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1
Content available Application of the compress sensing theory for improvement of the TOF resolution in a novel J-PET instrument
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.
Nukleonika
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2016
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Vol. 61, No. 1
35--39
EN
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.
2
Content available remote Trigger-less and reconfigurable data acquisition system for positron emission tomography
Korcyl G., Moskal P., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
37--40
EN
This article is focused on data acquisition system (DAQ) designed especially to be used in positron emission tomography (PET) or single-photon emission computed tomography. The system allows for continuous registration of analog signals during measurement. It has been designed to optimize registration and processing of the information carried by signals from the detector system in PET scanner. The processing does not require any rejection of data with a trigger system. The proposed system possesses also an ability to implement various data analysis algorithms that can be performed in real time during data collection.
3
Content available remote Simulations of γ quanta scattering in a single module of the J-PET detector
Szymański K., Moskal P., Bednarski T., Białas P., Czerwiński E., Giergiel K., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Moskal I., Niedźwiecki S., Pałka M., Pawlik-Niedźwiecka M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Witkowski P., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 2
71--77
EN
This article describes the simulations of the scattering of annihilation γ quanta in a strip of a plastic scintillator. Such strips constitute the basic detection modules in a newly proposed positron emission tomography (PET), which utilizes plastic scintillators instead of inorganic crystals. An algorithm simulating the chain of Compton scatterings was elaborated and a series of simulations have been conducted for the scintillator strip with a cross-section of 5×19 mm. The results indicate that secondary interactions occur only in the case of about 8% of the events and only 25% of these events take place in the distance larger than 0.5 cm from the primary interaction. Also, the light signals produced at the primary and secondary interactions overlap with the delay, the distribution of which is characterized by a full width at half-maximum (FWHM) of about 40 ps.
4
Content available remote Plastic scintillators for positron emission tomography obtained by the bulk polymerization method
Kapłon Ł., Kochanowski A., Molenda M., Moskal P., Wieczorek A., Bednarski T., Białas P., Czerwiński E., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
27--31
EN
This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillators, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.
5
Content available remote List-mode reconstruction in 2D strip PET
Białas P., Kowal J., Strzelecki A., Bednarski T., Czerwiński E., Giergiel K., Kapłon Ł., Kochanowski A., Korcyl G., Kowalski P., Kozik T., Krzemień W., Molenda M., Moskal I., Moskal P., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Szymański K., Wiślicki W., Witkowski P., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
9--12
EN
Using a theory of list-mode maximum likelihood expectation-maximization (MLEM) algorithm, in this contribution, we present a derivation of the system response kernel for a novel positron emission tomography (PET) detector based on plastic scintillators.
6
Content available remote J-PET analysis framework for the prototype TOF-PET detector
Krzemień W., Silarski M., Stoła K., Trybek D., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Molenda M., Moskal P., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Słomski A., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
33--36
EN
Novel time-of-flight positron emission tomography (TOF-PET) scanner solutions demand, apart from the state-of-the-art detectors, software for fast processing of the gathered data, monitoring of the whole scanner, and reconstruction of the PET image. In this article, we present an analysis framework for the novel STRIP-PET scanner developed by the J-PET collaboration in the Institute of Physics of the Jagiellonian University. This software is based on the ROOT package used in many particle physics experiments.
7
Content available remote Determination of the map of efficiency of the Jagiellonian Positron Emission Tomograph (J-PET) detector with the GATE package
Kowalski P., Raczyński L., Bednarski T., Białas P., Czerwiński E., Giergiel K., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kozik T., Krzemień W., Molenda M., Moskal I., Moskal P., Niedźwiecki S., Pałka M., Pawlik-Niedźwiecka M., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Szymański K., Wiślicki W., Witkowski P., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 2
85--90
EN
A novel PET detector consisting of strips of polymer scintillators is being developed by the Jagiellonian Positron Emission Tomograph (J-PET) collaboration. The map of efficiency and the map of geometrical acceptance of the two-strip J-PET scanner are presented. The map of efficiency was determined using the Monte Carlo simulation software GEANT4 Application for Tomographic Emission (GATE), which is based on GEANT4. Both maps were compared using a method based on the χ2-test.
8
Content available remote Database and data structure for the novel TOF-PET detector developed for the J-PET project
Czerwiński E., Zieliński M., Bednarski T., Białas P., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Kubicz E., Molenda M., Moskal P., Niedźwiecki S., Pałka M., Pawlik-Niedźwiecka M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Wieczorek A., Wiślicki W., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 2
79--83
EN
The complexity of the hardware and the amount of data collected during the PET imaging process require application of modern methods of efficient data organization and processing. In this article, we will discuss the data structures and the flow of collected data from the novel TOF-PET medical scanner that is being developed at the Jagiellonian University. The developed data format reflects the registration process of the γ quanta emitted from positron electron annihilation, front-end electronic structure, and required input information for the image reconstruction. In addition, the system database fulfills possible demands of the evolving J-PET project.
9
Content available remote Computing support for advanced medical data analysis and imaging
Wiślicki W., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Moskal P., Niedźwiecki S., Pałka M., Pawlik-Niedźwiecka M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Wieczorek A., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 2
53--58
EN
We discuss computing issues for data analysis and image reconstruction of positron emission tomography based on time-of-flight medical scanner or other medical scanning devices producing large volumes of data. Service architecture based on grid and cloud concepts for distributed processing is proposed and critically discussed.
10
Content available remote Calibration of photomultipliers gain used in the J-PET detector
Bednarski T., Czerwiński E., Moskal P., Białas P., Giergiel K., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Moskal I., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Szymański K. J., Wiślicki W., Witkowski P., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
13--17
EN
Photomultipliers are commonly used in commercial PET scanner as devices that convert light produced in scintillator by gamma quanta from positron-electron annihilation into electrical signal. For proper analysis of obtained electrical signal, a photomultiplier gain curve must be known, since gain can be significantly different even between photomultipliers of the same model. In this article, we describe single photoelectron method used for photomultiplier calibration applied for J-PET scanner, a novel PET detector being developed at Jagiellonian University. A description of calibration method, an example of calibration curve, and a gain of few Hamamatsu R4998 photomultipliers are presented.
11
Content available remote Application of WLS strips for position determination in strip PET tomograph based on plastic scintillators
Smyrski J., Moskal P., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Niedźwiecki S., Pałka M., Pawlik-Niedźwiecka M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Strzelecki A., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 2
59--63
EN
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.
12
Content available remote A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays
Silarski M., Czerwiński E., Bednarski T., Moskal P., Białas P., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Słomski A., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M., Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
19--25
EN
All of the present methods for calibration and monitoring of time-of-flight positron emission tomography (TOF-PET) scanner detectors utilize radioactive isotopes, such as 22Na or 68Ge, which are placed or rotate inside the scanner. In this article, we describe a novel method based on the cosmic rays application to the PET calibration and monitoring methods. The concept allows to overcome many of the drawbacks of the present methods and it is well suited for newly developed TOF-PET scanners with a large longitudinal field of view. The method enables also the monitoring of the quality of the scintillator materials and in general allows for the continuous quality assurance of the PET detector performance.
13
Content available remote A novel method based solely on field programmable gate array (FPGA) units enabling measurement of time and charge of analog signals in positron emission tomography (PET)
Pałka M., Moskal P., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Niedźwiecki S., Pawlik M., Raczyński L., Rudy Z., Salabura P., Gupta-Sharma N., Silarski M., Słomski A., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M, Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
41--45
EN
This article presents an application of a novel technique for precise measurements of time and charge based solely on a field programmable gate array (FPGA) device for positron emission tomography (PET). The described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics, and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of ~15 ps (rms) and thus enables sampling of signals in a voltage domain.
14
Content available remote 3D PET image reconstruction based on the maximum likelihood estimation method (MLEM) algorithm
Słomski A., Rudy Z., Bednarski T., Białas P., Czerwiński E., Kapłon Ł., Kochanowski A., Korcyl G., Kowal J., Kowalski P., Kozik T., Krzemień W., Molenda M., Moskal P., Niedźwiecki S., Pałka M., Pawlik M., Raczyński L., Salabura P., Gupta-Sharma N., Silarski M., Smyrski J., Strzelecki A., Wiślicki W., Zieliński M, Zoń N.
Bio-Algorithms and Med-Systems
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2014
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Vol. 10, no. 1
1--7
EN
A positron emission tomography (PET) scan does not measure an image directly. Instead, a PET scan measures a sinogram at the boundary of the field-of-view that consists of measurements of the sums of all the counts along the lines connecting the two detectors. Because there is a multitude of detectors built in a typical PET structure, there are many possible detector pairs that pertain to the measurement. The problem is how to turn this measurement into an image (this is called imaging). Significant improvement in PET image quality was achieved with the introduction of iterative reconstruction techniques. This was realized approximately 20 years ago (with the advent of new powerful computing processors). However, three-dimensional imaging still remains a challenge. The purpose of the image reconstruction algorithm is to process this imperfect count data for a large number (many millions) of lines of response and millions of detected photons to produce an image showing the distribution of the labeled molecules in space.
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