Abstracts of the 33rd International Austrian Winter Symposium

Abstract

Aim: To demonstrate the clinical capability of ultra-fast whole body PET acquisition enabled by digital photon counting PET (dPET) and to assess and compare its diagnostic and quantitative characteristics to current clinical PET acquisition. Methods: Twenty-five patients scheduled for FDG whole body PET/ CT were imaged using three separate acquisitions as part of intraindividual comparison study with a pre-commercial release dPET/CT (Vereos) and cPET/CT (Gemini, Philips, Cleveland). Standard cPET imaging was performed at~75 min p.i. of~450 MBq FDG with investigational dPET imaged at~55 min p.i. The first dPET acquisition was performed using 90s/bed position, immediately followed by a 9s/bed position. Acquisition which lead to average table times of~15 and~2 min. These were compared with standard-of-care 90s/bed position cPET. The 9s/bed dPET listmode data were reconstructed using a previously optimized methodology. All other aspects of image acquisition were kept identical. Three blinded reviewers evaluated the data sets regarding visual characteristics, diagnostic confidence and semiquantitative readouts. Results: Visual assessment scores were significantly higher for 90s/bed dPET whole body (p<0.01) with no difference between 9s/bed dPET and 90s/bed cPET. Quantitatively, the 9s/bed dPET images presented slightly increased background noise, however there was no significant impact on diagnostic confidence or SUV measures of FDG-avid lesions. Conclusion: Next generation digital photon counting PET detector technology enables a new capability of Ultra-Fast (~2min) wholebody acquisition with comparable diagnostic confidence and quantitative precision to current generation cPET acquisitions taking 10 times longer. This allows for new PET workflow concepts, improved patient comfort, minimized patient motion and whole-body pseudo-dynamic imaging of tracer uptake. Aim: Detection of the extent of local recurrence and of metastases in biochemical recurrence (BCR) of prostate cancer facilitates selection of appropriate treatment. The FALCON trial (NCT02578940) assessed the impact of 18F-fluciclovine PET/CT on the clinical management of men with BCR of prostate cancer following initial radical therapy. Methods: Men being considered for curative-intent salvage therapy following first BCR were recruited at 6 UK sites. Management plans were documented prior to and following 18F-fluciclovine PET/CT imaging. Post-scan changes to treatment modality such as salvage radiotherapy [RT] to systemic therapy were classed as 'major' , while changes within a modality (e.g. modified RT fields) were classed as 'other'. A pre-planned interim analysis of the first 85 patients was conducted; recruitment was to be stopped for efficacy if the number of treatment changes was > 45 (52.9%; 97.5% CI: 40.3-62.3%), or for futility if ≤ 8 (9.4%, 97.5% CI: 3.6-18.9%). Results: The 85 enrolled patients were a mean 4.8 y post-initial diagnosis, with a median age of 67 y and median PSA of 0.63ng/mL. Twelve (14.1%) had a Gleason score ≤ 6, 60 (70.6%) had ...