J-PET (Jagiellonian-PET TOMOGRAPHY)
Jagiellonian PET is the first Positron Emission Tomography scanner build from plastic scintillators. J-PET, as a multi-photon PET, enabled to make the first positronium image and the first multiphoton image [SciAdv2021].
The plastic scintillators, in contrast to inorganic ones, are relatively cheap and easy to shape and enable to make cost-effective total-body PET.
The primary aim of the group is to develop a technology for [PETClin2020]:
- the cost effective total-body PET,
- positronium imaging and
- a modular and transportable PET with the field of view adjustable to the patient size.
A first full scale J-PET prototype is shown in the photo below. It was used to demonstrate the first positronium image for Cardiac Myxoma and adipose tissue [SciAdv2021]. It is used also for studies of the discrete symmetries in the decays of positronium atoms [NatureComm2021] and multi-particle entanglement of photons originating from the decay of positronium [SciRep2019].
The J-PET prototype with the group members.
The Jagiellonian PET collaboration lead by P. Moskal is an interdisciplinary and international group including physicists, chemists, electronic engineers, computer scientists, quantum information physicists as well as bio and medical physicists from the Jagiellonian University, National Centre for Nuclear Research, Institute of Nuclear Physics, Maria Curie-Skłodowska University, John Paul II Hospital, University of Vienna, National Laboratory in Frascati and from the companies Nowoczesna Elektronika and Brain Waves Electronics.
The J-PET members photo.
Plastic scintillators are superior to the crystal ones in terms of their time resolution. The novelty of the J-PET detector lies also in the fact that the information about the place of gamma quanta interaction is extracted solely from the time, rather than the energy deposition measurement.
In each of the 192 modules of the J-PET detector there are two photomultipliers mounted at the both ends of a scintillator. Signals are sampled at four voltage levels at the leading and trailing edges with the newly developed, dedicated digital multi-threshold electronics [IEEETransMedImag2018][JINST2017]. The place of a gamma quantum interaction in the scintillator (Δl) is determined from the times measured at both ends of the same strip. For the determination of the position of the annihilation point along a line-of-response (Δx) a time-of-flight (TOF) method is used basing on the times registered in a pair of opposite strips [PhysMed2020]. Furthermore, timing of signals is used for suppression of scatterings via the the time-over-threshold (TOT) method [EJNMMI2020].
Left: The place of annihilation (marked as red spot) is estimated based on timing information gathered by two detection modules. First the interaction positions are determined based on time of arrival of light signal at both edges of plastic scintillator. This gives possibility to calculate delta L, distance from the center of a strip. Then one can connect two interaction positions constructing LOR (Line-Of-Response). Place of annihilation can be determined by comparison of interaction times between two modules. Right: Two exemplary signals from photomultipliers from each side of the same scintillator. Signal is measured at four thresholds, marked as horizontal black lines, at both edges. Such measurement gives opportunity to estimate place of interaction along the plastic strip as well as energy deposition of gamma quantum.
In order to compensate for the lower gamma quanta registration efficiency in the organic scintillators more detection layers can be used. This together with a large light attenuation length in the plastic scintillators allowed for construction of a tomograph with a large axial field-of-view, competitive in terms of spatial resolution and cheaper than commercially available scanners.
Furthermore, the J-PET constitues a high acceptance multi-purpose detecor optimized for the detection of photons from the positron-electron annihilation and can be used in the broad interdisciplinary investigations including, among others:
- positronium imaging [SciAdv2021] [NatureRev2019],
- studies of discrete symmetries in the decays of positronium atoms [NatureComm2021],
- quantum entanglement of high energy photons originating from the decay of ortho-positronium [SciRep2019],
- research in the field of life- and material-sciences [BioAlgMedSyst2021].
The first full scale prototype of the J-PET detector. The J-PET detector is made of three cylindrical layers of EJ-230 plastic scintillator strips (black) with dimension of 7 × 19 × 500 mm3 and Hamamatsu R9800 vacuum tube photomultipliers (grey). The signals from photomultipliers are probed in the voltage domain at four thresholds with a timing accuracy of 30 ps and the data acquisition is working in the trigger-less mode. The prototype was built with the support from the Polish National Center for Development and Research through grant INNOTECH-K1/IN1/64/159174/NCBR/12.
In the typical detectors with vacuum tube photomultipliers, only few first registered photons contribute to the leading edge of the electrical signal. Therefore, the time resolution may be improved by making a readout allowing to record timestamps from larger number of scintillation photons arriving at the scintillator edge. This can be achieved by the preparation of a a read-out system in the form of an array with several SiPM photomultipliers. In such a case, a set of all registered scintillation photons is divided into several subgroups and the time of the registration of the first photon in each subgroup is recorded.
The upper diagram shows a single detection element of the first J-PET detector consisting of the scintillator strip read out on two sides by vacuum tube photomultipliers. The lower part shows a diagram of an exemplary multi-SiPM readout allowing for determination of timestamps of 20 detected photons (10 on each side).
Based on aforementioned concept, new detection modules were designed. A single module of the new detection layer of the J-PET tomograph is an independent detection unit which sends information about timing of the signals via optical links to the data acquisition boards. It consists of 13 BC-404 plastic scintillator strips. Each strip has dimensions of 6x24x50 mm3. Scintillators are wrapped in Vikuiti ESR and Pokalon 100B foils. Each side of scintillator strip is read out by S13361-6674 Hamamatsu SiPMs (Silicon PhotoMultipliers) in a form of a 1x4 matrix. SiPMs output is connected to the preamplifier and power supply boards. Supply board allows tuning of voltage for each SiPM separately with high precision, while preamp board first enhances the signals and then splits them passively into two. Analog signals are then fed into LVDS buffer of FPGA chip, with second voltage set to constant value. Such approach works as makes measurement of time at constant threshold possible for each detector channel separately. Conversion of analog to digital is performed at the end of the module to enable as high timing performance as possible. Digital signals are then handled by two stage digital readout system which can process part of the data stream on the fly and in the end store it on the server. Whole detector is build out of 24 detection modules mounted in a metal frame. Each module can be easily taken out for maintenance and weights about 2 kg in total.
Due to the application of the matrix of the silicon photomultipliers, the new layer of the J-PET is characterized by even better timing resolution than the first prototype.
Left: Power supply board (green) providing voltage to each SiPM separately and TDC board (blue) converting analog signals to digital ones, containing the information of analog signal crossing at two selected constant thresholds. Right: Mobile J-PET prototype after mechanical assembly. Detector is build out of 24 detection modules. Each module can be easily taken out for maintenance and weights about 2 kg in total and consists of 13 scintillators read out at both sides by arrays of 1x4 SiPMs. Analog signals are digitized as close as possible to the SiPMs using TDC boards developed by the J-PET group.
Medical diagnostics: multiphoton PET and positronium imaging
Furthermore, the ability of the J-PET detector to reconstruct the decays of ortho-positronium (o-Ps) atoms into three photons was proven. The method is based on trilateration (GPS-like method) and allows for a simultaneous reconstruction of both location and time of the decay [NIMP2016]. Altough gamma quanta interact in the plastic scintillators predominantly via the Compton effect, making a direct measurement of their energy impossible, it was shown that the J-PET scanner will enable studies of the o-Ps→3γ decays with angular and energy resolution equal to σ(θ) ≈ 0.4o and σ(E) ≈ 4.1 keV, respectively.
Left: A diagram of the J-PET detector with gamma quantum hit positions marked in black and the o-Ps decay plane indicated in gray. Right: Diagram of the decay reconstruction reduced to a two-dimensional problem in the decay plane. Each of hit coordinates constitutes the center of a circle describing possible photon origin point, where radius of the circle depends on the recording time and the unknown o-Ps decay time.
The J-PET detector is also the first detector capable of positronium imaging. The positronium imaging is a concept, proposed by the founder of the J-PET group P. Moskal, that combines two kind of information that can be extracted from a positronium decay – position of the decay and the positronium lifetime. In particular, the lifetime of relatively long-lived o-Ps is an extremely precise structural indicator that has been extensively studied in the context of material and surface research. Changes in the mean o-Ps lifetime enables the characterization of the porosity of the material in the range of 1-100 nm.
The first positronium image was created by studying three-photon coincidences, where two photons were coming from the positronium annihilation and the third photon was coming from the deexcitation of the positron emitter nucleus (22Na → 22Ne* + e+ + νe; 22Ne* → 22Ne + γdeex). Annihilation photons from the two-photon decay of the positronium allows for the determination of the annihilation position, where the registration of the deexcitation photon allows for measurement of single lifetimes of the positronium. Simultaneous measurement of the annihilation position and positronium lifetime allowed to form image consisting of the o-Ps lifetime estimated in each voxel – positronium image. This is a complementary image to the standard PET image, which can extend not only the diagnostic capabilities of the PET technique, but also the applicability of PET scanners for example in material research. Additional structural information derived from the measurement of mean o-Ps lifetime may help in the detection of neoplastic lesions not detected with standard PET scans as well as in determining their degree of malignancy, and therefore constitute the so-called “virtual biopsy”.
The measurement scheme and the determined SUV and positronium images. The top left panel illustrates a part of a hemoglobin molecule with superimposed schemes, indicating decays of o-Ps (green circles) and parapositronium (p-Ps) (violet circle). o-Ps may undergo self-annihilation (pink arrows), pickoff process (gray arrows), or conversion to parapositronium, e.g., by interacting with oxygen molecule (green arrows). The top right panel shows the first part of the experimental workflow. Four samples from two patients were collected and divided into two classes: cardiac myxoma and adipose tissue. Each sample was inserted into a holder with the radioactive 22Na source, which was inserted into the J-PET detector. The blue and yellow circles show the locations of the samples during the measurement. Methods to reconstruct the image analogs to that of the SUV image (annihilation rate distribution) and positronium lifetime image are described in Methods. Reconstructed mean o-Ps lifetime in cardiac myxoma (1.9 ns) differs from the mean o-Ps lifetime in adipose tissue (2.6 ns). More comprehensive studies confirming the differences in the o-Ps mean lifetime in the healthy adipose tissue and cardiac myxoma tumor are described in the article to be submitted elsewhere.
More information can be found in:
- Patent application
- Trilateration-based reconstruction of ortho-positronium decays into three photons with the J-PET detector
- A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators
- Feasibility study of the positronium imaging with the J-PET tomograph
- Positronium imaging with the novel multiphoton PET scanner
- Positronium in medicine and biology
- The J-PET detector-a tool for precision studies of ortho-positronium decays
Development of J-PET range monitoring for hadron therapy
The main advantage of the proton therapy over the conventional radiotherapy (which uses X-ray or electrons) is the possibility to precisely deposit the radiation dose only in the tumor region. This is a consequence of the characteristic energy loss distribution of ionizing radiation when the proton beam moves through matter. The maximum of energy deposition is localized immediately before the maximum movement range (the Bragg peak).
Altought the range of the proton beam in a homogenous medium of know properties can be precisely calculated, the expected range in the patient's body is determined only with limited precision. Therefore, in order to cover the entire volume of tumor a margin of healthy tissues surrounding it are also exposed to radiation.
The availability of beam range monitoring would allow for more precise therapy planning and for a more complete usage of proton therapy benefits.
The result of proton beam interactions with the atoms in the patient's tissues is the emission of the secondary particles, mainly: neutrons, photons (promt-gamma) and charged particles. Additionally, due to the nuclear interaction isotopes which decay via the β+ decay are created. Emited positrons annihilate with the electrons from the patients body and two back to back gamma quanta with a minimum energy of 511 keV are emitted. These gamma quanta can escape from the patient's body and be registered. The aim of the project developed in colaboration with the Institute of Nuclear Physics of the Polish Academy of Sciences is to test the usefulness of the J-PET technology for the monitoring of the proton beam range.
In the middle of the October 2021 the experiment aimed at measuring the range of irradiation using proton beam in different phantoms was conducted. In the facility where the experiment was conducted mainly tumors located in inoperable positions are treated, especially those located very close to vital organs, e.g. brain. Thus knowing exact depth of proton interaction and possibility to modify it in a fast way is pivotal.
J-PET members in the Institute of Nuclear Physics of the Polish Academy of Sciences.
Positronium as a cancer biomarker
We are aiming for examining a possible biomedical application of positronium for the characterization of normal and cancer cells and tissues, hence if it can serve as a cancer biomarker. Studies were conducted on two models: benign cardiac myxoma specimens and malignant melanoma cultured cell lines. In both cases, positronium properties were compared to an appropriate normal tissue and cell line. Studies are performed for both fixed and living cells and tissues to investigate the influence of water and cell viability on the PALS signal. Obtained results show significant differences in positronium lifetime and its production intensity between cancer and normal cells and tissues in all studied cases, regardless of hydration and fixation of specimens.
Micrograph showing the culture of HEMa-LP, WM115, and WM266-4 cell lines. Scale bar has100µm. B:Exemplary PAL spectra for freeze-dried inmedium no. 5 WM115cell culture.Superimposed linesindicate distributions of particular components resulting from thefitted model. Green - para-Positronium, yellow - annihilation in the source material, turquoise - free positron annihilation, blue - ortho-Positronium, purple – background. The spectra do not start at zero because of the time offset between the detectors. C: Mean ortho-positronium lifetime for freeze-dried in different media melanocytes (HEMa-LP) and melanomas (WM115, WM266-4) cell culture.D: Viability change before and after PALS measurement for living cell culture studies. Each point is calculatedas an average anduncertainty as a standard deviation from3 consecutivemeasurements. E: Mean ortho-positronium lifetime for vital melanocytes (HEMa-LP) and melanoma (WM115,WM266-4) cell culture. Each point is calculated as an average and uncertainty as a standarddeviation from 3 consecutive measurements.
A scheme showing positronium lifetime measurements in cardiac myxoma and adipose tissues. (A) Photographs of non-fixed cardiac myxoma (CM) and adipose tissue samples. The numbers indicate patient ID. Each sectioned tissue has been cut in halves with a 22Na radionuclide placed between and inserted into the aluminum measurement chamber. (B) The left part of the panel depicts the scheme of the detection system: scintillators (S), photomultipliers (PM), attenuators (A), discriminators (D), coincidence units (C), digitizer, and a data acquisition system (DAQ). The photograph displays a part of the system together with the plastic rod localized between the scintillators. The superimposed scheme indicates an aluminum chamber inserted inside the rod. 22Na (red dot) emits (green arrow) positron (+), which annihilates (predominantly into two photons indicated in blue) with electrons (-) in the tissue. Following the positron emission, 22 Na changes into an excited nucleus of 22Ne, which deexcites almost instantly by the emission of the de-excitation photon (indicated in yellow). The PALS detection system, enables the measurement of the positronium lifetime by registering the time of emission of the deexcitation photon (corresponding to the time of positronium formation) and the time of creating the annihilation photons (corresponding to the time of the positronium decay). (C) For each sample, 1 x 106 coincidences between annihilation and deexcitation gamma quanta have been registered, resulting in the lifetime spectrum (example for the adipose tissue - patient ID 2). The analysis enables the extraction of the mean lifetime and intensities of para-Positronium (green line) and ortho-Positronium (blue line) atoms trapped in the intra-molecular voids . The dark yellow, turquoise, and purple lines denote direct annihilation in the source material, direct annihilation in the sample, and the background because of the accidental coincidences, respectively. The spectra are shifted by the delay coming from detection system configuration (~5ns). (D) Results of the mean ortho-Positronium (o-Ps) lifetime (upper) and intensity (lower panel) for CM (black squares) and mediastinal adipose (red circle) tissues
Comparing cardiac myxoma (CM) tissues and the isolated cell line.(A) Micrograph showing exemplary histopathology findings of cardiac myxoma (CM), for patient ID 2 and ID 3 in H&E staining. CM cells stained in purple (blue arrow) can have stellate (ID 3) or globular (ID 2) shape. The red/orange structures (white arrow) correspond to the blood vessels with erythrocytes. The surrounding myxoid matrix is stained in pink (green arrow). (B) Confocal microscopy image with the CM cells stained for F-Actin (red), nucleus (blue), and VE-cadherin (green). The scale bar is 50 μm. (C) Micro-computed tomography results for CM (upper row) and adipose tissues (lower row). Histograms on the left side present normalized X-ray attenuation within the sample: (i) the mineral deposits range from 0.6-1.0 in the CM samples; (ii) the blood vessels range from 0.75-1.0 in the adipose tissue samples. These attenuation ranges have been binarized to extract the mineral deposits and blood vessels for further analysis and visualization. The right side contains volume-rendered 3-D models of the two most representative samples, namely CM and adipose tissues. The internal mineral deposits have been highlighted in the CM model. Its diameter has been color-coded using a heat map. The blood vessels have been colored red in the adipose tissue. (D) Results of the mean ortho-Positronium (o-Ps) lifetime for CM tissue (red circles), isolated from the same patient myxoma cell line (black squares).
More information can be found in:
Positron Annihilation Lifetime Spectroscopy (PALS) is widely used to correlate the mean o-Ps lifetime value with cavity size in which annihilation takes place. PALS makes it possible to study many properties of materials such as the presence of defects, thermal expansion, temperature of phase transitions in polymers, processes of gas, or steams sorption in pores. Unfortunately it was applied in a very limited number of cases concerning living biological material. The PALS method combined with J-PET system will enable the determination of early and advanced stages of carcinogenesis by observing changes in biomechanical parameters between healthy and tumor cells.
The o-Ps lifetime as a function of the water vapor sorption time. The measurements were conducted in four stages: (1) in vacuum, (2) in dried air, (3) with the presence of water vapor, and (4) with drop of water placed in the chamber containing yeast.
Environmental scanning electron microscopy (ESEM) images of lyophilized yeasts (upper) and dried under normal conditions after addition of water (bottom).
More information can be found in:
- Patent application for a TOF-PET tomograph and a method of imaging using a TOF-PET tomograph, based on a probability of production and lifetime of a positronium,
- Positronium in medicine and biology,
- Studies of unicellular micro-organisms Saccharomyces cerevisiae by means of Positron Annihilation Lifetime Spectroscopy.
Pilot studies with cultured cell lines
Chosen normal (melanocytes) and cancer (melanoma) cell lines were cultured with standard procedures. For the PALS measurement cells were suspended in different freezing mediums, centrifugate and then lyophilised (freeze–dried). The composition of mediums were chosen from standard kryo - preservation reagents (DMSO) and some used in lyophilization process like PROH and trehalose. Viability studies performed before and after freeze-drying, showed best results for cells lyophilised in medium with DMSO and PROH/trehalose.
Ortho-positronium lifetime and intensities for cultured cell lines normal – melanocytes (red square), cancer – melanoma WM115 (blue circle), melanoma WM266 (yellow triangle) freeze–dried in different mediums, in order to determine which one will preserve cells the best without changing their structure. The optimal medium was choose to be 1.5 M PROH + 0.5 M Trehalose (based on viability and NMR studies before and after freeze-drying). For this medium significant differences beetwen o-Ps lifetime and intensity can be observed. Cells preserved with DMSO, even though they showed good viability, proved to not be applicable in PALS, since DMSO as a reagent gives strong signal itself.
Optical microscope image of melanoma cells in culture (left). Freeze–dried cells prepared for measurement in a holder – melanocytes (middle), melanoma (right).
Exemplary photos of a cardiac myxoma tumor (left) and normal adipose tissue (right).
Ortho-positronium lifetime and intensities for (left) cardiac myxoma tumors fixed in formaldehyde/non-fixed and adipose tissue measured on the PALS spectrometer. Results show significance differences between normal and tumor tissue. (right) Non-fixed cardiac myxoma tumor and adipose tissue measured on J-PET and then on PALS. Results for the sample measured on both detectors are consistent with each other, which proves J-PET can be used for morphometric imaging.
Holder with a sample during the measurement on a standard PALS spectrometer (left) and in J-PET detector (right).
Testing fundamental principles of physics
Tests of discrete symmetries with the J-PET tomograph are supported by the National Science Centre through the grants no. 2016/21/B/ST2/01222 and 2019/35/B/ST2/03562.
Positronium is the lightest purely leptonic object decaying into photons. As an atom bound by a central potential, it is a parity (P) eigenstate and as an atom built out of an electron and an antielectron it is an eigenstate of the charge conjugation (C) operator. Positronium in the ground substates with orbital angular momentum L = 0 is formed in a singlet state of the anti-parallel spins orientation (para-positronium, p-Ps), or in a triplet state of parallel spin orientation (ortho-positronium, o-Ps). Due to the symmetry of charge conjugation p-Ps undergoes annihilation with emission of an even number of photons (most often: two), while o-Ps undergoes annihilation with emission of an odd number of photons (most often: three).
The J-PET detector enables to perform tests of discrete symmetries in the leptonic sector via the determination of the expectation values of the discrete-symmetries odd operators, which may be constructed from the spin of o-Ps and the momenta and polarization vectors of photons originating from its annihilation.
With respect to the previous experiments performed with crystal based detectors, J-PET provides superior time resolution, higher granularity, lower pile-up and an opportunity of determining photon’s polarization. These features allow us to expect improvement by more than an order of magnitude in tests of discrete symmetries in decays of positronium atoms. The CPT symmetry being combination of the charge conjugation C, spatial parity P and reversal in time T, remains poorly tested in charged leptonic sector. The CPT noninvariance effects could be manifested in non-vanishing angular correlationsin the annihilations of the positronium atom - the lightest leptonic bound state. With the Jagiellonian PET (J-PET) prototype, plastic scintillator-based positron-emission-tomography scanner, we were able to measure almost entire available phase-space for ortho-positronium (o-Ps) annihilation into 3 photons. Using a novel technique of single-event estimation of o-Ps spin, the complete spectrum of an angular correlation operator sensitive to CPT-violating effects was determined. We reached the precision of CPT test at the 10−4 level, which is about threefold higher with respect to the previous measurement.
Methodology of the measurement of CPT-violation-sensitive angular correlation in three-photon annihilations of ortho-positronium. a) Photograph of the J-PET tomograph with the cylindrical positronium production chamber. Plastic scintillators (black strips) record photons produced in o-Ps → 3γ events (red arrows) and a prompt photon from β+ emitter de-excitation (green arrow). b) Photograph of the interior of the positronium production chamber and a schematic view of the transverse cross section of the J-PET tomograph. Plastic scintillators (with rectangular cross sections (blue)) form three coaxial rings. Annihilating o-Ps atoms are produced by positrons from a 22Na β+ source in the centre of a cylindrical vacuum chamber (grey), the walls of which are coated with porous silica, where positrons thermalise and form positronia. c) Reconstructed spatial locations of the identified o-Ps →3γevents obtained using three-photon annihilations, allowing us to reproduce a tomographic image of the vacuum chamber. The maximum density distribution is in a ring with a radius of 12 cm, equal to the radius of the positronium production chamber. d) For every selected event, the o-Ps spin axis is reconstructed, allowing calculation of the cosine of the angle between the spin (S) and annihilation plane orientation (n=k1 × k2), the distribution of which is sensitive to CPT-violating asymmetries. The histogram presents the determined cos θ distribution for 1.9 × 106 identified o-Ps → 3γ events.
More information can be found in:
- Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography
- Potential of the J-PET Detector for Studies of Discrete Symmetries in Decays of Positronium Atom - A Purely Leptonic System
- popular science description of investigations (wersja po polsku)
Together with research and development of the J-PET scanners new scintillating materials with properties suitable for time-of-flight PET devices are synthesized and investigated with the aim of developing plastic scintillators with better light output and timing properties than those commercially available [PLOSOne2017].
Left: Energy flow in plastic scintillators excited by gamma radiation. Compton scattering is main mechanism in J-PET scanner. Gamma quanta with energy 511 keV eject electrons which excite polymer. Energy from gamma quanta is transferred in three steps via fluorescence. Right: Emission spectra of the J-PET (solid line) and BC-420 (dashed line) plastic scintillators superimposed on the quantum efficiency dependence on photons wavelength for typical PMT with bialcali window (dotted line) and SiPM for PET applications light detectors (dashed-dotted line).
Plastic scintillator is an optical material converting ionizing radiation into light. It consist of two fluorescent dyes dissolved in polymeric base. Polymer-based scintillators emit about 10 000 blue photons per MeV of absorbed radiation energy with short pulse duration in range of few nanoseconds [BioAlgMedSys2021]. Fast timing of signals are foundation of time-of-flight PET scanners, for example J-PET scanner based on fast plastic scintillators. Additionally, large transparency of plastic scintillator material allows the construction of time-of-flight J-PET scanners with long field-of-view [IEEE2020]. High transparency of the plastic scintillators increases also time resolution of the total-body J-PET scanner because more light reaches silicon photomultipliers attached at both ends of the plastic scintillator strip.
Left: Three EJ-200 plastic scintillators with cross-sections 6 mm x 24 mm, 6 mm x 12 mm and 6 mm x 6 mm under UV lamp. Right: Example of light attenuation in blue-emitting commercial plastic scintillators with dimensions 6 mm x 24 mm x 1000 mm.
More information can be found in:
- Plastic scintillators laboratory
- Blue-emitting polystyrene scintillators for plastic scintillation dosimetry
List of articlesConcept
Positronium imaging with the novel multiphoton PET scanner,
Science Advances 7, eabh4394 (2021)
Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography,
Nature Communications 12, 5658 (2021)
Positronium in medicine and biology,
Nature Reviews Physics 1, 527 (2019)
Estimation of the NEMA characteristics of the J-PET tomograph using the GATE package,
Phys. Med. Biol. 63, 165008 (2018)
Simulating NEMA characteristics of the modular total-body J-PET scanner - an economic total-body PET from plastic scintillators,
Phys. Med. Biol. 66, 175015 (2021)
- Concept: patent application TOF-PET tomograph and a method of imaging using a TOF-PET tomograph, based on a probability of production and lifetime of a positronium
Trilateration-based reconstruction of ortho-positronium decays into three photons with the J-PET detector,
Nuclear Inst. and Methods in Physics Research A 819, 54 (2016)
- A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators,
Eur. Phys. J. C 76, 445 (2016)
Determination of the 3gamma Fraction from Positron Annihilation in Mesoporous Materials for Symmetry Violation Experiment with J-PET Scanner,
Acta Phys. Polon. B 47, 453 (2016)
- Feasibility study of the positronium imaging with the J-PET tomograph,
Phys. Med. Biol. 64, 055017 (2019)
- The J-PET detector-a tool for precision studies of ortho-positronium decays,
Nuclear Inst. and Methods in Physics Research A 1008, 165452 (2021)
Sampling FEE and Trigger-less DAQ for the J-PET Scanner,
Acta Phys. Polon. B 47, 491 (2016)
Overview of the software architecture and data flow for the J-PET tomography device,
Acta Phys. Polon. B 47, 561 (2016)
Multichannel FPGA based MVT system for high precision time (20 ps RMS) and charge measurement,
JINST 12, P08001 (2017)
Evaluation of Single-Chip, Real-Time Tomographic Data Processing on FPGA - SoC Devices,
IEEE Trans. Med. Imaging. 37, 11 (2018) 2526
Witnessing Entanglement In Compton Scattering Processes Via Mutually Unbiased Bases,
Nature: Scientific Reports 7, 15349 (2017)
Feasibility studies of the polarization of photons beyond the optical wavelength regime with the J-PET detector,
Eur. Phys. J. C 78, 970 (2018)
Measurement of gamma quantum interaction point in plastic scintillator with WLS strips,
Nuclear Instruments and Methods in Physics Research A 851, 39 (2017)
Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph,
Phys. Med. Biol. 61, 2025 (2016)
Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package,
Acta Phys. Pol A 127, 1505 (2015)
Scatter Fraction of the J-PET Tomography Scanner,
Acta Phys. Polon. B 47, 549 (2016)
A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals,
Nuclear Inst. and Methods in Physics Research A 775, 54 (2015)
Hit time and hit position reconstruction in the J-PET detector based on a library of averaged model signals,
Acta Phys. Pol A 127, 1495 (2015)
Calculation of the time resolution of the J-PET tomograph using kernel density estimation,
Phys. Med. Biol. 62, 5076 (2017)
Potential of the J-PET Detector for Studies of Discrete Symmetries in Decays of Positronium Atom - A Purely Leptonic System,
Acta Phys. Polon. B 47, 509 (2016)
Test of a single module of the J-PET scanner based on plastic scintillators,
Nucl. Instr. and Meth. A 764, 317 (2014)
A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals,
Nuclear Inst. and Methods in Physics Research A 775, 54 (2015)
- Plastic scintillators for positron emission tomography obtained by the bulk polymerization method;
- PALS investigations of free volumes thermal expansion of J-PET plastic scintillator synthesized in polystyrene matrix;
- Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators;
- Synthesis and characterization of plastic scintillators for the total-body J-PET scanner;
- Technical attenuation length measurement of plastic scintillator strips for the total-body J-PET scanner;
- Blue-emitting polystyrene scintillators for plastic scintillation dosimetry.
- Positronium as a biomarker of hypoxia
- New trends in theranostics
- Novel biomarker and drug delivery systems fortheranostics-extracellular vesicles
- Test of T, P and CP Symmetry in the decay of ortho-Positronium using the J-PET detector
- Development of positronium imaging with the 192-strip J-PET detector
- Characterization of melanoma cell spheroids by means of imaging techniques and positron annihilation lifetime spectroscopy
- Study of the Total Body J-PET sensitivity with the Toy Monte-Carlo model