Ultrasound as a treatment
Ultrasound is one of the most rapidly evolving technologies in the world of human and veterinary medicine. What began as a diagnostic imaging modality only, began to be adapted for therapeutic and physiotherapy purposes over a decade ago, seeing greatest uptake in human and equine sports medicine.
Now, we stand at the threshold of ultrasound as a widely used treatment method in itself.
Ultrasound drug delivery
With the advent of ultrasound microbubbles for contrast imaging came the possibility of using ultrasound for drug delivery. The concept was that by enclosing a drug inside the microbubble, the bubbles could be burst at the desired treatment site using ultrasound energy (at power levels achievable on regular diagnostic imaging machines), allowing the drug to be administered directly at the desired site within the body.
Ultrasound to to heat tissue
Another possibility is that of using the power of ultrasound to destroy tissue. Again, this can be done using microbubbles at normal diagnostic ultrasound power levels, given that the mass destruction of microbubbles could raise the temperature at the site by several degrees Celsius.
Today, however, the BBC reported on the use of hundreds of focused ultrasound beams to raise the temperature of a site inside the human brain sufficiently (up to 60 degrees Celsius) to destroy an unwanted region in the thalamus. Clearly, ultrasound waves at the power and frequencies used for diagnostic imaging are not suited for imaging through the skull (just think about the acoustic shadowing you witness distal to the ribs in a late gestation pregnancy, for example), and so in this instance, MRI served as the imaging modality – and ultrasound as the treatment.
Why this is important
Besides the interest factor (it’s nice to be working with such a progressive technology, isn’t it?), news like this also raises an important point about the power of ultrasound and our responsibility as users of it. Whilst therapies like this involve the use of over one thousand focused ultrasound beams, the fact still remains that a focused beam can and will raise the temperature of soft tissue, particularly under certain circumstances – such as scanning through bone. This is why human obstetric scans are performed to specific protocols, at specific times within the pregnancy, and why one should never attempt to scan a pregnant friend or relative “for fun.”
Similarly, it highlights the importance of using equipment that adheres by EU and FDA regulations regarding ultrasound power outputs, because using unapproved ultrasound machines from no-name suppliers is taking a huge step into the unknown. That is one of the things which separates AUA members from the rest of the pack. Members of the Animal Ultrasound Association are trained, remain up to date and educated on ultrasound, and use appropriate equipment and settings for the task in hand.
March 13, 2020
September 23, 2018