[2024] Dual-Frequency Ultrasound Neuromodulation for Minimally Invasive Brain Implants [TAKEN]

Focused ultrasound neuromodulation is an emerging therapeutic modality that can stimulate targeted regions deep in the brain [1]. One of the challenges in using ultrasound for neuromodulation is the skull, which attenuates ultrasound, especially at higher frequencies. This limits the spatial resolution achievable with transcranial focused ultrasound neuromodulation because the size of the focal spot is inversely proportional to frequency. A promising approach to overcome the effects of the skull and achieve a higher spatial resolution is to implant an ultrasound phased array, capable of steering an ultrasound beam, between the skull and the brain.

A major challenge for implanted ultrasound devices is on how to achieve high-enough acoustic intensities at the focal spot to stimulate neurons. Implanted medical devices powered by batteries or by induction have constraints on power consumption that external devices powered from the grid do not have.

This project aims to reduce the acoustic power that needs to be delivered by the implant by exploiting the constructive interference of ultrasound beams [2] at low- and at high-frequencies. The goal is to provide a portion of the acoustic power via a low-frequency, imprecise acoustic beam through the skull with an intensity that is not sufficient to stimulate neurons. The remaining portion of acoustic power needed to reach the neural stimulation threshold could then be administered by a low-power high-frequency focused acoustic beam from the implant at a resolution dictated by the high frequency.

References:

1. Tufail, Y. et al. Transcranial pulsed ultrasound stimulates intact brain circuits. Neuron 66, 681–94 (2010).

2. S. J. Ilham and M. Kiani, "Towards High-Resolution Ultrasound Neuromodulation With Crossed-Beam Phased Arrays," in IEEE Transactions on Biomedical Circuits and Systems, vol. 17, no. 3, pp. 534-546, June 2023,

Assignment

1^st part:  Literature review of ultrasound neuromodulation parameters (intensity, pulse length, frequency)

2^nd part: Simulation, design and experimental validation of a dual-frequency ultrasound system for high resolution ultrasound neuromodulation

Requirements

MSc students from Microelectronics, Biomedical Engineering, Mechanical Engineering or Applied Physics. Prior knowledge on biomedical ultrasound is preferred.

Interested students should include their CV, the list of courses attended, and a motivation letter, and send it to Tiago Costa (t.m.l.dacosta@tudelft.nl) and Samuel Desmarais (s.desmarais@tudelft.nl).

Contact

Last modified: 2024-04-02