The latest step towards that vision is something called biophotonic instrumentation . Now that we've named it, it's time to learn what it does.
At the moment when it's necessary to monitor a patient's heart rate, blood pressure, or blood glucose level a nurse or technician is required to attach a heart monitor, a blood pressure cuff, or to draw blood for testing. It's time consuming and requires a number of different pieces of equipment. But what if it were possible to monitor all of those parameters at the same time using nothing more than a laser beam and a camera?
Now it is.
When human skin is illuminated by a laser beam, the movement of blood under the skin manifests itself as vibrations at the skin’s surface. These vibrations create a secondary optical speckle pattern that correlates to the blood flux, which depends on blood viscosity (related to glucose concentration), blood pulse pressure, and heart rate.The system could be located above the patient's bed or off to one side in one corner of a room, yet allow unobtrusive monitoring of the three medical parameters. That means less need to tether a patient to the monitoring equipment, greater comfort for the patient, and less effort for medical personnel.
A few-milliwatt infrared (IR) laser at 1550 nm is used to illuminate the wrist of a patient at an oblique angle (see figure). The vertical-reflection speckle pattern is collected by an optical system that consists of a fast camera to record the reflected intensity pattern.
Although the distance between the light source and the subject’s skin was approximately 50 cm in the measurement setup, the researchers say they can also extract these biological parameters when the laser-skin distance is several-hundred meters. In addition, the parameters could be obtained not only from wrist-skin reflections, but also from chest and neck reflections.
There could also be certain security applications for this technology, such as monitoring passengers in an airport. A raised heart rate and blood pressure could trigger closer monitoring of some passengers as it's likely both parameters would be elevated in someone “up to no good.” Of course it might also mean a passenger is a nervous flier. But it would be another covert tool for use by airport security personnel in screening passengers before boarding a flight.