improvement of image quality for small lesion sizes in 18f-fdg prone breast silicon photomultiplier-based pet/ct imaging

Objective(s): we investigated image quality and standardized uptake values (suvs) for different lesion sizes using clinical data generated by 18f-fdg-prone breast silicon photomultiplier (sipm)-based positron emission tomography/computed tomography (pet/ct).methods: we evaluated the effect of point-spread function (psf) modeling and gaussian filtering (gau) and determined the optimal reconstruction conditions. we compared the signal-to-noise ratio (snr), contrast, %coefficient of variation (%cv), suv, and likert scale score between ordered-subset expectation maximization (osem) time-of-flight (tof) and osem+tof+psf in phantom and clinical studies. the conventional image was generated with osem+tof_gau 6 mm. the national electrical manufacturers association body phantom with 10-mm hot sphere data was acquired for 5 min. twenty-six patients (40 lesions, ranging from 3.7 to 63.0 mm) were examined using prone breast pet/ct with a breast positioner for breast cancer staging. pet data were acquired 125±9.7 min after intravenous injection of 220±16.1 mbq at 5 min/bed.results: in the phantom study, a high snr was obtained from a 3- to 5-mm gaussian filter for osem+tof+psf. the contrast obtained with osem+tof without gaussian filtering was superior to that obtained with osem+tof+psf_gau 4 mm. in the clinical study, the image quality depended on lesion size. the average snr was significantly higher at 40.8% for lesions >20 mm with osem+tof_gau 6 mm than with osem+tof without gaussian filtering. the average contrast for lesions ≤10 mm was significantly higher by 42.0% with osem+tof without gaussian filtering than with osem+tof_gau 6 mm. the average suvmax of osem+tof without gaussian filtering significantly increased by 53.3% for lesions ≤10 mm.conclusion: osem+tof without gaussian filtering provided good contrast and quantitative value for small lesions.