The usefulness of K-edge filters in automatic brightness controlled fluoroscopy and digital subtraction angiography

This paper presents the results of a study in which the efficacy of using high atomic number K-edge filters in place of non-selective filters, in Automatic Brightness Controlled fluoroscopy and Digital Subtraction Angiography was examined. Filters investigated in the study were copper, and aluminium [as examples of non-selective filters], gadolinium, erbium and tantalum. The results of this study would suggest, with the possible exception of gadolinium as an added filter in angiography of thin anatomical parts, that the selective K-edge filters offer no particular advantage over the non-selective filters from the viewpoint of either patient dose reduction or image contrast. Further, for imaging of all but the thinnest anatomical parts, their use adds substantially to the problems of x-ray tube loading.