Reduction of computed tomography metal artifacts due to the Fletcher-Suit applicator in gynecology patients receiving intracavitary brachytherapy.

PURPOSE To evaluate a method of reducing computed tomography (CT) metal artifacts due to the Fletcher-Suit applicator. METHODS AND MATERIALS We apply a projection-interpolation algorithm to CT images containing artifacts from the brachytherapy applicator. Regions of projection data containing the applicator are interpolated, removing the metal from the projections. A new image is then reconstructed, and a pixel-by-pixel correction factor applied to the original image to reduce the severity of metal artifacts. This technique is applied to phantom and patient image data. RESULTS Qualitative and quantitative comparisons of images produced before and after projection-interpolation show a significant reduction in metal artifacts. In patient images containing the tandem alone, this method almost completely eliminated the artifact. In slices containing both tandem and colpostats, the algorithm reduced artifacts but did not completely eliminate them. CONCLUSIONS The projection-interpolation method can be used to reduce the severity of metal artifacts caused by the Fletcher-Suit applicator.