A dual-wavelength continuous-wave diffuse optical tomography system using digital lock-in photon-counting technique

摘要

Diffuse optical tomography was recognized as one of the most potential methods to in-vivo imaging due to its advantages of non-invasiveness, high sensitivity and excellent specificity etc. This modality aims at portraying the concentration distribution of oxy-hemoglobin and deoxy-hemoglobin statically or dynamically by resolving the optical properties at multiple wavelengths. To further improve the instantaneity and sensitivity of the method, we have developed a continuous-wave diffuse optical tomography system based on lock-in photon-counting technique, which can perform dual-wavelength measurement simultaneously at ultra-high sensitivity. The system was configured by modulating the laser sources at different wavelengths with different frequencies and adopting a single photon-counting block based on the digital lock-in detection for the data demodulation. Phantom experiments were conducted to evaluate the capability of the method. Results have shown that the absorption contrast can be commendably reconstructed, and the system we proposed provides a promising tool for in-vivo imaging.