Views: 5 Author: Site Editor Publish Time: 2018-07-30 Origin: Site
In order to achieve quantitative analysis of the sound field characteristics of the HIFU piezo ceramic treatment probe in the single focus scanning mode, The following three key acoustic field characteristics are studied.
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For the focal region on the (focus plane) and the axial focal length. All 0.5 Pm ax, space area A is{(x, z)}0·SPmax: P, x, and z): Pmax}; where a is the second focusing in the region of interest.The spatial peak time and peak sound pressure is the sound pressure of the focus point, and (x, y, z) is the three-dimensional space view.Checking the coordinates. In the analysis of the sound field characteristics of high intensity focused ultrasound, the focal length is represented by two values of Length and width.The coke column is represented by Height; if Pf is <0.5 Detect a, think (Length, Width, Height) =(0,0,0), that is, the focal length is zero and the focus fails. Length is the focal field in the direction that parallel to the X-axis by the sound pressure .The half size defined by the full length at half maximum pressure (FLHM), Width is the focal length parallel to the dimension defined by FLHM in the Y-axis direction, Height is the focal field in the direction parallel to the Z-axis.The size is defined by FLHM.
For the deflection range RFD (mm). When the sound field characteristics of HIFU piezoelectric ceramic element are guaranteed to satisfy the gradel condition, the focus focus is the maximum distance deflected by a geometric focus point O in a specific direction in space (eg, parallel to the x-axis direction, parallel to the y-axis direction, parallel to the Z-axis direction).
For quantitative evaluation index of therapeutic sound field.In order to quantitatively judge whether the sound field focusing effect of the Hifu piezoelectric sensor array is good, we define a quantification criteria for sound field focus in the arrays in single-point focus mode. To ensure the safety of ultrasound therapy , the highest sound intensity of the grating lobe is at least 5dB to 10 dB less than the main lobe sound intensity. Therefore, The circle sets four criteria for quantitative evaluation of the sound field focus of the HIFU treatment probe in single-point focus.
