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

2020 ◽  
Vol 10 (23) ◽  
pp. 8388
Author(s):  
Ngoc Thang Bui ◽  
Thi My Tien Nguyen ◽  
Tran Thanh Nam Dinh ◽  
Quoc Cuong Bui ◽  
Tan Hung Vo ◽  
...  
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Pulse Generator ◽  
Small Animal ◽  
Industrial Applications ◽  
Good Spatial Resolution ◽  
Frequency Transducer ◽  
High Frequency Transducer ◽  
Animal Images ◽  
Overshoot And Undershoot

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.

scholarly journals NEMA NU4-2008 Performance Evaluation of Albira: A Two-Ring Small-Animal PET System Using Continuous LYSO Crystals

2016 ◽  
Vol 3 (1) ◽  
pp. 12-26 ◽  
Author(s):  
Malgorzata Z. Pajak ◽  
David Volgyes ◽  
Sally L. Pimlott ◽  
Carlos C. Salvador ◽  
Antonio S. Asensi ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Small Animal Imaging ◽  
Small Animal ◽  
Axial Direction ◽  
Small Animal Pet ◽  
Performance Review ◽  
Good Spatial Resolution ◽  
Positron Emission ◽  
Animal Images ◽  
Pet System

Goals:This paper presents the performance review based on a dual-ring Positron Emission Tomography (PET) scanner being a part of Bruker Albira: a multi-modal small-animal imaging platform. Each ring of Albira PET contains eight detectors arranged as octagon, and each detector is built using a single continuous lutetium-yttrium oxyorthosilicate crystal and multi-anode photo multiplier tube. In two-ring configuration, the scanner covers 94.4 mm in axial- and 80´80 mm in trans-axial direction, which is sufficient to acquire images of small animals (e.g.mice) without the need of moving the animal bed during the scan.Methods:All measurements and majority of data processing were performed according to the NEMA NU4-2008 standard with one exception. Due to the scanner geometry, the spatial resolution test was reconstructed using iterative algorithm instead of the analytical one. The main performance characteristics were compared with those of the other PET sub-systems of tri-modal small-animal scanners.Results:The measured spatial resolution at the centre of the axial field of view in radial, tangential and axial directions was 1.72, 1.70 and 2.45 mm, respectively. The scatter fraction for the mouse-like phantom was 9.8% and for the rat-like phantom, 21.8%. The maximum absolute sensitivity was 5.30%. Finally, the recovery co-efficients for 5, 4, 3, 2, 1 mm diameter rods in image quality phantom were: 0.90, 0.77, 0.66, 0.30 and 0.05, respectively.Conclusion:The Bruker Albira is a versatile small-animal multi-modal device that can be used for variety of studies. Overall the PET sub-system provides a good spatial resolution coupled with better-than average sensitivity and the ability to produce good quality animal images when administering low activities.

Identification of Ulnar Artery Perforators Using Color Doppler Ultrasonography

2020 ◽  
Vol 36 (09) ◽  
pp. 667-672
Author(s):  
Megumi Ishiko ◽  
Koichi Yano ◽  
Ema Onode ◽  
Kiyohito Takamatsu
Keyword(s):  
Healthy Volunteers ◽  
High Frequency ◽  
Doppler Ultrasonography ◽  
Color Doppler ◽  
Ulnar Artery ◽  
Color Doppler Ultrasonography ◽  
Doppler Us ◽  
Frequency Transducer ◽  
High Frequency Transducer ◽  
Color Doppler Us

Abstract Background The ulnar artery perforator (UAP) flap, which is hairless, thin, and pliable, has been used for the reconstruction of soft tissues from the finger to the elbow. Preoperative planning is essential for a perforator flap surgery, and there are some tests to identify perforators. Color Doppler ultrasonography (US) with a high-frequency transducer helps in detecting decreased flow in smaller vessels, such as perforators. The purpose of this study was to determine the anatomical locations and origins of perforators arising from the ulnar artery using color Doppler US in healthy volunteers. Methods Forty forearms of 20 healthy volunteers were included in the study. Perforators arising from the ulnar artery, within 100 mm proximal to the pisiform, were investigated using color Doppler US with a high-frequency transducer. Results A total of 205 perforators were identified. On comparing the locations in each 20 mm section from the pisiform, the largest number of perforators was 58 (28%), within 20 mm proximal to the pisiform. The axial view demonstrated 44 (21%), 64 (31%), 32 (16%), and 65 (32%) perforators in the radial, ulnar, superficial, and deep aspects of the ulnar artery, respectively. Fifty-two and 28 essential perforators were supplied by the UAPs arising from the superficial and ulnar aspect within 20 mm proximal to the pisiform and between 21 and 40 mm proximal to the pisiform, respectively, while elevating the UAP flap. Conclusion This is the first study to assess the UAP using color Doppler US. Identification of UAP using color Doppler US can be used as a preoperative assessment for reliable elevation of a UAP flap.

Pulse-echo acoustic properties evaluation method using high-frequency transducer

2020 ◽  
Vol 31 (12) ◽  
pp. 125011
Author(s):  
Zhangjian Li ◽  
Zhile Han ◽  
Xiaohua Jian ◽  
Weiwei Shao ◽  
Yang Jiao ◽  
...  
Keyword(s):  
High Frequency ◽  
Evaluation Method ◽  
Acoustic Properties ◽  
Frequency Transducer ◽  
High Frequency Transducer ◽  
Pulse Echo

scholarly journals High Frequency Transducer Dedicated to the High-resolution in Situ Measurement of the Distance between Two Nuclear Fuel Plates

2015 ◽  
Vol 70 ◽  
pp. 191-194 ◽  
Author(s):  
G. Zaz ◽  
A. Dekkious ◽  
P.A. Meignen ◽  
Y. Calzavara ◽  
E. Le Clézio ◽  
...  
Keyword(s):  
High Resolution ◽  
Nuclear Fuel ◽  
High Frequency ◽  
In Situ Measurement ◽  
Frequency Transducer ◽  
High Frequency Transducer
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