# Acoustic Cavitation Emission (ACE) Feedback Methods for Monitoring Histotripsy-Induced Tissue Fractionation In Situ

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2022 · $437,350

## Abstract

PROJECT SUMMARY/ABSTRACT
Histotripsy is a non-invasive, ultrasound based tissue ablation therapy which relies on the targeted generation
of cavitation events to mechanically fractionate and liquefy tissues. Quantifiable metrics by which the outcomes
of histotripsy therapy can be predicted as a function of therapy inputs are essential for ensuring reliable and
repeatable treatments, but do not currently exist. Although histotripsy-generated cavitation and liquefied tissue
can be detected in ultrasound imaging, there is no established metric to quantify induced tissue damage
versus cavitation exposure, which is known to vary with tissue properties, as well as among patients. With
clinical translation of histotripsy ongoing, it is critical to establish a dose metric by which cavitation energy
deposited to tissue during histotripsy can be monitored in situ to accurately predict therapy-generated damage.
In this project we propose to develop metrics for monitoring histotripsy-induced tissue fractionation by
monitoring the acoustic cavitation emission (ACE) signals generated by the cavitation events responsible for
therapy during histotripsy. The ACE signals encode information about the dynamics and energetics of the
cavitation events from which they are emitted, which depend on the mechanical properties/integrity of the
media in which the cavitation events were generated. As a result of exposure to cavitation during histotripsy,
targeted materials are mechanically disrupted which alters their mechanical properties, which can thus affect
the dynamics of the cavitation events. By developing methods to monitor features of the ACE signals the
mechanical state of the material in which the cavitation events were generated can be assessed in situ.
We will carry out experiments in which histotripsy will be used to generate cavitation in a range of tissue-
mimicking gel phantoms and tissues with a wide range of mechanical properties to ablate them. During
treatment, the ACE signals will be recorded. Following treatment, generated damage will be assessed optically
and histologically and the recorded ACE signals will be analyzed to identify the features in them that can be
correlated with the induced damage observed in images or histology. Establishing such correlations will allow
the ACE signals to be used as a metric for monitoring induced material fractionation during histotripsy
treatment. To enable robust monitoring, the ACE signals can be monitored using the transmitting elements of
the array as receivers in addition to hydrophones. This will ensure that an acoustically accessible path to the
generated cavitation events will always be available to provide accurate monitoring of the ACE signals, but will
require the development of sophisticated real-time algorithms to process owing to the large amount of data that
will be generated. Once correlations between features of the ACE signals and induced damage in gel
phantoms and ex vivo tissues have been identif...

## Key facts

- **NIH application ID:** 10415606
- **Project number:** 1R01EB032772-01
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Jonathan Robert Sukovich
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $437,350
- **Award type:** 1
- **Project period:** 2022-08-01 → 2026-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10415606

## Citation

> US National Institutes of Health, RePORTER application 10415606, Acoustic Cavitation Emission (ACE) Feedback Methods for Monitoring Histotripsy-Induced Tissue Fractionation In Situ (1R01EB032772-01). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10415606. Licensed CC0.

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