HOW IT WORKS

Ultrasound applied outside of our body can travel through several layers of tissue and converge to a small tissue volume. This focal volume is where all the action happens and we're here to develop innovative ways to probe and modify tissue so that we can diagnose and treat diseases.

Focused Ultrasound

Sound has the unique property of traveling through materials, which is the reason you can often hear your neighbour through opaque walls. Higher sound frequencies attenuate through the wall more so than lower frequencies. This is why you can hear lower tones from sources such as subwoofers.

In biomedical acoustics, very high frequencies known as ultrasound (0.25 to 10 MHz) are focused through several layers of tissue to converge to a small focal volume. This limits ultrasound-induced effects to a confined area while not affecting the surrounding healthy tissue. Ultrasound has unique properties when compared to other kinds of energy (e.g., light, magnetism):

  • Noninvasive
  • Deep penetration (several centimetres)
  • Non-ionising
  • Localisation (safety below certain intensities has been established)

Ultrasonically Generated Forces --> Novel Bioeffects

The focus of our laboratory is to functionally alter or probe biological tissue in a way that (1) is safe and temporary and (2) controllable at the micron- and nano-scale. We do NOT research high-intensity focused ultrasound (HIFU) or lithotripsy, which both use ultrasound to destroy tissue. In fact, we use pulse sequences, which more closely resemble ultrasound imaging pulses, which have an established safety profile. By carefully designing ultrasonic pulse sequences, we generate a wide range of ultrasonic phenomena within the focal volume:

  • Pushing
  • Expansion
  • Contraction
  • Heating (mild levels)

Our laboratory has an in-depth understanding of how the physics and biology are interacting with each other. We have the necessary balance of engineering, physics, and biology. Thus our manipulation and probing techniques are not limited to the size of the focal volume, but can be refined down to molecular and cellular behaviours through compartmentalisation of the phenomena (e.g., vascular, interstitial, and cellular compartments) and the use of sono-sensitive nano- and micro-particles (e.g., expansion and contraction of a microbubble). We can produce a range of safe and reversible bioeffects:

  • Increased vascular permeability
  • Increased cell membrane permeability
  • Displacement of fluid
  • Displacement of tissue