3D Radar Mammograms

No pain, more gain

October 26, 2009 – In Canada, one woman in nine will develop breast cancer during her lifetime. Doctors suggest regular exams to detect and diagnose possible tumours, but most women agree that mammograms are a less-than-desirable experience. The breast is compressed between two plates to provide an even distribution of tissue for the best possible image, but this causes considerable discomfort to the patient. Though the amount of radiation used during the procedure is low, exposure to this radiation limits the frequency with which x-ray mammograms are performed.

One NSERC-funded researcher is striving to make breast exams safer and easier for all women. Elise Fear of the University of Calgary has spent the last decade developing technology for a new imaging system that will provide a 3D rendering of the inside of the breast and any potential tumours.

Dr. Fear’s system is called Tissue Sensing Adaptive Radar (TSAR) and is based on an ultra-wideband radar system. A patient lies face down on a table and lowers a breast through a hole into a small tank of canola oil, which produces a better image because it reduces reflections from the skin without absorbing the microwaves. The tank then rotates around the breast and a small antenna inside moves with it, scanning the entire area with short microwave pulses that are reflected by the tissue within. Healthy fatty tissue appears translucent to microwaves, while tumours and glandular tissues produce increased reflections due to differences in their electromagnetic properties.

Approximately 200 locations in the breast are illuminated by the system, and any reflections are noted by a sensor. At the end of the scan, unwanted signals are filtered out and the different views are turned into a composite 3D image for examination. No equipment touches the breast tissue during the 30-minute procedure.

Making the procedure patient-friendly has been a central concern of the project, says Dr. Fear. Thanks to its no-contact approach, TSAR is completely painless. Furthermore, where mammograms utilize low-level ionized radiation, Dr. Fear’s technology uses microwaves less powerful than those emitted by a cell phone.

After ten years of development, clinical trials of the TSAR technology are only just beginning, but enthusiasm from women about the procedure has been overwhelming. There is still work to be done, and Dr. Fear estimates it will be at least another five years before this technology begins to appear in breast exam clinics across the country. In the meantime, she and her team are aiming to be able to identify sub-centimetre tumours, as x-ray mammography detects tumours of similar size. The research team also hopes to be able to provide more information about tumours they detect, a task that can sometimes require multiple types of images, followed by biopsies.

Easier. Safer. Better. Canadian research is finding a way to make this happen.