The winning article – A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries – was the work of researchers from the University of Wisconsin (Madison, WI) and the University of Calgary (Calgary, AB). The paper has been cited over 160 times since its publication in 2007 (according to Scopus).

The paper's lead author, Mariya Lazebnik, is awarded the Rotblat medal, named in honour of Prof. Sir Joseph Rotblat – PMB's second and longest-serving editor. The paper's co-authors each receive a certificate. Last week, senior author Susan Hagness accepted the medal on Lazebnik's behalf.

"I am very honoured and humbled to be receiving this prize, and I am grateful to my collaborators and co-authors on this work," said Lazebnik. "This prize highlights the importance of research in the field of breast cancer diagnosis and treatment using radio and microwave frequencies."

Large-scale study

The award-winning research was motivated by the possibility of using microwave energy for detection and treatment of breast cancer. This premise was driven by reports citing substantial contrast in the dielectric properties of malignant and normal breast tissues at microwave frequencies – a premise that the team sought to investigate further.

To do this, they measured the microwave dielectric properties of 155 freshly excised breast tissue samples, measured from 0.5 to 20 GHz. The set included 85 normal (adipose, glandular and fibroconnective), 60 cancerous (invasive and non-invasive ductal and lobular carcinomas) and 10 benign (fibroadenomas and cysts) samples, obtained from cancer surgeries.

Results showed that the dielectric properties of normal tissue samples varied immensely, due to differing levels of fat content. In contrast, malignant samples exhibited high dielectric properties that extended over a relatively small range. Considerable contrast in dielectric properties was seen between malignant tissues and normal adipose-dominated tissues, while the properties of malignant tissues and normal fibroglandular-dominated breast tissues differed by no more than 10%.

"Previous studies reporting the dielectric properties of breast tissues generally involved small patient populations and did not consider the heterogeneity of normal and malignant breast tissue," said Lazebnik, now a senior scientist at Medtronic in Minneapolis, MN. "The key developments were the large scale and statistical rigour of the study, the wide frequency range of collected data, and the number of different normal and malignant breast tissue types."

Hagness, a professor at the University of Wisconsin-Madison, added: "Another key feature of our study was the careful correlation between the histopathology analysis and the microwave measurements, to ensure that we knew what the tissue composition was within the sensing volume of our dielectric probe."

The authors concluded by suggesting that microwave imaging may prove suitable for developing into a clinical diagnostic tool. Since the publication of this paper, and a companion study (Phys. Med. Biol. 52 2637), research activity in the field of microwave breast imaging has indeed continued to grow.

"The papers provided the research community with important new insights about the nature of the dielectric properties of breast tissue," explained Hagness. "Those insights have significantly influenced and guided the development of microwave breast imaging technology over the past several years. Several clinical systems are undergoing development or refinement."

Hagness noted that the researchers have also followed up on the paper's suggestion of using microwave hyperthermia techniques for breast-cancer treatment. "In fact, we recently published a paper on this topic in Physics in Medicine & Biology," she said (Phys. Med. Biol. 55 3611).

• The winner of the 2011 Physics in Medicine & Biology (PMB) citations prize is: A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries Mariya Lazebnik, Dijana Popovic, Leah McCartney, Cynthia B Watkins, Mary J Lindstrom, Josephine Harter, Sarah Sewall, Travis Ogilvie, Anthony Magliocco, Tara M Breslin, Walley Temple, Daphne Mew, John H Booske, Michal Okoniewski and Susan C Hagness 2007 Phys. Med. Biol. 52 6093