A hand-held magnetic probe made by physicists could find a place in cancer surgery.

Determining the spread of breast cancer at present involves locating, removing and microscopically examining the sentinel lymph node. However, a new device developed by Endomagnetics — a spinout company from the University of Houston and University College London (UCL)— could put the detection of the lymph nodes entirely in the hands of the surgeons. All the surgeon has to do is inject the tumour with a magnetic nanoparticle dye, wait ten minutes for the dye to accumulate in the lymph nodes, and then run the SentiMAG probe over the patient.

Quentin Pankhurst of UCL first met fellow physicist Audrius Brazdeikis of Houston through an initiative called the UK–Texas Bioscience Collaboration in 2003. They later teamed up with Simon Hattersley, a systems engineer, and co-workers to design and build the probe, which exploits the ability of a device known as a SQUID to detect extremely weak magnetic fields, such as those produced by the nanoparticles in the dye, even in busy and unshielded environments, such as operating theatres.

How did they know what surgeons wanted? “There is no substitute to getting out there, knocking on doors, and talking one-on-one to the people you think are going to benefit from what you want to do”, says Pankhurst. “However, the medics and surgeons we really needed to talk to were precisely those who had hardly any time to talk to us.”

A turning point, says Pankhurst, was a meeting with a famous breast cancer surgeon in London. “It took me five weeks to get a 15 minute slot with him, but once we were in his office, he immediately put me in touch with exactly the right person for us — an innovative breast cancer surgeon called Michael Douek who has been our champion and guide in the development of the probe”.