Laser Doppler sensor for laser assisted injection

Superficial and endoscopic injection of expensive drug solutions of exactly controlled volume needs a sensor guided injection system to find the right path into the veins. To combine the sensor technology and a laser assisted channel forming device with the endoscope, all information and the radiati on of the power laser (Ho :YAG) must be passed through a single fiber. The Doppler effect proved to be an appropriate method for sensing the blood Row of veins, even in deeper tissue layers. Comparison with ultrasound shows t hat ultrasound does not meet the requirements for such a system. Strong eff orts have been undertaken to eliminate distortions of the Doppler signal. T he results demonstrate the practicability of this device.