Dual-Direction Optical Measurement Instrument for Assisting X-Ray Mammography

This study aims at developing an optical measurement instrument to implement a diffuse optical imaging system that is incorporated with the X-ray mammogram for the purpose of obtaining functional images for breast tumor detection. In this paper, a dual-direction scanning device to project illuminated near infrared (NIR) light with a multiple-channel switching for both sources and detectors was designed and constructed. The device operates to compress breastlike phantoms by two compression plates to reduce the distance between sources and detectors for enhancing the signal to noise ratio (SNR) of measurements and obtaining more reliable data. A dual-direction projection scheme was employed to obtain double information that can benefit image reconstruction. Besides, we also implemented an improved image reconstruction algorithm for a dual-modality imaging scheme by combining the functional images of diffuse optical tomography (DOT) with the structure information of X-ray mammograms. The enhanced computation scheme was validated by using designated cases including various size, contrast, and location of inclusions to background. As a comparison, both simulation and experiments were performed to reconstruct functional optical-coefficient images. A mean square error (MSE) was used for the quantitative evaluation on all reconstruction images.