Radiopaque nitinol alloys for medical devices

Abstract

A radiopaque nitinol medical device such as a stent for use with or implantation in a body lumen is disclosed. The stent is made from a superelastic alloy such as nickel-titanium or nitinol, and includes a ternary element selected from the group of chemical elements consisting of iridium, platinum, gold, rhenium, tungsten, palladium, rhodium, tantalum, silver, ruthenium, or hafnium. The added ternary element improves the radiopacity of the nitinol stent comparable to that of a stainless steel stent of the same size and strut pattern coated with a thin layer of gold. The nitinol stent has improved radiopacity yet retains its superelastic and shape memory behavior and further maintains a thin strut/wall thickness for high flexibility.

1 - 18 . (canceled) 
   
   
       19 . An alloy, comprising:
 titanium in an amount ranging from about 30 to about 52 atomic percent;   platinum in an amount ranging from greater than 0 to about 15 atomic percent; and   the balance nickel.   
   
   
       20 . The alloy of  claim 19 , wherein platinum is present in an amount greater than or equal to 2.5 atomic percent. 
   
   
       21 . The alloy of  claim 20 , wherein the platinum is present in an amount ranging from greater than or equal to 2.5 atomic percent to less than or equal to about 15 atomic percent. 
   
   
       22 . The alloy of  claim 19 , further comprising a quaternary alloying element. 
   
   
       23 . The alloy of  claim 22 , wherein said quaternary alloying element is iron. 
   
   
       24 . A radiopaque super-elastic alloy, comprising:
 about 37.49 atomic percent titanium;   about 39.48 atomic percent nickel; and   the balance of platinum.   
   
   
       25 . The radiopaque super-elastic alloy of  claim 24 , further comprising a quaternary alloying element. 
   
   
       26 . The radiopaque super-elastic alloy of  claim 25 , wherein said quaternary alloying element is iron.