scholarly journals Feasibility of noninvasive thermometry in hyperthermia regime using harmonics generated by nonlinear ultrasound wave propagation

2021 ◽  
Author(s):  
Borna Maraghechi
Keyword(s):  
Wave Propagation ◽  
Temperature Dependence ◽  
Harmonic Generation ◽  
Ex Vivo ◽  
Motion Artifacts ◽  
Propagation Model ◽  
Lower Sensitivity ◽  
Nonlinear Ultrasound ◽  
Bovine Muscle ◽  
Muscle Tissues

Hyperthermia is a cancer treatment modality that could be delivered as a stand-alone treatment or in conjunction with chemotherapy or radiation therapy. Noninvasive and real-time temperature monitoring of the heated tissue improves the efficacy and safety of the treatment. Ultrasound-based thermometry requires a temperature-sensitive acoustic parameter that can be used to estimate the temperature by tracking changes in that parameter during heating. This dissertation describes the experiments and simulations performed to obtain the temperature dependence of acoustic harmonics generated by nonlinear ultrasound propagation in several media including: water, an attenuating tissue-mimicking liquid, ex vivo bovine muscle tissues, and tissue-mimicking gel phantoms. The mechanisms of action of harmonic generation in water and in the attenuating liquid, made by a mixture of 90% glycerol and 10% water (by volume), as a function of temperature at various frequencies have been investigated using a temperature dependent Khokhlov–Zabolotskaya–Kuznetsov (KZK) nonlinear acoustic wave propagation model. The simulation results were compared with and validated by measurements. In water, the harmonic amplitudes decrease with increasing the temperature at low frequencies (1 and 3.3 MHz), while the opposite temperature dependence was observed at higher frequencies (13 and 20 MHz). The harmonic generation significantly increased with temperature in the tissue-mimicking liquid at both frequencies of 5 and 13 MHz. The temperature dependence of harmonics in tissue-mimicking gel phantoms and ex vivo bovine muscle tissues were measured using a commercial high-frequency ultrasound imaging system, and a new noninvasive ultrasound-based thermometry has been developed that is based on the backscattered energy of the harmonics. The sensitivity of this new thermometry technique to medium’s motion was studied and compared with the conventional echo-shift thermometry technique. Based on this study, it is suggested that noninvasive temperature estimation is feasible using acoustic harmonics with lower sensitivity to motion artifacts compared to the conventional echo-shift technique.

scholarly journals Feasibility of noninvasive thermometry in hyperthermia regime using harmonics generated by nonlinear ultrasound wave propagation

2021 ◽  
Author(s):  
Borna Maraghechi
Keyword(s):  
Wave Propagation ◽  
Temperature Dependence ◽  
Harmonic Generation ◽  
Ex Vivo ◽  
Motion Artifacts ◽  
Propagation Model ◽  
Lower Sensitivity ◽  
Nonlinear Ultrasound ◽  
Bovine Muscle ◽  
Muscle Tissues

Hyperthermia is a cancer treatment modality that could be delivered as a stand-alone treatment or in conjunction with chemotherapy or radiation therapy. Noninvasive and real-time temperature monitoring of the heated tissue improves the efficacy and safety of the treatment. Ultrasound-based thermometry requires a temperature-sensitive acoustic parameter that can be used to estimate the temperature by tracking changes in that parameter during heating. This dissertation describes the experiments and simulations performed to obtain the temperature dependence of acoustic harmonics generated by nonlinear ultrasound propagation in several media including: water, an attenuating tissue-mimicking liquid, ex vivo bovine muscle tissues, and tissue-mimicking gel phantoms. The mechanisms of action of harmonic generation in water and in the attenuating liquid, made by a mixture of 90% glycerol and 10% water (by volume), as a function of temperature at various frequencies have been investigated using a temperature dependent Khokhlov–Zabolotskaya–Kuznetsov (KZK) nonlinear acoustic wave propagation model. The simulation results were compared with and validated by measurements. In water, the harmonic amplitudes decrease with increasing the temperature at low frequencies (1 and 3.3 MHz), while the opposite temperature dependence was observed at higher frequencies (13 and 20 MHz). The harmonic generation significantly increased with temperature in the tissue-mimicking liquid at both frequencies of 5 and 13 MHz. The temperature dependence of harmonics in tissue-mimicking gel phantoms and ex vivo bovine muscle tissues were measured using a commercial high-frequency ultrasound imaging system, and a new noninvasive ultrasound-based thermometry has been developed that is based on the backscattered energy of the harmonics. The sensitivity of this new thermometry technique to medium’s motion was studied and compared with the conventional echo-shift thermometry technique. Based on this study, it is suggested that noninvasive temperature estimation is feasible using acoustic harmonics with lower sensitivity to motion artifacts compared to the conventional echo-shift technique.

scholarly journals Simulation of Three Constitutive Behaviors Based on Nonlinear Ultrasound

2020 ◽  
Vol 10 (6) ◽  
pp. 1982 ◽  
Author(s):  
Zaifu Zhan ◽  
Shen Wang ◽  
Fuping Wang ◽  
Songling Huang ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Nonlinear Theory ◽  
Constitutive Models ◽  
Propagation Model ◽  
Ultrasound Wave ◽  
Single Tone ◽  
Nonlinear Ultrasound ◽  
Structure Response ◽  
Ultrasonic Propagation ◽  
Wave Propagation Model

Nonlinear ultrasound has attracted more and more attention. In classical acoustic nonlinear theory, the source of nonlinearity is the change of constitutive relation of materials. Structure response that distorts after a single tone ultrasound wave is important to detect imperfection. This is rarely found in current simulations. The current simulation always introduces defects which do not match to the classical acoustic nonlinear theory. In this manuscript, the recurrence expressions of three kinds of imperfect materials for subroutine are given. The verifying simulation model that is used for verifying recurrence equations and wave propagation model that are used for analysing the process of ultrasonic propagation are established. The results show that the two constitutive models are effective in the verifying simulation and the hysteresis material has some special characteristics. Finally, ultrasonic propagation in two types of materials produce the expected harmonics, which build foundations for simulations of nonlinear ultrasound.

The coastal refraction-diffraction wave propagation model

1995 ◽  
Vol 17 (4) ◽  
pp. 6-12
Author(s):  
Nguyen Tien Dat ◽  
Dinh Van Manh ◽  
Nguyen Minh Son
Keyword(s):  
Wave Propagation ◽  
Field Data ◽  
Surf Zone ◽  
Propagation Model ◽  
Wave Transformation ◽  
Diffraction Effect ◽  
Linear Wave ◽  
Diffraction Wave ◽  
Linear Wave Propagation ◽  
Wave Propagation Model

A mathematical model on linear wave propagation toward shore is chosen and corresponding software is built. The wave transformation outside and inside the surf zone is considered including the diffraction effect. The model is tested by laboratory and field data and gave reasonables results.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

Multi-layer Intrabody Terahertz Wave Propagation Model for Nanobiosensing Applications

2017 ◽  
Vol 14 ◽  
pp. 9-15 ◽  
Author(s):  
Hadeel Elayan ◽  
Raed M. Shubair ◽  
Josep Miquel Jornet ◽  
Raj Mittra
Keyword(s):  
Wave Propagation ◽  
Terahertz Wave ◽  
Propagation Model ◽  
Wave Propagation Model
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