scholarly journals Ultrasound Axicon: Systematic Approach to Optimize Focusing Resolution through Human Skull Bone

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3433 ◽  
Author(s):  
Fabián Acquaticci ◽  
Sergio E. Lew ◽  
Sergio N. Gwirc
Keyword(s):  
Systematic Approach ◽  
Focused Ultrasound ◽  
High Spatial Resolution ◽  
Skull Bone ◽  
Acoustic Beam ◽  
Human Skull ◽  
Materials Properties ◽  
Focusing Distance ◽  
Ultrasound Applications ◽  
Type Transducer

The use of axicon lenses is useful in many high-resolution-focused ultrasound applications, such as mapping, detection, and have recently been extended to ultrasonic brain therapies. However, in order to achieve high spatial resolution with an axicon lens, it is necessary to adjust the separation, called stand-off (δ), between a conventional transducer and the lens attached to it. Comprehensive ultrasound simulations, using the open-source k-Wave toolbox, were performed for an axicon lens attached to a piezo-disc type transducer with a radius of 14 mm, and a frequency of about 0.5 MHz, that is within the range of optimal frequencies for transcranial transmission. The materials properties were measured, and the lens geometry was modelled. Hydrophone measurements were performed through a human skull phantom. We obtained an initial easygoing design model for the lens angle and optimal stand-off using relatively simple formulas. The skull is not an obstacle for focusing of ultrasound with optimized axicon lenses that achieve an identical resolution to spherical transducers, but with the advantage that the focusing distance is shortened. An adequate stand-off improves the lateral resolution of the acoustic beam by approximately 50%. The approach proposed provides an effective way of designing polydimethylsiloxane (PDMS)-based axicon lenses equipped transducers.

scholarly journals How the Future of Sonography May Change the Outlook for Patients With Osteosarcoma

2018 ◽  
Vol 34 (5) ◽  
pp. 368-373
Author(s):  
Stacey Hoya ◽  
Linda Wogeman ◽  
Sara Allstadt ◽  
Glen King
Keyword(s):  
Quality Of Life ◽  
Focused Ultrasound ◽  
Treatment Plan ◽  
Treatment Options ◽  
Therapeutic Ultrasound ◽  
Bone Lesions ◽  
Pulsed Ultrasound ◽  
Low Intensity Pulsed Ultrasound ◽  
Ultrasound Applications

Sonography currently provides a variety of tools to support the diagnosis and treatment of osteosarcoma and, with the development of therapeutic ultrasound practices, could play an increasingly important role in the treatment of future patients with osteosarcoma. Currently, computed tomography, magnetic resonance imaging, and radiography are the preferred imaging modalities for bone lesions; treatment options for osteosarcoma primarily include highly toxic chemotherapies and surgeries that often result in limb loss. Unfortunately, osteosarcoma is rarely eliminated, and despite this, patients lose their lives after having a significant reduction in quality of life. Evolving therapies such as high-frequency focused ultrasound, ultrasound-enhanced delivery of photodynamic therapy, and low-intensity pulsed ultrasound may offer these patients an improved quality of life while also increasing efficacy of treatment. This canine case study illustrates the various ways in which sonography might contribute to the treatment plan for patients with osteosarcoma. It may provide a comparable model for the reimagining of treatment for future patients with osteosarcoma using a suite of therapeutic ultrasound applications.

Magnetic Resonance Imaging–guided High-intensity Focused Ultrasound Applications in Pediatrics

2018 ◽  
Vol 27 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Karun V. Sharma ◽  
Pavel S. Yarmolenko ◽  
Avinash Eranki ◽  
Ari Partanen ◽  
Haydar Celik ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Resonance Imaging ◽  
Ultrasound Applications

Dynamics of Single Cavitation Bubble Oscillation Inside an Elastic Tube

2007 ◽  
Author(s):  
Georgy N. Sankin ◽  
Pei Zhong
Keyword(s):  
Blood Vessels ◽  
Focused Ultrasound ◽  
Bubble Dynamics ◽  
Tissue Injury ◽  
Elastic Tube ◽  
Ultrasound Contrast Agents ◽  
High Intensity Focused Ultrasound ◽  
Rigid Boundary ◽  
Bubble Oscillation ◽  
Ultrasound Applications

Understanding the dynamics of bubble oscillation in tissue-constrained media such as within blood vessels is important for many current and potential therapeutic ultrasound applications. Cavitation is a primary mechanism responsible for vessel rupture and tissue injury in shock wave lithotripsy [1]. In sonoporation cavitation can be used to increase permeability of biological membranes. Particularly, ultrasound contrast agents are widely used for imaging of blood vessels and for enhancement of ultrasound-mediated gene delivery [2]. Modeling of non-linear oscillations of bubbles in acrylic capillaries in a high-intensity focused ultrasound field revealed a clear dependence of bubble displacement and fragmentation on tube diameter [3]. However, the effect of elastic boundary on bubble dynamics may differ significantly from that of a rigid boundary [4, 5]. In this study, experimental investigation of the dynamics of bubble oscillation in an elastic tube was performed and preliminary results from tubes of different inner diameters are presented.

Novel bilayer aberration-inducing gel phantom for high-intensity focused ultrasound applications

2019 ◽  
Vol 146 (4) ◽  
pp. 3072-3072
Author(s):  
Alex T. Peek ◽  
Tatiana D. Khokhlova ◽  
Pavel B. Rosnitskiy ◽  
Petr V. Yuldashev ◽  
Christopher R. Bawiec ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Ultrasound Applications ◽  
Gel Phantom

scholarly journals An Investigation on the Correlation between the Mechanical Properties of Human Skull Bone, Its Geometry, Microarchitectural Properties, and Water Content

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jik Hang Clifford Lee ◽  
Benjamin Ondruschka ◽  
Lisa Falland-Cheung ◽  
Mario Scholze ◽  
Niels Hammer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Soft Tissues ◽  
Mechanical Load ◽  
Bone Microarchitecture ◽  
Mechanical Analysis ◽  
Assessment Criteria ◽  
Skull Bone ◽  
Human Skull ◽  
Detailed Imaging

With increasingly detailed imaging and mechanical analysis, modalities need arises to update methodology and assessment criteria for skull bone analysis to understand how bone microarchitecture and the presence of attached tissues may affect the response to mechanical load. The main aim was to analyze the effect of macroscopic and microstructural features, as well as periosteal attachment, on the mechanical properties of human skull bone. Fifty-six skull specimens from ethanol-phenoxyethanol-embalmed cadavers were prepared from two human cadavers. Assuming symmetry of the skull, all samples from one-half each were stripped of periosteum and dura mater, while the soft tissues were kept intact on the remaining samples on the contralateral side. The specimens were analyzed using microcomputed tomography to assess trabecular connectivity density, total surface area, and volume ratio. The specimens were loaded under three-point bend tests until fracture with optical co-registration. The bone fragments were then lyophilized to measure their water content. With increasingly detailed imaging and mechanical analysis modalities, there is a need to update methodology and assessment criteria for skull bone analysis to understand how the bone microarchitecture and the presence of attached tissues may affect the response to mechanical load. The mechanical properties were negatively correlated to bone thickness and water content. Conversely, most microarchitectural features did not influence either mechanical parameter. The correlation between mechanical response data and morphologic properties remains similar between the results of embalmed tissues presented here and fresh osseous tissue from literature data. The findings presented here add to the existing methodology to assess human skull for research purposes. The interaction between most microarchitectural features in ethanol-phenoxyethanol-embalmed embalmed skull samples and bending stress appear to be minute.

Experimental study of the bone behaviour of the human skull bone for the development of a physical head model

2007 ◽  
Vol 12 (2) ◽  
pp. 101-108 ◽  
Author(s):  
R Delille ◽  
D Lesueur ◽  
P Potier ◽  
P Drazetic ◽  
E Markiewicz
Keyword(s):  
Experimental Study ◽  
Head Model ◽  
Skull Bone ◽  
Human Skull

scholarly journals Longitudinal and shear mode ultrasound propagation in human skull bone

2006 ◽  
Vol 32 (7) ◽  
pp. 1085-1096 ◽  
Author(s):  
P.J. White ◽  
G.T. Clement ◽  
K. Hynynen
Keyword(s):  
Shear Mode ◽  
Skull Bone ◽  
Human Skull ◽  
Ultrasound Propagation
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