. In particular, lesion detectability was better in 3D than in 2D at equal scan times and 3D acquisition provided images comparable in quality to 2D in approximately half the time. Interobserver variability was lower in evaluation of 3D scans and lesion shape and volume were better depicted.

Conclusion: In oncological applications, the D-STE system demonstrated good performance in 2D and 3D acquisition, while 3D exhibited better image quality, data accuracy and consistency of lesion detectability, resulting in shorter scan times and higher patient throughput.