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Researchers find better way to detect spread of cancer

by Peter Krieg

Magnetometer probe with a digital readout allows surgeons to accurately identify the sentinel lymph node in complex cancer types. Image by artist Nic Arrighi.Magnetometer probe with a digital readout allows surgeons to accurately identify the sentinel
lymph node in complex cancer types. Image by artist Nic Arrighi.

UniSA researchers have developed a new technology to detect the spread of cancer in the body, providing surgeons with more accurate information and offering patients a better standard of care.

Using magnetic tracers instead of radioactive agents, Ian Wark Research Institute PhD candidate Aidan Cousins’ new magnetometer cancer probe provides five times the accuracy of current methods, at a fraction of the cost.

Aidan explains that cancer spreads when malignant cells enter the lymphatic system and travel to other organs. He says detecting this spread, known as metastasis, is crucial to providing appropriate treatment and care.

Currently metastasis is detected using radioactive agents, which are injected close to the cancer site and traced as they move through the lymphatic system. The first lymph node they arrive at is known as the sentinel node.

Surgeons identify the sentinel node during surgery using a handheld radiation-detecting probe. Once identified, the node can be removed and analysed for cancer cells. If cancer cells are found, it is likely that the cancer has spread in the body, and the extent of the spread can be determined.

“While this technique is well established, and performs effectively for cancers such as breast cancer and melanoma, the low spatial resolution of nuclear imaging procedures and the radiation probe makes it difficult to identify the sentinel node for cancers of the internal organs, such as gastrointestinal cancer, where lymph nodes may be tightly clustered or in close proximity to the primary tumour,” Aidan says.

“My new approach replaces radioactive agents with magnetic tracers, which are injected in the same way.

“Using the magnetometer probe, it is possible to achieve much greater spatial resolution, making the technology particularly useful for deep cancers.

“More accurate identification of the sentinel node means the spread of cancer can be more reliably detected.

“This means the most appropriate treatment for that cancer stage can be administered, and also helps avoid unnecessary procedures, which benefits both patients and hospitals.”

Supervised by Ian Wark Research Institute Associate Professor Benjamin Thierry and the School of Engineering’s Dr Bruce Wedding, and working closely with Royal Adelaide Hospital surgeon Dr Sarah Thompson, Aidan has applied new thinking to improve detection without impacting on surgical processes.

“Surgeons already use a handheld probe to detect the radioactive agents,” Aidan says. “We’ve switched the underlying technology, so they can benefit from the new type of probe without changing any of their surgical procedures.

“The technology also offers logistical benefits to hospitals, as it reduces the need for the specialised rooms, equipment and training currently required for radioactive agents.”

In addition, Aidan says, magnetic tracers have a much greater shelf life than radioactive agents – measured in years rather than hours – which reduces storage and supply complications. Furthermore, the magnetometer probe itself is dramatically cheaper to manufacture.

Pre-clinical animal studies have confirmed the function of the magnetometer probe, and the research team is now investigating opportunities for commercialisation through ITEK, UniSA’s technology commercialisation arm. The project, which combines the fields of physics, engineering and nanotechnology, has already received funding from the South Australian Government Medical Device Partnering Program towards the development of a clinical prototype.