A comparison of image quality between digital and analog pet for spatial resolution: A phantom study

Background:The positron emission tomography (PET) technology has undergone continuous innovation in recent years.New-technology digital PETs are silicon photomultiplier (SiPM) PET systems with digital readouts, which contribute to improved image resolution.This study aimed to compare the image quality of subcentimeter lesions of NEMA PET phantom images obtained under identical imaging conditions (identical lesion volumes, identical activity and identical scanning time) using dPET, analog PET-1 and analog PET-2 acquired in the clinic.Materials and Methods: For image analysis, a standard NEMA IEC body phantom was used.In the present study, the lesion detection performance of all PETs was evaluated in two categories, sub-and over-centimeter size.The imaging durations of this study were 1, 2, 3, and 5 minutes, while the injection doses were 2.33 and 5.33 kBq/ml for the 1/4 and 1/8 background-to-lesion ratios, respectively.For a quantitative assessment of image quality, a circular ROI with activity concentrations (ACmean) and the mean recovery coefficient were calculated for each lesion via the ACmean.Results: Our study revealed approximately 15% greater RCmean values for dPET with SiPM technology compared to the analog PET-2 with PMT technology.However, analog PET-1 exhibited a significant lack of performance, especially when compared to analog PET -2 and dPET.Conclusion: Although dPET, the first generation of dPETs analyzed in the present study, yields relatively better RCmean values than analog PETs, it is not able to entirely eliminate the unfavorable impacts of PVE for sub-centimeter lesions.