Doctors are conducting a pilot using a handheld device which can detect head injuries before a patient arrives at hospital.
The Infrascanner can detect blood clots on the brain, allowing for earlier diagnosis of serious injuries.
The scanner is intended to speed up patients' access to appropriate treatment when they arrive at London hospitals.
Doctor Mark Wilson said it could have a "big impact".
Dr Wilson, a doctor with the Air Ambulance charity and consultant neurosurgeon at Imperial College London, said: "Head injuries are fairly common, and currently we manage all patients in same way as we can't tell what's going on inside your head".
He said identifying problems before the patient reaches hospital would create the best chance of minimising neuronal loss.
The year-long trial began in spring 2015 and has treated 60 patients to date.
If the results are encouraging it is expected to be used more widely by ambulance services.
The device has a 90% accuracy rate for finding clinically relevant blood clots on the brain, according to the London Air Ambulance.
Last year London's Air Ambulance treated 1,806 patients, 60% of whom were involved in road traffic collisions and falls from heights - types of incident commonly associated with head injuries.