scholarly journals Design, Fabrication, and Evaluation of Multifocal Point Transducer for High-Frequency Ultrasound Applications

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 609 ◽  
Author(s):  
Thanh Nguyen ◽  
Nguyen Truong ◽  
Nhat Bui ◽  
Van Nguyen ◽  
Giang Hoang ◽  
...  
Keyword(s):  
High Frequency ◽  
Polyvinylidene Fluoride ◽  
Focal Point ◽  
Cnc Machining ◽  
Numerical Control ◽  
Center Frequency ◽  
Pvdf Film ◽  
High Frequency Ultrasound ◽  
Linear Pattern ◽  
Frequency Ultrasound

The present study illustrates the design, fabrication, and evaluation of a novel multifocal point (MFP) transducer based on polyvinylidene fluoride (PVDF) film for high-frequency ultrasound application. The fabricated MFP surface was press-focused using a computer numerical control (CNC) machining tool-customized multi-spherical pattern object. The multi-spherical pattern has five spherical surfaces with equal area and connected continuously to have the same energy level at focal points. Center points of these spheres are distributed in a linear pattern with 1 mm distance between each two points. The radius of these spheres increases steadily from 10 mm to 13.86 mm. The designed MFP transducer had a center frequency of 50 MHz and a −6 dB bandwidth of 68%. The wire phantom test was conducted to study and demonstrate the advantages of this novel design. The obtained results for MFP transducer revealed a significant increase (4.3 mm) of total focal zone in the near-field and far-field area compared with 0.48 mm obtained using the conventional single focal point transducer. Hence, the proposed method is promising to fabricate MFP transducers for deeper imaging depth applications.

Micro/Nano Piezoelectric Composites for Advanced M/NEMS

2007 ◽  
Author(s):  
Xiaoning Jiang ◽  
Jian R. Yuan ◽  
An Cheng ◽  
Kevin Snook ◽  
Wesley Hackenberger
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Center Frequency ◽  
High Frequency Ultrasound ◽  
Piezoelectric Composites ◽  
Deep Etching ◽  
High Frequency Ultrasound Imaging ◽  
Electromechanical Devices ◽  
Frequency Ultrasound

In this paper piezoelectric composites are presented for advanced micro and nano electromechanical devices. The properties of piezoelectric composites (1-3 and 2-2 connectivity) were analyzed and a micromachining process for bulk piezo materials deep etching was developed for piezoelectric composites fabrication. As an example, micromachined piezoelectric composites with center frequency of 20–50 MHz were prototyped. The micro-piezoelectric composites were characterized showing unprecedented properties for high frequency ultrasound imaging and M/NEMS applications.

Design and Experiment of Capacitive Micromachined Ultrasonic Transducer Array for High-Frequency Underwater Imaging

2020 ◽  
Vol 13 ◽  
Author(s):  
Yuanyu Yu ◽  
Jiujiang Wang ◽  
Xin Liu ◽  
Sio Hang Pun ◽  
Weibao Qiu ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Ultrasonic Transducer ◽  
Center Frequency ◽  
Design Parameters ◽  
Underwater Imaging ◽  
Release Process ◽  
Steel Wires ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Frequency Ultrasound

Background:: Ultrasound is widely used in the applications of underwater imaging. Capacitive micromachined ultrasonic transducer (CMUT) is a promising candidate to the traditional piezoelectric ultrasonic transducer. In underwater ultrasound imaging, better resolutions can be achieved with a higher frequency ultrasound. Therefore, a CMUT array for high-frequency ultrasound imaging is proposed in this work. Methods:: Analytical methods are used to calculate the center frequency in water and the pull-in voltage for determining the operating point of CMUT. Finite element method model was developed to finalize the design parameters. The CMUT array was fabricated with a five-mask sacrificial release process. Results:: The CMUT array owned an immersed center frequency of 2.6 MHz with a 6 dB fractional bandwidth of 123 %. The pull-in voltage of the CMUT array was 85 V. An underwater imaging experiment was carried out with the target of three steel wires. Conclusion:: In this study, we have developed CMUT for high-frequency underwater imaging. The experiment showed that the CMUT can detect the steel wires with the diameter of 100 μm and the axial resolution was 0.582 mm, which is close to one wavelength of ultrasound in 2.6 MHz.

scholarly journals Effectiveness of high frequency ultrasound on pressure ulcer

Medicine ◽  
2019 ◽  
Vol 98 (37) ◽  
pp. e17111 ◽  
Author(s):  
Xiang-qin Gao ◽  
Xiao-mei Xue ◽  
Jian-kang Zhang ◽  
Fei Yan ◽  
Qiu-xia Mu
Keyword(s):  
Pressure Ulcer ◽  
High Frequency ◽  
High Frequency Ultrasound ◽  
Frequency Ultrasound

Evaluation of frontal fibrosing alopecia with ultra‐high‐frequency ultrasound

2021 ◽  
Author(s):  
Carolina Ávila de Almeida ◽  
Simone Guarçoni ◽  
Bruna Duque Estrada ◽  
Maria Carolina Zafra Páez ◽  
Clarissa Canella
Keyword(s):  
High Frequency ◽  
High Frequency Ultrasound ◽  
Ultra High Frequency ◽  
Frequency Ultrasound

scholarly journals Morphologic Features of Cutaneous T-Cell Lymphomas Using Dermoscopy and High Frequency Ultrasound

2020 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Iris Wohlmuth-Wieser ◽  
Joel M. Ramjist ◽  
Neil Shear ◽  
Raed Alhusayen
Keyword(s):  
T Cell ◽  
High Frequency ◽  
Early Stage ◽  
Skin Lesions ◽  
Diagnostic Tools ◽  
Skin Thickness ◽  
High Frequency Ultrasound ◽  
T Cell Lymphomas ◽  
Standardized Parameters ◽  
Frequency Ultrasound

The diagnosis of cutaneous T-cell lymphomas (CTCL) is frequently delayed by a median of three years and requires the clinical evaluation of an experienced dermatologist and a confirmatory skin biopsy. Dermoscopy and high-frequency ultrasound (HFUS) represent two non-invasive diagnostic tools. While dermoscopy is inexpensive and widely used for the diagnosis of melanoma and non-melanoma skin cancers, HFUS of skin lymphomas represents a novel diagnostic approach that is not yet implemented in the routine dermatologic practice. The aim of our study was to prospectively assess skin lesions of patients with either CTCL patches or plaques with dermoscopy and HFUS and to compare the findings with atopic dermatitis (AD) and psoriasis. Thirteen patients with an established diagnosis of CTCL, psoriasis, or AD were studied: Dermoscopy features including spermatozoa-like structures and the presence of white scales could assist in differentiating between early-stage CTCL and AD. HFUS measurements of the skin thickness indicated increased epidermal-, thickness in CTCL, and psoriasis compared with AD. Our results support the use of dermoscopy as a useful tool to diagnose CTCL. HFUS could augment the dermatologic assessment, but further studies will be needed to define standardized parameters.

Sign in / Sign up

Export Citation Format

Share Document