Feels like a regular needle
In a new paper, published in Scientific Reports, the team is sharing with the wider world how well these ultrasonic vibrating needles work. “The vibrations provide energy to the tissue to make it more fluid-like,” explains the first author of the paper, Emanuele Perra, who works in Nieminen’s group at Aalto University. “The vibrations are localised to just the tip, so it doesn’t affect any other tissue except a small region around the needle. We were able to show that the ultrasonic vibrations increase the biopsy yield by 3 to 6 times compared to the same needle without ultrasound, which was even greater than we hoped for.” The vibrations are far above the hearing range for humans, and the amplitude of the waves is small enough that it shouldn’t feel much different to a normal blood test.
The big increase in the amount of tissue extracted in the biopsy means it is very useful for the growing trend for high-tech cancer treatment. One such example is molecular diagnostics, which examine the chemical makeup of tumours, to allow doctors to target treatment more effectively to a specific cancer type. “Molecular diagnostics is an expensive process, and it is an expensive waste of money to have it fail because the quality of the material gathered in the biopsy wasn’t previously good enough,” explains Pritzker.
The technology that powers the needle is non-linear acoustics, where vibrations passing through a material have such large amplitude that they interact with the material itself. These interactions allowed the needle’s designers to focus all the energy to just the tip of the needle, and measure their effects. “We’ve been able to characterise the vibrations at the end of the needle really well. We’ve used high speed cameras that have allowed us to study the physical effects of the vibrating needle on boundaries between fluids, solids and air in unprecedented detail,” says Nieminen. “The rich understanding we’ve managed to get of the physics allowed us to design the medical device and understand how it could be used for different medical purposes.”
Medical trials getting underway
The needle is expected soon to move into studies with real cancer patients, although for the time being only four-legged ones. A specialist veterinary hospital in Canada is soon expected to be trialing the device on domestic pets with cancer, and if all goes as expected, the team hopes that their needles will be used in human patients soon after.
“Modern oncology doesn't just take a biopsy at the beginning of treatment”, explains Nieminen. “Increasingly, oncologists want to be able to take multiple biopsies to track how the tumors are changing and responding over the course of the treatment. We want the tools for these biopsies to be as effective and painless as possible.”
While the team is preparing the needles for the real world biopsies, they are also excited about future applications that they are still researching. “The effect that ultrasonic vibrations have on tissue might also be able to work the other way” explains Perra, “the vibrations might make it easier to deliver pharmaceuticals in a targeted way to tissue like the liver. They might also be able to break up small hard objects in soft tissue, like kidney stones, or even small tumours - all minimally invasively.” By combining experts in acoustics physics with experts in medical technology, the team hopes that many more innovations will arise from their 21st century upgrade of the humble medical needle.
The paper Ultrasonic Actuation of a Fine-Needle Improves Biopsy Yield, is published in Scientific Reports DOI: https://doi.org/10.1038/s41598-021-87303-x The work was funded by the Academy of Finland. Professors Nieminen and Pritzker are shareholders in Swan Cytologics Inc., Toronto, Canada, which aims to commercialise the technology and hold pending patents for it.
Contact details
Heikki Nieminen
Professor
Aalto University
Email: [email protected]
tel:+358505019280
Kenneth Pritzker
Professor Emeritus
University of Toronto Temerty Faculty of Medicine, Mount Sinai Hospital Toronto
Email: [email protected]
Emanuele Perra
Doctoral researcher
Aalto University
Email: [email protected]