Researchers at Massachusetts General Hospital in Boston have developed a system that can detect tumors by analysing a few thousands cells, sparing patients from the larger biopsies currently used.

The palm-sized device sits on the patient’s bedside table, operated through a simple smartphone app. At the core is a micro nuclear magnetic resonance (microNMR) chip, a scaled-down version of the technology found in magnetic resonance imaging (MRI) scanners. It works by using magnetic nanoparticles to measure protein levels, looking for specific markers that indicate the presence of cancer. Doctors can see the readout from the chip on their phone’s screen.