Abstract

Monitoring Doppler frequency shifts in scattered radiation used in various biomedical sensing and imaging modalities provides a useful technique for analysis of internal motions in living systems. Continuous- and pulsed-wave Doppler ultrasound are commonly used for clinical monitoring of blood flow dynamics, while color-Doppler techniques combine spatially resolved imaging with flow and motion analysis¹. Current medical ultrasonic Doppler imaging techniques are limited to >150 μm spatial resolution. Laser Doppler velocimetry, which takes advantage of optical heterodyning of coherent optical signals scattered from tissue volumes, has been used to estimate mean blood flows in the peripheral microcirculation². However, strong multiple scattering in most human tissues limits the spatial resolution obtained with this technique and prevents localized analysis of flow in specific vessels.

© 1996 Optical Society of America