Optical biomarkers for breast cancer derived from dynamic diffuse optical tomography

Diffuse optical tomography (DOT) is a noninvasive, nonionizing imaging modality that uses near-infrared light to visualize optically relevant chromophores. A recently developed dynamic DOT imaging system enables the study of hemodynamic effects in the breast during a breath-hold. Dynamic DOT imaging was performed in a total of 21 subjects (age 54±10  years) including 3 healthy subjects and 18 subjects with benign (n=8) and malignant (n=14) masses. Three-dimensional time-series images of the percentage change in oxygenated and deoxygenated hemoglobin concentrations ([HbO2] and [Hb]) from baseline are obtained over the course of a breath-hold. At a time point of 15 s following the end of the breath-hold, [Hb] in healthy breasts has returned to near-baseline values (1.6%±0.5%), while tumor-bearing breasts have increased levels of [Hb] (6.8%±3.6%, p<0.01). Further, healthy subjects have a higher correlation between the breasts over the course of the breath-hold as compared with the subjects with breast cancer (healthy: 0.96±0.02; benign: 0.89±0.02; malignant: 0.78±0.23, p<0.05). Therefore this study shows that dynamic features extracted from DOT measurements can differentiate healthy and diseased breast tissues. These features provide a physiologic method for identifying breast cancer without the need for ionizing radiation.