Abstract
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Introduction: This study aims to investigate the sensitivity of the 18F-FDG total-body (TB) PET/CT and a conventional digital PET/CT using a head-to-head comparison with the pathological findings as reference.
Methods: The prospective study was conducted on 125 consecutive patients who underwent a TB PET/CT scan and a conventional digital PET/CT scan in random sequence after a single 18F-FDG injection (3.7MBq/kg). Finally, 67 patients (median age, 65 years; 24 female and 43 male patients) were enrolled in this study. PET raw data of TB PET/CT were acquired within 5 min and reconstructed using data from the first 1, 2, 3, 4, and 5 min (G1, G2, G3, G4, G5). The images of conventional digital PET/CT were referred to as G0. Two nuclear medicine physicians independently assessed subjective image quality using a 5-point Likert scale and interpreted images for staging. Objective image quality and lesions characteristics were measured and compared with G0. Sub-analysis on regional lymphocytes was also performed.
Results: A total of 241 lesions (69 primary lesions; 140 local lymphocyte metastases; 32 distal metastases) of 67 patients with ten types of cancer, proved by pathology, were analyzed. The subjective image quality score and SNR increased gradually from G1 to G5, significantly higher than G0 (all p < 0.05). In addition, G4 and G5 of TB PET/CT detected additional 13 lesions (2 primary lesions; 6 lymphocyte metastases; 5 distant lesions) and enabled correct treatment recommendations for six patients (6/67?9.0%) compared with conventional PET/CT.
Conclusions: This study showed that 4-min acquisition in TB PET/CT using regular dose is appreciated for optimal detection efficiency in various lesions, including small and low-uptake lesions. And TB PET/CT enables more appropriate management than conventional digital PET/CT for detecting more lesions as well as higher image quality.