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Wyszukujesz frazę "HIFU" wg kryterium: Temat

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    Wyświetlanie 1-5 z 5
    Tytuł:
    Design and Verification of Sector Vortex Archimedean Spiral Phased Array Transducer for Improving Focus Acoustic Pressure
    Autorzy:
    Lu, Xiaodan
    Zeng, Deping
    Powiązania:
    https://bibliotekanauki.pl/articles/31339756.pdf
    Data publikacji:
    2024
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    phased array transducer
    Archimedean spiral
    high-intensity focused ultrasound
    HIFU
    focal deflection
    Opis:
    The emergence of high-intensity focused ultrasound applications brings great potential to establish noninvasive therapeutic treatment in place of conventional surgery. However, the development of ultrasonic technology also poses challenges to the design and manufacture of high-power ultrasound transducers with sufficient acoustic pressure. Here, the design of a sector vortex Archimedean spiral phased array transducer that is able to enhance focal acoustic pressure is proposed by maximizing the filling factor of the piezoelectric array. The transducer design was experimentally verified by hydrophone measurements and matched well with acoustic simulation studies. The focal deflection was shown to be feasible up to ±9 mm laterally and up to ±20 mm axially, where the effective focal acoustic pressure can be maintained above 50% and the level of the grating lobe below 30%. Furthermore, a homogeneous pressure distribution without secondary focus was observed in the pre-focal region of the transducer. The rational design of a high-intensity focused ultrasound transducer indicates promising development in the treatment of deep tissue thermal ablation for clinical applications.
    Źródło:
    Archives of Acoustics; 2024, 49, 1; 73-81
    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
    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:
    Experimental Assessment of the Impact of Sonication Parameters on Necrotic Lesions Induced in Tissues by HIFU Ablative Device for Preclinical Studies
    Autorzy:
    Fura, Łukasz
    Dera, Wojciech
    Dziekoński, Cezary
    Świątkiewicz, Maciej
    Kujawska, Tamara
    Powiązania:
    https://bibliotekanauki.pl/articles/1953466.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    automated ultrasound imaging-guided HIFU ablation system
    ex vivo tissue
    ultrasonic exposure parameters
    extent of necrotic lesions
    Opis:
    We have designed and built ultrasound imaging-guided HIFU ablative device for preclinical studies on small animals. Before this device is used to treat animals, ex vivo tissue studies were necessary to determine the location and extent of necrotic lesions created inside tissue samples by HIFU beams depending on their acoustic properties. This will allow to plan the beam movement trajectory and the distance and time intervals between exposures leading to necrosis covering the entire treated volume without damaging the surrounding tissues. This is crucial for therapy safety. The objective of this study was to assess the impact of sonication parameters on the size of necrotic lesions formed by HIFU beams generated by 64-mm bowl-shaped transducer used, operating at 1.08 MHz or 3.21 MHz. Multiple necrotic lesions were created in pork loin samples at 12.6-mm depth below tissue surface during 3-s exposure to HIFU beams with fixed duty-cycle and varied pulse-duration or fixed pulse-duration and varied duty-cycle, propagated in two-layer media: water-tissue. After exposures, the necrotic lesions were visualized using magnetic resonance imaging and optical imaging (photos) after sectioning the samples. Quantitative analysis of the obtained results allowed to select the optimal sonication and beam movement parameters to suport planning of effective therapy.
    Źródło:
    Archives of Acoustics; 2021, 46, 2; 341-352
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Selection of Exposure Parameters for a HIFU Ablation System Using an Array of Thermocouples and Numerical Simulations
    Autorzy:
    Fura, Łukasz
    Kujawska, Tamara
    Powiązania:
    https://bibliotekanauki.pl/articles/177347.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    automated HIFU ablation system
    threshold acoustic power of HIFU beam
    ex vivo tissue
    necrotic lesion
    thermocouple array
    Opis:
    Image-guided High Intensity Focused Ultrasound (HIFU) technique is dynamically developing technologyfor treating solid tumors due to its non-invasive nature. Before a HIFU ablation system is ready for use, the exposure parameters of the HIFU beam capable of destroying the treated tissue without damaging the surrounding tissues should be selected to ensure the safety of therapy. The purpose of this work was to select the threshold acoustic power as well as the step and rate of movement of the HIFU beam, generated by a transducer intended to be used in the HIFU ablation system being developed, by Rusing an array of thermocouples and numerical simulations. For experiments a bowl-shaped 64-mm, 1.05 MHz HIFU transducer with a 62.6 mm focal length (f-number 0.98) generated pulsed waves propagating in two-layer media: water/ex vivo pork loin tissue (50 mm/40 mm) was used. To determine a threshold power of the HIFU beam capable of creating the necrotic lesion in a small volume within the tested tissue during less than 3 s each tissue sample was sonicated by multiple parallel HIFU beams of different acoustic power focused at a depth of 12.6 mm below the tissue surface. Location of the maximum heating as well as the relaxation time of the tested tissue were determined from temperature variations recorded during and after sonication by five thermo-couples placed along the acoustic axis of each HIFU beam as well as from numerical simulations. The obtained results enabled to assess the location of each necrotic lesion as well as to determine the step and rate of the HIFU beam movement. The location and extent of the necrotic lesions created was verified using ultrasound images of tissue after sonication and Visual inspection after cutting the samples. The threshold acoustic power of the HIFU beam capable of creating the local necrotic lesion in the tested tissue within 3 s without damaging of surrounding tissues was fund to be 24 W, and the pause between sonications was found to be more than 40 s.
    Źródło:
    Archives of Acoustics; 2019, 44, 2; 349-355
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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