# Transcranial focused ultrasound systems (Exablate Neuro, SonoCloud)

Source: https://onco.cc/technologies/transcranial-focused-ultrasound-systems/  
OnCo record `transcranial-focused-ultrasound-systems` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A helmet of a thousand ultrasound emitters, or a small implant under the skull, that sends sound through the bone into the brain. Approved for tremor, it is being tested in brain tumours to open the brain's protective barrier for a few hours so that drugs can reach the tumour.

## Summary

Insightec's Exablate Neuro places the patient's shaved head, fixed in a stereotactic frame, inside a hemispherical transducer of over a thousand elements filled with cooled degassed water, inside an MRI scanner. CT of the skull lets the software correct each element's phase for the bone it passes through, so the beams converge on a target a few millimetres across. At high intensity the system ablates tissue, the basis of its approval for essential tremor in 2016; at low intensity with intravenous microbubbles it makes the vessel walls of the blood-brain barrier temporarily permeable, the mode being trialled in glioblastoma with temozolomide or chemotherapy, in brain metastases with antibodies, and for releasing tumour DNA into the blood as a liquid biopsy. Sunnybrook in Toronto performed the first such openings in brain tumour patients and continues the trials. Carthera's SonoCloud takes a different route: a small unfocused ultrasound implant fixed in the skull window left after tumour surgery, activated at each chemotherapy visit to open the barrier across a wide region in a few minutes without MRI. NaviFUS in Taiwan uses a neuronavigated headset.

Both approaches are still investigational for cancer. The helmet demands MRI time, head shaving and a frame, and reaches only a limited volume per session; the implant covers more brain but needs surgery to place and cannot be steered. Whether opening the barrier improves survival is the question the current trials are asking.

## Fields

- Kind: Technology
- Status: phase-2
- Last checked: 2026-09-17
- Tags: machines-wave2
- Principle: Phase-corrected ultrasound from a hemispherical array, or an implanted transducer, passes through the skull; at low intensity with circulating microbubbles it transiently opens the blood-brain barrier, and at high intensity it thermally ablates a focal target under MRI thermometry.
- Since: 2016
- Strengths: Non-invasive opening of the blood-brain barrier; MRI-guided targeting and temperature monitoring; Approved platform with a safety record from tremor treatment
- Limitations: Small treated volume per helmet session; Implant covers more brain but needs surgery; Survival benefit in tumours unproven

## Sources

- Mainprize et al., Blood-brain barrier opening in primary brain tumours with non-invasive MR-guided focused ultrasound (Scientific Reports 2019): https://doi.org/10.1038/s41598-018-36340-0
- Idbaih et al., Safety and feasibility of repeated and transient blood-brain barrier disruption by pulsed ultrasound in patients with recurrent glioblastoma (Clinical Cancer Research 2019): https://doi.org/10.1158/1078-0432.CCR-18-3643
- Insightec: Exablate Neuro: https://insightec.com/

## Connected records

- technologies: [Focused ultrasound & histotripsy](https://onco.cc/technologies/hifu-histotripsy/), [Focused-ultrasound blood-brain barrier opening](https://onco.cc/technologies/bbb-focused-ultrasound/), [Laser interstitial thermal therapy systems (NeuroBlate, Visualase)](https://onco.cc/technologies/litt-systems/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MRI](https://onco.cc/technologies/mri/), [Sonodynamic therapy](https://onco.cc/technologies/sonodynamic-therapy/), [Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/), [Tumour treating fields (TTFields)](https://onco.cc/technologies/ttfields/)
- cancers: [Brain and spinal cord tumours (all types)](https://onco.cc/cancers/brain-tumours/), [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [Paediatric low-grade glioma](https://onco.cc/cancers/paediatric-low-grade-glioma/)
- terms: [Brain metastases (intracranial disease)](https://onco.cc/terms/brain-metastases/)
- fronts: [Devices & Physical Therapies](https://onco.cc/fronts/devices/), [Surgery & Interventional](https://onco.cc/fronts/surgery/)
- drugs: [Carboplatin](https://onco.cc/drugs/carboplatin/), [Temozolomide](https://onco.cc/drugs/temozolomide/), [Trastuzumab](https://onco.cc/drugs/trastuzumab/)
- companies: [Carthera](https://onco.cc/companies/carthera/), [Insightec](https://onco.cc/companies/insightec/)
- institutions: [Sunnybrook Odette Cancer Centre](https://onco.cc/institutions/sunnybrook-odette/)

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