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1

Perspectives of brain imaging with PET systems

Majewski Stan

Bio-Algorithms and Med-Systems

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2021

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Vol. 17, no. 4

269--291

EN

In this partial review and partial attempt at vision of what may be the future of dedicated brain PET scanners, the key implementations of the PET technique, we postulate that we are still on a development path and there is still a lot to be done in order to develop optimal brain imagers. Optimized for particular imaging tasks and protocols, and also mobile, that can be used outside the PET center, in addition to the expected improvements in sensitivity and resolution. For this multi-application concept to be more practical, flexible, adaptable designs are preferred. This task is greatly facilitated by the improved TOF performance that allows for more open, adjustable, limited angular coverage geometries without creating image artifacts. As achieving uniform very high resolution in the whole body is not practical due to technological limits and high costs, hybrid systems using a moderate-resolution total body scanner (such as J-PET) combined with a very high performing brain imager could be a very attractive approach. As well, as using magnification inserts in the total body or long-axial length imagers to visualize selected targets with higher resolution. In addition, multigamma imagers combining PET with Compton imaging should be developed to enable multitracer imaging.

2

Analysis of the effectiveness of selected segmentation methods of anatomical brain structures

Dzierżak R., Michalska M.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2018

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T. 8, nr 2

58--61

EN

An important aspect of analysis medical images is acknowledging the role of the segmentation process of individual anatomical structures. This process allows to show the most important diagnostic details. Owing to the segmentation the areas of interest (ROI) it is possible to adapt the methods of further image analysis considering the specification of selected elements. This process has been widely used in medical diagnostics. The article presents the use of segmentation by thresholding, segmentation by region growth and by edge detection to extract the parts of the human brain the user is interested in. The series of MRI (magnetic resonance imaging) images were used. The aim of the research was to develop the methods that would allow comparing the effectiveness various types of anatomical brain structures’ segmentation in two dimensions. The above methods present the different impact that selected types of segmentation, masks or parameters have on the most accurate depiction of a selected human brain element.

PL

Istotnym aspektem analizy obrazów medycznych jest dostrzeżenie roli procesu segmentacji poszczególnych struktur anatomicznych. Proces ten pozwala na ukazanie najistotniejszych pod względem diagnostycznym szczegółów. Dzięki segmentacji obszarów zainteresowania (ROI) możliwe jest odpowiednie dostosowanie metod dalszej analizy obrazów uwzględniając specyfikę wybranych elementów. Proces ten znalazł rozległe zastosowanie w diagnostyce medycznej. W artykule przedstawiono wykorzystanie segmentacji przez progowanie, przez rozrost regionów oraz przez wykrywanie krawędzi, w celu wyodrębnienia interesujących użytkownika części ludzkiego mózgu. Wykorzystano serie obrazów MRI (rezonans magnetyczny). Celem badań było opracowanie metod, które pozwolą porównać skuteczność różnych typów segmentacji struktur anatomicznych mózgu w dwóch wymiarach. Zaprezentowane metody pokazują różny wpływ wybranych rodzajów segmentacji, masek czy parametrów na dokładniejsze ukazanie poszczególnych elementów ludzkiego mózgu.

3

Graph Model Simulation of Human Brain’s Functional Activity at Resting State by Means of the FD Model

Dulio P., Finotelli P., Frosini A., Pergola E., Presenti A.

Fundamenta Informaticae

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2018

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Vol. 163, nr 1

93--109

EN

It is commonly accepted that the various parts of the human brain interact as a network at macroscopic, mesoscopic and microscopic level. Recently, different network models have been proposed to mime the brain behavior both at resting state and during tasks: Our study concerns one of those model that consider both the physical and functional connectivity as well as topological metrics of the brain networks. We provide evidence of the soundness of the model by means of a synthetic dataset based on the existing literature concerning the active cerebral areas at the resting state. Furthermore, we consider Ruzicka similarity measure in order to stress the predictive capability of the model and provide a thresholding criterium. Some network statistics are finally provided.

4

Preliminary design and simulation of a spherical brain PET system (SBPET) with liquid xenon as scintillator

Moghaddam N. M., Karimian A., Mostajaboddavati S. M., Vondervoort E., Sossi V.

Nukleonika

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2009

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Vol. 54, No. 1

33-38

EN

Preliminary design of a spherical brain PET (SBPET) using liquid xenon (LXe) as detector is considered in this research work. The major advantage of a spherical design is the large solid angle of acceptance which improves the sensitivity and increases signal-to-noise ratio (SNR) of the image. The use of a liquid active medium enabled us to design a spherical detector. LXe, due to the intrinsic physical properties, is an excellent liquid medium for accurate tracking of gamma rays in the relevant energy range. The performance of SBPET was evaluated by Monte Carlo simulation tools (GATE) and compared to ECAT HRRT. The numerical results showed the SBPET has a sensitivity of 1.14% and spatial resolution of ~2.7 mm FWHM which is superior to ECAT HRRT especially at high-count rates.

5

Comparison of SPECT cerebral images examination methods based on luminance level and morphological spectra evaluation

Przytulska M., Kulikowski J. L., Bajer A., Królicki L.

Biocybernetics and Biomedical Engineering

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2009

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Vol. 29, no. 1

29-42

EN

It is presented a method of SPECT (single-photon emission tomography) cerebral images examination based on morphological spectra. The advantages of the SPECT imaging in early diagnosing of encephalic diseases are emphasized. The detected radiation levels in the SPECT imaging are visualized by luminance levels which give insight into the lesions of cerebral tissue. It is shown that a rough, on luminance level based, examination of the SPECT images can be improved if more sophisticated analytical methods are used. Basic notions and properties of morphological spectra and their applicability as tools for biomedical image analysis are shortly reminded. A simple formula for reversing transformation reconstructing of original image on the basis of a given morphological spectrum is presented. Results of experiments consisting in comparison of the morphological spectra calculated for selected pairs of testing windows in the SPECT cerebral images are shown. It has been shown that the morphological spectra can better suit to an effective comparison of views of the cerebral regions located symmetrically with respect to the brain axis separating the left and right cerebral hemispheres than the averaged luminance level.