Probe Detects Breast Cancer Metastasis

High-temperature superconductors may be the answer to a handheld tool for surgeons. They promise to be more accurate, cost-effective, and safer than existing techniques for staging and treating various cancers, including breast cancer.

Dr. Audrius Brazdeikis, a research assistant professor of physics in the College of Natural Sciences and Mathematics at the University of Houston (UH; TX, USA), and Dr. Quentin Pankhurst, a professor of physics from the University College of London (UCL; UK), have developed an innovative detection procedure combining nanotechnology and sophisticated magnetic sensing based on high-temperature superconductors. Their innovation will enable surgeons to more effectively locate the sentinel lymph node--the first lymph node to which a tumor's metastasizing cancer cells will drain.

The researchers produced an ultrasensitive magnetic probe to detect tiny magnetic fields in the body. The probe is a supersensitive magnetometer--an instrument used to track the presence of clinically introduced magnetic nanoparticles. During the breast cancer surgery, a surgeon will inject a magnetic nanoparticle dye, already approved as an imaging contrast agent by the U.S. Food and Drug Administration (FDA), into the tumor or into tissues surrounding the tumor.

Dr. Michael Douek, a London surgeon who specializes in breast surgery and is a senior lecturer at UCL, is overseeing clinical trial of women undergoing breast cancer surgery at University College Hospital, London, and used the probe for the first time in surgery in December 2006.

According to Dr. Brazdeikis, who heads the Biomedical Imaging Group at the Texas Center for Superconductivity at UH (TCSUH), a goal of the project was to commercialize biomedical technology developed at universities through collaborative research. He and Dr. Pankhurst, deputy director of the London Centre for Nanotechnology, have formed a medical devices company--Endomagnetics, Inc.--to bring their technology to the marketplace and patented the probe.

A surgeon holds the probe, which incorporates two sets of coils connected to a sensor. One set of coils magnetizes the magnetic particles, and the second detects the magnetic response from those particles. The sensor, known as an HTS SQUID (high-temperature superconducting quantum interference device), is located in a cryogenic vessel on a cart, and is submerged in liquid nitrogen cooling the sensor to 77° K.

Existing practice calls for a breast cancer patient to receive two preoperative injections--a radioactive isotope and a blue dye--eight to 12 hours before surgery, frequently requiring hospitalization the night before the procedure. Later, in the operating room, the surgeon uses a handheld gamma probe, aided by the visual observation of the dye, to locate the lymph node with the highest radioactivity.

The UH-UCL technology allows a surgeon to administer just one injection--the magnetic dye that takes only 10 to 15 minutes to work--and eliminates the need for a nuclear medicine clinician to inject the radioactive material. A patient therefore may not have to be hospitalized while waiting, and the technology eliminates unnecessary patient and surgeon exposure to radioactivity.






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