DBT can provide a high resolution structural image, whereas DOT can provide the functional information. Therefore, we suggest to scan both DBT and DOT for the same object and overlay the two different images to see the high resolution structural information and the functional information at the same time. Designed to have similar scanning geometry to each other, the DBT image can be used as a mask guide for the DOT reconstruction mesh. The scattering dominant interaction near the air-tissue boundary, which causes severe boundary artifacts and affects to the overall image quality, can be improved using the DBT-mask meshes. Even when the DBT and DOT were not simultaneously scanned and thereby there existed the marginal anatomical deformation between the two images, the DBT mask guide was extremely effective in removinge the boundary artifact for the DOT image. For the calibration of the raw data, a homogeneous phantom with known optical properties was used so that the source power variance and the detector sensitivity variance can be reduced. The raw data was sorted according to signal amplitude to avoid air-contaminated information. With the calibrated and sorted raw data, the bulk absorption and scattering coefficients were estimated. The NIRFAST software package was used as the core iterative reconstruction. For the clinical validation, 27 patients in total were scanned with both DBT and DOT. The sensitivity and specificity were 0.92 and 0.64 respectively with the DBT images, 0.61 and 0.85 with the DOT images, whereas with the DBT and DOT overlaid images, 1 and 0.93 respectively.
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