These techniques could save many lives and are more effective, less invasive and simpler than currently available alternatives. Clinical studies are now being planned.
The Chalmers team expects to be able to test two different techniques on patients within the next six months. One method is an alternative to mammography, i.e. using X-rays to detect breast cancer. The other aims to treat tumours in the head and neck by heating the cancer cells.
Microwaves can be used to create medical images – a new technique known as microwave tomography. Andreas Fhager, Associate Professor of Biomedical Electromagnetics, has developed a system to detect breast cancer with the new technique. He points out that the method has several advantages over mammography.
“We obtain three-dimensional images showing significantly better contrast between healthy and malignant tissue compared to X-rays. That makes it easier to detect even really small tumours that may currently be obscured by healthy tissue, thus creating the preconditions for much more reliable diagnosis.”
“Unlike X-rays, the technique also emits negligible doses of non-ionising radiation – less than a hundredth of the radiation to which you are exposed when talking on a mobile phone.”
Andreas Fhager’s “microwave tomograph” currently consists of some thirty antennas arranged around a cylindrical container adapted to the breast. All antennas act both as transmitters and receivers. The microwaves spread out in a complex pattern that is analysed by advanced algorithms, which reconstruct an image of the breast tissue in 3D. Credit: Jan-Olof Yxell
The idea is to use the technique in conjunction with a treatment couch, equipped with holes for the breasts, to which the thirty or so antennas required by the examination are connected. It should be considerably more comfortable for patients than mammography. The method is also much less expensive, not only because microwave equipment is not so costly, but also because the clearer images make interpretation easier for the doctors.
In the second Chalmers project, the microwaves are actually used to destroy the tumours by heating them, a process known as hyperthermia. Clinical studies have shown that treatment with conventional radiotherapy and chemotherapy in combination with hyperthermia may double the long-term ability to cure certain forms of cancer, such as cervical cancer and soft-tissue sarcoma.
“We are now developing a new hyperthermia system that can reach deep-seated tumours in the head and neck with high accuracy,” says Hana Dobšíček Trefná, a PhD in Biomedical Engineering. “In this way, higher temperatures can be reached in the tumour without affecting the surrounding tissue.”
The antennas transmit microwaves with high efficiency, perfectly synchronised to heat up individual tumours. The process can be likened to creating a tidal wave in the region of the tumour while the surrounding sea remains calm. Before clinical tests are carried out on patients, the system will be tested on anatomically correct models. Credit: Daniel Kvist & Daniel Svärd
With time, the Chalmers team hope to be able to combine both methods. As soon as a tumour is detected, the already connected antennas could be used to start treating the tumour directly while at the same time monitoring that the right tissue is heated up. The method should also be applicable for other parts of the body than breasts, head and neck.
Theranostics – the treatment and diagnosis of diseases in a single system – is a growing area of research, and the Chalmers team believe that microwaves have great potential in the field. The underlying microwave technology is already being used in the “Strokefinder”, a helmet that can distinguish between blood clots and bleeding in the brain. The Strokefinder is currently undergoing clinical trials at Sahlgrenska Hospital.
Read more about the Strokefinder:
Microwaves are electromagnetic radiation within the higher RF band, i.e. with wavelengths shorter than “usual” radio waves, but longer than those of visible light and X-rays, for instance. Although no exact definition exists, in general the term tends to refer to frequencies from 0.3 to about 30 GHz. The Chalmers team use frequencies of around 0.5 – 3 GHz.
For more information, please contact:
Andreas Fhager, Associate Professor of Biomedical Electromagnetics, +46 76 125 70 12, +46 31 772 17 23, firstname.lastname@example.org
Mikael Persson, Professor of Biomedical Electromagnetism, +46 31 772 15 76, email@example.com
Hana Dobšíček Trefná, PhD (Biomedical Engineering), +46 31 772 50 52, firstname.lastname@example.org
Johanna Gellermann, MD and Professor of Radio-Oncology, +46 31 772 50 52, email@example.com