Abstract
Purpose To explore the feasibility of a low dose regimen with short acquisition time of 68Ga-DOTATATE total-body PET/CT without compromising image quality of patients with NETs. Methods Fifty-seven consecutive NETs patients who underwent 68Ga-DOTATATE total-body PET/CT, with a low dose regimen (0.8-1.2 MBq/kg) of 68Ga-DOTATATE and acquisition time of 10 min prior to any treatment, were enrolled in the present study. The PET data were split into 1 min, 2 min, 3 min, 4 min, 5 min, 8 min and 10 min reconstruction groups, referenced as R1, R2, R3, R4, R5, R8 and R10. The subjective evaluation of image quality was scored in 5-point Likert scale based on three aspects: the overall impression of the image quality, the image noise, the lesion detectability. The objective image quality was assessed by the signal-to-noise ratio of liver (SNRL), the coefficient of variation (CV), the SUVmax, SUVmean, SD of liver, mediastinal blood pool and lesion, the tumor-liver ratio (TLR), the tumor-mediastinal blood pool-ratio (TMR) of lesion. Results The sufficient subjective image quality with a score of 3.44±0.53 could be obtained at 3 min acquisition duration, with a kappa value of 0.90. In quantitative analysis, the value of SNRL is over 10 in all reconstruction groups. As the acquisition time increases, SNRL was increased and CV was decreased within 3 min, while SNRL and CV showed no significant different between R4-R10. There was no significant different in TMR and TLR of lesion between R1-R10 (all p < 0.05). Referenced as PET images of R10, 90 SSTR-positive lesions are identified, and all those lesions are found in the R1-R10 groups (100%).Conclusion The low-dose (0.8-1.2 MBq/kg) 68Ga-DOTATATE total-body PET/CT not only shortens acquisition time, but maintains a sufficient image quality for the NETs patients.
Image quality and lesion detectability in low-dose paediatric 18F-FDG scans using total-body PET/CT