Method for determining non-linear HIFU (High Intensity Focused Ultrasound) sound filed of biological tissues

Abstract

The invention discloses a method for determining the non-linear HIFU (High Intensity Focused Ultrasound) sound field of biological tissues, which belongs to the technical field of sound field measurement. The method mainly comprises the following steps of: (a) transmitting a signal through a pulse receiving-transmitting instrument; (b) calibrating an energy transducer; (c) exciting a dual-frequency ultrasonic signal in a sample to be tested; (d) receiving the signal, sampling at equal intervals on different space and time domains, and performing FFT (Fast Fourier Transform) processing on the signal; (e) calculating the attenuation and dispersion of a sample material, smoothing a signal windowed function, and processing the signal by using two-dimensional Fourier transform to obtain the dispersion and attenuation spectrum of an ultrasonic signal; and (f) simulating the sound field in the sample by using a computer through a dispersion and an attenuation value obtained in the step (e). Due to the adoption of the method, the sound wave condition of sound filed transmitted in the biological tissues can be determined really and accurately; and the method has the characteristics of simple measuring method and high result precision.

Description

technical field [0001] The invention relates to the technical field of sound field measurement, and more specifically relates to an improved simulation method suitable for the particularity of biological tissues. Background technique [0002] High Intensity Focused Ultrasound (HIFU) therapy, as an emerging non-invasive targeted tumor therapy technology, has attracted more and more attention. Its principle is to use external ultrasonic energy to focus on the target tissue in the body, rapidly increase the temperature in the target tissue area in a short period of time, and cause coagulation necrosis of tumor cells, so as to achieve the therapeutic effect, and have little impact on normal tissue in the non-focused area . HIFU technology has been applied in the clinical treatment of tumors, such as: breast cancer, thyroid cancer, prostate cancer, etc. Accurate description of HIFU sound field helps to improve the accuracy and safety of treatment. The Khokhlov-Zabolotskaya-Kuz...

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Problems solved by technology

[0008] At present, there is no accurate measurement method for the focused ultrasonic sound field of biological tissues, and the original KZK equation does not consider the special dispersion and attenuation problems when ultrasound propagates in biological tissues, and the original KZK equation cannot accurately measure the focused sound field. To describe the problem, the present invention provides a method for determining the nonlinear HIFU sound field of biological tissue, which is measured and calculated through reasonable steps, and at the same time, the fractional derivative is introduced into the KZK equation, and the attenuation term and sound velocity of the KZK equation are corrected according to the fractional derivative theory. To solve the problem that the sound attenuation coefficient has a power relationship with the frequency when the sound field propagates in biological tissue

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