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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

A 3D-CNT micro-electrode array for zebrafish ECG study including directionality measurement and drug test

Shih Mulaine, Kuo Chia-Tung, Lin Min-Hsuan, Chuang Yung-Jen, Chen Hsin, Yew Tri-Rung

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 2

701--708

EN

This study aims to demonstrate the applicability of three dimensional-carbon-nanotubes (3D-CNT) micro-electrode array for electrocardiogram (ECG) study on the premier vertebrate model zebrafish. The small-feature size and vectorial array of 3D-CNT micro-electrodes were designed to detect ECG signals with high spatial resolution. With 30 μm–85 μm spacing between electrodes, it enables to detect the directionality of the ECG signals, the change of the characteristic ECG wave-forms at different locations of an adult zebrafish heart. Besides, the preliminary drug response tests using 3D-CNT micro-electrode were also carried out, which validated the capability of real-time observation on drug-induced ECG signal changes. The 3D-CNT micro-electrode array is thus feasible for ECG research and cardiac drug screenings, and holds high potential for studying bioelectric signals of other living organ-isms in the future.

3

Wpływ stężenia molowego domieszki GeO2 w rdzeniu światłowodu wielomodowego na rozdzielczość temperaturową rozłożonego czujnika temperatury z wymuszonym rozproszeniem Ramana

Torbus Sławomir Andrzej

Przegląd Elektrotechniczny

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2019

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R. 95, nr 3

155--159

PL

W pracy krótko scharakteryzowano wielomodowe włókna światłowodowe, które można wykorzystywać do budowy rozłożonych czujników temperatury z wymuszonym rozproszeniem Ramana (SRS). Scharakteryzowano wymuszone rozproszenie Ramana oraz budowę, zasadę działania i podstawowe parametry rozłożonych czujników temperatury działających na bazie niniejszego rozproszenia. Przedstawiono wyniki badań dotyczących wpływu stężenia molowego domieszki GeO2 w rdzeniu światłowodu wielomodowego na rozdzielczość temperaturową rozpatrywanego czujnika. Sformułowano wnioski dotyczące doboru włókna światłowodowego i długości fali świetlnej (sondującej) w celu uzyskania optymalnej rozdzielczości temperaturowej rozłożonego czujnika temperatury z wymuszonym rozproszeniem Ramana.

EN

In this paper multimode optical fibers, which can be used to build distributed temperature sensors with stimulated Raman scattering (SRS) are briefly characterized. Stimulated Raman scattering and construction, principle of operation and parameters of distributed temperature sensors with this scattering have been characterized. The results of researches on the influence of the molar concentration of the GeO2 dopant in the multimode optical fiber core on the temperature resolution of the considered sensor are presented. Conclusions regarding the selection of optical fiber and light wavelength (probing) in order to obtain the optimal temperature resolution of the distributed temperature sensor with stimulated Raman scattering were formulated.

4

GATE Simulation Study of the Siemens Biograph mCT 20 Excel PET/CT System

Saaidi Rahal, Toufique Yassine, Zeghari Abdelkrim, El kharrim Abderrahman, Cherkaoui El Moursli Rajaâ

Polish Journal of Medical Physics and Engineering

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2019

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Vol. 25, Iss. 1

7--14

EN

We used GATE simulation to study the effect of the coincidence time window (CTW) along with the block gap and the intercrystal gap on the count rate performance and the spatial resolution of the Biograph™ mCT 20 Excel. We ran simulations on our local cluster to reduce computation time. The task was split into several jobs that were then triggered simultaneously on the cluster nodes. The BiographTM mCT 20 Excel was validated using the NEMA NU 2-2012 protocol. Our results showed good agreement with experimental data. The simulated sensitivity, peak true count rate, peak noise equivalent count rate (NECR), and scatter fraction showed agreement within 3.62%, 5.77%, 0.6%, and 2.69%, respectively. In addition, the spatial resolution agreed within <0.51 mm. The results showed that a decrease in the coincidence time window and the block gap and an increase in the intercrystal gap increase the count rate performance and improve the spatial resolution. The results also showed that decreasing the coincidence time window increased the NECR by 27.37%. Changing the intercrystal gap from 0 to 0.2 mm and the block gap and from 4 to 0.4 mm increased the NECR by 5.53% and improved the spatial resolution at 1 cm by 2.91 % and that at 10 cm by 3.85%. The coincidence time window, crystal gap, and block gap are important parameters with respect to improving the spatial resolution.

5

Automated MTF measurement in CT images with a simple wire phantom

Anam Choirul, Fujibuchi Toshioh, Haryanto Freddy, Budi Wahyu Setia, Sutanto Heri, Adi Kusworo, Muhlisin Zaenul, Dougherty Geoff

Polish Journal of Medical Physics and Engineering

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2019

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Vol. 25, Iss. 3

179--187

EN

This study developed a simple wire phantom and an algorithm to automatically measure the modulation transfer function (MTF) in computed tomography (CT) and implemented it to evaluate the effect of focal spot size and reconstruction filter type. The phantom consisted of a resin cylinder filled with water, with a tin wire of diameter 0.1 mm positioned along the center of the cylinder. The automated MTF algorithm used an axial image of the phantom and comprised several steps. The center position of a region of interest (ROI) was automatically determined at the center of the wire image. The pixels were then summed along the y-direction to obtain the profile of the pixel values at a point along the x-direction. Following this, both edges of the profile were made equal to zero. The profile curve was then normalized so that the total of all the data was equal to unity. The normalized profile curve is the line spread function (LSF), and the MTF curve was obtained by taking its Fourier transform. Our system (phantom and algorithm) is able to differentiate the MTFs of CT images from different focal sizes and reconstruction filter types.

6

Ocena rozdzielczości geometrii w cyfrowym modelu topograficznym

Bielawski B.

Roczniki Geomatyki

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2018

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T. 16, z. 2(81)

77--87

PL

Artykuł przedstawia wyniki prac badawczych autora zarówno w zakresie metodyki oceny Rozdzielczości Geometrii, jak i próby praktycznego wykorzystania postulowanych metod do oceny rzeczywistych zbiorów danych. Na wstępie autor przybliża problematykę związaną z aktualnie stosowaną metodą oceny rozdzielczości zbiorów danych, serii zbiorów danych lub usług. W dalszej części artykułu autor podaje założenia przyjętej metodyki, wprowadza i definiuje cztery rodzaje Rozdzielczości Geometrii charakteryzujące różne aspekty geometrii obiektów przestrzennych: Rozdzielczość Współrzędnych, Maksymalną Rozdzielczość Geometrii, Rzeczywistą Rozdzielczość Geometrii oraz Nominalną Rozdzielczość Geometrii. W ostatniej części artykułu autor podejmuje próbę oceny postulowanych rozdzielczości na przykładzie rzeczywistych zbiorów danych. Uzyskane wyniki oceny Rozdzielczości Geometrii mogą stanowić alternatywę dla aktualnie stosowanej metody opisu rozdzielczości zbiorów danych, serii zbiorów danych, to jest mianownika skali.

EN

This article presents the results of the author’s research both in the methodology of the Geometry Resolution assessment and attempts to use the postulated methods to evaluate actual data sets. At the beginning, the author introduces issues related to the currently used method of assessing the resolution of data sets, dataset series or services. Further in the paper, the author presents the assumptions of the adopted methodology, introduces and defines four types of Geometry Resolution characterizing various aspects of spatial geometry: Coordinate Resolution, Maximum Geometry Resolution, Actual Geometry Resolution and Nominal Geometry Resolution. In the last part of the paper, the author attempts to evaluate the postulated resolutions on the example of real data sets. Obtained results of the Geometry Resolution assessment may be an alternative to the currently used method of describing the resolution of data sets, dataset series – known as the scale denominator.

7

Opracowywanie procedur badań ultradźwiękowych techniką TOFD w odniesieniu do stref martwych i rozdzielczości przestrzennej

Kaczmarek R., Kaczmarek K.

Przegląd Spawalnictwa

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2018

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R. 90, nr 7

30--35

PL

Obserwowany w ostatnich latach wzrost zastosowań nowoczesnych technik badań ultradźwiękowych (TOFD, phased array) wiąże się z koniecznością opracowywania stosownych procedur badawczych, różniących się istotnie od typowych procedur dotyczących konwencjonalnych badań ultradźwiękowych. Z tego względu w pracy opisano najistotniejsze zagadnienia, które powinny zostać przeanalizowane i uwzględnione na etapie przygotowania procedury badania ultradźwiękowego techniką czasu przejścia wiązki dyfrakcyjnej TOFD. Szczególną uwagę zwrócono na analizę wielkości stref martwych TOFD oraz zmian rozdzielczości przestrzennej na grubości badanego złącza, a także doprecyzowanie zasad oceny wskazań niemierzalnych w kierunku wysokości.

EN

The increase in the use of advanced ultrasonic testing techniques such as TOFD and Phased Array, observed in recent years is connected with the necessity of development of appropriate testing procedures, differing siqnificantly from typical procedures for conventional ultrasound examinations. For this reason, the paper describes the most important issues that should be analyzed and taken into account at the stage of preparation of the ultrasonic examination procedure with the time of flight diffraction TOFD technic. Particular attention has been paid to the size of TOFD dead zones and changes in spatial resolution on the thickness of the joint tested, as well as the clarification of the principles for the assessment of unmeasurable in the direction of joint thickness indications.

8

Bezpośrednia radiografia cyfrowa

Jezierski G.

Postępy Techniki Jądrowej

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2017

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z. 2

37--44

PL

Dynamiczny rozwój radiografii cyfrowej (bazującej na elektronice) jaki obserwujemy w ostatnich latach skutkuje także zastosowaniem tej techniki do badań nieniszczących w przemyśle (NDT). Jednakże biorąc pod uwagę istotne różnice, przede wszystkim znacznie wyższe energie promieniowania rentgenowskiego stosowane do badania różnych obiektów przemysłowych (np. złącza spawane, odlewy, połączenia w elektronice), jak również konieczność dysponowania niekiedy lekkimi, przenośnymi detektorami powoduje, że nie da się bezpośrednio przenieść rozwiązań z medycyny do przemysłu. W niniejszej publikacji przedstawiono współczesne trendy oraz praktyczne rozwiązania detektorów cyfrowych do zastosowań w NDT.

EN

Application of digital radiography (based on electronics) for imaging in medical practice has been recently dynamically developing, which results in implementation of this technique to industrial non-destructive testing (NDT). However, with respect to significant differences that include, first of all, much higher X-ray energies used for testing various object in industry (e.g. welds, castings, joints in electronic engineering) and often also necessity of using light, portable digital detectors, it is impossible to transfer solutions directly from medicine to industry. In this paper, modern trends and practical solutions of digital detectors designed for NDT are presented.

9

Improving the spatial resolution of DICOM data using the Lanczos resampling filter

Budzik G., Turek P.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2017

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Vol. 23, nr 2

106--112

EN

This paper presents an initial study to improve the spatial resolution of DICOM data using the Lanczos resampling filter. DICOM data from the cranium area of three patients, were obtained using a Somatom Sensation Open 40 scanner. A model with voxel dimension 0.4×0.4×2.4 mm was chosen as the gold standard, over the modeling approach using voxel dimensions 0.4×0.4×4.8 mm. Using the Lanczos resampling filter, changed the slice thickness from 4.8 mm to 2.4 mm. The influence of the Lanczos resampling filter on improving the spatial resolution of data was very similar across all 3 patients. The Lanczos filter changed the spatial resolution of the data and improved the accuracy of reconstruction of cranium geometry. The presented research highlights new opportunities to control deviations at the data processing and modeling of geometry stages.

PL

Artykuł przedstawia badania wstępne, dotyczące poprawy rozdzielczości przestrzennej danych DICOM, poprzez zastosowanie filtru Lanczos. Dane DICOM trzech pacjentów, zostały zebrane przy użyciu tomografu Somatom Sensation Open 40 i obrazują obszar sklepienia czaszki. Model ze strukturą voxela 0,4×0,4×2,4 mm został wybrany jako nominalny, względem modelu o strukturze voxela 0,4×0,4×4,8 mm. Stosując filtr Lanczos, zmieniono grubość warstwy obrazu z 4,8 mm na 2,4 mm. W wyniku zastosowania filtru Lanczos, polepszono rozdzielczość przestrzenną danych oraz dokładność odwzorowania geometrii sklepienia czaszki. Przedstawione badania, otwierają nowe możliwości pozwalające na minimalizacje błędów powstałych na etapie przetwarzania danych oraz odtwarzania geometrii obszaru sklepienia czaszki.

10

Technique for Measuring Spatial Distribution of the Surface Acoustic Wave Velocity in Metals

Mokryy O., Tsyrulnyk O.

Archives of Acoustics

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2016

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Vol. 41, No. 4

741--746

EN

In this paper a possibility of determining a local velocity of the surface acoustic Rayleigh waves using a transducer, with the rigidly connected emitting and receiving parts, is considered. A problem on spatial resolution of such a transducer for investigation of inhomogeneous specimens is also examined. A high spatial resolution can be obtained due to the transducer displacement by a value less than the distance between the emitting and receiving parts. It is shown that in this case it is not necessary to measure the transducer displacement with a high accuracy for precise determination of the velocity. Such an effect is obtained through measuring the velocity of surface waves in one local region of the specimen with respect to the other. The criterion for optimal spatial resolution selection during spatially inhomogeneous specimens study is also proposed. The proposed criterion use is illustrated on the example of the determination of spatial distribution of the surface acoustic velocity in a steel specimen subjected to inhomogeneous plastic deformation.

11

Wybrane problemy lokalizacji obiektów ukrytych w ośrodku mętnym optycznie z użyciem diody LED i światłowodu

Rybaczewski P., Wiczyński G.

Przegląd Elektrotechniczny

|

2015

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R. 91, nr 5

60-63

PL

Jednym z podstawowych parametrów opisujących metodę obrazowania jest jej rozdzielczość. W pracy podjęto próbę wyznaczenia rozdzielczości i kontrastu proponowanej metody. W tym celu do przygotowanego fantomu jednorodnego wprowadzano zaburzenie absorpcyjne w postaci stalowych prętów o różnych średnicach. Przeszkody umieszczano w określonych konfiguracjach przestrzennych względem siebie. Pomiary powtarzano odtwarzając ułożenie prętów dla różnych grubości warstwy badanej (różnych poziomów cieczy).

EN

The resolution is one of the basic parameters describing the imaging method. This paper attempts to determine the resolution and contrast for the proposed method. Steel rods of various diameters were placed in the homogeneous phantom. The barriers were placed relatively to each other, in a specific spatial configuration. The measurements were repeated for different thickness of the tested layer (different levels of liquid).

12

Research methods for improving satellite images based on Pan-Sharpening

Dorozhynskyy O., Obroslak R., Stusyak Y.

Geomatics, Landmanagement and Landscape

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2015

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no. 3

29--43

EN

The authors of the article consider five classic methods to improve images with pan sharpening and it present their mathematical models and technological schemes, the estimation of their positive effects both on color distortion and fragmentation in spatial resolution. Results of impact methods were observed and compared in two sofware products: Erdas Imagine 10.0 and ArcGIS 10.2. For comparison were used satellite images with ultrahigh spatial resolution and high spatial resolution.

13

Entering the digital era of the Open Skies Treaty

Orych A.

Geodesy and Cartography

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2015

|

Vol. 64, no. 1

65--74

EN

The Open Skies Treaty has been a peace-building instrument between North American and European nations for over two decades. This agreement is based on the possibility for each country-signatory of the Treaty to independently conduct observation flights and obtain aerial imagery data of the territories of other Treaty States-Parties. This imagery data was originally acquired only using traditional photographic film cameras. Together with the rapid development and advancement of digital sensor technologies, the logical step forward was to amend the Treaty provisions to allow for the use of these types of sensors during observation missions. This paper describes this transition process and highlights a number of technical problems which needed to be addressed by experts working within the Open Skies Consultative Commission workgroups.

PL

Od ponad 20 lat, Traktat o Otwartych Przestworzach pełni rolę narzędzia wspierającego pokój pomiędzy krajami Ameryki Północnej oraz Europy. Porozumienie to opiera się na umożliwianiu każdemu państwu- sygnatariuszowi Traktatu samodzielne wykonywanie lotów obserwacyjnych oraz pozyskiwanie informacji obrazowej na temat terytorium innych Państw-Stron Traktatu. Oryginalnie Traktat zakładał jedynie pozyskiwanie danych obrazowych za pomocą tradycyjnych aparatów fotograficznych na kliszę fotograficzną. Wraz z nagłym rozwojem technologii sensorów cyfrowych, kolejnym logicznym krokiem w przód było dostosowanie zapisów Traktatu, tak aby umożliwić wykorzystanie tego typu sensorów podczas misji obserwacyjnych. Artykuł ten opisusje ten proces przejścia oraz opisuje wybrane problemy techniczne jakie zostały poruszone przez ekspertów pracujących w grupach roboczych Komisji Konsultatywnej Traktatu o Otwartych Przestworzach (KKOP)

14

Analysis of hot-wire measurements accuracy in turbulent boundary layer

Dróżdż A., Elsner W.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

|

nr 145

39--40

EN

The paper discusses the problem of measuring velocity fluctuations of turbulent boundary layer using hot-wire probes. The study highlighted the problem of spatial resolution, which is essential when measuring small-scale in wall-bounded flows. Additionally, the attention was paid to the inconsistency in streamwise fluctuation measurements using single and X-wire probes. To clarify this problem the energy spectra using wavelet transformation were calculated. The analysis was performed for turbulent boundary layer flow, which was characterized by the Reynolds number based on the friction velocity equal ReƮ≈1000.

15

Wybrane problemy wyznaczania zdolności rozdzielczej sensorów wykorzystywanych w ramach misji Open Skies

Walczykowski P., Orych A.

Biuletyn Wojskowej Akademii Technicznej

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2010

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Vol. 59, nr 2

309-323

PL

Precyzyjne wyznaczanie terenowej zdolności rozdzielczej sensorów jest kluczowym problemem przy pozyskiwaniu zobrazowań z pułapu lotniczego, zwłaszcza w ramach traktatu Open Skies. Ustalono w nim minimalną, dopuszczalną, terenową zdolność rozdzielczą dla poszczególnych rodzajów sensorów. Ponieważ rozdzielczość terenowa większości rodzajów sensorów jest uzależniona od ich wysokości nad odwzorowywanym terenem, konieczne jest wyznaczenie minimalnej wysokości lotu obserwacyjnego, na której dozwolona rozdzielczość terenowa nie zostanie przekroczona. W tym celu wykonuje się przeloty i pozyskuje zobrazowania nad specjalnie skonstruowanymi celami kalibracyjnymi. Na pozyskanych zobrazowaniach mogą występować pewne błędy, artefakty, mające wpływ na poprawność wyznaczania zdolności rozdzielczej. W przypadku badań w zakresie widzialnym błędy spowodowane są przeważnie pracą sensora oraz sposobem rejestracji danych. W przypadku sensorów termalnych, dodatkowym elementem mogącym wprowadzać błędy są same cele kalibracyjne. W Zakładzie Teledetekcji i Fotogrametrii WAT prowadzone są obecnie prace nad stworzeniem nowych celów kalibracyjnych, których konstrukcja będzie minimalizowała te błędy.

EN

The precise determination of resolving power of sensors is a key problem especially when establishing which sensors can be used for Open Skies missions. The Treaty on Open Skies dictates the lowest acceptable resolving power of sensors which can be used during observation flights. Because the resolving power of most sensors differs with the height of the sensor above the terrain, it is essential to determine the minimal flying altitude, at which the permitted spatial resolution will not be exceeded. A series of test flights above especially constructed calibration targets is conducted in order to acquire imagery of these tests at different altitudes. The spatial resolution of these images is determined by evaluating the visibility of each of the components of these calibration targets. In theory, such a methodology would allow for the precise calculation of the resolving power. In reality, however, the acquired images can be burdened with a number of artifacts, or deformities, which can have a negative effect on accuracy of our calculations. When acquiring imagery in the visible range, these errors are usually caused by the detector itself or by the method by which the data is registered. However, imagery in the thermal range can additionally contain errors caused by the design of the calibration targets used. In recent years, at the Department of Remote Sensing and Photogrammetry at the Military University of Technology in Warsaw, we have designed and constructed a number of calibration targets used during Open Skies missions. One such target had been recently laid out during a Ukrainian observation flight over Polish territories. The aim of the experiment was to establish the resolving power of a new Ukrainian film. A series of images had been acquired by means of the AFA-41/7.5 analogue frame camera from a height of 1100 m. This height is the theoretical Hmin for this film, meaning the spatial resolution of imagery acquired from this altitude, will be close to 30 cm. Based on imagery acquired during this flight, it had been established that the spatial resolution of the resultant imagery is much worse than 30 cm, which means that the chosen Hmin value had been too high. We are currently in the process of constructing a new set of calibration targets, whose design will minimize the aforementioned errors. Additionally, the targets have been designed in such a way, that they will be used for determining the spatial resolution of both thermal and optical sensors. The effectiveness of these new targets will be tested shortly.

16

Spatial Resolution of Attenuation Imaging

Klimonda Z., Litniewski J., Nowicki A.

Archives of Acoustics

|

2009

|

Vol. 34, No. 4

461-470

EN

The attenuating properties of biological tissue are of great importance in ultrasonic examination even though its anatomical variability limits diagnostics effectiveness. We are currently developing a technique for parametric imaging of attenuation and we intend to apply it for in vivo characterization of tissue. The diagnostic usefulness of the proposed technique crucially depends on the precision of the attenuation estimate and the resolution of the parametric image. These two parameters are highly correlated, since the resolution is reduced whenever averaging is used to minimize the errors introduced by the random character of the backscatter. Here we report on the results of numerical processing of both, simulated and recorded from a tissue-mimicking phantom echoes. We have analyzed the parameters of the estimation technique and examined their influence on the precision of the attenuation estimate and on the parametric image resolution. The optimal selection of attenuation image parameters depending on its intended diagnostic use, was also considered

17

Improvement of spatial resolution of Brillouin optical time domain reflectometer using spectral decomposition

Zhang D., Shi B., Cui H.L., Xu H.Z.

Optica Applicata

|

2004

|

Vol. 34, nr 2

291-301

EN

Brillouin optical time domain reflectometer (BOTDR) has been used for strain and temperature measurement and health monitoring in infrastructural systems. However, the spatial measurement resolution of BOTDR cannot yet meet the measuring needs of some specific local strains, such as the strain caused by a narrow crack or fissure in structures. In this paper, a spectral decomposition method is proposed and used for improving the spatial resolution. Based on the proportion of the strain length within the spatial resolution, taking the spectrum of the strain section from the measured spectrum, and fitting the decomposed Brillouin gain spectrum with the Lorentzian curve, the actual strain within a spatial resolution along optical fibers can be obtained. The experimental results demonstrate that this method is applicable to the modification of the measured strain whether its strained length is less or greater than the spatial resolution without considering the installation method of the optical fiber