Accounting for point source propagation properties in 3D fluorescence OPT
Darrell A., Marias K., Garofalakis A., Meyer H., Brady M., Ripoll J.
Reconstructing images from projections in fluorescence Optical Projection Tomography (OPT) is a relatively new problem requiring attention from researchers in this emerging field. There are several aspects of fluorescence OPT which require different treatment compared with non-fluorescence tomography. One significant problem, and the subject of this paper, is that fluorophores emit light isotropically and so the intensity of light captured at a microscope lens is inversely proportional to the square of the distance of the fluorophore from the focal point of the lens. Standard back-projection techniques do not account for this phenomenon and we show numerically that net effect is that fluorophores close to the centre of a body are assigned relatively low values in standard reconstructions. This is an inherent limitation of the standard back-projection method for quantitative fluorescence applications (e.g. in molecular imaging). In this paper we present a working, though computationally intensive, method to account for this, and discuss how more sophisticated (and less computationally intense) methods could be derived in the near future. © 2006 IEEE.