Abstract:Abstract. Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the… Show more
“…In present day Positron Emission Tomography (PET) imaging systems, suspected false coincidence events are removed using energy discrimination and correction techniques. With the advent of Compton camera technology [1][2][3][4][5], it has been suggested that entanglement of the annihilation photons can be used as an additional discriminator to increase the accuracy of eliminating false coincidence events, thereby improving image quality [6]. However, before entanglement can be used, fundamental issues relating to kinematic outcomes of Compton scattering of annihilation photons must be resolved.…”
This theoretical research aims to examine areas of the Compton cross section of entangled annihilation photons for the purpose of testing for possible break down of theory, which could have consequences for predicted optimal capabilities of Compton PET systems. We provide maps of the cross section for entangled annihilation photons for experimental verification. We introduce a strategy to derive cross sections in a relatively straight forward manner for the Compton scattering of a hypothetical separable, mixed and entangled states. To understand the effect that entanglement has on the cross section for annihilation photons, we derive the cross section so that it is expressed in terms of the cross section of a hypothetical separable state and of a hypothetical forbidden maximally entangled state. We find lobe-like structures in the cross section which are regions where entanglement has the greatest effect. We also find that mixed states do not reproduce the cross section for annihilation photons, contrary to a recent investigation which reported otherwise. We review the motivation and method of the most precise Compton scattering experiment for annihilation photons, in order to resolve conflicting reports regarding the extent to which the cross section itself has been experimentally verified.
“…In present day Positron Emission Tomography (PET) imaging systems, suspected false coincidence events are removed using energy discrimination and correction techniques. With the advent of Compton camera technology [1][2][3][4][5], it has been suggested that entanglement of the annihilation photons can be used as an additional discriminator to increase the accuracy of eliminating false coincidence events, thereby improving image quality [6]. However, before entanglement can be used, fundamental issues relating to kinematic outcomes of Compton scattering of annihilation photons must be resolved.…”
This theoretical research aims to examine areas of the Compton cross section of entangled annihilation photons for the purpose of testing for possible break down of theory, which could have consequences for predicted optimal capabilities of Compton PET systems. We provide maps of the cross section for entangled annihilation photons for experimental verification. We introduce a strategy to derive cross sections in a relatively straight forward manner for the Compton scattering of a hypothetical separable, mixed and entangled states. To understand the effect that entanglement has on the cross section for annihilation photons, we derive the cross section so that it is expressed in terms of the cross section of a hypothetical separable state and of a hypothetical forbidden maximally entangled state. We find lobe-like structures in the cross section which are regions where entanglement has the greatest effect. We also find that mixed states do not reproduce the cross section for annihilation photons, contrary to a recent investigation which reported otherwise. We review the motivation and method of the most precise Compton scattering experiment for annihilation photons, in order to resolve conflicting reports regarding the extent to which the cross section itself has been experimentally verified.
“…However, resolution of the Z coordinate (along the scintillator strips) and of photon recording time in J-PET are correlated and dependent on the signal reconstruction method used due to the specific features of this detector [16,[24][25][26]. Moreover, they are subject to a possible future improvement with an advancement of reconstruction methods applied in J-PET based on multi-SiPM readout [27]. Therefore, reconstruction studies were performed both for fixed detector resolutions of σ(t hit )=80 ps and σ(z hit )=0.93 cm presently achieved with prototypes [15] and for these resolutions varying in the range from 0 ps to 160 ps and from 0 cm to 2 cm, respectively.…”
Section: Principle Of the O-ps→ 3γ Decay Reconstructionmentioning
This work reports on a new reconstruction algorithm allowing to reconstruct the decays of ortho-positronium atoms into three photons using the places and times of photons recorded in the detector. The method is based on trilateration and allows for a simultaneous reconstruction of both location and time of the decay. allows for discrimination of background from random three-photon coincidences as well as for application of a novel method for determination of the linear polarization of ortho-positronium atoms, which is also introduced in this work.
“…3Simulated spectra of deposited energy in plastic scintillators for gamma quanta from annihilation and for de-excitation gamma quanta originating from isotopes indicated in the legend. The spectra were simulated including the energy resolution of the J-PET detector [20] and were normalized to the same number of eventsFig. 4Scheme of sodium decay and formation of ortho-positronium…”
Section: Performance Assessment: Monte Carlo Simulationsmentioning
confidence: 99%
“…The spectra were simulated including the energy resolution of the J-PET detector [20] and were normalized to the same number of events…”
Section: Performance Assessment: Monte Carlo Simulationsmentioning
confidence: 99%
“…This solution allows to sample fast signals (5 ns) [10, 20–23] and build more extended geometries, in comparison to commercially used PET detectors [20]. In this paper we study the feasibility of the three gamma annihilation measurements using the J-PET detector.…”
We present a study of the application of the Jagiellonian positron emission tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the decays with angular and energy resolution equal to and , respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.
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