The laser at 50: the laser is a major force in medicine, with clinicians exploiting the technology across all manner of cosmetic, therapeutic and diagnostic applications. Right now, one of the biggest growth areas is in vivo diagnostics – the use of laser-based technologies to diagnose early-stage disease and treat that disease before it becomes incurable. Brian Pogue, professor of engineering at the Thayer School of Engineering, Dartmouth College, US, explains what laser scientists and innovators can do to ensure that today’s ground-breaking research makes it out of the laboratory and into the hospital.