Influence of BPL-based reconstruction algorithm on image quality for quantitative 90Y-PET imaging
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2021
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LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st
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Introduction: PET/CT technology and image reconstruction
algorithms are constantly being improved.
This leads to changes in the resulting images which need
to be tested and clinically validated. This study evaluated
the performance and clinical use of the Bayesian
Penalized-Likelihood (BPL) reconstruction algorithm
on the state-of-the-art SiPM-based PET/CT for quantitative
90Y-PET imaging.
Method: An image quality (IQ) phantom with an 8:1 hot
sphere-to-background ratio was scanned on a GE Discovery
MI 3-rings PET/CT system during a single bed
scan. 90Y acquisition time was 14h and 20 min (representative
for clinical count statistics) for an activity concentration
of 218 kBq/ml. Reconstructions were performed
using: 3-iterations OSEM algorithm with 16
subsets and Gaussian post-filter FWHM ranging from
4.5 to 10 mm; BPL-based algorithm employing a block
sequential regularized expectation maximization
(BSREM) with Beta parameter varying from 300 to
3000. Time-of-flight and point-spread function modellings
were included in all reconstructions. Contrast recovery
(CR), background noise levels (coefficient of
variation, COV), contrast-to-noise ratio (CNR) and metabolic
tumour volume (MTV) were compared to investigate
whether the BSREM reconstruction algorithm
leads to an improvement in clinical image quality using
90Y.
Results: The results for CR versus background COV
of the IQ phantom are shown in Fig. 1. All plots show a
similar trend: CRs values were as expected with higher
CRs for lower β and post-filter FWHM values. The Contrast-
to-noise ratio was significantly better in BSREM
reconstructions when compared with OSEM in phantom
studies. In terms of CR mapping, a BSREM β of 1000
corresponded to 5-6 mm post-filter for TOF-OSEM. Regarding
noise characteristics of the 14h data, BSREM
outperformed TOF-OSEM reconstructions in terms of
noise levels with a 2-3 times lower background COV
and improved SUVmean and MATV values for all spheres
sizes. Lowering the counts for 20 min data, BSREM
noise reduction can be controlled by increasing the β-
parameter, but caution should be taken to avoid losing
CR information. An optimal range of 1500-3000 β values,
can provide a compromise between noise and CR at
clinical count statistics.
Conclusions: Based on a quantitative phantom
study, the BPL-based reconstruction algorithm improves
image quality and allows better noise characteristics
for 90Y acquisitions when compared to OSEM reconstructions.
BSREM reconstructions substantially improved
contrast-to-noise ratio and MATVvalues for
longer 90Y measurements with better count statistics.
For clinically relevant count statistics, BSREM with β
values lower than 500 had a limited impact on noise levels
of 90Y-PET.
The potential improvements of BPL applied to dosimetry
calculations are currently being investigated to
determine if BSREM can be used to avoids accuracy
degradation in the absorbed dose distribution aiming at
patient comfort.
Como referenciar
CARIBE, P.R.R.V.; BONIFACIO, D.A.B.; CORDEIRO, L.P.; SILVA, A.M.M. da. Influence of BPL-based reconstruction algorithm on image quality for quantitative 90Y-PET imaging. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... Disponível em: http://repositorio.ipen.br/handle/123456789/32925. Acesso em: 04 May 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.