New generation of integrated probes for laser Doppler perfusion monitoring: construction and in vivo results

Integrated probes have been developed containing the essential optoelectronic components necessary for monitoring tissue perfusion using the laser Doppler principle. The device contains a VCSEL for illumination, and a chip with photodetectors, amplifiers for signal enhancement, and digital circuitry for external probe control. VCSEL and detector chip are mounted on a common ceramic platform. A Peltier element may be included for temperature stabilisation, or thermal cycling for physiological purposes. Two special chips have been developed: one containing an array of five detectors, at various distances from the laser, which will allow for some degree of depth discrimination, and a single detector chip. In this paper the probe designs are presented and some results of in vivo measurements are shown