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. 2025 Aug 26;12(1):80.
doi: 10.1186/s40658-025-00790-z.

Phantom imaging demonstration of positronium lifetime with a long axial field-of-view PET/CT and 124I

Lorenzo Mercolli  1   2   3 , William M Steinberger  4 , Narendra Rathod  5   6 , Maurizio Conti  4 , Paweł Moskal  7   8 , Axel Rominger  5 , Robert Seifert  5 , Kuangyu Shi  5 , Ewa Ł Stępień  7   8 , Hasan Sari  5   6   9
Affiliations

Phantom imaging demonstration of positronium lifetime with a long axial field-of-view PET/CT and 124I

Lorenzo Mercolli et al. EJNMMI Phys. .

Erratum in

Abstract

Purpose: Measuring the ortho-positronium (oPs) lifetime in human tissue bears the potential of adding clinically relevant information about the tissue microenvironment to conventional positron emission tomography (PET). Through phantom measurements, we investigate the voxel-wise measurement of oPs lifetime using a commercial long-axial field-of-view (LAFOV) PET scanner.

Methods: We prepared four samples with mixtures of Amberlite XAD4, a porous polymeric adsorbent, and water and added between 1.12 and 1.44 MBq of 124I. The samples were scanned in two different setups: once with a couple of centimeters between each sample (15 min scan time) and once with all samples taped together (40 min scan time). For each scan, we determine the oPs lifetime for the full samples and at the voxel level. The voxel sizes under consideration are 10.03 mm3, 7.13 mm3 and 4.03 mm3.

Results: Amberlite XAD4 allows the preparation of samples with distinct oPs lifetime. Using a Bayesian fitting procedure, the oPs lifetimes in the whole samples are 2.52 ± 0.03 ns, 2.37 ± 0.03 ns, 2.27 ± 0.04 ns and 1.82 ± 0.02 ns, respectively. The voxel-wise oPs lifetime fits showed that even with 4.03 mm3 voxels the samples are clearly distinguishable and a central voxels have good count statistics. However, the situation with the samples close together remains challenging with respect to the spatial distinction of regions with different oPs lifetimes.

Conclusions: Our study shows that positronium lifetime imaging on a commercial LAFOV PET/CT is feasible using 124I.

Keywords: 124I; Long axial field-of-view PET/CT; Positronium lifetime imaging.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: Not applicable. Competing interests: WMS and MC are full-time employees of Siemens Medical Solutions USA, Inc. HS is a part-time employee of Siemens Healthineers International AG. PM is an inventor on a patent related to this work. Patent nos.: (Poland) PL 227658, (Europe) EP 3039453, and (United States) US 9,851,456, filed (Poland) 30 August 2013, (Europe) 29 August 2014, and (United States) 29 August 2014; published (Poland) 23 January 2018, (Europe) 29 April 2020, and (United States) 26 December 2017. AR has received research support and speaker honoraria from Siemens. KS received research grants from Novartis and Siemens and conference sponsorships from United Imaging, Siemens, and Subtle Medical not related to the submitted work. RS has received research/travel support from Boehringer Ingelheim Fund and Else Kröner-Fresenius-Stiftung, as well as travel support and lecture fees from Novartis and Boston Scientific, outside the submitted work. All other authors have no conflict of interest to report.

Figures

Fig. 1
Fig. 1
Picture of the experimental setup with the four samples separated from each other
Fig. 2
Fig. 2
MIP of the coincidence PET images of the four separate tubes
Fig. 3
Fig. 3
Top view of a CT slice (right) and 3D rendering of the CT (left) of the setup with the four tubes taped together
Fig. 4
Fig. 4
Side-view MIP of the histoimage of the separated tubes (left) and top-viw MIP of the tubes taped together (right)
Fig. 5
Fig. 5
Single-voxel TDD together with the fit prediction, posterior 68% HDI and oPs component in logarithmic scale (4×4×4mm3 voxel size). The fit results are reported in Table 2
Fig. 6
Fig. 6
Slices of the oPs lifetime images along the x-axis for the separated tubes. The voxel size is increasing from top to bottom
Fig. 7
Fig. 7
Slices of the oPs lifetime images along the y-axis for the tubes taped together. The voxel size is increasing from top to bottom
Fig. 8
Fig. 8
MIP of the relative uncertainties of τ3 for the two separated (top) and taped together (bottom) experimental setups
See this image and copyright information in PMC

References

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