Sub-transducer element spatial resolution ultrasound wavefront modification using passive twin-layer compensators

Jones, Michael W. M.; Shortell, Mathew P.; Wille, Marie‐Luise; Langton, Christian

doi:10.1016/j.apacoust.2017.10.013

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…From a perspective of potentially improving transcranial ultrasound imaging of the brain, the spatial resolution of the UPIC concept will depend upon the spatial resolutions of both the x-ray CT/MRI image data and that of the 3D-printer utilised. It has recently been demonstrated however that the UPIC concept has potential to provide superior ultrasound spatial resolution than provided by the current active approach, since the latter is primarily determined by the generally larger physical dimensions of the individual transducer elements [10].…”

Section: Discussionmentioning

confidence: 99%

“…The variables that determine the relative thickness of the two UPIC layers, z u1 (i) and z u2 (i), are their corresponding ultrasound velocities, v u1 and v u2 , relative to the sample material velocity (v s ), as illustrated in figure 3. The thickness of the two UPIC layers is equal if the expressions described in equation (10) are equal, as illustrated in figure 3(a).…”

Section: Scenario 2: Upic Materials Velocity Cannot Match Single Mate...mentioning

confidence: 99%

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Design of a 3D-printed ultrasound phase-interference compensator (UPIC) for various test sample environment scenarios

Langton¹

2019

Biomed. Phys. Eng. Express

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For ultrasound propagation through a complex tissue composite such as the skull, phase-interference induced wave degradation may occur due to anatomical variations in shape and composition. A fundamentally simplistic passive twin-layer ultrasound phase-interference compensator (UPIC) has recently been introduced, creating an environment of constant path-length (spatial criterion) and constant transit time (temporal criterion) throughout the test sample. The aim of this Note was to develop UPIC designs for various test sample environment scenarios ranging from both sample and UPIC created from the same 3D print material, a single sample material whose ultrasound velocity may not be matched by a 3D print material, to a multi-material compartment sample of complex shape. A simplified solution is presented where a rectangular analysis region may be defined. Future clinical development of the UPIC concept could utilise conventional DICOM-format x-ray CT and MR image data within the design process.

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Section: Discussionmentioning

confidence: 99%

Section: Scenario 2: Upic Materials Velocity Cannot Match Single Mate...mentioning

confidence: 99%

Design of a 3D-printed ultrasound phase-interference compensator (UPIC) for various test sample environment scenarios

Langton¹

2019

Biomed. Phys. Eng. Express

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“…A significant benefit of the ‘passive’ UPIC concept has recently been reported, demonstrating that ultrasound wavefront correction may be implemented for features that are smaller than the dimensions of the ultrasound transducer element(s), being the primary spatial resolution limiting factor for the current ‘active’ approach. 15 The passive UPIC concept offers a broad utility and the authors consider that it may be applied to single-element and linear-array ultrasound transducers of any frequency and dimension. Future work should determine UPIC’s performance associated with utility of a concave transducer and/or a curved sample surface such as the skull.…”

Section: Discussionmentioning

confidence: 99%

A 3D-printed passive ultrasound phase-interference compensator for reduced wave degradation in cancellous bone – an experimental study in replica models

2018

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The current ‘active’ solution to overcome the impediment of ultrasound wave degradation associated with transit-time variation in complex tissue structures, such as the skull, is to vary the transmission delay of ultrasound pulses from individual transducer elements. This article considers a novel ‘passive’ solution in which constant transit time is achieved by propagating through an additional material layer positioned between the ultrasound transducer and the test sample. To test the concept, replica models based on four cancellous bone natural tissue samples and their corresponding passive ultrasound phase-interference compensator were 3D-printed. Normalised broadband ultrasound attenuation was used as a quantitative measure of wave degradation, performed in transmission mode at a frequency of 1 MHz and yielding a reduction ranging from 57% to 74% when the ultrasound phase-interference compensator was incorporated. It is suggested that the passive compensator offers a broad utility and, hence, it may be applied to any ultrasound transducer, of any complexity (single element or array), frequency and dimension.

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“…With such acoustic lenses, we were able to focus through a set of 3 human skulls, and show comparable levels of precision and efficiency to those attained by conventional, multi-element systems. Nevertheless, such an approach suffers from an inherent limitation: each lens is designed for one given patient and one given target [54], meaning thatfor a given patient -a surgeon could neither change the target after the fabrication of the lens, nor treat a large area over the course of the surgery, without making a new lens. Correcting aberrations with an acoustic lens thus seemed like a less flexible method than using multi-element arrays, with which new phase sets can be electronically changed to aim at another target during treatment procedure [42].…”

Section: Introductionmentioning

confidence: 99%

Steering Capabilities of an Acoustic Lens for Transcranial Therapy: Numerical and Experimental Studies

Maimbourg

Houdouin

Thomas

et al. 2020

IEEE Trans. Biomed. Eng.

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Brain therapy by transcranial focused ultrasound needs to compensate for the delays locally induced by the skull. The patient-specific phase profile is currently generated by a multi-element array with a growing number of elements. We recently introduced a disruptive approach, consisting in using a single element transducer coupled to an acoustic lens of controlled thickness: by adjusting the local thickness of the lens, we were able to induce a phase difference which compensated that of the skull. Nevertheless, such an approach suffers from an apparent limitation: the lens is a priori designed for one specific target. In this paper, we demonstrate the possibility of taking advantage of the isoplanatic angle of the aberrating skull in order to steer the focus by mechanically moving the transducer/acoustic lens pair around its initial focusing position. This study, conducted on three human skull samples, confirms that tilting of the transducer with the lens restores a single focus at 914 kHz for a steering up to 11mm in the transverse direction, and 10mm in the longitudinal direction, around the initial focal region. Acoustic lens, transcranial ultrasound, therapeutic ultrasound

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Sub-transducer element spatial resolution ultrasound wavefront modification using passive twin-layer compensators

Cited by 3 publications

References 12 publications

Design of a 3D-printed ultrasound phase-interference compensator (UPIC) for various test sample environment scenarios

Design of a 3D-printed ultrasound phase-interference compensator (UPIC) for various test sample environment scenarios

A 3D-printed passive ultrasound phase-interference compensator for reduced wave degradation in cancellous bone – an experimental study in replica models

Steering Capabilities of an Acoustic Lens for Transcranial Therapy: Numerical and Experimental Studies

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