Temperature fields induced in rat liver in vitro by pulsed low intensity focused ultrasound

• Autorzy: Kujawska T. , Wójcik J. , Nowicki A.
• Języki publikacji: EN

Abstrakty

EN

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.

• Wydawca: Polskie Towarzystwo Akustyczne. Oddział Gdański
• Czasopismo: Hydroacoustics
• Rocznik: 2010
• Tom: Vol. 13
• Strony: 153--162
• Opis fizyczny: Bibliogr. 9 poz., rys., tab.

Twórcy

autor

Kujawska T.

autor

Wójcik J.

autor

Nowicki A.

• Institute of Fundamental Technological Research Polish Academy of Sciences Świętokrzyska 21, 00-049 Warsaw, Poland,

Bibliografia

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