Improved cone beam local tomography

In this paper, we study cone beam local tomography (LT). A new LT function g is proposed. It is shown that g contains non-local artefacts, but their strength is an order of magnitude smaller than those of the previously known LT function g(Lambda) of Louis A K and Maass P (1993 IEEE Trans. Med. Imaging 12 764-69). We also investigate LT reconstruction in the dynamic case, i.e. when the object f being scanned is undergoing some changes during the scan. Properties of g are studied, the notion of visible singularities is suitably generalized, and a relationship between the wave fronts of f and g is established. It is shown that the changes in f do not cause any smearing of the singularities of g. Numerical implementation of the new LT function is discussed, and results of numerical experiments are presented.