Tiny magnetic particles can be used to track cancer far more accurately than present techniques and reduce the need for surgery, scientists have found.

Establishing how far cancer has spread is crucial to choosing the right treatment and predicting outcomes.

Examining lymph nodes removed by surgery, ultrasound and CT and MRI scans are the main techniques now used for “staging” cancer. But often these are unduly invasive or not accurate enough.

The new system developed by US scientists involves injecting a solution of tiny magnetic nanoparticles into the patient which homes in on the lymph nodes.

A computer program linked to an MRI (magnetic resonance imaging) scan tracks the particles and recognises abnormal patterns indicating the presence of cancer. The information can also provide a virtual picture of the affected nodes.

The scientists, led by Ralph Weissleder and Mukesh Harisinghani at Massachusetts General Hospital in Boston, developed the technique with the help of one group of 36 cancer patients and tested it on another group of 34.

Cancer which had spread to the lymph nodes was correctly predicted in 90% of cases, the researchers reported in the journal PloS Medicine.

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