Ultrasound Assisted Optical Imaging

Abstract

Abstract : We are continually conducting clinical experiments at the UConn Health Center and Hartford Hospital. The statistical analysis of the first 65 cases (including 8 cases of cancers and 57 cases of benign lesions) shows strong correlation between the total hemoglobin concentration and malignance. There is about two-fold increase in the total hemoglobin concentration for cancers compared with the typical values for benign lesions. This agrees with our hypothesis that optically available parameters can significantly improve the accuracy of breast cancer detection. To further improve the performance of optical imaging system, we are pursuing the time-resolved method. We have developed a time-resolved diffusive optical tomography system via a novel spread spectrum approach. A low power (%5 mW) laser diode modulated with pseudo-random bit sequences replaces the short pulse laser used in conventional time-resolved optical systems, while the time-resolved transmittance is retrieved by correlating the detected signal with the stimulation sequence. Temporal point spread functions of diffusive light propagating through a turbid medium have been measured with remarkably low noise levels. 2-dimensional scanning imaging experiments were performed to demonstrate the great potential of this new imaging technique. Sub-nanosecond temporal resolution (approx. 0.9 ns) has been achieved.