Iterative method and apparatus for x-ray computed tomographic fluoroscopy

In the present invention, an iterative process is provided for computed tomographic fluoroscopy (CTF) based upon an ordered-subset based algorithm or an adaptation of the row-action expectation maximization (RAEM) formula. This process is applied to reduce metal artifacts in CTF imaging, reduce image noise and provide rapid-image updating suitable for real-time applications. In one embodiment, generation of a projection mask and computation of a relaxation matrix are used to compensate for beam divergence and data incompleteness, and a priori knowledge such as a known image support is used to reduce image reconstruction errors.