The first PET tomograph based on plastic scintillators was designed and built at the Institute of Physics of the Jagiellonian University.
Jagiellonian PET (J-PET) is a unique research device on a global scale that allows not only to visualize the metabolism of selected substances in living organisms, but also for imaging tissue pathology in-vivo by measuring the properties of positronium (an atom made of electron and positron).
Tissue pathology imaging is a unique feature of the J-PET tomograph based on the fact that during PET diagnosis positronium atoms are formed in human tissues in intramolecular spaces (atoms composed of an electron from tissue and a positron emitted by a radioisotope).
This phenomenon, not used so far in medicine, may create new possibilities for medical diagnostics.
For example, the average lifetime of positronium within tissues depends on the size of free space between atoms and on the concentration of free radicals in cells and can serve as a new indicator (bio-marker) for determining the degree of malignancy in tumors in vivo.
A positronium atom, being a system built of electron and positron bound by electromagnetic interaction, is both an atom and an anti-atom. As an atom made of electron and anti-electron, unlike ordinary atoms, is symmetrical when exchanging particles for antiparticles.
That is why positronium is an ideal system for studying symmetry between matter and antimatter in nature.
In particular, it enables tests of invariance of physical phenomena due to discrete transformations (symmetries) such as: conversion of particles into antiparticles (C), reversal of time (T), spatial reflection (P) and combinations of these symmetries, such as CP or CPT. Discrete symmetry tests touch upon fundamental questions such as:
Why stars exist? Why do we exist? Why does the universe exist? Are there other particles and forces unknown to us that are responsible for the survival of matter to our times?
The survival of matter in the universe remains an unexplained mystery, given the far too small measured asymmetry between matter and antimatter, so far observed only in processes of weak interaction. To date, no signs of similar asymmetries have been observed in gravitational, electromagnetic and strong interactions.
The lecture will discuss the principle of the J-PET tomograph and its possible applications for studying metabolism throughout the whole human body simultaneously. Also discussed will be the principle of positronium imaging, the principle of testing discrete symmetry with a J-PET tomograph, as well as the principle of measuring the polarization and quantum entanglement of photons formed as a result of positronium annihilation.
J-PET as a tomograph made of plastic detectors is currently a unique device that allows the study of quantum entanglement of photons arising from positronium annihilation. The first positronium images and the results of discrete symmetry tests in positronium atom decays obtained with J-PET tomograph will also be presented.
They are so far the most precise tests in the world in electrically charged leptons
J-PET technology makes it possible to build a PET tomograph for the entire human body – the total-body PET. Access to such a device would open up new research opportunities in medicine, including, for example:
- pharmacokinetic studies of new compounds or drug binding at the tissue level in vivo,
- in-vivo detection of malignancy,
- research on metabolic and chronic diseases at the cellular and tissue level.
The lecture will also discuss the prospects of building such a total-body PET in Poland.