Optical Tomography is a new medical imaging modality that
is at the threshold of realisation. A large amount of clinical
work has shown the very real benefits that such a method could
provide. At the same time a considerable effort has been put
into theoretical studies of its probable success. At present
there exist gaps between these two realms. In this paper, the
underlying basis for the image reconstruction process is reviewed,
and examples are presented that show the realistic resolution,
contrast and specificity that may be expected. In particular
we discuss problems of acquistion time, computational efficiency
and reconstruction artefacts. We suggest in particular that
both time-resolved, and intensity-modulated systems can reconstruct
variations in both optical absorption and scattering, but that
unmodulated, non-time-resolved systems are prone to severe artefact.
Furthermore, classical back-projection style reconstructions
are insufficient and iterative methods are required.