Clinical comparison of HiRez versus non-HiRez LSO crystal sampling for lesion detection and SUV quantification

The aim of this work was to evaluate the clinical impact the new HiRez crystal arrangement (Biograph PET scanner) on lesions detection and quantification. Twelve non-HiRez patient sinograms were generated from the original HiRez sinograms. Data conversion (smoothing) from HiRez to non-HiRez geometry was based on real acquisitions and Monte-Carlo simulations of point sources in air for the HiRez and non-HiRez models. The averaged tumor volume reduction on the HiRez images compared to the non-HiRez images for the 41 lesions considered was -13.9 plusmn 19.4% (p < 0.01, paired t-test). Although significant SUVs modifications were found (Max SUVs were statistically higher in HiRez images than in non-HiRez images: 4.2 plusmn 3.1 vs 4.0 plusmn 2.9 respectively; p < 0.001), no difference was observed in terms of lesion detection in our small series, possibly due to lesion characteristics (isolated lesions, high tissue-to-background ratio).