A 256-element ultrasonic phased array system for the treatment of large volumes of deep seated tissue

Daum, D.R.; Hynynen, Kullervo

doi:10.1109/58.796130

Cited by 118 publications

(84 citation statements)

References 41 publications

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“…Tradeoffs between these parameters, the cost of manufacturing and control electronics, and the difficulty of fabrication constrain HIFU phased array transducer design. Current HIFU transducer configurations vary in the number of elements (256-element, 5,6 512-element, 7,8 and 1000 element systems 9 ), frequency of operation [670 kHz to 4 MHz 10 ] and the interelement spacing (random, semirandom, and uniform); each configuration represents a tradeoff between the transducer complexity and the desired beam characteristics for a specific clinical application.…”

Section: Introductionmentioning

confidence: 99%

The effect of electronically steering a phased array ultrasound transducer on near‐field tissue heating

et al. 2011

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Purpose: This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. Methods: The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes' bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Results: Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Conclusions: Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will help to ensure patient safety during an MRgHIFU treatment.

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Section: Introductionmentioning

confidence: 99%

The effect of electronically steering a phased array ultrasound transducer on near‐field tissue heating

et al. 2011

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“…The focused ultrasound beam can be achieved geometrically with a curved piezoelectric bowl or acoustic lens or electrically with a multi-element phased array. The combination of both approaches is also common, with many arrays with overall concave geometry for focusing used in research and clinical practice [4][5][6]. This is because concave arrays can provide higher focal intensities than planar arrays with similar overall dimensions.…”

Section: Introductionmentioning

confidence: 99%

Implementation of a PMN-PT piezocrystal-based focused array with geodesic faceted structure

Qiu

Démoré

et al. 2016

Ultrasonics

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Abstract-The higher performance of relaxor-based piezocrystals compared with piezoceramics is now well established, notably including improved gain-bandwidth product, and these materials have been adopted widely for biomedical ultrasound imaging. However, their use in other applications, for example as a source of focused ultrasound for targeted drug delivery, is hindered in several ways. One of the issues, which we consider here, is in shaping the material into the spherical geometries used widely in focused ultrasound.Unlike isotropic unpoled piezoceramics that can be shaped into a monolithic bowl then poled through the thickness, the anisotropic structure of piezocrystals make it impossible to machine the bulk crystalline material into a bowl without sacrificing performance. Instead, we report a novel faceted array, inspired by the geodesic dome structure in architecture, which utilizes flat piezocrystal material and maximizes fill factor.Aided by 3D printing, a prototype with f#  1.2, containing 96 individually addressable elements was manufactured using 1-3 connectivity PMN-PT piezocrystal -epoxy composite. The fabrication process is presented and the array was connected to a 32-channel controller to shape and steer the beam for preliminary performance demonstration. At an operating frequency of 1 MHz, a focusing gain around 30 was achieved and the side lobe intensities were all at levels below -12 dB compared to main beam. We conclude that, by taking advantage of contemporary fabrication techniques and driving instrumentation, the geodesic array configuration is suitable for focused ultrasound devices made with piezocrystal.

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“…Several researches have proposed the use of spherical shell phased arrays in which elements are distributed randomly or in a specific order, this will allow the combination of two types of focusing (i.e. electronic, and geometric) (N'Djin et al, 2008;Gavrilov & Hand, 2000a;Daum & Hynynen, 1999;Goss et al, 1996;Ebbini & Cain, 1991).…”

Section: Related Workmentioning

confidence: 99%

A Dual Curvature Shell Phased Array Simulation for Delivery of High Intensity Focused Ultrasound

Al-smadi¹,

Al-Hazaimeh²,

Alhindawi³

et al. 2014

CIS

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This paper describes the design and the evaluation for a simulation model for the dual curvature ultrasound phased array. The main goal of this simulation is to enhance the usage of dual curvature ultrasound phased array in ultrasound therapy with three dimensional phased arrays. In our simulation, focusing the total acoustic power within a specific phase can be controlled dynamically for each individual element. Moreover, a 45 steering angle in x-z plan was achieved. A software based simulation using MATLAB was performed to verify focusing and steering capability of the proposed array for three different types of arrays. The results showed a safety improvement for both of focusing and steering angle for the dual curvature phased array compared with planner and spherical types. Furthermore, the phased arrays have three different shapes; the planner phased array which was used as reference, spherical, and dual curvature shapes. Based on the conducted experiments, the results showed that the spherical and dual curvature shapes have a better focusing and steering angle generally compared with the reference phased array. As well as, the dual curvature phased array has additional capability of focusing outside the geometric volume, without any grating lobe effects.

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A 256-element ultrasonic phased array system for the treatment of large volumes of deep seated tissue

Cited by 118 publications

References 41 publications

The effect of electronically steering a phased array ultrasound transducer on near‐field tissue heating

The effect of electronically steering a phased array ultrasound transducer on near‐field tissue heating

Implementation of a PMN-PT piezocrystal-based focused array with geodesic faceted structure

A Dual Curvature Shell Phased Array Simulation for Delivery of High Intensity Focused Ultrasound

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