Researchers have modified the standard biopsy needle to create a high-tech needle that can improve cancer diagnostics and reduce discomfort for patients.
Currently, cancer diagnosis almost always needs a biopsy. Despite many areas of diagnostic treatment seeing huge advances in technology, the technology of medical needles has not changed dramatically in 150 years. In cancer management, the needles currently in use are struggling to provide adequate tissue samples for new diagnostic techniques.
To combat this problem, a team of researchers at Aalto University has modified the biopsy needle to create ultrasonic vibrating needles that vibrate rapidly at 30,000 times per second. This ultrasonic vibration enables the needle to provide sufficient data for current diagnostic needs. The researchers say this method is also potentially less painful and less traumatic for patients.
The study has been published in Scientific Reports.
Modern diagnostic techniques
For more advanced diagnostic treatments, such as those used in cancer, fine needles alone do not get enough material for the biopsy, meaning current practice is often to use a much thicker needle, called a core needle.
Professor Heikki Nieminen, at Aalto University, Department of Neuroscience and Biomedical Engineering, said: “Biopsy yields – the amount of tissue extracted – are often inadequate, with some studies showing that up to a third of fine-needle biopsies struggle to get enough tissue for a reliable diagnosis. A biopsy can be painful, and the wait for the results from a diagnostic test can be a highly distressing time for the patient and family, especially if diagnosis needs re-biopsies to be conclusive.
“We wanted to make the procedure more gentle for the patient, and increase the certainty that the test will be able to give us an answer on the first attempt.”
Pritzker says core needles are painful and cause bleeding: “They are painful for the patient and can also cause bleeding – you don’t want to use a core needle unless you have to. At body temperature, human tissue exists as something that behaves part-way between being a solid and a liquid. The breakthrough here is that by making the needle tip vibrate ultrasonically, we’re able to make the tissue flow more like a liquid, which allows us to extract more of it through a narrow needle.”
“The vibrations provide energy to the tissue to make it more fluid-like,” added 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 three to six times compared to the same needle without ultrasound, which was even greater than we hoped for.” The increase in the amount of tissue extracted in the biopsy means it is useful for the growing trend for high-tech cancer treatment such as 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.
Non-linear acoustics powers the needle – whereby 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.”
The needle is expected to move into studies with animal cancer patients at a specialist veterinary hospital in Canada, with the hopes of trialling the device in human patients if they achieve successful results.
“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 tumours 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.”
Perra added: “The effect that ultrasonic vibrations have on tissue might also be able to work the other way, 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.”