Autor: Dadgar, Meysam - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Feasibility study of lesion detection by means of Total-Body Jagiellonian Positron Emission Tomography scanner
Studium wykonalności wykrywania zmian za pomocą skanera Jagiellońskiej Pozytonowej Tomografii Emisyjnej Całkowitego Ciała
Autorzy:: Dadgar, Meysam
Współwytwórcy:: Moskal, Paweł
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Tytuł:: GATE simulation study of the 24-module J-PET scanner : data analysis and image reconstruction
Autorzy:: Kowalski, P.
Dadgar, Meysam
Opis:: The Jagiellonian Positron Emission Tomograph (J-PET) is a novel PET device that, in contrast to commercial PET scanners, is based on plastic scintillator strips. Modular J-PET is the latest prototype that consists of 24 modules arranged in a cylinder. In this study, 6 point-like sources defined in the NEMA spatial resolution standard were simulated twice with total activities of 60 kBq and 60 MBq, respectively. Results of simulations were processed with the GOJA software and reconstructed with the QETIR package.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

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Skocz do pozycji: 4.

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Skocz do pozycji: 5.

Tytuł:: Transformation of PET raw data into images for event classification using convolutional neural networks
Autorzy:: Curceanu, Catalina
Chug, Neha
Kapłon, Łukasz
Niedźwiecki, Szymon
Coussat, Aurélien
Konieczka, Paweł
Czerwiński, Eryk
Skurzok, Magdalena
Kumar, Deepak
Kacprzak, Krzysztof
Korcyl, Grzegorz
Hiesmayr, Beatrix C.
Shivani, Shivani
Dulski, Kamil
Dadgar, Meysam
Baran, Jakub
Gajos, Aleksander
Raczyński, Lech
Shopa, Roman Y.
Stępień, Ewa
Fedoruk, Oleksandr
Klimaszewski, Konrad
Wiślicki, Wojciech
Parzych, Szymon
Tayefi Ardebili, Faranak
Sharma, Sushil
Krzemień, Wojciech
Moskal, Paweł
Kopka, Przemysław
Kozik, Tomasz
Perez del Rio, Elena
Opis:: In positron emission tomography (PET) studies, convolutional neural networks (CNNs) may be applied directly to the reconstructed distribution of radioactive tracers injected into the patient's body, as a pattern recognition tool. Nonetheless, unprocessed PET coincidence data exist in tabular format. This paper develops the transformation of tabular data into n-dimensional matrices, as a preparation stage for classification based on CNNs. This method explicitly introduces a nonlinear transformation at the feature engineering stage and then uses principal component analysis to create the images. We apply the proposed methodology to the classification of simulated PET coincidence events originating from NEMA IEC and anthropomorphic XCAT phantom. Comparative studies of neural network architectures, including multilayer perceptron and convolutional networks, were conducted. The developed method increased the initial number of features from 6 to 209 and gave the best precision results (79.8) for all tested neural network architectures; it also showed the smallest decrease when changing the test data to another phantom.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 6.

Tytuł:: Comparative studies of the sensitivities of sparse and full geometries of Total-Body PET scanners built from crystals and plastic scintillators
Autorzy:: Chug, Neha
Kapłon, Łukasz
Niedźwiecki, Szymon
Czerwiński, Eryk
Skurzok, Magdalena
Tayefi Ardebili, Keyvan
Kumar, Deepak
Korcyl, Grzegorz
Shivani, Shivani
Dulski, Kamil
Konieczka, P.
Dadgar, Meysam
Baran, Jakub
Gajos, Aleksander
Raczyński, L.
Hiesmayr, B. C.
Stępień, Ewa
Curceanu, C.
Klimaszewski, Konrad
Vandenberghe, S.
Valsan Eliyan, Kavya
Parzych, Szymon
Wiślicki, W.
Tayefi Ardebili, Faranak
Sharma, Sushil
Panek, Dominik
Shopa, R. Y.
Krzemień, Wojciech
Moskal, Paweł
Kozik, Tomasz
Perez del Rio, Elena
Opis:: 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 ($\sim$ 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.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 7.

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Skocz do pozycji: 8.

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Skocz do pozycji: 9.

Tytuł:: Efficiency determination of J-PET : first plastic scintillators-based PET scanner
Autorzy:: Chug, Neha
Kapłon, Łukasz
Niedźwiecki, Szymon
Czerwiński, Eryk
Skurzok, Magdalena
Tayefi Ardebili, Keyvan
Kumar, Deepak
Kacprzak, Krzysztof
Korcyl, Grzegorz
Shivani, Shivani
Dulski, Kamil
Konieczka, P.
Dadgar, Meysam
Baran, Jakub
Gajos, Aleksander
Raczyński, L.
Hiesmayr, B. C.
Stępień, Ewa
Curceanu, C.
Klimaszewski, Konrad
Valsan Eliyan, Kavya
Parzych, Szymon
Wiślicki, W.
Tayefi Ardebili, Faranak
Sharma, Sushil
Gupta-Sharma, Neha
Panek, Dominik
Shopa, R. Y.
Krzemień, Wojciech
Moskal, Paweł
Kozik, Tomasz
Perez del Rio, Elena
Opis:: Background: The Jagiellonian Positron Emission Tomograph is the 3-layer prototype of the first scanner based on plastic scintillators, consisting of 192 half-metre-long strips with readouts at both ends. Compared to crystal-based detectors, plastic scintillators are several times cheaper and could be considered as a more economical alternative to crystal scintillators in future PETs. JPET is also a first multi-photon PET prototype. For the development of multi-photon detection, with photon characterized by the continuous energy spectrum, it is important to estimate the efficiency of J-PET as a function of energy deposition. The aim of this work is to determine the registration efficiency of the J-PET tomograph as a function of energy deposition by incident photons and the intrinsic efficiency of the J-PET scanner in detecting photons of different incident energies. In this study, 3-hit events are investigated, where 2-hits are caused by 511 keV photons emitted in e$^{+}$e$^{-}$ annihilations, while the third hit is caused by one of the scattered photons. The scattered photon is used to accurately measure the scattering angle and thus the energy deposition. Two hits by a primary and a scattered photon are sufficient to calculate the scattering angle of a photon, while the third hit ensures the precise labeling of the 511 keV photons. Results: By comparing experimental and simulated energy distribution spectra, the registration efficiency of the J-PET scanner was determined in the energy deposition range of 70–270 keV, where it varies between 20 and 100%. In addition, the intrinsic efficiency of the J-PET was also determined as a function of the energy of the incident photons. Conclusion: A method for determining registration efficiency as a function of energy deposition and intrinsic efficiency as a function of incident photon energy of the J-PET scanner was demonstrated. This study is crucial for evaluating the performance of the scanner based on plastic scintillators and its applications as a standard and multi-photon PET systems. The method may be also used in the calibration of Compton-cameras developed for the ion−beam therapy monitoring and simultaneous multi-radionuclide imaging in nuclear medicine.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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