Steering single-element lead zirconate titanate ultrasound transducers using biaxial driving

Delgado, Sagid; Curiel, Laura; Pichardo, Samuel

doi:10.1016/j.ultras.2020.106241

Cited by 6 publications

(2 citation statements)

References 28 publications

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“…The ultrasound waves are generated by the mechanical deformation of the piezoceramic under the effect of the inverse piezoelectric effect. A different ultrasound generation by the piezoceramic can be obtained by applying 'biaxial' driving (Cole et al 2014, Pichardo et al 2015, Delgado et al 2021. This approach involves two sets of electrodes to produce two orthogonal electric fields: the first set attaches to faces perpendicular to the poling axis (P-electrodes), and the second set attaches to faces parallel or lateral to the poling axis (lateral or L-electrodes).…”

Section: Introductionmentioning

confidence: 99%

“…The interaction between the orthogonal electric fields produces a combination of extensional and shear deformations as a function of the phase difference between them, translating into the ability to dynamically steer the beam in prismatic-shaped piezoceramics (Delgado et al 2021) (figure 1(A)). The intensity of the lateral electric field further helps to control steering levels, where a steering angle of up to 30°has been demonstrated in prismatic-shaped transducers (Delgado et al 2021). This differs from traditional steering, accomplished with phased arrays by applying delays to elements based on time-of-flight to modify where the beam will converge (Hynynen and Jones 2016).…”

Section: Introductionmentioning

confidence: 99%

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Biaxial ultrasound driving technique for small animal blood–brain barrier opening

Pellow,

Li,

Delgado

et al. 2023

Phys. Med. Biol.

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Biaxial driving can more efficiently convert electrical power to forward acoustic power in piezoelectric materials, and the interaction between the orthogonal electric fields can produce a combination of extensional and shear deformations as a function of the phase difference between them to allow dynamic steering of the beam with a single-element. In this study, we demonstrate for the first time the application of a single-element biaxially driven ring transducer in vivo for blood–brain barrier opening in mice, and compare it to that achieved with a conventional single-element highly focused (F# = 0.7) spherical transducer operating at a similar frequency. Transcranial focused ultrasound (0.45 MPa, 10 ms pulse length, 1 Hz repetition frequency, 30 s duration) was applied bilaterally to mice with a 40 μl/kg bolus of DefinityTM microbubbles, employing either a single-element biaxial ring (1.482 MHz, 10 mm inner diameter, 13.75 mm outer diameter) or spherical (1.5 MHz, 35 mm diameter, F# = 0.7; RK50, FUS Instruments) transducer on each side. Follow-up MRI scans (T1 pre- and post- 0.2 mmol/kg Gd injection, T2) were acquired to assess blood–brain barrier opening volume and potential damage. Compared to blood–brain barrier opening achieved with a conventional single-element spherical focused transducer, the opening volume achieved with a single-element biaxial ring transducer was 35% smaller (p = 0.002) with a device of a ring diameter of 40% the aperture size. Axial refocusing was further demonstrated with the single-element biaxial ring transducer, yielding a 1.63 mm deeper, five-fold larger opening volume (p = 0.048) relative to its small-focus mode. The biaxial ring transducer achieved a more localized opening compared to the spherical focused transducer under the same parameters, and further enabled dynamic axial refocusing with a single-element transducer with a smaller fabrication footprint.

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Section: Introductionmentioning

confidence: 99%