A continuous wave non-contact diffuse optical tomographic measurement system and the corresponding image reconstruction algorithm for dense sampling data

Abstract

In this paper, we constructed a continuous wave non-contact diffuse optical tomography (DOT) system for the dense sampling of both the illumination and detection by using a laser raster scanning and a CCD-based data acquisition. For dealing with the large size of measurement data obtained from the non-contact system, a fast tomographic image reconstruction scheme for reconstructing the absorption coefficient of a slab is developed. The proposed algorithm is carried out with the spatial-frequency encoding in both the measurement and the image spaces, and involves a strategy for selecting the useful spatial frequency based on the transfer function of tissue. Dense sampling offers an effective way of improving the image reconstruction performances and the developed algorithm is expected to considerably reduce the calculation time for reconstruction whilst retain the quality of the reconstructed images. Reconstructions from the experimental data show that the inversion scheme developed in this paper can get an absorption image within 20s, which has higher quality than those reconstructed in several hours by using the conventional reconstruction method.