Autor: Szczucka, K. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: E.Cam DUET gamma camera model validation in GATE
Autorzy:: Borys, D.
Szczucka, K.
Gorczewski, K.
Bekman, B.
Powiązania:: https://bibliotekanauki.pl/articles/333872.pdf
Data publikacji:: 2007
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: symulacja Monte Carlo
GATE
model gamma-kamera
Monte Carlo simulation
gamma camera model
99mTc
Opis:: Monte Carlo simulations are more and more popular trend in nuclear medicine imaging. They were also widely used in radiotherapy and brachytherapy with use of more general simulation software. GATE (Geant4 Application for Tomographic Emission) is a platform developed on general Monte Carlo code designed for simulating and tracking the passage of particles through matter (Geant4) but is specifically designed for nuclear medicine imaging purposes. The aim of this work was to create and validate a model of specific gamma-camera (E.Cam DUET), used in our department, for further use in image analysis and dosimetry field, with GATE simulation platform. We have modeled in first step a point source in the air in three configurations of gamma camera (without collimator, with low-energy high-resolution (LEHR) collimator and with high-energy (HE collimator)), then we have created a phantom with three spherical sources of different sizes but with the same concentration of the radiopharmaceutical. Simulation results were compared to the measured values of the energy spectrum and images obtained on the detectors, and show a good agreement for the point source experiments and revealed some differences for the phantom studies. This results shows that some additional tests and refinements are required but also allows us to study the image degrading quality factors, such as septal penetration and to work towards eliminating them from the pictures.
Źródło:: Journal of Medical Informatics & Technologies; 2007, 11; 245-252
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: System matrix computation for iterative reconstruction algorithms in SPECT based on direct measurements
Autorzy:: Borys, D.
Szczucka-Borys, K.
Gorczewski, K.
Powiązania:: https://bibliotekanauki.pl/articles/907829.pdf
Data publikacji:: 2011
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:: SPECT
metoda iteracyjna
obrazowanie ilościowe
iterative reconstruction
quantitative imaging
Opis:: A method for system matrix calculation in the case of iterative reconstruction algorithms in SPECT was implemented and tested. Due to a complex mathematical description of the geometry of the detector set-up, we developed a method for system matrix computation that is based on direct measurements of the detector response. In this approach, the influence of the acquisition equipment on the image formation is measured directly. The objective was to obtain the best quality of reconstructed images with respect to specified measures. This is indispensable in order to be able to perform reliable quantitative analysis of SPECT images. It is also especially important in non-hybrid gamma cameras, where not all physical processes that disturb image acquisition can be easily corrected. Two experiments with an 131I point source placed at different distances from the detector plane were performed allowing the detector response to be acquired as a function of the point source distance. An analytical Gaussian function was fitted to the acquired data in both the one- and the two-dimensional case. A cylindrical phantom filled with a water solution of 131I containing a region of 'cold' spheres as well as a uniform solution (without any spheres) was used to perform algorithm evaluation. The reconstructed images obtained by using four different of methods system matrix computation were compared with those achieved using reconstruction software implemented in the gamma camera. The contrast of the spheres and uniformity were compared for each reconstruction result and also with the ranges of those values formulated by the AAPM (American Association of Physicists in Medicine). The results show that the implementation of the OSEM (Ordered Subsets Expectation Maximization) algorithm with a one-dimensional fit to the Gaussian CDR (Collimator-Detector Response) function provides the best results in terms of adopted measures. However, the fit of the two-dimensional function also gives satisfactory results. Furthermore, the CDR function has the potential to be applied to a fully 3D OSEM implementation. The lack of the CDR in system matrix calculation results in a very noisy image that cannot be used for diagnostic purposes.
Źródło:: International Journal of Applied Mathematics and Computer Science; 2011, 21, 1; 193-202
1641-876X
2083-8492
Pojawia się w:: International Journal of Applied Mathematics and Computer Science
Dostawca treści:: Biblioteka Nauki

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