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Wyszukujesz frazę "Litniewski, J." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Spatial and Frequency Compounding in Application to Attenuation Estimation in Tissue
Autorzy:
Klimonda, Z.
Litniewski, J.
Karwat, P.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/177604.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tissue attenuation estimation
parametric imaging
synthetic aperture
spatial compounding
frequency compounding
Opis:
The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.
Źródło:
Archives of Acoustics; 2014, 39, 4; 519-527
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noninvasive Imaging of Thermal Fields Induced in Soft Tissues In Vitro by Pulsed Focused Ultrasound Using Analysis of Echoes Displacement
Autorzy:
Karwat, P.
Litniewski, J.
Kujawska, T.
Secomski, W.
Krawczyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/176451.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high intensity focused ultrasound
HIFU
therapeutic ultrasound
ultrasonic imaging
echo strain estimation
Opis:
Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the most suitable for the temperature control. This paper presents an implementation of the ultrasonic echoes displacement estimation technique for monitoring of local temperature rise in tissue during its heating by focused ultrasound The results of the estimation were compared to the temperature measured with thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique.
Źródło:
Archives of Acoustics; 2014, 39, 1; 139-144
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of ultrasound to noninvasive imaging of temperature distribution induced in tissue
Autorzy:
Karwat, P.
Kujawska, T.
Secomski, W.
Gambin, B.
Litniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/332286.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
HIFU
echo phase shift
parametric imaging
velocity/brightness CNR
Opis:
Therapeutic and surgical applications of High Intensity Focused Ultrasound (HIFU) require monitoring of local temperature rises induced inside tissues. It is needed to appropriately target the focal plane, and hence the whole focal volume inside the tumor tissue, prior to thermo-ablative treatment, and the beginning of tissue necrosis. In this study we present an ultrasound method, which calculates the variations of the speed of sound in the locally heated tissue. Changes in velocity correspond to temperature change. The method calculates a 2D distribution of changes in the sound velocity, by estimation of the local phase shifts of RF echo-signals backscattered from the heated tissue volume (the focal volume of the HIFU beam), and received by an ultrasound scanner (23). The technique enabled temperature imaging of the heated tissue volume from the very inception of heating. The results indicated that the contrast sensitivity for imaging of relative changes in the sound speed was on the order of 0.06%; corresponding to an increase in the tissue temperature by about 2 °C.
Źródło:
Hydroacoustics; 2016, 19; 219-228
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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