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Development of correction techniques for the J-PET scanner

Das Manish, Bayerlein Reimund, Sharma Sushil, Parzych Szymon, Niedzwiecki Szymon, Badawi Ramsey D., Beyene Ermias Yitayew, Chug Neha, Curceanu Catalina, Czerwiński Eryk, Eliyan Kavya V., Głowa Bogusław, Hubalewska-Dydejczyk Alicja, Kacprzak Krzysztof, Kaplanoglu Tevfik, Kasperska Kamila, Korcyl Grzegorz, Khreptak Aleksander, Kubat Karol, Kumar Deepak, Lisowski Edward, Lisowski Filip, Mędrala-Sowa Justyna, Moyo Simbarashe, Mryka Wiktor, Opalińska Marta, Pandey Piyush, Rädler Martin, Skurzok Magdalena, Sowa-Staszczak Anna, Spencer Benjamin A., Tanty Pooja, Ardebili Keyvan Tayefi, Venadan Anoop K., Perez del Rio Elena, Stępień Ewa Ł., Moskal Paweł

Bio-Algorithms and Med-Systems

2024

Vol. 20, no. 1

101--110

Objective: Positron emission tomography (PET) is a widely used medical imaging technique that allows for non-invasive imaging of metabolic processes. However, traditional PET scanners rely on costly inorganic scintillators that limit their accessibility, especially in light of emerging long axial field-of-view devices. The modular J-PET scanner, an innovative alternative, uses 50-cm-long plastic scintillator strips, offering a cost-effective and modular solution. In this study we develop and assess the PET data correction techniques required for quantitative image reconstruction. Methods: We present methods for attenuation correction, random coincidence correction using the delayed time window (DTW) technique and scatter correction based on Monte Carlo simulations. Phantom studies using the NEMA IQ phantom were performed to qualitatively evaluate these corrections. Results: The results demonstrate that our implemented corrections for attenuation and random and scattered coincidences successfully improve the uniformity of tracer distribution in homogenous volumes and significantly reduce undesired activity in cold regions. Despite limitations in sensitivity and axial resolution, the applied correction techniques effectively enhance image quality, providing promising results for future applications. Conclusions: These findings highlight the potential of the modular J-PET system to offer affordable PET imaging and to pave the way for a total-body PET scanner based on plastic scintillators. Future work will focus on quantitative validation and the implementation of these corrections for human subject imaging.

Feasibility study of positronium application for blood clots structural characteristics

Moyo Simbarashe, Moskal Paweł, Stępień Ewa Ł.

Bio-Algorithms and Med-Systems

2022

Vol. 18, no. 1

163--167

Positron-electron annihilation in living organisms occurs in about 30% via the formation of a metastable ortho-positronium atom that annihilates into two 511 keV photons in tissues because of the pick-off and conversion processes. Positronium (Ps) annihilation lifetime and intensities can be used to determine the size and quantity of defects in a material's microstructure, such as voids or pores in the range of nanometers. This is particularly true for blood clots. Here we present pilot investigations of positronium properties in fibrin clots. The studies are complemented by the use of SEM Edax and micro-computed tomography (µCT) to evaluate the extracted thrombotic material's properties. µCT is a versatile characterization method offering in situ and in operando possibilities and is a qualitative diagnostic tool. With µCT the presence of pores, cracks, and structural errors can be verified, and hence the 3D inner structure of samples can be investigated.