First positronium imaging of humans using modular J-PET scanner

Jagiellonian PET (J-PET) is a novel cost-effective positron emission tomography technology based on plastic scintillators [1,2], and positronium imaging is a newly invented method of imaging the properties of positronium in living organisms [3,4,5]. Both methods were invented and are being developed at the Jagiellonian University. During positron emission tomography about 40% of positron annihilations occur through the creation of positronium [6]. Positronium, which may be formed in human tissues in the intramolecular spaces, is an exotic atom composed of an electron from tissue and the positron emitted by the radionuclide. Positronium decay in the patient's body is sensitive to the nanostructure and metabolism of human tissues [6]. This phenomenon is not used in present PET diagnostics, yet it is in principle possible to exploit such environment-modified properties of positronium as diagnostic biomarkers for cancer assessment. The first in-vitro positronium images have shown differences in the positronium mean lifetime and production probability in healthy and cancerous tissues, indicating that they may be used as indicators for in-vivo cancer classification [3]. In the talk the method of positronium imaging and the pilot in-vitro and in-vivo positronium images obtained with the J-PET tomograph (the first portable PET system based on plastic scintillators capable of multi-photon imaging [7]) will be presented and explained. The basis of operation of the J-PET tomograph - the first device enabling imaging of positronium properties in living organisms will be also presented and explained. We will also present arguments demonstrating that the advent of high sensitivity total-body PET systems and the invention of the method of positronium imaging, open perspectives for the application of positronium as a biomarker for in-vivo assessment of the degree of hypoxia [8]. [1] P. Moskal et al., Phys. Med. Biol. 66 (2021) 175015.

[2] P. Moskal, E. Ł. Stępień, PET Clinics 15, 439 (2020).

[3] P. Moskal et al., Science Advances 7, eabh4394 (2021).

[4] P. Moskal et al., Phys. Med. Biol. 64, 055017 (2019).

[5] P. Moskal et al., EJNMMI Phys. 7, 44 (2020).

[6] P. Moskal et al., Nature Reviews Physics 1, 527 (2019).

[7] P. Moskal et al., Nature Communication 12, 5658 (2021).

[8] P. Moskal, E. Ł. Stępień, Bio-Algorithms and Med-Systems 17, 311 (2021).