CCD-based projectional imaging of fluorescent probes in tissue-like media: experimental setup and characterization

In this article, a non-contact imaging setup for the acquisition of multiple 2D projections of fluorescent probes in tissue-like phantoms is described. The setup basically consists of a high-sensitivity CCD camera for the detection of fluorescence and a rotating broad-beam light source for the continuous illumination of a rotatable phantom located in the rotation center. This allows for imaging of various projections in a full angular projection range of 360°. Beside the detailed description of the system layout, important key characteristics of the setup are outlined. The setup is demonstrated with projectional measurements of a tissue-like phantom and the results are verified by comparison of the projection-dependent fluorescence intensity distributions with corresponding 2D simulations. It is shown that the instrument is suitable for the sensitive detection of fluorescence emanating from fluorescent objects in tissue-like phantoms. Such setup could facilitate the collection of large projection data sets as they are used in optical fluorescence tomography of small animals.