19 results on '"Dulski, K."'
Search Results
2. Estimating relationship between the time over threshold and energy loss by photons in plastic scintillators used in the J-PET scanner
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Sharma, S., Chhokar, J., Curceanu, C., Czerwiński, E., Dadgar, M., Dulski, K., Gajewski, J., Gajos, A., Gorgol, M., Gupta-Sharma, N., Del Grande, R., Hiesmayr, B.C., Jasińska, B., Kacprzak, K., Kapłon, Ł., Karimi, H., Kisielewska, D., Klimaszewski, K., Korcyl, G., Kowalski, P., Kozik, T., Krawczyk, N., Krzemień, W., Kubicz, E., Mohammed, M., Niedzwiecki, Sz., Pałka, M., Pawlik-Niedźwiecka, M., Raczyński, L., Raj, J., Ruciński, A., Shivani, S., Shopa, R.Y., Silarski, M., Skurzok, M., Stępień, E.Ł., Wiślicki, W., Zgardzińska, B., and Moskal, P.
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- 2020
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3. Comparative studies of the sensitivities of sparse and full geometries of Total-Body PET scanners built from crystals and plastic scintillators.
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Dadgar, M., Parzych, S., Baran, J., Chug, N., Curceanu, C., Czerwiński, E., Dulski, K., Elyan, K., Gajos, A., Hiesmayr, B. C., Kapłon, Ł., Klimaszewski, K., Konieczka, P., Korcyl, G., Kozik, T., Krzemien, W., Kumar, D., Niedzwiecki, S., Panek, D., and Perez del Rio, E.
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PLASTIC crystals ,SCANNING systems ,SCINTILLATORS ,IMAGING phantoms ,POSITRON emission tomography ,COMPARATIVE studies ,DETECTORS - Abstract
Background: Alongside the benefits of Total-Body imaging modalities, such as higher sensitivity, single-bed position, low dose imaging, etc., their final construction cost prevents worldwide utilization. The main aim of this study is to present a simulation-based comparison of the sensitivities of existing and currently developed tomographs to introduce a cost-efficient solution for constructing a Total-Body PET scanner based on plastic scintillators. Methods: For the case of this study, eight tomographs based on the uEXPLORER configuration with different scintillator materials (BGO, LYSO), axial field-of-view (97.4 cm and 194.8 cm), and detector configurations (full and sparse) were simulated. In addition, 8 J-PET scanners with different configurations, such as various axial field-of-view (200 cm and 250 cm), different cross sections of plastic scintillator, and multiple numbers of plastic scintillator layers (2, 3, and 4), based on J-PET technology have been simulated by GATE software. Furthermore, Siemens' Biograph Vision has been simulated to compare the results with standard PET scans. Two types of simulations have been performed. The first one with a centrally located source with a diameter of 1 mm and a length of 250 cm, and the second one with the same source inside a water-filled cylindrical phantom with a diameter of 20 cm and a length of 183 cm. Results: With regards to sensitivity, among all the proposed scanners, the ones constructed with BGO crystals give the best performance (∼ 350 cps/kBq at the center). The utilization of sparse geometry or LYSO crystals significantly lowers the achievable sensitivity of such systems. The J-PET design gives a similar sensitivity to the sparse LYSO crystal-based detectors while having full detector coverage over the body. Moreover, it provides uniform sensitivity over the body with additional gain on its sides and provides the possibility for high-quality brain imaging. Conclusion: Taking into account not only the sensitivity but also the price of Total-Body PET tomographs, which till now was one of the main obstacles in their widespread clinical availability, the J-PET tomography system based on plastic scintillators could be a cost-efficient alternative for Total-Body PET scanners. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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4. Synchronization and Calibration of the 24-Modules J-PET Prototype With 300-mm Axial Field of View.
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Moskal, P., Bednarski, T., Niedzwiecki, Sz., Silarski, M., Czerwinski, E., Kozik, T., Chhokar, J., Bala, M., Curceanu, C., Grande, R. Del, Dadgar, M., Dulski, K., Gajos, A., Gorgol, M., Gupta-Sharma, N., Hiesmayr, B. C., Jasinska, B., Kacprzak, K., Kaplon, L., and Karimi, H.
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POSITRON emission tomography ,DATA acquisition systems ,COINCIDENCE ,CALIBRATION ,PROTOTYPES ,ATTENUATION of light - Abstract
Research conducted in the framework of the Jagiellonian-PET (J-PET) project aims to develop a cost-effective total-body positron emission tomography scanner. As a first step on the way to construct a full-scale J-PET tomograph from long strips of plastic scintillators, a 24-strip prototype was built and tested. The prototype consists of detection modules arranged axially forming a cylindrical diagnostic chamber with the inner diameter of 360 mm and the axial field-of-view of 300 mm. Promising perspectives for a low-cost construction of a total-body PET scanner are opened due to an axial arrangement of strips of plastic scintillators, which have a small light attenuation, superior timing properties, and the possibility of cost-effective increase of the axial field-of-view. The presented prototype comprises dedicated solely digital front-end electronic circuits and a triggerless data acquisition system which required the development of new calibration methods including time, thresholds, and gain synchronization. The system and elaborated calibration methods, including first results of the 24-module J-PET prototype, are presented and discussed. The achieved coincidence resolving time equals to ${\mathrm {CRT}}=490\pm 9$ ps. This value can be translated to the position reconstruction accuracy $\sigma (\Delta l) =18$ mm, which is fairly position independent. [ABSTRACT FROM AUTHOR]
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- 2021
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5. 3D TOF-PET image reconstruction using total variation regularization.
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Raczyński, L., Wiślicki, W., Klimaszewski, K., Krzemień, W., Kopka, P., Kowalski, P., Shopa, R.Y., Bała, M., Chhokar, J., Curceanu, C., Czerwiński, E., Dulski, K., Gajewski, J., Gajos, A., Gorgol, M., Del Grande, R., Hiesmayr, B., Jasińska, B., Kacprzak, K., and Kapłon, L.
- Abstract
• TV regularization in image space is more efficient than usual iterative approaches. • The efficiency of proposed method comes from the one-time TOF backprojection step. • The overall operator can be modelled with a closed-form analytical formula. • The operator models TOF uncertainty and spatial detection uncertainty inside detector. In this paper we introduce a semi-analytic algorithm for 3-dimensional image reconstruction for positron emission tomography (PET). The method consists of the back-projection of the acquired data into the most likely image voxel according to time-of-flight (TOF) information, followed by the filtering step in the image space using an iterative optimization algorithm with a total variation (TV) regularization. TV regularization in image space is more computationally efficient than usual iterative optimization methods for PET reconstruction with full system matrix that use TV regularization. The efficiency comes from the one-time TOF back-projection step that might also be described as a reformatting of the acquired data. An important aspect of our work concerns the evaluation of the filter operator of the linear transform mapping an original radioactive tracer distribution into the TOF back-projected image. We obtain concise, closed-form analytical formula for the filter operator. The proposed method is validated with the Monte Carlo simulations of the NEMA IEC phantom using a one-layer, 50 cm-long cylindrical device called Jagiellonian PET scanner. The results show a better image quality compared with the reference TOF maximum likelihood expectation maximization algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. PALS Avalanche -- A New PAL Spectra Analysis Software.
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DULSKI, K.
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SPECTRUM analysis , *AVALANCHES , *SOFTWARE compatibility , *POSITRON emission tomography , *IMAGE analysis - Abstract
A novel concept for tomography of the human body developed by the Jagiellonian Positronium Emission Tomography (J-PET) project provides the possibility to combine metabolic information collected by standard PET with structural information obtained from positronium lifetime. This results in a morphometric image. To this end, there is a need to develop software compatible with the J-PET Framework for fast online analysis during imaging. PALS Avalanche is a software developed on UNIX system and based on ROOT software, which allows one to decompose positronium annihilation lifetime spectra in the form of a set of single time differences and histogram. Performance of the PALS Avalanche will be tested by analysing simulated PAL spectra. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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7. A METHOD FOR TIME CALIBRATION OF PET SYSTEMS USING FIXED β+ RADIOACTIVE SOURCE.
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DULSKI, K., SILARSKI, M., and MOSKAL, P.
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CALIBRATION , *EMISSION tomography equipment , *POSITRON emission tomography - Abstract
A method for the time calibration of the Time-of-Flight Positron Emmission Tomograph (TOF-PET) systems using fixed sources is described. Compared to the commercially used calibration methods, the new method gives a chance to run the calibration during the medical scan. Reduction of the time needed for calibration can increase the number of patients examined by PET. The process of calibration of the Jagiellonian Positron Emission Tomograph (J-PET) detector is shown as an example. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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8. Feasibility Study of the Time Reversal Symmetry Tests in Decay of Metastable Positronium Atoms with the J-PET Detector.
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Gajos, A., Curceanu, C., Czerwiński, E., Dulski, K., Gorgol, M., Gupta-Sharma, N., Hiesmayr, B. C., Jasińska, B., Kacprzak, K., Kapłon, Ł., Kisielewska, D., Korcyl, G., Kowalski, P., Kozik, T., Krzemień, W., Kubicz, E., Mohammed, M., Niedźwiecki, Sz., Pałka, M., and Pawlik-Niedźwiecka, M.
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POSITRONIUM ,METASTABLE states ,LEPTONS (Nuclear physics) ,POSITRON emission tomography ,DETECTORS - Abstract
This article reports on the feasibility of testing of the symmetry under reversal in time in a purely leptonic system constituted by positronium atoms using the J-PET detector. The present state of T symmetry tests is discussed with an emphasis on the scarcely explored sector of leptonic systems. Two possible strategies of searching for manifestations of T violation in nonvanishing angular correlations of final state observables in the decay of metastable triplet states of positronium available with J-PET are proposed and discussed. Results of a pilot measurement with J-PET and assessment of its performance in reconstruction of three-photon decays are shown along with an analysis of its impact on the sensitivity of the detector for the determination of T-violation sensitive observables. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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9. Evaluation of Single-Chip, Real-Time Tomographic Data Processing on FPGA SoC Devices.
- Author
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Korcyl, G., Bialas, P., Curceanu, C., Czerwinski, E., Dulski, K., Flak, B., Gajos, A., Glowacz, B., Gorgol, M., Hiesmayr, B. C., Jasinska, B., Kacprzak, K., Kajetanowicz, M., Kisielewska, D., Kowalski, P., Kozik, T., Krawczyk, N., Krzemien, W., Kubicz, E., and Mohammed, M.
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POSITRON emission tomography ,IMAGE reconstruction ,INFORMATION storage & retrieval systems ,ELECTRONIC data processing ,IMAGE processing - Abstract
A novel approach to tomographic data processing has been developed and evaluated using the Jagiellonian positron emission tomography scanner as an example. We propose a system in which there is no need for powerful, local to the scanner processing facility, capable to reconstruct images on the fly. Instead, we introduce a field programmable gate array system-on-chip platform connected directly to data streams coming from the scanner, which can perform event building, filtering, coincidence search, and region-of-response reconstruction by the programmable logic and visualization by the integrated processors. The platform significantly reduces data volume converting raw data to a list-mode representation, while generating visualization on the fly. [ABSTRACT FROM AUTHOR]
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- 2018
- Full Text
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10. Studies of discrete symmetries in a purely leptonic system using the Jagiellonian Positron Emission Tomograph.
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Moskal, P., Alfs, D., Bednarski, T., Białas, P., Czerwiński, E., Dulski, K., Gajos, A., Głowacz, B., Gupta-Sharma, N., Kamińska, D., Khreptak, O., Korcyl, G., Krawczyk, N., Kubicz, E., Mohammed, M., Niedźwiecki, Sz., Pawlik-Niedńwiecka, M., Rudy, Z., Silarski, M., and Smyrski, J.
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DISCRETE symmetries ,PARITY (Physics) ,CHARGE conjugation ,TIME reversal ,POSITRON emission tomography - Abstract
Discrete symmetries such as parity (P), charge-conjugation (C) and time reversal (T) are of fundamental importance in physics and cosmology. Breaking of charge conjugation symmetry (C) and its combination with parity (CP) constitute necessary conditions for the existence of the asymmetry between matter and antimatter in the observed Universe. The presently known sources of discrete symmetries violations can account for only a tiny fraction of the excess of matter over antimatter. So far CP and T symmetries violations were observed only for systems involving quarks and they were never reported for the purely leptonic objects. In this article we describe briefly an experimental proposal for the test of discrete symmetries in the decays of positronium atom which is made exclusively of leptons. The experiments are conducted by means of the Jagiellonian Positron Emission Tomograph (J-PET) which is constructed from strips of plastic scintillators enabling registration of photons from the positronium annihilation. J-PET tomograph together with the positronium target system enable to measure expectation values for the discrete symmetries odd operators constructed from (i) spin vector of the ortho-positronium atom, (ii) momentum vectors of photons originating from the decay of positronium, and (iii) linear polarization direction of annihilation photons. Linearly polarized positronium will be produced in the highly porous aerogel or polymer targets, exploiting longitudinally polarized positrons emitted by the sodium
22 Na isotope. Information about the polarization vector of orthopositronium will be available on the event by event basis and will be reconstructed from the known position of the positron source and the reconstructed position of the orthopositronium annihilation. In 2016 the first tests and calibration runs are planned, and the data collection with high statistics will commence in the year 2017. [ABSTRACT FROM AUTHOR]- Published
- 2016
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11. Time Calibration of the J-PET Detector.
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SKURZOK, M., SILARSKI, M., ALFS, D., BIAŁAS, P., SHIVANI, CURCEANU, C., CZERWIŃSKI, E., DULSKI, K., GAJOS, A., GŁOWACZ, B., GORGOL, M., HIESMAYR, B. C., JASIŃSKA, B., KISIELEWSKA-KAMIŃSKA, D., KORCYL, G., KOWALSKI, P., KOZIK, T., KRAWCZYK, N., KRZEMIEŃ, W., and KUBICZ, E.
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POSITRON emission tomography ,RADIOPHARMACEUTICALS ,POSITRON annihilation ,COMPUTED tomography ,SPECTRUM analysis - Abstract
The Jagiellonian positron emission tomograph project carried out in the Institute of Physics of the Jagiellonian University is focused on construction and tests of the first prototype of PET scanner for medical diagnostic which allows for the simultaneous 3D imaging of the whole human body using organic scintillators. The J-PET prototype consists of 192 scintillator strips forming three cylindrical layers which are optimized for the detection of photons from the electron-positron annihilation with high time-and high angular resolutions. In this article we present time calibration and synchronization of the whole J-PET detection system by irradiating each single detection module with a
22 Na source and a small detector providing common reference time for synchronization of all the modules. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
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12. COMMISSIONING OF THE J-PET DETECTOR FOR STUDIES OF DECAYS OF POSITRONIUM ATOMS.
- Author
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CZERWIŃSKI, E., DULSKI, K., BIAŁAS, P., CURCEANU, C., GAJOS, A., GŁOWACZ, B., GORGOL, M., HIESMAYR, B. C., JASIŃSKA, B., KISIELEWSKA, D., KORCYL, G., KOWALSKI, P., KOZIK, T., KRAWCZYK, N., KRZEMIEŃ, W., KUBICZ, E., MOHAMMED, M., NIEDŹWIECKI, SZ., PAŁKA, M., and PAWLIK-NIEDŹWIECKA, M.
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POLARIZATION (Nuclear physics) , *POSITRON emission tomography , *POSITRONIUM , *ANGULARJS (Software framework) , *ANGULAR measurements - Abstract
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging of the whole human body as well as for physics studies involving detection of electron-positron annihilation into photons. J-PET has high angular and time resolution, and allows for measurement of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for the background rejection in the decays of positronium atoms. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. THREE-DIMENSIONAL IMAGE RECONSTRUCTION IN J-PET USING FILTERED BACK-PROJECTION METHOD.
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SHOPA, R. Y., KLIMASZEWSKI, K., KOWALSKI, P., KRZEMIEŃ, W., RACZYŃSKI, L., WIŚLICKI, W., BIAŁAS, P., CURCEANU, C., CZERWIŃSKI, E., DULSKI, K., GAJOS, A., GŁOWACZ, B., GORGOL, M., HIESMAYR, B., JASIŃSKA, B., KISIELEWSKA-KAMIŃSKA, D., KORCYL, G., KOZIK, T., KRAWCZYK, N., and KUBICZ, E.
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IMAGE reconstruction ,POSITRON emission tomography ,IMAGE processing ,INTERPOLATION algorithms ,IMAGING systems - Abstract
We present a method and preliminary results of the image reconstruction in the Jagiellonian PET tomograph. Using GATE (Geant4 Application for Tomographic Emission), interactions of the 511 keV photons with a cylindrical detector were generated. Pairs of such photons, flying backto- back, originate from e
+ e- annihilations inside a 1 mm spherical source. Spatial and temporal coordinates of hits were smeared using experimental resolutions of the detector. We incorporated the algorithm of the 3D Filtered Back Projection, implemented in the STIR and TomoPy software packages, which differ in approximation methods. Consistent results for the Point Spread Functions of ~ 5÷7 mm and ~ 9÷20 mm were obtained, using STIR, for transverse and longitudinal directions, respectively, with no time-of-flight information included. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
14. J-PET: A NEW TECHNOLOGY FOR THE WHOLE-BODY PET IMAGING.
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NIEDŹWIECKI, S., BIAŁAS, P., CURCEANU, C., CZERWIŃSKI, E., DULSKI, K., GAJOS, A., GŁOWACZ, B., GORGOL, M., HIESMAYR, B. C., JASIŃSKA, B., KAPŁON, Ł., KISIELEWSKA-KAMŃNSKA, D., Korcyl, G., KOWALSKI, P., KOZIK, T., KRAWCZYK, N., KRZEMIEŃ, W., KUBICZ, E., MOHAMMED, M., and PAWLIK-NIEDŹWIECKA, M.
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JAGELLON dynasty ,POSITRON emission tomography ,SCINTILLATORS ,COMPUTED tomography ,ELECTROMAGNETIC waves - Abstract
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET built from plastic scintillators. J-PET prototype consists of 192 detection modules arranged axially in three layers forming a cylindrical diagnostic chamber with the inner diameter of 85 cm and the axial field-of-view of 50 cm. An axial arrangement of long strips of plastic scintillators, their small light attenuation, superior timing properties, and relative ease of the increase of the axial field-of-view opens promising perspectives for the cost effective construction of the whole-body PET scanner, as well as construction of MR and CT compatible PET inserts. Present status of the development of the J-PET tomograph will be presented and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
15. J-PET detector system for studies of the electron-positron annihilations.
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Pawlik-Niedźwiecka, M., Khreptak, O., Gajos, A., Alfs, D., Bednarski, T., Białas, P., Czerwiński, E., Dulski, K., Głowacz, B., Gupta-Sharma, N., Kamińska, D., Korcyl, G., Krawczyk, N., Kubicz, E., Mohammed, M., Niedźwiecki, Sz., Rudy, Z., Silarski, M., Zieliński, M., and Moskal, P.
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ELECTRON-positron interactions ,POSITRON emission tomography ,POLARIZED photons ,STANDARD model (Nuclear physics) - Abstract
Jagiellonian Positron Emission Tomograph (J-PET) has been recently constructed at the Jagiellonian University as a prototype of a cost-effective scanner for the metabolic imaging of the whole human body. J-PET detector is optimized for the measurement of momentum and polarization of photons from the electron-positron annihilations. It is built out of strips of plastic scintillators, forming three cylindrical layers. As detector of gamma quanta it will be used for studies of discrete symmetries and multiparticle entanglement of photons originating from the decays of ortho-positronium atoms. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
16. Commissioning of the J-PET detector in view of the positron annihilation lifetime spectroscopy.
- Author
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Dulski, K., Curceanu, C., Czerwiński, E., Gajos, A., Gorgol, M., Gupta-Sharma, N., Hiesmayr, B. C., Jasińska, B., Kacprzak, K., Kapłon, Ł., Kisielewska, D., Klimaszewski, K., Korcyl, G., Kowalski, P., Krawczyk, N., Krzemień, W., Kozik, T., Kubicz, E., Mohammed, M., and Niedźwiecki, Sz.
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POSITRON emission tomography , *POSITRON annihilation , *POSITRONIUM , *POROUS polymers , *SPECTRUM analysis - Abstract
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET device built from plastic scintillators. It is a multi-purpose detector designed for medical imaging and for studies of properties of positronium atoms in porous matter and in living organisms. In this article we report on the commissioning of the J-PET detector in view of studies of positronium decays. We present results of analysis of the positron lifetime measured in the porous polymer. The obtained results prove that J-PET is capable of performing simultaneous imaging of the density distribution of annihilation points as well as positron annihilation lifetime spectroscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. Comparative studies of plastic scintillator strips with high technical attenuation length for the total-body J-PET scanner.
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Kapłon, Ł., Baran, J., Chug, N., Coussat, A., Curceanu, C., Czerwiński, E., Dadgar, M., Dulski, K., Gajewski, J., Gajos, A., Hiesmayr, B., Valsan, E. Kavya, Klimaszewski, K., Korcyl, G., Kozik, T., Krzemień, W., Kumar, D., Moskal, G., Niedźwiecki, S., and Panek, D.
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SCINTILLATORS , *PHOTODETECTORS , *POSITRON emission tomography , *VISIBLE spectra , *PLASTICS , *ATTENUATION of light - Abstract
Plastic scintillator strips are considered as one of the promising solutions for the cost-effective construction of total-body positron emission tomography, (PET) system. The purpose of the performed measurements is to compare the transparency of long plastic scintillators with dimensions 6 mm × 24 mm × 1000 mm and with all surfaces polished. Six different types of commercial, general purpose, blue-emitting plastic scintillators with low attenuation of visible light were tested, namely: polyvinyl toluene-based BC-408, EJ-200, RP-408, and polystyrene-based Epic, SP32 and UPS-923A. For determination of the best type of plastic scintillator for total-body Jagiellonian positron emission tomograph (TB-J-PET) construction, emission and transmission spectra, and technical attenuation length (TAL) of blue light-emitting by the scintillators were measured and compared. The TAL values were determined with the use of UV lamp as excitation source, and photodiode as light detector. Emission spectra of investigated scintillators have maxima in the range from 420 nm to 429 nm. The BC-408 and EJ-200 have the highest transmittance values of about 90% at the maximum emission wavelength measured through a 6 mm thick scintillator strip and the highest technical attenuation length reaching about 2000 mm, allowing assembly of long detection modules for time-of-flight (TOF) J-PET scanners. Influence of the 6 mm × 6 mm, 12 mm × 6 mm, 24 mm × 6 mm cross-sections of the 1000 mm long EJ-200 plastic scintillator on the TAL and signal intensity was measured. The highest TAL value was determined for samples with 24 mm × 6 mm cross-section. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
18. Measurement of gamma quantum interaction point in plastic scintillator with WLS strips.
- Author
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Smyrski, J., Alfs, D., Bednarski, T., Białas, P., Czerwiński, E., Dulski, K., Gajos, A., Głowacz, B., Gupta-Sharma, N., Gorgol, M., Jasińska, B., Kajetanowicz, M., Kamińska, D., Korcyl, G., Kowalski, P., Krzemień, W., Krawczyk, N., Kubicz, E., Mohammed, M., and Niedźwiecki, Sz.
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SCINTILLATORS , *QUANTUM optics , *GAMMA rays , *PHOTONS , *ANNIHILATION reactions - Abstract
The feasibility of measuring the aśxial coordinate of a gamma quantum interaction point in a plastic scintillator bar via the detection of scintillation photons escaping from the scintillator with an array of wavelength-shifting (WLS) strips is demonstrated. Using a test set-up comprising a BC-420 scintillator bar and an array of sixteen BC-482A WLS strips we achieved a spatial resolution of 5 mm ( σ ) for annihilation photons from a 22 Na isotope. The studied method can be used to improve the spatial resolution of a plastic-scintillator-based PET scanner which is being developed by the J-PET collaboration. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. Optimisation of the event-based TOF filtered back-projection for online imaging in total-body J-PET.
- Author
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Shopa, R.Y., Klimaszewski, K., Kopka, P., Kowalski, P., Krzemień, W., Raczyński, L., Wiślicki, W., Chug, N., Curceanu, C., Czerwiński, E., Dadgar, M., Dulski, K., Gajos, A., Hiesmayr, B.C., Kacprzak, K., Kapłon, Ł., Kisielewska, D., Korcyl, G., Krawczyk, N., and Kubicz, E.
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MONTE Carlo method , *POSITRON emission tomography , *IMAGE reconstruction algorithms , *IMAGE reconstruction , *HIGHPASS electric filters , *ALGORITHMS , *POSITRONIUM - Abstract
• Parallel reconstruction of each emission is a foundation for real-time PET imaging. • Image domain asymmetric 3-component kernel and time-of-flight used for filtering. • High time resolution and low-pass filters are the cornerstones for short scans. • Optimal kernel parameters can be trained for the best bias-variance trade-off. [Display omitted] We perform a parametric study of the newly developed time-of-flight (TOF) image reconstruction algorithm, proposed for the real-time imaging in total-body Jagiellonian PET (J-PET) scanners. The asymmetric 3D filtering kernel is applied at each most likely position of electron-positron annihilation, estimated from the emissions of back-to-back γ -photons. The optimisation of its parameters is studied using Monte Carlo simulations of a 1-mm spherical source, NEMA IEC and XCAT phantoms inside the ideal J-PET scanner. The combination of high-pass filters which included the TOF filtered back-projection (FBP), resulted in spatial resolution, 1.5 times higher in the axial direction than for the conventional 3D FBP. For realistic 10-minute scans of NEMA IEC and XCAT, which require a trade-off between the noise and spatial resolution, the need for Gaussian TOF kernel components, coupled with median post-filtering, is demonstrated. The best sets of 3D filter parameters were obtained by the Nelder-Mead minimisation of the mean squared error between the resulting and reference images. The approach allows training the reconstruction algorithm for custom scans, using the IEC phantom, when the temporal resolution is below 50 ps. The image quality parameters, estimated for the best outcomes, were systematically better than for the non-TOF FBP. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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