Detection of single and multiple targets in tissue phantoms with fluorescence-enhanced optical imaging: Feasibility study

PURPOSE: To evaluate the feasibility of reconstructing single and multiple targets by using fluorescence-enhanced tomography of a breast tissue phantom. MATERIALS AND METHODS: Frequency-domain fluorescence measurements were performed in cup-shaped tissue phantoms of clinically relevant size (diameter, 10 cm) in which single or multiple 0.5-1.0-cm(3) targets that contained micromolar concentrations of indocyanine green with 1:0 and 100:1 target-to-background (T:B) contrast ratios had been embedded. Rapid acquisition of time-dependent fluorescent light measurements was performed at the phantom surface in response to point illumination of excitation light by using a gain-modulated intensified charge-coupled device detection system. Boundary surface measurements were used to tomographically reconstruct the interior targets located with various experimental conditions. RESULTS: Single 1.0-cm(3) targets located between 1.43 and 2.82 cm deep from the phantom surface at a T:B contrast ratio of 100:1 and three approximately 0.55-cm(3) targets located about 1.30 cm deep at a T:B contrast ratio of 1:0 were reconstructed with minimal or no artifacts by using boundary surface fluorescence measurements and an approximate extended Kalman filter algorithm. CONCLUSION: It is feasible to detect single or multiple fluorescent targets in tissue phantoms of clinically relevant size by using fluorescence-enhanced optical tomography. (C) RSNA, 2005.