Endocavity Histotripsy for Efficient Tissue Ablation–Transducer Design and Characterization

Stocker, Greyson; Zhang, Man; Xu, Zhen; Hall, Timothy L.

doi:10.1109/tuffc.2021.3055138

Cited by 7 publications

(3 citation statements)

References 62 publications

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“…The transducers have a 10 mm outer diameter with a 4 mm hole in the center for an imaging endoscope. This is considerably smaller than the next smallest reported histotripsy device at 35 mm diameter with no image guidance [ 24 ]. Our devices operate at a higher acoustic frequency (~6 MHz) than previous designs, which should result in a tighter focus and therefore smaller ablation volumes than previously possible.…”

Section: Introductionmentioning

confidence: 95%

Endoscopic Coregistered Ultrasound Imaging and Precision Histotripsy: Initial In Vivo Evaluation

et al. 2022

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Objective. Initial performance evaluation of a system for simultaneous high-resolution ultrasound imaging and focused mechanical submillimeter histotripsy ablation in rat brains. Impact Statement. This study used a novel combination of high-resolution imaging and histotripsy in an endoscopic form. This would provide neurosurgeons with unprecedented accuracy in targeting and executing nonthermal ablations in minimally invasive surgeries. Introduction. Histotripsy is a safe and effective nonthermal focused ablation technique. However, neurosurgical applications, such as brain tumor ablation, are difficult due to the presence of the skull. Current devices are too large to use in the minimally invasive approaches surgeons prefer. We have developed a combined imaging and histotripsy endoscope to provide neurosurgeons with a new tool for this application. Methods. The histotripsy component had a 10 mm diameter, operating at 6.3 MHz. Affixed within a cutout hole in its center was a 30 MHz ultrasound imaging array. This coregistered pair was used to ablate brain tissue of anesthetized rats while imaging. Histological sections were examined, and qualitative descriptions of ablations and basic shape descriptive statistics were generated. Results. Complete ablations with submillimeter area were produced in seconds, including with a moving device. Ablation progress could be monitored in real time using power Doppler imaging, and B-mode was effective for monitoring post-ablation bleeding. Collateral damage was minimal, with a 100 μm maximum distance of cellular damage from the ablation margin. Conclusion. The results demonstrate a promising hardware suite to enable precision ablations in endoscopic procedures or fundamental preclinical research in histotripsy, neuroscience, and cancer.

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Section: Introductionmentioning

confidence: 95%

Endoscopic Coregistered Ultrasound Imaging and Precision Histotripsy: Initial In Vivo Evaluation

et al. 2022

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“…Histotripsy is a nonionizing, noninvasive, and nonthermal tissue focal tumor treatment that creates mechanical destruction via short duration (< 20 µs), high‐pressure (> 15 MPa) focused ultrasound pulses 1 . Multi‐element curvilinear histotripsy therapy transducers transmit ultrasound pulses into target tissue through a coupling medium (degassed water) 2 . Cavitation is the rapid expansion and collapse of tissue intrinsic gas microbubbles under high negative pressures, a threshold phenomenon that occurs at the therapeutic ultrasound beam focus 3 .…”

Section: Introductionmentioning

confidence: 99%

“… 1 Multi‐element curvilinear histotripsy therapy transducers transmit ultrasound pulses into target tissue through a coupling medium (degassed water). 2 Cavitation is the rapid expansion and collapse of tissue intrinsic gas microbubbles under high negative pressures, a threshold phenomenon that occurs at the therapeutic ultrasound beam focus. 3 Cellular structures turn into an acellular homogenate, as they are mechanically sheared within cavitation bubble clouds.…”

Section: Introductionmentioning

confidence: 99%

A target containing phantom for accuracy assessment of cone‐beam CT‐guided histotripsy

Kutlu,

Minesinger,

Laeseke

et al. 2024

J Applied Clin Med Phys

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PurposeHistotripsy is a nonionizing, noninvasive, and nonthermal focal tumor therapy. Cone‐beam computed tomography (CBCT) guidance was developed for targeting tumors not visible on ultrasound. This approach assumes cavitation is formed at the geometrical focal point of the therapy transducer. In practice, the exact location might vary slightly between transducers. In this study, we present a phantom with an embedded target to evaluate CBCT‐guided histotripsy accuracy and assess the completeness of treatments.MethodsSpherical (2.8 cm) targets with alternating layers of agar and radiopaque barium were embedded in larger phantoms with similar layers. The layer geometry was designed so that targets were visible on pre‐treatment CBCT scans. The actual histotripsy treatment zone was visualized via the mixing of adjacent barium and agar layers in post‐treatment CBCT images. CBCT‐guided histotripsy treatments of the targets were performed in six phantoms. Offsets between planned and actual treatment zones were measured and used for calibration refinement. To measure targeting accuracy after calibration refinement, six additional phantoms were treated. In a separate investigation, two groups (N = 3) of phantoms were treated to assess visualization of incomplete treatments (“undertreatment” group: 2 cm treatment within 2.8 cm tumor, “mistarget” group: 2.8 cm treatment intentionally shifted laterally). Treatment zones were segmented (3D Slicer 5.0.3), and the centroid distance between the prescribed target and actual treatment zones was quantified.ResultsIn the calibration refinement group, a 2 mm offset in the direction of ultrasound propagation (Z) was measured. After calibration refinement, the centroid‐to‐centroid distance between prescribed and actual treatment volumes was 0.5 ± 0.2 mm. Average difference between the prescribed and measured treatment sizes in the incomplete treatment groups was 0.5 ± 0.7 mm. In the mistarget group, the distance between prescribed and measured shifts was 0.2 ± 0.1 mm.ConclusionThe proposed prototype phantom allowed for accurate measurement of treatment size and location, and the CBCT visible target provided a simple way to detect misalignments for preliminary quality assurance of CBCT‐guided histotripsy.

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An 8 mm endoscopic histotripsy array with integrated high-resolution ultrasound imaging

Mallay,

Landry,

Brown

2024

Ultrasonics

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Endocavity Histotripsy for Efficient Tissue Ablation–Transducer Design and Characterization

Cited by 7 publications

References 62 publications

Endoscopic Coregistered Ultrasound Imaging and Precision Histotripsy: Initial In Vivo Evaluation

Endoscopic Coregistered Ultrasound Imaging and Precision Histotripsy: Initial In Vivo Evaluation

A target containing phantom for accuracy assessment of cone‐beam CT‐guided histotripsy

An 8 mm endoscopic histotripsy array with integrated high-resolution ultrasound imaging

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