scholarly journals Effect of split-aperture transmission on cavitation bubbles and ultrasonic heating outside focal region in high-intensity focused ultrasound exposure

2020 ◽  
Vol 41 (6) ◽  
pp. 909-912
Author(s):  
Yui Tanaka ◽  
Shin-ichiro Umemura ◽  
Shin Yoshizawa
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Focal Region ◽  
Ultrasound Exposure ◽  
Cavitation Bubbles

scholarly journals Segmentation Method for Magnetic Resonance-Guided High-Intensity Focused Ultrasound Therapy Planning

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
A. Vargas-Olivares ◽  
O. Navarro-Hinojosa ◽  
M. Maqueo-Vicencio ◽  
L. Curiel ◽  
M. Alencastre-Miranda ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Segmentation Algorithm ◽  
Focal Region ◽  
Therapy Planning ◽  
Mr Images ◽  
Monitoring Method ◽  
Data Set

High-intensity focused ultrasound (HIFU) is a minimally invasive therapy modality in which ultrasound beams are concentrated at a focal region, producing a rise of temperature and selective ablation within the focal volume and leaving surrounding tissues intact. HIFU has been proposed for the safe ablation of both malignant and benign tissues and as an agent for drug delivery. Magnetic resonance imaging (MRI) has been proposed as guidance and monitoring method for the therapy. The identification of regions of interest is a crucial procedure in HIFU therapy planning. This procedure is performed in the MR images. The purpose of the present research work is to implement a time-efficient and functional segmentation scheme, based on the watershed segmentation algorithm, for the MR images used for the HIFU therapy planning. The achievement of a segmentation process with functional results is feasible, but preliminary image processing steps are required in order to define the markers for the segmentation algorithm. Moreover, the segmentation scheme is applied in parallel to an MR image data set through the use of a thread pool, achieving a near real-time execution and making a contribution to solve the time-consuming problem of the HIFU therapy planning.

High-Intensity Focused Ultrasound Scattering at Mammal Vertebrae

2020 ◽  
Author(s):  
David Sanford ◽  
Christoph Schaal
Keyword(s):  
High Intensity ◽  
Laboratory Experiments ◽  
Energy Deposition ◽  
Focused Ultrasound ◽  
Complex Geometry ◽  
Ex Vivo ◽  
Pulsed Laser ◽  
High Intensity Focused Ultrasound ◽  
Focal Region ◽  
Homogeneous Media

Abstract High-intensity focused ultrasound (HIFU) is used clinically to heat cells therapeutically or to destroy them through heat or cavitation. In homogeneous media, the highest wave amplitudes occur at a predictable focal region. However, HIFU is generally not used in the proximity of bones due to wave absorption and scattering. Ultrasound is passed through the skull in some clinical trials, but the complex geometry of the spine poses a greater targeting challenge and currently prohibits therapeutic ultrasound treatments near the vertebral column. This paper presents a comprehensive experimental study involving shadowgraphy and hydrophone measurements to determine the spatial distribution of pressure amplitudes from induced HIFU waves near vertebrae. First, a bone-like composite plate that is partially obstructing the induced waves is shown to break the conical HIFU form into two regions. Wave images are captured using pulsed laser shadowgraphy, and hydrophone measurements over the same region are compared to the shadowgraphy intensity plots to validate the procedure. Next, shadowgraphy is performed for an individual, clean, ex-vivo feline vertebra. The results indicate that shadowgraphy can be used to determine energy deposition patterns and to determine heating at a specific location. The latter is confirmed through additional temperature measurements. Overall, these laboratory experiments may help determine the efficacy of warming specific nerve cells within mammal vertebrae without causing damage to adjacent tissue.

scholarly journals Development of a High-intensity Focused Ultrasound Exposure Device for Reducing Skin Burn Risk

2020 ◽  
Vol 32 (1) ◽  
pp. 1-9
Author(s):  
Shogo NISHII ◽  
Kohei SEO ◽  
Aleksander Tatsuya IZDEBSKI ◽  
Miki KUSHIMA ◽  
Ryo TAKAGI ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Skin Burn ◽  
Ultrasound Exposure

Characterization of the Harmonic Generation from Cavitating Bubbles Interacted with a Diagnostic Ultrasound in the Focal Region of High Intensity Focused Ultrasound

2006 ◽  
Vol 321-323 ◽  
pp. 1123-1128 ◽  
Author(s):  
Min Joo Choi ◽  
Gwan Suk Kang ◽  
Dong Guk Paeng ◽  
Sung Min Rhim ◽  
Moo Ho Bae ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Harmonic Generation ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Harmonic Component ◽  
Diagnostic Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Focal Region ◽  
Current Harmonic

Harmonic image (HI) has been proposed to be promising for visualizing lesions produced by therapeutic high intensity focused ultrasound (HIFU). The study characterizes harmonics generated from the bubble cavitating at the focal region of a therapeutic HIFU field in response to a typical diagnostic ultrasound. Based on Gilmore model, it was simulated the nonlinear dynamics of the bubble being resonated at 1 MHz of the therapeutic ultrasound and driven by a typical 3.5 MHz diagnostic pulse. It was shown that harmonic generation increased with MI in a sigmoid pattern where the rapid and transient changes occurred between 0.5 and 2 in MI. For whole ranges of MI (less than 8), the sub-harmonic was the predominant in magnitudes over other harmonic bands. This reveals that, if HI is considered for improving the detection of focal legion highly cavitating caused by a HIFU field, the sub-harmonic component would be a preferred parameter rather than the 2nd harmonic which has been commonly used in current harmonic imaging.

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