Autor: Raczynski, L. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Application of Density Based Clustering to Microarray Data Analysis
Autorzy:: Raczynski, L.
Wozniak, K.
Rubel, T.
Zaremba, K.
Tematy:: microarrays
cluster analysis
DBSCAN; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226804.pdf Link otwiera się w nowym oknie
Opis:: In just a few years, gene expression microarrays have rapidly become a standard experimental tool in the biological and medical research. Microarray experiments are being increasingly carried out to address the wide range of problems, including the cluster analysis. The estimation of the number of clusters in datasets is one of the main problems of clustering microarrays. As a supplement to the existing methods we suggest the use of a density based clustering technique DBSCAN that automatically defines the number of clusters. The DBSCAN and other existing methods were compared using the microarray data from two datasets used for diagnosis of leukemia and lung cancer.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Overview of the software architecture and data flow for the J-PET tomography device
Autorzy:: Kubicz, Ewelina
Niedźwiecki, Szymon
Czerwiński, Eryk
Rudy, Zbigniew
Białas, Piotr
Korcyl, Grzegorz
Zieliński, Marcin
Alfs, Dominika
Strzelecki, Adam
Gajos, Aleksander
Głowacz, Bartosz
Jasińska, B.
Pawlik-Niedźwiecka, Monika
Kisielewska, Daria
Kowalski, P.
Kozik, Tomasz
Wiślicki, W.
Krzemień, Wojciech
Moskal, Paweł
Silarski, Michał
Wieczorek, Anna
Raczyński, L.
Opis:: Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article, we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET Collaboration. We discuss the data acquisition system, reconstruction framework and image reconstruction software. Also, the concept of computing outside hospitals in the remote centers such as Świerk Computing Centre in Poland is presented.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: Scatter fraction of the J-PET tomography scanner
Autorzy:: Pałka, Marek
Moskal, Paweł
Gajos, Aleksander
Wiślicki, W.
Kowalski, P.
Zgardzińska, B.
Kubicz, Ewelina
Głowacz, Bartosz
Mohammed, Muhsin
Czerwiński, Eryk
Niedźwiecki, Szymon
Krzemień, Wojciech
Silarski, Michał
Korcyl, Grzegorz
Wieczorek, Anna
Raczyński, L.
Kisielewska, Daria
Rudy, Zbigniew
Białas, Piotr
Alfs, Dominika
Bednarski, Tomasz
Pawlik-Niedźwiecka, Monika
Zieliński, Marcin
Jasińska, J.
Kozik, Tomasz
Opis:: A novel Positron Emission Tomography system, based on plastic scintillators, is being developed by the J-PET Collaboration. In this article, we present the simulation results of the scatter fraction, representing one of the parameters crucial for background studies defined in the NEMA-NU-2-2012 norm. We elaborate an event selection methods allowing to suppress events in which gamma quanta were scattered in the phantom or underwent the multiple scattering in the detector. The estimated scatter fraction for the single-layer J-PET scanner varies from 37% to 53% depending on the applied energy threshold.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 4.

Tytuł:: Beam profile investigation of the new collimator system for the J-PET detector
Autorzy:: Czerwiński, Eryk
Korcyl, Grzegorz
Głowacz, Bartosz
Krzemień, Wojciech
Silarski, Michał
Gajos, Aleksander
Kubicz, Ewelina
Kisielewska, Daria
Raczyński, L.
Niedźwiecki, Szymon
Wieczorek, Anna
Jasińska, B.
Mohammed, Muhsin
Białas, Piotr
Bednarski, Tomasz
Pawlik-Niedźwiecka, Monika
Moskal, Paweł
Kowalski, P.
Alfs, Dominika
Strzelecki, Adam
Zgardzińska, B.
Moskal, Ines
Zieliński, Marcin
Rudy, Zbigniew
Wiślicki, W.
Kozik, Tomasz
Opis:: Jagiellonian Positron Emission Tomograph (J-PET) is a multi-purpose detector which will be used for search for discrete symmetries violations in the decays of positronium atoms and for investigations with positronium atoms in life-sciences and medical diagnostics. In this article, we present three methods for determination of the beam profile of collimated annihilation gamma quanta. Precise monitoring of this profile is essential for time and energy calibration of the J-PET detector and for the determination of the library of model signals used in the hit-time and hit-position reconstruction. We have shown that usage of two lead bricks with dimensions of $5 \times 10 \times 20 cm^{3}$ enables to form a beam of annihilation quanta with Gaussian profile characterized by 1 mm FWHM. Determination of this characteristic is essential for designing and construction the collimator system for the 24-module J-PET prototype. Simulations of the beam profile for different collimator dimensions were performed. This allowed us to choose optimal collimation system in terms of the beam profile parameters, dimensions and weight of the collimator taking into account the design of the 24-module J-PET detector.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 5.

Tytuł:: System response kernel calculation for list-mode reconstruction in strip PET detector
Autorzy:: Kapłon, Łukasz
Niedźwiecki, Szymon
Pałka, Marek
Czerwiński, Eryk
Bednarski, Tomasz
Białas, Piotr
Rudy, Zbigniew
Molenda, Marcin
Korcyl, Grzegorz
Zieliński, Marcin
Kowal, Jakub
Smyrski, Jerzy
Strzelecki, Adam
Kochanowski, Andrzej
Pawlik-Niedźwiecka, Monika
Kowalski, P.
Salabura, Piotr
Kozik, Tomasz
Słomski, Artur
Wiślicki, W.
Gupta-Sharma, Neha
Krzemień, Wojciech
Moskal, Paweł
Silarski, Michał
Raczyński, L.
Opis:: Reconstruction of the image in Positron Emission Tomographs (PET) requires the knowledge of the system response kernel which describes the contribution of each pixel (voxel) to each tube of response (TOR). This is especially important in list-mode reconstruction systems, where an efficient analytical approximation of such function is required. In this contribution, we present a derivation of the system response kernel for a novel 2D strip PET.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Inne

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Skocz do pozycji: 6.

Tytuł:: Application of compressive sensing theory for the reconstruction of signals in plastic scintillators
Autorzy:: Pałka, Marek
Moskal, Paweł
Słomski, Artur
Kochanowski, Andrzej
Kowalski, P.
Gupta-Sharma, Neha
Wiślicki, W.
Czerwiński, Eryk
Niedźwiecki, Szymon
Krzemień, Wojciech
Kapłon, Łukasz
Silarski, Michał
Korcyl, Grzegorz
Smyrski, Jerzy
Salabura, Piotr
Raczyński, L.
Molenda, Marcin
Rudy, Zbigniew
Białas, Piotr
Bednarski, Tomasz
Pawlik-Niedźwiecka, Monika
Zieliński, Marcin
Kowal, Jakub
Strzelecki, Adam
Kozik, Tomasz
Opis:: Compressive Sensing theory says that it is possible to reconstruct a measured signal if an enough sparse representation of this signal exists in comparison to the number of random measurements. This theory was applied to reconstruct signals from measurements of plastic scintillators. Sparse representation of obtained signals was found using SVD transform.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Inne

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Skocz do pozycji: 7.

Tytuł:: Searches for discrete symmetries violation in ortho-positronium decay using the J-PET detector
Autorzy:: Kamińska, D.
Gajos, A.
Czerwiński, E.
Bednarski, T.
Białas, P.
Gorgol, M.
Jasińska, B.
Kapłon, Ł.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Sharma, N. G.
Silarski, M.
Słomski, A.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zgardzińska, B.
Moskal, P.
Tematy:: discrete symmetries
J-PET
ortho-positronium; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/147408.pdf Link otwiera się w nowym oknie
Opis:: In this paper, we present prospects for using the Jagiellonian positron emission tomograph (J-PET) detector to search for discrete symmetries violations in a purely leptonic system of the positronium atom. We discuss tests of CP and CPT symmetries by means of ortho-positronium decays into three photons. No zero expectation values for chosen correlations between ortho-positronium spin and momentum vectors of photons would imply the existence of physics phenomena beyond the standard model. Previous measurements resulted in violation amplitude parameters for CP and CPT symmetries consistent with zero, with an uncertainty of about 10−3. The J-PET detector allows to determine those values with better precision, thanks to the unique time and angular resolution combined with a high geometrical acceptance. Achieving the aforementioned is possible because of the application of polymer scintillators instead of crystals as detectors of annihilation quanta.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Application of the compress sensing theory for improvement of the TOF resolution in a novel J-PET instrument
Autorzy:: Raczyński, L.
Moskal, P.
Kowalski, P.
Wiślicki, W.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Kapłon, Ł.
Kochanowski, A.
Korcyl, G.
Kowal, J.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Rudy, Z.
Salabura, P.
Gupta-Sharma, N.
Silarski, M.
Słomski, A.
Smyrski, J.
Strzelecki, A.
Wieczorek, A.
Zieliński, M.
Zoń, N.
Tematy:: compressed sensing
positron emission tomography
time-of-flight; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/146280.pdf Link otwiera się w nowym oknie
Opis:: Nowadays, in positron emission tomography (PET) systems, a time of fl ight (TOF) information is used to improve the image reconstruction process. In TOF-PET, fast detectors are able to measure the difference in the arrival time of the two gamma rays, with the precision enabling to shorten signifi cantly a range along the line-of-response (LOR) where the annihilation occurred. In the new concept, called J-PET scanner, gamma rays are detected in plastic scintillators. In a single strip of J-PET system, time values are obtained by probing signals in the amplitude domain. Owing to compressive sensing (CS) theory, information about the shape and amplitude of the signals is recovered. In this paper, we demonstrate that based on the acquired signals parameters, a better signal normalization may be provided in order to improve the TOF resolution. The procedure was tested using large sample of data registered by a dedicated detection setup enabling sampling of signals with 50-ps intervals. Experimental setup provided irradiation of a chosen position in the plastic scintillator strip with annihilation gamma quanta.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Reconstruction of hit time and hit position of annihilation quanta in the J-PET detector using the Mahalanobis distance
Autorzy:: Sharma, N. G.
Silarski, M.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Gorgol, M.
Jasińska, B.
Kamińska, D.
Kapłon, Ł.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Słomski, A.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zgardzińska, B.
Moskal, P.
Tematy:: J-PET detector
Mahalanobis distance
time resolution
threshold levels; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/146937.pdf Link otwiera się w nowym oknie
Opis:: The J-PET detector being developed at the Jagiellonian University is a positron emission tomograph composed of the long strips of polymer scintillators. At the same time, it is a detector system that will be used for studies of the decays of positronium atoms. The shape of photomultiplier signals depends on the hit time and hit position of the gamma quantum. In order to take advantage of this fact, a dedicated sampling front-end electronics that enables to sample signals in voltage domain with the time precision of about 20 ps and novel reconstruction method based on the comparison of examined signal with the model signals stored in the library has been developed. As a measure of the similarity, we use the Mahalanobis distance. The achievable position and time resolution depend on the number and values of the threshold levels at which the signal is sampled. A reconstruction method as well as preliminary results are presented and discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Application of WLS strips for position determination in strip PET tomograph based on plastic scintillators
Autorzy:: Kapłon, Łukasz
Niedźwiecki, Szymon
Pałka, Marek
Czerwiński, Eryk
Bednarski, Tomasz
Białas, Piotr
Rudy, Zbigniew
Molenda, Marcin
Zoń, Natalia
Korcyl, Grzegorz
Zieliński, Marcin
Kowal, Jakub
Smyrski, Jerzy
Strzelecki, Adam
Kochanowski, Andrzej
Pawlik-Niedźwiecka, Monika
Kowalski, P.
Salabura, Piotr
Kozik, Tomasz
Słomski, Artur
Wiślicki, W.
Gupta-Sharma, Neha
Moskal, Paweł
Krzemień, Wojciech
Silarski, Michał
Raczyński, L.
Opis:: A method of the determination of a γ-quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. An application of this method for the improvement of position resolution in newly proposed positron emission tomography (PET) detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in the reconstruction of images, which occurs in the presently used PET scanners.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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