X-ray Analysis of Stents and their Markers

Abstract

Balloon expandable stents can be used to treat coronary stenosis. During stent implantation, X-ray imaging is used. In order to assist the doctors, it was decided to improve the cardiovascular stents’ X-ray absorption ability by placing a unique marker in the stent strut. Tantalum powder, with 98% purity and 3-10 μm grains diameter, was used as the stent integrated marker. The stents were laser cut from a 1.81 mm external diameter stainless steel tube. The integrated marker was made by laser ablation, micro-welding and cutting. The X-ray absorption ability of the stent struts with and without markers was compared and a new analyzing method was created by which the volume of the stent integrated marker can be determined. The stent integrated tantalum powder increased the stent’s local X-ray visibility by 0.73%. A new index-number was introduced using which the stent’s X- ray absorption ability can be estimated at the stent’s planning stage.