Optical mammographer with single channel detection

In this paper, we presents a newly developed near-infrared optical tissue imaging system with single channel detection based on the principles of frequency-domain spectroscopy, which uses diffusive photons to detect the breast cancer. The patient's breast is slightly compressed between two parallel glass plates, which are located between the source fiber and the detector fiber. The laser beam travels in the source fiber to the breast, and the transmitted light is detected by a photomultiplier tube and then demodulated. The ac amplitude of the signal is sampled to the computer by an A/D board. The source fiber and the detector fiber are driven by stepper motors and move synchronously in two dimensions, which enable the fibers to scan the entire breast. The scanning process is automatically controlled by computer. And the optical mammograms are displayed on the computer screen after the scanning process. In comparison with our former instrument that uses multichannel and scans only in one dimension to shorten the time of scanning, the new prototype has only one transmitter and one detector. This structure not only reduces the costs of the apparatus but also leads to a much more simplified system. Unfortunately, it makes the scanning time much longer. However, a new sampling mode is developed for the system to sample the data continuously, which compensates the disadvantage of the single-channel structure and reduces the scanning time. The results of intralipid experiments and pre-clinical experiments prove the potential of this approach to distinguish between tumors and healthy tissues.