Multi-frequency partition excitation method for phase-controlled ultrasonic transducer based on random distribution of 82 array elements

Abstract

The invention discloses a multi-frequency partition excitation method based on 82 array elements randomly distributed phased array ultrasonic transducers. The steps are as follows: divide each array element into different excitation regions according to the three-dimensional space coordinates of the array elements; Under the condition of equal area, sine waves with different operating frequencies are applied to the array elements of different partitions; in the numerical simulation model under the craniotomy state, the influence of the number of frequency partitions and the frequency difference between different partitions on the focusing performance of HIFU is studied, and Obtain the number of frequency divisions and corresponding frequency combinations when the focusing effect is the best; based on the number of frequency divisions when the focusing effect is the best obtained in the craniotomy numerical simulation model, perform two divisions on the 82-element phased transducer in the transcranial model Excitation, to study the effect of the frequency difference between different partitions on the focusing performance of transcranial HIFU, and determine the frequency combination for optimal focusing performance. The invention reduces the input power and treatment time required for tissue ablation, and at the same time increases the temperature of the focal region and the volume of the treatable focal region.

Description

technical field [0001] The invention relates to the technical field of high-intensity focused ultrasound, in particular to a multi-frequency partition excitation method based on an 82-element randomly distributed phased array ultrasonic transducer. Background technique [0002] High-Intensity Focused Ultrasound (HIFU) has been used in the clinical treatment of solid soft tissue tumors such as breast cancer, prostate cancer, and uterine fibroids due to its advantages of non-invasive / minimally invasive and repeatable treatment. In the process of transcranial treatment, due to the strong attenuation of the skull to ultrasonic waves and the highly heterogeneous structure and density of the skull, the ultrasonic beams emitted by the transducers in different directions have different attenuation degrees after propagating through the skull. The difference in the energy of the beam reaching the focal area is relatively large, which eventually leads to a lower temperature in the foca...

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Problems solved by technology

In 2010, McDannold et al. used ExAblate 3000 transcranial magnetic resonance-guided focused ultrasound system to treat three patients with glioblastoma (47 years old, 23 years old, and 34 years old). The highest temperature in the region only reached 42°C, 51°C, and 48°C respectively, failing to reach the target focal region temperature set at 55°C, and did not form a lethal therapeutic effect on target tissue; in 2014, Chang et al. used the ExAblate 4000 treatment system Defibrillation therapy was performed on 11 tremor patients, and the trial results showed that three of them failed due to the low temperature of the target area

The above-mentioned experts have conducted research on multi-frequency ultrasound excitation based on single-array focused transducers, but they did not involve the phase-controlled transducers used in transcranial therapy, and did not discuss in detail the effect of the number of frequency partitions and the frequency difference between adjacent intervals on HIFU. Focus performance impact

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