18F-Fluciclovine (FACBC) is an amino acid PET radiotracer approved for recurrent prostate cancer imaging. We investigate the use of Bayesian penalised likelihood (BPL) reconstruction for 18F-fluciclovine PET.
Fifteen 18F-fluciclovine scans were reconstructed using OSEM, OSEM+point spread function modeling (PSF) and BPL using β values 100-600. Lesion SUVmax, organ SUVmean and standard deviation were measured. De-identified reconstructions (OSEM, PSF, BPL using β200-600) from 10 cases were visually analysed by two readers who indicated their most and least preferred reconstructions, and scored overall image quality (IQ), noise level, background marrow IQ and lesion conspicuity.
Comparing BPL to OSEM, there were significant increments in lesion SUVmax and signal-to-background up to β400, with highest gain in β100 reconstructions (mean ΔSUVmax 3.9, p<0.0001). Organ noise levels increased on PSF, β100 and β200 reconstructions. Across BPL reconstructions, there was incremental reduction in organ noise with increasing β, statistically significant beyond β300-500 (organ-dependent). Comparing with OSEM and PSF, lesion signal-to-noise was significantly increased in BPL reconstructions where β≥300 and β≥200 respectively. On visual analysis, β300 had the first and second highest scores for IQ, β500 and β600 equal highest scores for marrow IQ and least noise, PSF and β200 had first and second highest scores for lesion conspicuity. For overall preference, one reader preferred β300 in 9/10 cases and the other preferred β200 in all cases.
BPL reconstruction of 18F-fluciclovine PET images improves SNR, affirmed by overall reader preferences. On balance, β300 is suggested for 18F-fluciclovine whole body PET image reconstruction using BPL. Advances in knowledge: The optimum β is different to that previously published for 18F-FDG, and has practical implications for a relatively new tracer in an environment with modern reconstruction technologies.
The British journal of radiology. 2018 Jan 05 [Epub ahead of print]
Eugene J Teoh, Daniel R McGowan, David M Schuster, Maria Tsakok, Fergus V Gleeson, Kevin M Bradley
1 Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, UK., 2 Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, UK., 4 Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA.