Evaluating and comparing the image quality and quantification accuracy of SiPM-PET/CT and PMT-PET/CT

Objective: The aim of this study was to evaluate the image quality and the quantification accuracy of Biograph Vision PET/CT scanner as a SiPM-PET in comparison to the conventional PMT-PET, Biograph mCT PET/CT scanner.

Methods: This study consisted of a phantom study and a retrospective clinical analysis where patients underwent ¹⁸F-FDG PET/CT in both PET systems. The body phantom of the NEMA IEC with 10-37 mm diameter spheres were filled with an ¹⁸F-FDG solution. The root mean square error (RMSE) of SUV, the detectability of 10-mm sphere, NEC_phantom, the background variability (N_10mm) and the contrast-noise-ratio (Q_{H,10 mm}/N_10mm) were calculated based on the phantom analysis. We also examined the quality of the acquired clinical images using the NEC_patient, NEC_density, SNR_liver, SUV_liver and SUV_lesion.

Results: In the phantom study on Vision scanner, RMSE was relatively lower when the iteration number was 2, 3 or 4. To satisfy a visual score of 1.5 and the reference range of Q_{H,10 mm}/N_10mm, a 60-s or longer acquisition was required. Our clinical findings show that NEC_patient averaged 17.4 ± 1.72 Mcounts/m in mCT and 29.1 ± 2.83 Mcounts/m in Vision. Furthermore, NEC_density averaged 0.29 ± 0.05 kcounts/cm³ in mCT and 0.53 ± 0.09 kcounts/cm³ in Vision, respectively, whereas SNR_liver averaged 14.6 ± 3.77% in mCT and 21.3 ± 1.69% in Vision (P = 0.0156), respectively. Finally, SUV_liver averaged 2.82 ± 0.28 and 2.55 ± 0.30, SUV_lesion ranged 1.6-17.6 and 1.9-22.9 in mCT and Vision, respectively.

Conclusion: SiPM-PET/CT provides superior image quality and quantification accuracy compared to PMT-PET/CT.