Phase cancellation system for tumor imaging using targeted fluorescent contrast agents

Recent developments in receptor specific targeting fluorescent contrast agents can give tumor/tissue contrasts in the excess of 10, and are capable of selectively labeling various pre-cancer/cancer signatures to enhance the sensitivity and specificity of cancer detection [reference: Weissleder et al, Achilefu et al]. We have developed a novel imaging system for fast and accurate localization of fluorescent contrast agent labeled tumor embedded several centimeters inside the highly scattering medium mimicking breast tissue using the phased cancellation configuration (0° and 180° source-pair) with a goniometric probe. Phantom tests and intratumor injection of fluorescent dye, Indocyanine Green (ICG), have demonstrated the capability of two-dimensional localization of tumor labeled with fluorescent contrast agents about 3.0 cm deep within several millimeters error range. The accuracy of the localization suggests that this system would be helpful to guide the clinical fine-needle biopsy for early detection of breast cancer.