A new wearable device could revolutionise the diagnosis of brain tumours and heart disease, with the potential to ‘read’ patients’ thoughts.

The prototype, developed by San Francisco-based start-up Openwater, can scan the brain and body with a resolution a billion times higher than that of a traditional MRI (magnetic resonance imaging) device.

By using opto-electronics, the wearable scanner could replace the functionality of bulky MRI machines and enable constant monitoring, aiding the treatment of cancer, cardiovascular diseases, internal bleeding, mental diseases and neurodegenerative diseases.

The device is designed to be worn inside a ski-hat or similar piece of clothing, and uses infrared light to scan the brain or body in minute detail. The image is then relayed back to a display screen, shrinking the pixels on display to almost the wavelength of light.

Tumours and clogged arteries can be detected by scanning the surrounding blood flow, and Openwater’s goal is to have the device track the flow of oxygenated blood to different parts of the brain and effectively ‘read’ thoughts.

While the technology that powers this device is currently available, it is limited by the cost and size of the equipment. Openwater’s device is not only smaller, but also much more affordable than current MRI machines.

“It is a thousand times cheaper than an MRI machine and a billion times higher resolution,” Openwater founder Mary Lou Jepse told the Financial Times in February. “That’s a lot of zeros.”

Once developed, the wearable MRI scanner will have the capability to receive clear images based on blood-flow in the brain, which could allow a person to upload their thoughts directly to a computer.

This technology opens up debate about the ethical implications of mind-reading, however. Jepsen has previously discussed whether a subject’s thoughts could be deleted once shared, and the device would have to be approved by the government before commercial use.

Openwater plans to release a very limited number of prototypes to early access partners next year.