Measurement of ultrasound speed and attenuation coefficient of brain phantom using pulse echo and through transmission method

2018 ◽  
Author(s):  
C. J. Reyes Hernandez ◽  
L. Leija Salas ◽  
A. Vera Hernandez
Keyword(s):  
Attenuation Coefficient ◽  
Transmission Method ◽  
Pulse Echo ◽  
Brain Phantom ◽  
Ultrasound Speed

Ultrasonic Characterization of EB-PVD Thermal Barrier Coatings Irradiated by HIPIB

2008 ◽  
Vol 373-374 ◽  
pp. 358-362 ◽  
Author(s):  
Li Lin ◽  
Y. Zhao ◽  
J. Chen ◽  
X.M. Li ◽  
M.K. Lei
Keyword(s):  
Reflection Coefficient ◽  
Attenuation Coefficient ◽  
Physical Vapor Deposition ◽  
Ion Beam ◽  
Phase Spectrum ◽  
Transmission Model ◽  
Compact Structure ◽  
Shot Number ◽  
Ultrasonic Reflection Coefficient ◽  
Pulse Echo

High-intensity pulsed ion beam (HIPIB) irradiation at 300 A/cm2 with a shot number of 1, and 5 was performed on the coatings and caused the modification of properties. Porosity and rough surface of EB-PVD (Electron Beam-Physical Vapor Deposition) deposited ZrO2-7%Y2O3 coatings with the thickness of 150 μm on heat-resistant steel have been characterized using the ultrasonic reflection coefficient phase spectrum. With increasing the shot number, the surface remelting and ablating filled gaps and caves between columns, and induced more uniform and compact structure. The ultrasonic measurement was investigated using immersion focusing pulse echo method with a 10 MHz transducer. The ultrasonic reflection coefficient related to frequency, velocity and attenuation coefficient were analyzed based on the acoustic transmission model in a multi-layered structure. For the as-deposited coating and coatings irradiated by HIPIB with the shot number of 1 and 5, the ultrasonic velocity changed from 2950 to 3170, and 3255 m/s respectively. The relationship between the attenuation coefficient and the frequency has been deduced based on the numerical fitting of the phase spectrum. The corresponded expressions are 1.35 α = 0.105 f , 1.2 α = 0.045 f and 1.14 α = 0.035 f , which displays that the attenuation coefficient decreases with the increasing of shot number. The ultrasonic results are in agreement with SEM observations, which have indicated that the coatings became denser and uniform with increasing the shot number. From the velocity and attenuation coefficient, the density, porosity, and microcracks of the coatings can be nondestructively evaluated utilizing the method of this paper.

Ultrasonic evaluation of cattle

1983 ◽  
Vol 36 (3) ◽  
pp. 363-370 ◽  
Author(s):  
C. A. Miles ◽  
G. A. J. Fursey ◽  
R. W. Pomeroy
Keyword(s):  
Adipose Tissue ◽  
Predictive Value ◽  
Hind Limb ◽  
Ultrasonic Pulse ◽  
Living Animal ◽  
Transmission Method ◽  
Ultrasonic Evaluation ◽  
Speed Of Ultrasound ◽  
Pulse Echo ◽  
Selection Of

ABSTRACTOne hundred and fourteen castrated male cattle of various breeds were measured ultrasonically immediately prior to slaughter and the data were examined for correlations with the proportion of adipose tissue in the carcasses. Two flaw detectors and a simple scanner, the Scanogram, were used to make ultrasonic pulse-echo measurements of tissue thicknesses and areas. These were used to compute volumes of adipose tissue and muscle in a region of the back of each animal and the ratio of the volumes of the two tissues was examined for correlation with carcass fatness. Three individuals interpreted the Scanogram photographs and two made measurements using flaw detectors.In general, pulse-echo measurements made by different individuals differed in magnitude and predictive value, even when identical scans were measured. Equally there were substantial differences between measurements when the same animals were measured by the same individual using different ultrasonic instruments.In a parallel experiment, the speed of ultrasound transmission was measured at various locations on the living animal and the data were examined for correlations with carcass fatness. Unlike the pulse-echo technique, the transmission method was not prone to errors of subjective interpretation and did not require skill to interpret. Predictions based on speed measurements at two sites in the hind limb were as well related to carcass fatness as were those made on the basis of the best estimate of tissue volumes in the back. The use of two speed measurements in a multiple regression with the best Scanogram data significantly improved the accuracy of predictions of side fatness made on the basis of speed or pulseecho measurements alone.Two types of analysis were used to examine the effectiveness of Ultrasonic selection of lean animals from a group of 50 Hereford castrated males of similar age and weight.

Estimate of Attenuation Coefficient for Ultrasonic Tissue Characterization Using Time-Varying State-Space Model

1988 ◽  
Vol 10 (2) ◽  
pp. 90-109 ◽  
Author(s):  
Li Y. Shih ◽  
Casper W. Barnes ◽  
Leonard A. Ferrari
Keyword(s):  
State Space ◽  
Attenuation Coefficient ◽  
Tissue Characterization ◽  
Wigner Distribution ◽  
Output Coupling ◽  
Pathological State ◽  
Identification Algorithm ◽  
Time Varying ◽  
Pulse Echo

The images generated from ultrasound pulse-echo signals have long been used to aid clinical diagnosis. Recently, there has been a growing interest in quantitatively determining the acoustic parameters of the tissue as a means of classification and diagnosis. For example, the frequency-dependent attenuation is known to be correlated with different diseases in the liver. In this paper we introduce a new technique for estimating the attenuation coefficient. The effect of attenuation on an interrogating signal with a gaussian-shaped spectrum can be obtained by studying the Wigner distribution of reflected rf data based on a one-dimensional signal model. We show that under the condition that the attenuation varies linearly with frequency, the spectral mean of the reflected signal decreases linearly with time. The estimation algorithm models the pulse-echo signal as the output of a second-order time-varying state-space innovations model driven by white noise. The state coupling matrix A and the output coupling vector C vary with time in a known fashion; moreover, they are also functions of an unknown constant parameter θ. The attenuation coefficient, which is one of the elements of θ, can be estimated directly using a recursive system identification algorithm. The algorithm was verified using both computer-generated synthetic data and in-vivo liver data of known diagnosis. The results show correlation between the estimated parameter and the pathological State Of the tissue.

scholarly journals Measurement of Linear Attenuation Coefficient of Tc-99m using Planar Gamma Camera Image

2015 ◽  
Vol 17 (1) ◽  
pp. 61-66
Author(s):  
Md Nahid Hossain ◽  
Kamila Afroj Quadir ◽  
Md Nurul Islam ◽  
Tanvir Ahmed Biman ◽  
Ferdoushi Begum
Keyword(s):  
Attenuation Coefficient ◽  
Gamma Camera ◽  
Accurate Estimation ◽  
Transmission Factor ◽  
Activity Measurement ◽  
Linear Attenuation Coefficient ◽  
Transmission Method ◽  
Transmission Imaging ◽  
Camera Image ◽  
Transmission Measurements

Introduction: Attenuation is one of the most important factors which have an impact on the accuracy on quantitation of activity when using gamma camera image in a medium. Due to attenuation a number of photons are lost and there is also loss of counts which otherwise would have been included in the images. The purpose of this study is to estimate the linear attenuation coefficient for Tc-99m with water filled phantom using conjugate view method and transmission method and compare the obtained measurements with the reference values. Materials and Methods: To determine the linear attenuation coefficient of radionuclide Tc-99m using conjugate view method, the sensitivity of the gamma camera was determined. 30 MBq of Tc-99m was taken which was measured in dose calibrator and gamma camera images were acquired. Then the sensitivity was calculated as CPS/MBq. A Jaszczak phantom was filled up with water and a small sized cylindrical container filled with activity of 30 MBq Tc-99m liquid was placed inside the Jaszczak phantom centrally. The phantom was scanned on a dual head gamma camera and the images were taken and counts from the images were estimated. After estimation of all values, the linear attenuation coefficient was calculated using conjugate view formula. The linear attenuation coefficient was also measured from the transmission imaging. The transmission factor (TF) was determined by measuring the ratio of count rates obtained with Tc-99m under gamma camera, with and without the phantom. Results: The linear attenuation coefficient was calculated 0.1467 ± 0.0057 from conjugate view method and 0.1483 ± 0.0023 from transmission measurements. Both results were found within ±5% of the established value (0.15 cm-1). Conclusions: Correction for attenuation is required for the accurate estimation of activity. For conjugate view method, the attenuation coefficient was measured with a known activity of Tc-99m. The attenuation coefficient was also estimated by transmission measurements. The accuracy of the activity measurement is highly dependent on the accuracy of the attenuation coefficient used in the calculation. DOI: http://dx.doi.org/10.3329/bjnm.v17i1.22493 Bangladesh J. Nuclear Med. 17(1): 61-66, January 2014

An ultrasound method for characterization of viscoelastic properties in frequency domain at small deformations

2021 ◽  
pp. 095440622110057
Author(s):  
A Sakhnevych ◽  
A Genovese ◽  
A Maiorano ◽  
F Timpone ◽  
F Farroni
Keyword(s):  
Attenuation Coefficient ◽  
Viscoelastic Properties ◽  
Loss Factor ◽  
Wave Attenuation ◽  
Acoustic Properties ◽  
Master Curves ◽  
Ultrasound Technique ◽  
Pulse Echo ◽  
Pulse Echo Method

Background The ultrasound technique, usually based on the transmission mode, is capable of providing the viscoelastic properties of polymers. Further techniques involving pulse-echo methods were also described in literature, but they still exhibit inaccuracies in the evaluation of the acoustic properties. Objective The manuscript focuses on an innovative approach for the characterization of the viscoelastic behavior of polymers employing the ultrasound methodology. The proposed procedure is based on the pulse-echo method in order to overcome possible inaccuracies in acoustic properties evaluation and in issues related to transmitter mode applications. Methods Starting from the pulse-echo method adopted for the acquisition, a novel formulation for data processing has been developed and described, allowing to determine the wave attenuation coefficient, in comparison to the commonly employed procedures involving ultrasound in polymers characterization, based on transmitter mode inspections. To carry out the study, a specifically designed ultrasound bench has been set up and three different polymers have been tested in the temperature range of interest. Results According to the proposed methodology, the loss factor towards the temperature is determined starting from the data acquired considering the identified attenuation coefficient and the measured sound velocities. The trustworthiness of the novel procedure has been proved comparing the obtained viscoelastic loss factor quantities to the reference master curves obtained by the standard Dynamic Mechanical Analysis characterizations carried out on the same polymer specimens. Conclusions A novel methodology involving ultrasound technology aiming to evaluate the viscoelasticity of the polymers using non-destructive approach has been developed. The results obtained are agreement with the standard viscoelastic master curves determined through the DMA.

scholarly journals The Application of Adaptive Time Gain Compensation in an Improved Breast Ultrasound Tomography Algorithm

2019 ◽  
Vol 9 (12) ◽  
pp. 2574
Author(s):  
Chang Liu ◽  
Binzhen Zhang ◽  
Chenyang Xue ◽  
Guojun Zhang ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
Attenuation Coefficient ◽  
Ultrasonic Transducer ◽  
Correlation Method ◽  
Reconstruction Algorithm ◽  
Ultrasound Tomography ◽  
Attenuation Coefficients ◽  
Gain Compensation ◽  
Adaptive Time ◽  
Pulse Echo ◽  
Horizontal Slice

In order to better detect information about a mass in breast tissue, an ultrasound tomography algorithm based on adaptive time gain compensation (TGC) was designed. Field II was utilized to automatically evaluate the phantom attenuation coefficient and compensate for the attenuated image. The image reconstruction algorithm process is presented here. Furthermore, the experimental setup with the cylindrical motion of a piezoelectric micromachined ultrasonic transducer (PMUT) linear array was used to detect the mass in the breast model. The attenuation coefficient was evaluated by using the spectral cross-correlation method. According to the acquired attenuation coefficients, TGC compensates for the pulse-echo signal, and the horizontal slice image was reconstructed using the tomography algorithm. The experimental results show that this algorithm can evaluate the attenuation coefficient of the breast model and improve the ability to detect an internal mass. At the same time, the realization of attenuation compensation with software is beneficial to the development of portable medical equipment.

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