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Warianty tytułu
Języki publikacji
Abstrakty
Beneficial biological effects in soft tissues can be induced by focused ultrasound of low intensity (LIFU). For example, increasing of cells immunity to stress can be accomplished through the enhanced heat shock proteins (Hsp) expression induced by the low intensity focused ultrasound. The possibility to control the Hsp expression enhancement in soft tissues in vivo can be the potential new therapeutic approach to neurodegenerative diseases that utilizes the known feature of cells to increase their immunity to stresses through the Hsp expression enhancement. The controlling of the Hsp expression enhancement by adjusting the level of exposure to ultrasound energy would allow evaluating of ultrasound-mediated treatment efficiency. Our objective was to develop the numerical model capable of predicting in space and time temperature fields induced in multilayer nonlinear attenuating media by a circular focused transducer generating pulsed acoustic waves and to compare the results calculated for two-layer configuration of media: water - fresh rat liver with the experimental data. The measurements of temperature variations versus time at 5 points on the acoustic beam axis within the tissue sample were performed using 0.2-mm diameter thermocouples. Temperature fields were induced by the transducer with 15-mm diameter, 25-mm focal length and 2-MHz centre frequency generating tone bursts with the intensity ISPTA varied between 0.45 W/cm2 and 1.7 W/cm2 and duration varied between 20 and 500 cycles at the same 20-% duty cycle and 20-min exposure time. Quantitative analysis of the obtained results allowed to show that, for example, for the acoustic beam with intensity ISPTA = 1.13 W/cm2 exposure time to ultrasound should not be longer than 10 min to avoid cells necrosis following the 43-oC temperature threshold exceeding.
Słowa kluczowe
Czasopismo
Rocznik
Tom
Strony
153--162
Opis fizyczny
Bibliogr. 9 poz., rys., tab.
Twórcy
autor
autor
autor
- Institute of Fundamental Technological Research Polish Academy of Sciences Świętokrzyska 21, 00-049 Warsaw, Poland, tkujaw@ippt.gov.pl
Bibliografia
- [1] H.G. Zhank, K. Mehta, P. Cohen, C. Guha, Hyperthermia on immune regulation: A temperature's story, Cancer Letters, 271, 191-204, 2008.
- [2] T. Kujawska, A new method for determination of the acoustic nonlinearity parameter B/A in multilayer biological media, Proc. 5th World Congress on Ultrasound, Paris, 81-84, 2003.
- [3] T. Kujawska, J. Wójcik and L. Filipczyński, Determination of the B/A of biological media by measuring and modeling nonlinear distortion of pulsed acoustic wave in two-layer system of media, International Acoustical Imaging Symposium AI'30, Springer, 101-110, 2009.
- [4] A.C. Baker, K. Anastasiadis, V.F. Humphrey, The nonlinear pressure field of a plane circular piston: theory and experiment, J. Acoust. Soc. Am., 84, 1483-1487, 1988.
- [5] J. Wójcik, A. Nowicki, P.A. Lewin, P.E. Bloomfield, T. Kujawska, L. Filipczyński, Wave envelopes method for description of nonlinear acoustic wave propagation, Ultrasonics, 44, 310-329, 2006.
- [6] H.H. Pennes, Analysis of tissue and arterial blood temperatures in the resting human Forearm, J. Appl. Physiol., 1, 93-122, 1948.
- [7] T. Kujawska, J. Wójcik, L. Filipczyński, Possible temperature effects computed for acoustic microscopy used for living cells, Ultrasound in Medicine and Biology, 30, 1, 93-101, 2004.
- [8] K.R. Holmes, Biological structures and heat transfer. In: The future of biothermal engineering, Allerton Workshop, University of Illinois, 14-37, 1997.
- [9] F.A. Duck, Physical properties of tissue: A comprehensive reference book, London, Academic Press, 1990.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BWM1-0007-0018