A novel combined ultrasound and near infrared diffusive light imaging using a two-dimensional hybrid array

A novel imaging method which combines ultrasound and NIR optical images provides a new way to utilize optical contrast and ultrasound imaging capability and has a great potential to independently distinguish tumor from normal tissues. The key technical issue for the combined ultrasound and NIR breast imaging is the co-registration of ultrasound and optical images. Co-registration enables the joint evaluation of acoustic and optical properties of the breast lesion and thereby improving detection sensitivity and specificity. Two issues have to be addressed regarding co-registration. First is the optimal deployment of an ultrasound array and optical sensors so that both imaging sensors view the same geometry of the breast. Second is the collocation of images of the same target obtained from ultrasound and NIR light. Since sound and diffusive light propagation paths are different, ultrasound and optical images of the same target may not be collocated. The experimental results reported in this paper demonstrate that an ultrasound array and NIR sensors can be optimally deployed on the same probe and co-registration can be achieved.