Deblurring subject to nonnegativity constraints when known functions are present with application to object-constrained computerized tomography

The reconstruction of tomographic images is often treated as a linear deblu rring problem. When a high-density, man-made metal object is present somewh ere in the image field, it is a deblurring problem in which the unknown fun ction has a component that is known except for some location and orientatio n parameters. We first address general linear deblurring problems in which a known function having unknown parameters is present. We then show how the resulting iterative solution can be applied to tomographic imaging in the presence of man-made foreign objects, and we apply the result, in particula r, to X-ray computed tomography imaging used in support of brachytherapy tr eatment of advanced cervical cancer.