Photoacoustic tomography and fluorescence molecular tomography: a comparative study based on indocyanine green.

Purpose: Both photoacoustic tomography (PAT) and fluorescence molecular tomography (FMT) can be used for molecular imaging when contrast agents are administrated. The goal of this work is to comparatively evaluate the performance of reflection-mode PAT and FMT in common phantom when indocyanine green (ICG) was used as a contrast agent.

Methods: Reflection-mode PAT and FMT systems were developed. Target embedded in a background phantom with different ICG concentration, size, and depth location was examined. Comparisons were made in terms of target morphology, spatial resolution, and sensitivity between the two modalities.

Results: Phantom results showed that PAT and FMT gave different image morphology. PAT offered higher spatial resolution, while FMT provided higher sensitivity. Thus, improved target detection could be achieved by correlating the complementary information obtained from the two modalities.

Conclusions: The combination of high resolution PAT and high sensitivity FMT will provide a more complete range of pathology spectra for more reliable target detection, suggesting a potentially better diagnostic tool when this combination coupled with the administration of ICG as contrast agent is applied to clinical problems in the future.