Minimally invasive therapeutic ultrasound: Ultrasound-guided ultrasound ablation in neuro-oncology

Micah Belzberg; Smruti Mahapatra; Alexander Perdomo-Pantoja; Francisco Chavez; Kyle Morrison; Kah Timothy Xiong; Nao J Gamo; Stephen Restaino; Nitish Thakor; Youseph Yazdi; Rajiv Iyer; Betty Tyler; Nicholas Theodore; Mark G Luciano; Henry Brem; Mari Groves; Alan R Cohen; Amir Manbachi

doi:10.1016/j.ultras.2020.106210

Minimally invasive therapeutic ultrasound: Ultrasound-guided ultrasound ablation in neuro-oncology

Ultrasonics. 2020 Dec:108:106210. doi: 10.1016/j.ultras.2020.106210. Epub 2020 Jun 20.

Authors

Micah Belzberg¹, Smruti Mahapatra², Alexander Perdomo-Pantoja³, Francisco Chavez⁴, Kyle Morrison⁴, Kah Timothy Xiong⁴, Nao J Gamo⁵, Stephen Restaino⁵, Nitish Thakor², Youseph Yazdi², Rajiv Iyer³, Betty Tyler³, Nicholas Theodore⁶, Mark G Luciano⁶, Henry Brem⁶, Mari Groves³, Alan R Cohen³, Amir Manbachi⁷

Affiliations

¹ Department of Dermatology, Johns Hopkins University, Baltimore, MD, USA.
² Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
³ Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA.
⁴ Sonic Concepts, Inc., Bothell, WA, USA.
⁵ Maryland Development Center, Baltimore, MD, USA.
⁶ Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA.
⁷ Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA. Electronic address: Amir.Manbachi@jhu.edu.

Abstract

Introduction: To improve patient outcomes (eg, reducing blood loss and infection), practitioners have gravitated toward noninvasive and minimally invasive surgeries (MIS), which demand specialized toolkits. Focused ultrasound, for example, facilitates thermal ablation from a distance, thereby reducing injury to surrounding tissue. Focused ultrasound can often be performed noninvasively; however, it is more difficult to carry out in neuro-oncological tumors, as ultrasound is dramatically attenuated while propagating through the skull. This shortcoming has prompted exploration of MIS options for intracranial placement of focused ultrasound probes, such as within the BrainPath™ (NICO Corporation, Indianapolis, IN). Herein, we present the design, development, and in vitro testing of an image-guided, focused ultrasound prototype designed for use in MIS procedures. This probe can ablate neuro-oncological lesions despite its small size.

Materials & methods: Preliminary prototypes were iteratively designed, built, and tested. The final prototype consisted of three 8-mm-diameter therapeutic elements guided by an imaging probe. Probe functionality was validated on a series of tissue-mimicking phantoms.

Results: Lesions were created in tissue-mimicking phantoms with average dimensions of 2.5 × 1.2 × 6.5 mm and 3.4 × 3.25 × 9.36 mm after 10- and 30-second sonification, respectively. 30 s sonification with 118 W power at 50% duty cycle generated a peak temperature of 68 °C. Each ablation was visualized in real time by the built-in imaging probe.

Conclusion: We developed and validated an ultrasound-guided focused ultrasound probe for use in MIS procedures. The dimensional constraints of the prototype were designed to reflect those of BrainPath trocars, which are MIS tools used to create atraumatic access to deep-seated brain pathologies.

Keywords: Ablation; Acoustic probes; Engineering design; Focused ultrasound; Minimally invasive surgery; Neurosurgery; Oncology; Therapeutic ultrasound; Transducer design; Ultrasound.

Publication types

Validation Study

MeSH terms

Brain Diseases / surgery*
Equipment Design
High-Intensity Focused Ultrasound Ablation / instrumentation*
Humans
Phantoms, Imaging
Transducers*
Ultrasonography, Interventional*

Grants and funding

KL2 TR003099/TR/NCATS NIH HHS/United States