Efficiency and data correction for OFAPT sensors with fiber receivers

This paper addresses the problem of calculations of the efficiency, as well as the necessary raw data correction, essential for the design of an optically induced fluorescence auto-projection tomography (OFAPT) sensor head. Instead of discretizing an analytically derived equation, relevant to a certain symmetry, discretization is implemented on the algorithmic level, thus developing a universal, fully numerical approach to sensitivity and efficiency calculations. The algorithm is built around the calculation of the efficiency of the fluorescence collection from a small discrete voxel. Further, the contributions from all voxels, excited by the OFAPT laser beam at a given distance from the receiver's tip, are added together, to yield the efficiency of the sensor head. OFAPT measurements are simulated on a 64/spl times/64 phantom and the proposed algorithm for correction of the raw data is implemented and assessed. The effect of the magnitude of the absorption coefficient on the data, collected under certain sensor head geometry, is studied in detail. On this basis, optimal excitation beam and receiver configurations are discussed.