scholarly journals Grid-characteristic numerical method for medical ultrasound

2021 ◽  
Vol 2090 (1) ◽  
pp. 012164
Author(s):  
Katerina Beklemysheva ◽  
Alexey Vasyukov ◽  
Alexey Ermakov

Abstract Grid-characteristic method (GCM) is a fast and reliable numerical method that allows to model wave effects in viscoelastic media with high accuracy, including surface and contact waves. This research is dedicated to the application of GCM to the problem of medical ultrasound. Calculations for High-Intensity Focused Ultrasound (HIFU) were performed on 3D model statements for homogenous and inhomogeneous media, and a qualitative correspondence with experimental data was achieved. Numerical results include estimation of consumed energy (based on Maxwell viscosity model), velocity vector and stress tensor components. Various material parameters were considered, including relaxation time and inclusions of different types.

Author(s):  
Prasanna Hariharan ◽  
Ronald A. Robinson ◽  
Matthew R. Myers ◽  
Rupak K. Banerjee

A new, non-perturbing optical measurement technique was developed to characterize medical ultrasound fields generated by High Intensity Focused Ultrasound (HIFU) transducers using a phenomenon called ‘acoustic streaming’. The acoustic streaming velocity generated by HIFU transducers was measured experimentally using Digital Particle Image Velocimetry (DPIV). The streaming velocity was then calculated numerically using the finite-element method. An optimization algorithm was developed to back-calculate acoustic power and intensity field by minimizing the difference between experimental and numerical streaming velocities. The intensity field and acoustic power calculated using this approach was validated with standard measurement techniques. Results showed that the inverse method was able to predict acoustic power and intensity fields within 10% of the actual value measured using standard techniques, at the low powers where standard methods can be safely applied. This technique is also potentially useful for evaluating medical ultrasound transducers at the higher power levels used in clinical practice.


2021 ◽  
Author(s):  
Elyahb Kwizera ◽  
Samantha Stewart ◽  
Md Musavvir Mahmud ◽  
Xiaoming He

Abstract Magnetic nanoparticles, especially superparamagnetic nanoparticles (SPIONs), have attracted tremendous attention for various biomedical applications. Facile synthesis and functionalization together with easy control of the size and shape of SPIONS to customize their unique properties, have made it possible to develop different types of SPIONs tailored for diverse functions/applications. More recently, considerable attention has been paid to the thermal effect of SPIONs for the treatment of diseases like cancer and for nanowarming of cryopreserved/banked cells, tissues, and organs. In this mini-review, recent advances on the magnetic heating effect of SPIONs for magnetothermal therapy and enhancement of cryopreservation of cells, tissues, and organs, are discussed, together with the non-magnetic heating effect (i.e., high Intensity focused ultrasound or HIFU-activated heating) of SPIONs for cancer therapy. Furthermore, challenges facing the use of magnetic nanoparticles in these biomedical applications are presented.


2006 ◽  
Vol 175 (4S) ◽  
pp. 86-86
Author(s):  
Makoto Sumitomo ◽  
Junichi Asakuma ◽  
Yasumasa Hanawa ◽  
Kazuhiko Nagakura ◽  
Masamichi Hayakawa

2005 ◽  
Vol 173 (4S) ◽  
pp. 379-380
Author(s):  
James E. Kennedy ◽  
Rowland O. Illing ◽  
Feng Wu ◽  
Gail R. ter Haar ◽  
Rachel R. Phillips ◽  
...  

Praxis ◽  
2016 ◽  
Vol 105 (16) ◽  
pp. 971-977
Author(s):  
Jan Brachlow ◽  
Martin Kälin ◽  
Marco Randazzo ◽  
Beat Förster ◽  
Hubert John

Zusammenfassung. Das Prostatakarzinom zeigt eine hohe Prävalenz und ist daher für die behandelnden Ärzte medizinisch, aber auch gesundheitspolitisch relevant. PSA-Screening senkt die karzinomspezifische Mortalität, ist jedoch aufgrund der hohen Prävalenz mit einer Überdiagnostik verbunden. Dies fordert im Gegenzug einen verantwortungsbewussten Umgang mit dem PSA-Test («smarter screening»). Durch die robotergestützte Prostatektomie steht eine Therapie mit geringer Morbidität zur Behandlung des lokalisierten Prostatakarzinoms zur Verfügung. Das fokale Behandlungskonzept der HIFU (high-intensity focused ultrasound) ist vielversprechend, jedoch noch klinisch experimentell und sollte im Rahmen von Studien angeboten werden. Die Behandlungsmöglichkeiten beim metastasierten Prostatakarzinom wurden entscheidend vervielfältigt. Chemotherapie und die sekundäre Hormontherapie werden voraussichtlich vermehrt in früheren Phasen der Krankheit eine Rolle spielen, wodurch die Therapie für den einzelnen Patienten immer komplexer wird und individuell angepasst werden muss.


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