Breast tumor images of a hemodynamic information using a contrast agent with back projection and FFT enhancement

Recent TRS results of breast tumor images revealed to us that it may be difficult to diagnosis cancer from optical characteristics of tumors by solely absorption coefficient and scattering coefficient. Benign tumors develop blood vessels surrounding tumors as well as cancers do. Scattering coefficient can be lower or higher than in normal tissues, therefore it cannot be used for diagnosis. While there is very active work on characterizing cancers with optical methods, we sought a different approach to find a “cancer signature” in the area of hemodynamics. It is known that cancers will create hypoxic lesions as well as high oxygen lesion, and we hypothesized that these hypoxic and hyperoxic lesions attributed to heterogeneity of hemodynamics, i.e. some areas have a high velocity of blood circulation, and others have extravasation, causing high and low contrast agent clearance. We used an optically visible contrast agent; ICG injected intravenously into 6 tumor bearing women, and imaged then- breasts with CWS system, which has 16 sets of source and detector in a circular holder. Time resolution was 8 seconds for 1 image thus enough to follow the time course of the ICG appearance-decay curves in each 16×16 source-detector combination. The data were saved in a PC and later analyzed using a back projected FFT enhanced image re-construction algorithm. The data suggest that indeed cancers have more heterogeneity as indicated by the time constant of ICG decay curves, and time of decay is generally longer. In contrast, in benign adenoma, the time constant was shorter. In conclusion, we have used the dynamics of ICG uptake and disappearance in cancer as compared to normal breast and benign tumor cases as a diagnostic approach.