Acoustic impedance measurement of tissue mimicking materials by using scanning acoustic microscopy

Altun, Burak; Demirkan, Irem; Kocatürk, Özgür; Ünlü, Mehmet; Gari̇pcan, Bora

doi:10.1016/j.ultras.2020.106274

Cited by 18 publications

(7 citation statements)

References 44 publications

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“…For example, water has an acoustic impedance of 1.5 MRayl, while human soft tissue demonstrates an acoustic impedance of 1.63 MRayl. [ 97 ] The typical values for bulk or plate‐type piezoelectric ceramics are >30 MRayl, and polymeric piezoelectric ≈4.5 MRayl. [ 98 ] Acoustic impedance mismatch, much like light diffraction through different materials, can lead to wave reflection and reduced powering efficiency.…”

Section: Piezoelectric Ultrasound‐powered Implantsmentioning

confidence: 99%

Ultrasound‐Powered Implants: A Critical Review of Piezoelectric Material Selection and Applications

Turner

Senevirathne

Kilgour

et al. 2021

Adv Healthcare Materials

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Ultrasound‐powered implants (UPIs) represent cutting edge power sources for implantable medical devices (IMDs), as their powering strategy allows for extended functional lifetime, decreased size, increased implant depth, and improved biocompatibility. IMDs are limited by their reliance on batteries. While batteries proved a stable power supply, batteries feature relatively large sizes, limited life spans, and toxic material compositions. Accordingly, energy harvesting and wireless power transfer (WPT) strategies are attracting increasing attention by researchers as alternative reliable power sources. Piezoelectric energy scavenging has shown promise for low power applications. However, energy scavenging devices need be located near sources of movement, and the power stream may suffer from occasional interruptions. WPT overcomes such challenges by more stable, on‐demand power to IMDs. Among the various forms of WPT, ultrasound powering offers distinct advantages such as low tissue‐mediated attenuation, a higher approved safe dose (720 mW cm−2), and improved efficiency at smaller device sizes. This study presents and discusses the state‐of‐the‐art in UPIs by reviewing piezoelectric materials and harvesting devices including lead‐based inorganic, lead‐free inorganic, and organic polymers. A comparative discussion is also presented of the functional material properties, architecture, and performance metrics, together with an overview of the applications where UPIs are being deployed.

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Section: Piezoelectric Ultrasound‐powered Implantsmentioning

confidence: 99%

Ultrasound‐Powered Implants: A Critical Review of Piezoelectric Material Selection and Applications

Turner

Senevirathne

Kilgour

et al. 2021

Adv Healthcare Materials

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“…Two perfectly matched layers are used to match these two hemispheres to eliminate the effect of boundary, creating the ideal situation without unnecessary acoustic reflection. Because silicone oil's acoustic characteristics are similar to that of the human body, the human body is replaced by silicone oil in this model [16,23,24]. The properties of materials are shown in Table II.…”

Section: B Finite Simulationmentioning

confidence: 99%

A Bionic MEMS Electronic Stethoscope With Double-Sided Diaphragm Packaging

et al. 2021

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In this paper, an electronic stethoscope is designed based on a bionic Micro-Electro-Mechanical System (MEMS) sound-sensitive sensor. Inspired by the strong sound reflection effect of the water-air interface, a double-sided diaphragm MEMS electronic stethoscope (DMES) encapsulated by a novel double-sided diaphragm packaging is proposed. The double-sided diaphragm packaging's superiority is verified by comparing a single diaphragm MEMS electronic stethoscope (SMES) with DMES. The frequency of the clinical heart sound signal is mostly in the range of 20-600 Hz. Finite simulation results show that for the same incident sound source, the sound pressure level inside double-sided diaphragm packaging is 4dB higher than that of single diaphragm packaging in this frequency band. Furthermore, the actual auscultation test results show that the signal-to-noise ratio (SNR) of DMES reaches 41.3dB, which is 2.2dB higher than SMES. Besides, comparing the heart sound signals collected by DMES and a commercial electronic stethoscope (Model 3200, 3M Littmann, USA), the high consistency of the two signals' characteristic parameters in the time domain and frequency domain proves the feasibility of DMES. Finally, DMES has the advantages of low cost, and its SNR is 10.2db higher than that of the 3M electronic stethoscope. All these show that DMES has a broad prospect in the popularization of basic medical treatment.

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“…Burak Altun et al used the SAM system to analyze the impedance measurement of tissue. Their research plays an important role in ensuring the quality of ultrasound diagnostics [7]. Ryo Nagaoka et al have developed a new calculation method for the SAM system to measure objects with a thickness of 1.95 um with an accuracy of 0.0016% [2].…”

Section: Introductionmentioning

confidence: 99%

“…For high-frequency transducers with small focal zones, small dimensions can be detected in the structure to be tested [10]. Therefore, the ultrasonic transducer strategy, which converts electrical energy into high-frequency sound waves, is an important consideration for optimizing system performance and achieving high image quality [2,7].…”

Section: Introductionmentioning

confidence: 99%

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Design of a Multichannel Pulser/Receiver and Optimized Damping Resistor for High-Frequency Transducer Applied to SAM System

et al. 2020

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Scanning acoustic microcopy (SAM) is widely used in biomedical and industrial applications in dermatology, ophthalmology, intravascular imaging, and small animal images, owing to SAM’s ability to photograph small structures with a good spatial resolution. One of the most important devices of this system is the pulser/receiver (P/R) (PRN-300, Ohlabs Corporation, Nam-gu Busan, Republic of Korea), which generates pulses to trigger a high-frequency transducer. This article presents the design of a pulse generator to excite high-frequency transducers with four channels. The characteristics of the pulses, such as time and frequency, can be reconfigured by using a high-speed field programmable gate array (FPGA). The configuration software was developed for communicating with the P/R device via a USB connector for easy, feasible pulse selection and real-time pulse management. Besides that, during the design and implementation of the hardware, we optimized the damping resistor value to reduce the overshoot and undershoot part of the signal, ensuring the best effect on the transducer signal. The test results show that unipolar pulses worked with transducers with frequencies over 100 MHz. The SAM systems can work simultaneously with multiple transducers, and the resulting images have different resolutions of regions.

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Acoustic impedance measurement of tissue mimicking materials by using scanning acoustic microscopy

Cited by 18 publications

References 44 publications

Ultrasound‐Powered Implants: A Critical Review of Piezoelectric Material Selection and Applications

Ultrasound‐Powered Implants: A Critical Review of Piezoelectric Material Selection and Applications

A Bionic MEMS Electronic Stethoscope With Double-Sided Diaphragm Packaging

Design of a Multichannel Pulser/Receiver and Optimized Damping Resistor for High-Frequency Transducer Applied to SAM System

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