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    Analysis of nonlinear acoustic wave propagation in HIFU treatment using westervelt equation

    , Article Scientia Iranica ; Volume 25, Issue 4 , 2018 , Pages 2087-2097 ; 10263098 (ISSN) Haddadi, S ; Ahmadian, M. T ; Sharif University of Technology
    Sharif University of Technology  2018
    Currently, the HIFU (High-Intensity Focused Ultrasound) therapy method is known as one of the most advanced surgical techniques of tumor ablation therapy. Simulation of the non-linear acoustic wave and tissue interaction is essential in HIFU planning to improve the usefulness and efficiency of treatment. In this paper, linear, thermoviscous, and nonlinear equations are applied using two different media: liver and water. Transducer power of 8.3-134 Watts with the frequency of 1.1 MHz is considered as the range of study to analyze the interaction of wave and tissue. Results indicate that the maximum focal pressure of about 0.5-4.3 MPa can be achieved for transducer power rates of 8.3 to 134 W.... 

    Propagation Modeling of High Intensity Focused Ultrasound Wave through Multi Layer Tissue along with Experimental Validation

    , Ph.D. Dissertation Sharif University of Technology Haddadi, Samaneh (Author) ; Ahmadian, Mohammad Taghi (Supervisor)
    One of the main problems in human health, both in advanced societies and in growing societies, is a variety of cancers, one of which is brain tumor. One of the non-invasive methods of treating tumors is the use of ultrasound.HIFU (High Intensity Focused Ultrasound) therapy method is known as one of the most advanced surgical techniques in tumor ablation therapy. HIFU are produced and concentrated by powerful transducers. The two main mechanisms in HIFU are mechanical and thermal mechanisms, and the effects of these two mechanisms appear as thermal effects and cavitation. The fundamental mechanism in the HIFU is to absorb ultrasonic waves and to convert them into heat.The purpose of this... 

    Numerical and experimental evaluation of high-intensity focused ultrasound-induced lesions in liver tissue ex vivo

    , Article Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine ; Volume 37, Issue 6 , 2018 , Pages 1481-1491 ; 15509613 (ISSN) Haddadi, S ; Ahmadian, M. T ; Sharif University of Technology
    OBJECTIVES: Recent advances in the field of acoustics and piezoelectric and ultrasound transducers have led to new approaches to the diagnosis and treatment of certain diseases. One method of treatment with ultrasonic waves is high-intensity focused ultrasound (HIFU) treatment, which is a thermal therapeutic method used to treat malignant tumors. Although a variety of treatment-planning strategies using ultrasonic waves have been investigated, little clinical success has been achieved. Computational modeling is a powerful tool for predicting device performance. METHODS: The heating induced by a concave transducer with operating powers of 85 and 135 W was studied, and the experimental results...