The modern medicine, developing towards personalized treatment of patients, requires high specificity in assessing the disease. Our research aims at improvement of specificity of the PET diagnosis by use of positronium as a theranostic agent. During the positron emission tomography about 40% of positronsannihilations occur through the creation of positronium. Positronium is formed in human tissues in intramolecular spaces, as exotic atom composed of an electron from tissue and a positron emitted by a radioisotop. Positronium decays in thepatient body are sensitive to the nanostructure and metabolism of thetissues. This phenomenon is not used in the present PET diagnostics,yet it is in principle possible to use environment modified propertiesof positronium as diagnostic biomarkers for cancer therapy. Firstin-vitro studies show differences of positronium mean lifetime andproduction probability in the healthy and cancerous tissues,indicating that they may be used as indicators for in-vivo cancerclassification. For the application in medical diagnostics the properties of positronium atoms need to be determined in a spatially resolved manner. For that purpose we developed a method of positronium lifetimeimaging in which the lifetime and position of positronium atoms isdetermined on an event-by-event basis. The method requires applicationof β+ decaying isotope emitting prompt gamma. We will argue that with the total-body PETscanners the sensitivity of the positronium lifetime imaging, whichrequires coincident registration of the back-to-back annihilationphotons and the prompt gamma is comparable to the sensitivities forthe metabolic imaging with standard PET scanners.
P. Moskal et al., Nature Reviews Physics 1 (2019) 527.
J-PET: P. Moskal et al., Nature Communication 12 (2021) 5658.
J-PET: P. Moskal et al., Science Advances 7 (2021) eabh4394.
