Pre-clinical Positron Emission Tomography Reconstruction Algorithm Effect on Cu-64 ATSM Lesion Hypoxia

Abstract

Objective:Application of distinct positron emission tomography (PET) scan reconstruction algorithms can lead to statistically significant differences in measuring lesion functional properties. We looked at the influence of two-dimensional filtered back projection (2D FBP), two-dimensional ordered subset expectation maximization (2D OSEM), three-dimensional ordered subset expectation maximization (3D OSEM) without 3D maximum a posteriori and with (3D OSEM MAP) on lesion hypoxia tracer uptake using a pre-clinical PET scanner.Methods:Reconstructed images of a rodent tumor model bearing P22 carcinosarcoma injected with hypoxia tracer Copper-64-Diacetyl-bis (N4-methylthiosemicarbazone) (i.e. Cu-64 ATSM) were analyzed at 10 minute intervals till 60 minute post injection. Lesion maximum standardized uptake values (SUVmax) and SUVmax/background SUVmean (T/B) were recorded and investigated after application of multiple algorithm and reconstruction parameters to assess their influence on Cu-64 ATSM measurements and associated trends over time.Results:SUVmaxSUVmax or T/B between 2D FBP, exhibited convergence for OSEM reconstructions while ANOVA results showed a significant difference in SUVmax or T/B between 2D FBP, 2D OSEM, 3D OSEM and 3D OSEM MAP reconstructions across all time frames. SUVmax and T/B were greatest in magnitude for 2D OSEM followed by 3D OSEM MAP, 3D OSEM and then 2D FBP at all time frames respectively. Similarly SUVmax and T/B standard deviations (SD) were lowest for 2D OSEM in comparison with other algorithms.Conclusion:Significantly higher magnitude lesion SUVmax and T/B combined with lower SD were observed using 2D OSEM reconstruction in comparison with 2D FBP, 3D OSEM and 3D OSEM MAP algorithms at all time frames. Results are SUVmax or T/B between 2D FBP, consistent with other published studies however more specimens are required for full validation.

Optimizing scan time and bayesian penalized likelihood reconstruction algorithm in copper-64 PET/CT imaging: a phantom study

“…Most research studies evaluating Cu-64 PET image quality have used Ordered Subset Expectation Maximization with Point-Spread Function modeling (OSEM-PSF) reconstruction algorithms [13]. OSEM-PSF reconstruction algorithms suffer from increased noise after each iteration, which often this limits the total number of iterations that can be performed due to suboptimal image quality.…”

Establishing Reliable Cu-64 Production Process: From Target Plating to Molecular Specific Tumor Micro-PET Imaging

“…A number of radiotracers involving 64 Cu as radionuclide have been applied in nuclear medicine as a means of studying their PET imaging [ 4 , 5 , 6 ]. Incorporation of 64 Cu into diacetyl-bis( N 4 -methylthiosemicarbazone) (ATSM) ligand was used for PET hypoxia imaging, such as in head and neck cancer, and cardiac conditions [ 7 , 8 ].…”