[Paper Review] First ex-vivo positronium imaging of tissues with modular J-PET scanner using $^{44}$Sc radionuclide

Karol Kubat, Manish Das+42 more|arXiv (Cornell University)|Feb 7, 2026

Medical Imaging Techniques and Applications1 citations

TL;DR

This study demonstrates the first ex-vivo positronium imaging of human tissues using the modular J-PET scanner with the 44Sc radionuclide, validating ortho-positronium lifetimes in adipose tissue, cardiac myxoma, thrombi, and other materials.

ABSTRACT

This study presents the first ex-vivo positronium imaging of human tissues using the modular J-PET scanner with the $^{44}$Sc radionuclide. The $^{44}$Sc isotope was produced via the $^{44}$Ca(p, n)$^{44}$Sc nuclear reaction and used to perform positronium imaging of phantom composed of human adipose tissue, cardiac myxoma tissue, thrombi blood clot, and also porous polymer XAD4, and a certified reference material (CRM) made from fused silica. The experiment demonstrates the suitability of $^{44}$Sc as a positron source for positronium imaging. The performance of J-PET for positronium imaging with $^{44}$Sc was validated by proper reconstruction of the mean orthopositronium lifetime for CRM material and XAD-4 polymer. The mean ortho-positronium (oPs) lifetimes determined for adipose tissue, cardiac myxoma tissues and thrombi were consistent with results of previous experiments. The study highlights the potential $^{44}$Sc radionuclide for positronium lifetime imaging (PLI).

Motivation & Objective

• Demonstrate ex-vivo positronium imaging of human tissues using the modular J-PET scanner with 44Sc.
• Assess the suitability of 44Sc as a positron source for positronium imaging.
• Validate J-PET performance for positronium imaging through reconstruction of mean ortho-positronium lifetimes in reference materials.
• Compare tissue o-Ps lifetimes with previous experimental results to establish consistency.

Proposed method

• Produce 44Sc via the 44Ca(p, n)44Sc nuclear reaction and use it as the positron source.
• Image phantom assemblies including human adipose tissue, cardiac myxoma tissue, thrombi, XAD-4 porous polymer, and CRM from fused silica.
• Perform ex-vivo positronium imaging with the modular J-PET scanner.
• Reconstruct mean orthopositronium lifetime for CRM material and XAD-4 to validate imaging performance.
• Compare o-Ps lifetimes measured in adipose tissue, myxoma tissue, and thrombi with prior experimental results.

Experimental results

Research questions

• RQ1 Can 44Sc serve as an effective positron source for positronium imaging on a modular J-PET scanner?
• RQ2 What are the mean ortho-positronium lifetimes in biological tissues (adipose, cardiac myxoma, thrombi) and in reference materials (CRM, XAD-4) using 44Sc?
• RQ3 Do the measured o-Ps lifetimes in tissues align with lifetimes reported in previous experiments, validating the imaging approach?

Key findings

• This work reports the first ex-vivo positronium imaging of human tissues with a modular J-PET scanner using 44Sc.
• 44Sc is demonstrated as a suitable positron source for positronium imaging.
• Mean ortho-positronium lifetimes were reconstructed for CRM material and XAD-4 polymer, validating J-PET performance for this modality.
• Mean o-Ps lifetimes for adipose tissue, cardiac myxoma tissues, and thrombi were consistent with prior experimental results.