Microwaves Used to Create Medical Images

This new technology could save many lives and are more effective, less invasive, and simpler than currently available alternatives. Clinical studies are now being planned.

The Chalmers University of Technology (Gothenburg, Sweden) researchers expect to be able to evaluate two different techniques on patients within the next six months. One method is an alternative to mammography, such as using X-rays to detect breast cancer. The other aims to treat tumors 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 pointed out that the technology 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 tumors 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 nonionizing radiation--less than a hundredth of the radiation to which you are exposed when talking on a mobile phone.”

The strategy is to use the technique in combination with a treatment couch, equipped with holes for the breasts, to which the approximately 30 antennas required by the examination are connected. It should be significantly more comfortable for patients than mammography. The method is also much less costly, not only because microwave equipment is not so expensive, but also because the clearer images make interpretation easier for the clinicians.

In the second Chalmers project, the microwaves are essentially used to destroy the tumors 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 soft-tissue sarcoma and cervical cancer.

“We are now developing a new hyperthermia system that can reach deep-seated tumors in the head and neck with high accuracy,” said Hana Dobšíček Trefná, a PhD in biomedical engineering. “In this way, higher temperatures can be reached in the tumor without affecting the surrounding tissue.”

With time, the Chalmers investigators hope to be able to combine both methods. As soon as a tumor is detected, the already connected antennas could be used to start treating the tumor 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 is a growing area of study, and the Chalmers team believes that microwaves have a lot of possibilities in the field. The underlying microwave technology is already being used in the “Strokefinder,” a helmet that can differentiate between blood clots and bleeding in the brain. The Strokefinder is currently undergoing clinical trials at Sahlgrenska Hospital (Gothenburg, Sweden).

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