Annihilation photons are quantum-entangled in polarization, a phenomenon that has not been exploited in medical diagnostics so far. We present the first in vivo imaging of the degree of quantum entanglement of photons originating from positron-electron annihilation within a human subject. This study utilized the Jagiellonian Positron Emission Tomography (J-PET) scanner, constructed from plastic scintillators. In plastics, annihilation photons interact primarily via the Compton effect, which provides simultaneous information regarding the photon interaction position and time, as well as the photon polarization plane. The patient was injected with a DOTA-TATE radiopharmaceutical labeled with the ^68Ga radionuclide. Using the J-PET scanner, we determined the image of the radiopharmaceutical uptake and, simultaneously, the image of the degree of quantum entanglement. The latter was determined from the relative angle between the polarization planes of the annihilation photons. The values of the degree of quantum entanglement extracted for the liver and the spleen are smaller than those predicted for maximally entangled two-photon states, yet larger than expected for separable photons. This demonstration opens new perspectives for the application of quantum entanglement in clinical diagnostics.

After its first ex-vivo and in-vivo demonstration, Positronium Lifetime Imaging (PLI) has received considerable interest as a potential new diagnostic biomarker. High sensitivity Positron Emission Tomography (PET) systems are needed for PLI since it requires simultaneous registration of annihilation photons and prompt gamma. In this simulation-based study, a feasibility of PLI with the long axial field-of-view Biograph Vision Quadra (Quadra) and the Total Body J-PET scanner was investigated. The study was performed using the GATE software. Background radiation, present within the Quadra tomograph, was added to the simulation. First, the optimal placement of the energy window for the registration of the prompt gamma was investigated. Next, the organ-wise sensitivity of Quadra was calculated for the ^68 Ga, ^44 Sc, ^22 Na and ^124 I radioisotopes. Finally, the sensitivity for the scandium isotope was compared to the sensitivities obtainable with the Total Body J-PET scanner, as well as with the modular J-PET prototype. The PLI sensitivities for the Quadra with the background radiation are estimated to 9.22(3), 10.46(4), 5.91(3), and 15.39(4) cps/kBq for the ^44 Sc, ^68 Ga, ^22 Na and ^124 I radioisotopes, respectively. The highest sensitivity was obtained when the energy window for the deexcitation photon is adjacent to the energy window for the annihilation photons. In case of J-PET, the sensitivities for the ^44 Sc were estimated to 0.062(08) and 1.714(40) cps/kBq for the modular and Total Body J-PET scanners, respectively. The determined PLI sensitivities with Quadra and the Total Body J-PET are in the order of sensitivities of metabolic PET imaging with the short axial field-of-view ( ∼ 20 cm) PET scanners based on pure positron emitter isotopes. The PLI sensitivity of Quadra has been computed for the ^68 Ga, ^44 Sc, ^22 Na and ^124 I radioisotopes. A sensitivity gain by a factor of 150 was estimated relative to the modular J-PET system previously used for the first in-vivo PLI. Additionally, the sensitivity for Total Body J-PET is expected to be about 30 times higher than for modular J-PET.

Positronium lifetime imaging (PLI), an emerging extension of conventional positron emission tomography (PET) imaging, offers a novel window for probing the submolecular properties of biological tissues by imaging the mean lifetime of the positronium atom. Currently, the method is under rapid development in terms of reconstruction and detection systems. Recently, the first in vivo positronium lifetime imaging (PLI) of the human brain was performed using the J-PET scanner utilizing the 68Ga isotope. However, this isotope has limitations due to its comparatively low prompt gamma yields, which is crucial for positronium lifetime measurement. Among alternative radionuclides, Sc-44 stands out as a promising isotope for PLI, characterized by a clinically suitable half-life (4.04 h) emitting 1157 keV prompt gamma in 100% cases after the emission of the positron. This study reports the first experimental demonstration of PLI with Sc-44 , carried out on a NEMA-image quality (IQ) phantom using the Modular J-PET tomograph-the first plastic scintillators-based PET scanner.

Objective. The goal of the work is to develop methods of calibrating the positron emission tomography system built from plastic scintillators, and to present results of the modular J-PET scanner calibration. Methods. Measurements with radionuclide 22Na and 44Sc (used as a point-like source and enclosed in a collimator) were performed using the modular J-PET scanner, and the data were analysed with a dedicated software framework. The detection modules were synchronised using signals from annihilation photons and prompt gamma. Results. The application of the time calibration methods yields a fully synchronised detector. Time-of-Flight resolution for modular J-PET is determined to be about 490 ps (FWHM). Conclusions. J-PET scanner built from plastic scintillators can be calibrated using β+γ emitters and taking advantage of the fact that the direction of propagation of annihilation and prompt photons are not correlated.

This study presents the first ex-vivo positronium imaging of human tissues using the modular J-PET scanner with the ^44Sc radionuclide. The ^44Sc isotope was produced via the ^44Ca(p, n)^44Sc 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 ^44Sc as a positron source for positronium imaging. The performance of J-PET for positronium imaging with ^44Sc 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 ^44Sc radionuclide for positronium lifetime imaging (PLI).

We present the first measurements of the Dalitz plot for ortho-positronium annihilation to three photons. Our measurements, accurate to about 3

Objective.This work presents and evaluates a Monte Carlo (MC) -based scatter correction (SC) method developed for the Jagiellonian positron emission tomography (J-PET) scanner, a modular PET system based on plastic scintillators.Approach.The algorithm employs SimSET-based simulations integrated into a time-of-flight ordered-subsets expectation maximization reconstruction framework to estimate scatter contributions. Phantom studies using the NEMA image quality (IQ) phantom and a proof-of-principle human subject scan with the J-PET scanner were analyzed. To accelerate computation, lutetium-yttrium oxyorthosilicate (LYSO) crystals were also assessed in simulations as a surrogate for the native plastic material BC-404.Main results.In phantom experiments, SC improved contrast recovery coefficients by over 20% and reduced background variability by 8.5%, without introducing significant noise. Residual activity in cold regions was also considerably reduced. Substituting LYSO in the simulations decreased runtime by nearly one order of magnitude, while maintaining deviations below 6% in IQ metrics compared to BC-404. Human subject data demonstrated qualitatively reduced residual scatter and improved organ delineation. Quantitative comparison with the commercial PET/CT scanner by General Electric HealthCare (GE) discovery MI Gen 2 showed consistent activity concentration ratios across organs, although higher noise and residual scatter between organs were observed in J-PET, which most likely originates from lower count density.Significance.The proposed MC-based SC method provides robust scatter removal for J-PET, improving quantitative performance and establishing a foundation for advanced correction and reconstruction techniques. These results bring the plastic scintillator-based J-PET scanner closer to enabling clinically relevant quantitative PET imaging.

Abstract This study demonstrates the applicability of $$^{52}$$ Mn and $$^{55}$$ Co radionuclides for positronium imaging. Positronium Lifetime Imaging (PLI) extends positron emission tomography by using the lifetime of positronium atoms as a probe of tissue molecular architecture. However, its practical use requires $$\beta ^{+}$$ emitters that also provide an additional prompt $$\gamma$$ ray to mark the positron creation time. In this work, we report the first PLI measurements performed with $$^{52}$$ Mn and $$^{55}$$ Co using the modular J-PET. Four samples were studied in each experiment: two Certified Reference Materials (polycarbonate and fused silica) and two human tissues (cardiac myxoma and adipose). The selection of PLI events was based on the registration of two 511 keV annihilation photons and one prompt gamma in triple coincidence. From the resulting lifetime spectra we extracted the mean ortho-positronium lifetime $$\tau _{\text {oPs}}$$ and the mean positron lifetime $$\Delta T_{\text {mean}}$$ for each sample. The measured values of $$\tau _{\text {oPs}}$$ in polycarbonate using both isotopes matches well with the certified reference values. Furthermore, $$^{55}$$ Co reproduced identical results for fused-silica measurements at their respective uncertainty levels. In contrast, measurements with $$^{52}$$ Mn in fused silica show a minor deviation, which could be caused by the Parafilm spacer. In myxoma and adipose tissue, the reduced $$\tau _{\text {oPs}}$$ values are mainly linked to the long storage history of the samples rather than to the choice of isotope. Comparing peak-to-background ratios and spectral purity, $$^{55}$$ Co provides cleaner PLI data under the same experimental conditions. Although $$^{52}$$ Mn offers a longer half-life and a multi gamma cascade enhancing $$\beta ^{+}$$ + $$\gamma$$ coincidences, but at the expense of higher background. In this study, we demonstrate that the applied selection criteria on the data measured with the modular J-PET can be used for PLI studies even with radionuclides with complex decay patterns.

Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET (Jagiellonian Positron Emission Tomography) system is demonstrated.

The μPPET [mu(μ)on Probe with J-PET] project aims to investigate the “Muon Puzzle” seen in cosmic ray air showers. This puzzle arises from the observation of a significantly larger number of muons on Earth’s surface than that predicted by the current theoretical models. The investigated hypothesis is based on recently observed asymmetries in the parameters for the strong interaction cross-section and trajectory of an outgoing particle due to projectile–target polarization. The measurements require detailed information about muons at the ground level, including their track and charge distributions. To achieve this, the two PET scanners developed at the Jagiellonian University in Krakow (Poland), the J-PET detectors, will be employed, taking advantage of their well-known resolution and convenient location for detecting muons that reach long depths in the atmosphere. One station will be used as a muon tracker, while the second will reconstruct the core of the air shower. In parallel, the existing hadronic interaction models will be modified and fine-tuned based on the experimental results. In this work, we present the conceptualization and preliminary designs of μPPET.

Positronium Lifetime Imaging (PLI) extends positron emission tomography by using the lifetime of positronium atoms as a probe of tissue molecular architecture. In this work, we report the first PLI measurements performed with ^52Mn and ^55Co using the modular J-PET. Four samples were studied in each experiment: two Certified Reference Materials (polycarbonate and fused silica) and two human tissues (cardiac myxoma and adipose). The selection of PLI events was based on the registration of two 511 keV annihilation photons and one prompt gamma in triple coincidence. From the resulting lifetime spectra we extracted the mean ortho-positronium lifetime τ_oPs and the mean positron lifetime ΔT_mean for each sample. The measured values of τ_oPs in polycarbonate using both isotopes matches well with the certified reference values. Furthermore, ^55Co reproduced identical results for fused-silica measurements at their respective uncertainty levels. In contrast, measurements with ^52Mn in fused silica show a minor deviation, which could be caused by the Parafilm spacer. In myxoma and adipose tissue, the reduced τ_oPs values are mainly linked to the long storage history of the samples rather than to the choice of isotope. Comparing peak-to-background ratios and spectral purity, ^55Co provides cleaner PLI data under the same experimental conditions. Although ^52Mn offers a longer half-life and a multi gamma cascade enhancing β^+ + γ coincidences, but at the expense of higher background. In this study, we demonstrate that the applied selection criteria on the data measured with the modular J-PET can be used for PLI studies even with radionuclides with complex decay patterns.

The coupled INDRA-FAZIA apparatus is operating in GANIL since 2019, when its first experiment has been carried out. In this experiment, the four reactions 58,64Ni+58,64Ni at 32 and 52 MeV/nucleon have been investigated in order to highlight the isospin transport effects on the neutron content of light and heavy fragments, particularly those belonging to the QP phase space which are collected by FAZIA. Here, we give an overview of the characteristics and performances of the coupled apparatus, as well as a summary of the most recent results and observations on this first rich dataset.

A Bayesian analysis aimed at tuning two parameters of the AMD model, one of them related to the in medium nucleon nucleon cross-section and the other to the clustering, has been performed. Experimental data collected with four blocks of the FAZIA setup have been compared with simulated data built with different values of the investigated parameters.

Constraining the nuclear equation of state (EoS) parameters makes it possible to better understand the properties of the matter that constitutes our Universe. Many probes can be used to test the EoS, from the observation of neutron star mergers to heavy-ion collisions at intermediate energies. The fragments and particles emitted in collisions need to be identified with isotopic discrimination in order to give valuable information. In this regard, a specifically designed apparatus, such as FAZIA, may be used to study the equation of state. This review summarizes the advanced characteristics of the FAZIA detector array and the achievements obtained by the FAZIA collaboration in the last 15 years.

Total-Body PET is one of the most promising medical diagnostics modalities. The high sensitivity provided by Total-Body technology can be advantageous for novel tomography methods like positronium imaging. Several efforts are ongoing to lower the price of the TB-PET systems. Among the alternatives, the Jagiellonian PET (J-PET) technology, based on plastic scintillator strips, offers a low-cost alternative. The work aimed to compare five Total-Body J-PET geometries as a possible next generation J-PET scanner design. We present comparative studies of performance characteristics of the cost-effective Total-Body PET scanners using J-PET technology. We investigated in silico five Total-Body scanner geometries. Monte Carlo simulations of the XCAT phantom, the 2-meter sensitivity line source and positronium sensitivity phantoms were performed. We compared the sensitivity profiles for 2-gamma and 3-gamma tomography, relative cost of the setups and performed quantitative analysis of the reconstructed images. The analysis of the reconstructed XCAT images reveals the superiority of the seven-ring scanners over the three-ring setups. However, the three-ring scanners would be approximately 2-3 times cheaper. The peak sensitivity values for two-gamma vary from 20 to 34 cps/kBq. The sensitivity curves for the positronium tomography have a similar shape to the two-gamma sensitivity profiles. The peak values are lower compared to the two-gamma cases, from about 20-28 times, with a maximum of 1.66 cps/kBq. The results show the feasibility of multi-organ imaging of all the systems to be considered for the next generation of TB J-PET designs. The relative cost for all the scanners is about 10-4 times lower compared to the cost of the uExplorer. These properties coupled together with J-PET cost-effectiveness, make the J-PET technology an attractive solution for broad application in clinics.

BACKGROUND:Total-body (TB) Positron Emission Tomography (PET) is one of the most promising medical diagnostics modalities, opening new perspectives for personalized medicine, low-dose imaging, multi-organ dynamic imaging or kinetic modeling. The high sensitivity provided by total-body technology can be advantageous for novel tomography methods like positronium imaging, demanding the registration of triple coincidences. Currently, state-of-the-art PET scanners use inorganic scintillators. However, the high acquisition cost reduces the accessibility of TB PET technology. Several efforts are ongoing to mitigate this problem. Among the alternatives, the Jagiellonian PET (J-PET) technology, based on axially arranged plastic scintillator strips, offers a low-cost alternative solution for TB PET. PURPOSE:The work aimed to compare five total-body J-PET geometries with plastic scintillators suitable for multi-organ and positronium tomography as a possible next-generation J-PET scanner design. METHODS:We present comparative studies of performance characteristics of the cost-effective total-body PET scanners using J-PET technology. We investigated in silico five TB scanner geometries, varying the number of rings, scanner radii, and other parameters. Monte Carlo simulations of the anthropomorphic XCAT phantom, the extended 2-m sensitivity line source and positronium sensitivity phantoms were used to assess the performance of the geometries. Two hot spheres were placed in the lungs and in the liver of the XCAT phantom to mimic the pathological changes. We compared the sensitivity profiles and performed quantitative analysis of the reconstructed images by using quality metrics such as contrast recovery coefficient, background variability and root mean squared error. The studies are complemented by the determination of sensitivity for the positronium lifetime tomography and the relative cost analysis of the studied setups. RESULTS:The analysis of the reconstructed XCAT images reveals the superiority of the seven-ring scanners over the three-ring setups. However, the three-ring scanners would be approximately 2-3 times cheaper. The peak sensitivity values for two-gamma vary from 20 to 34 cps/kBq and are dominated by the differences in geometrical acceptance of the scanners. The sensitivity curves for the positronium tomography have a similar shape to the two-gamma sensitivity profiles. The peak values are lower compared to the two-gamma cases, from about 20-28 times, with a maximum value of 1.66 cps/kBq. This can be contrasted with the 50-cm one-layer J-PET modular scanner used to perform the first in-vivo positronium imaging with a sensitivity of 0.06 cps/kBq. CONCLUSIONS:The results show the feasibility of multi-organ imaging of all the systems to be considered for the next generation of TB J-PET designs. Among the scanner parameters, the most important ones are related to the axial field-of-view coverage. The two-gamma sensitivity and XCAT image reconstruction analyzes show the advantage of seven-ring scanners. However, the cost of the scintillator materials and SiPMs is more than two times higher for the longer modalities compared to the three-ring solutions. Nevertheless, the relative cost for all the scanners is about 10-4 times lower compared to the cost of the uExplorer. These properties coupled together with J-PET cost-effectiveness and triggerless acquisition mode enabling three-gamma positronium imaging, make the J-PET technology an attractive solution for broad application in clinics.

In this contribution, we review the recent results from the INDRA and FAZIA Collaborations. It will cover the results from INDRA-VAMOS experiments at GANIL, the first two INDRA-FAZIA campaigns at GANIL and FAZIA experiments at LNS Catania. Recent detector upgrades and developpements will also be discussed. Those results are better explained and more detailed in the following report presentations of this issue and just a brief overview will be mentionned here, with mostly the main conclusions addressed.

In state-of-the-art positron emission tomography (PET), information about annihilation photon polarization is unavailable. Here, we present a PET scanner built from plastic scintillators, where annihilation photons primarily interact via the Compton effect, providing information about both photon polarization and propagation direction. Using this plastic-based PET, we determined the distribution of the relative angle between polarization planes of photons from positron-electron annihilation in a porous polymer. The amplitude of the observed distribution is smaller than predicted for maximally quantum entangled two-photon states but larger than expected for separable photons. This result can be well explained by assuming that photons from pick-off annihilation are not entangled, while photons from direct and parapositronium annihilations are maximally entangled. Our result indicates that the degree of entanglement depends on the annihilation mechanism in matter, opening avenues for exploring polarization correlations in PET as a diagnostic indicator.

Studies based on imaging the annihilation of the electron (e$^{-}$) and its antiparticle positron (e$^{+}$) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the direct conversion of e$^{+}$e$^{-}$ into photons and the formation of their atomically bound state, the positronium atom (Ps), which can be used as a probe for fundamental studies. With the ability to produce large quantities of Ps, manipulate them in long-lived Ps states, and image their annihilations after a free fall or after passing through atomic interferometers, this purely leptonic antimatter system can be used to perform inertial sensing studies in view of a direct test of Einstein equivalence principle. It is envisioned that modular multistrip detectors can be exploited as potential detection units for this kind of studies. In this work, we report the results of the first feasibility study performed on a e$^{+}$ beamline using two detection modules to evaluate their reconstruction performance and spatial resolution for imaging e$^{+}$e$^{-}$ annihilations and thus their applicability for gravitational studies of Ps.

Positronium is abundantly produced within the molecular voids of a patient's body during positron emission tomography (PET). Its properties dynamically respond to the submolecular architecture of the tissue and the partial pressure of oxygen. Current PET systems record only two annihilation photons and cannot provide information about the positronium lifetime. This study presents the in vivo images of positronium lifetime in a human, for a patient with a glioblastoma brain tumor, by using the dedicated Jagiellonian PET system enabling simultaneous detection of annihilation photons and prompt gamma emitted by a radionuclide. The prompt gamma provides information on the time of positronium formation. The photons from positronium annihilation are used to reconstruct the place and time of its decay. In the presented case study, the determined positron and positronium lifetimes in glioblastoma cells are shorter than those in salivary glands and those in healthy brain tissues, indicating that positronium imaging could be used to diagnose disease in vivo.