NONMAGNETIC HYPODERMIC NEEDLES FOR MRI ENVIRONMENTS

A NONFERROUS AND NONMAGNETIC HYPODERMIC NEEDLE BASED ON TITANIUM ALLOY METALLURGY IS TO BE FABRICATED AS AN ALTERNATIVE FOR USE IN SERVICE ENVIRONMENTS INVOLVING HIGH MAGNETIC FIELDS AND LONG-TERM IMPLANTATION. STAINLESS-STEELHYPODERMIC NEEDLES COMMONLY USED IN INTRAVENOUS TREATMENT BECOME HAZARDOUS TO PATIENTS UNDERGOING MAGNETIC RESONANCE IMAGING (MRI) DUE TO THE FORCES EXERTED BY THE HIGH MAGNETICFIELDS. HOWEVER, THE DESIRED COMBINATION OF BIOCOMPATIBILITY, FORMABILITY, HIGH STRENGTH, AND DUCTILITY ARE AVAILABLE IN ONLY A FEW METALS. THE MAJORITY OF THE AVAILABLE ALLOY SYSTEMS ARE BASED ON FERROMAGNETIC ELEMENTS AND EXHIBIT HIGH MAGNETIC PERMEABILITIES. A NOVEL METHOD FOR THE FABRICATION OF SMALL-DIAMETER TITANIUM ALLOY TUBES FOR SURGICAL PROCEDURES IS PLANNED. TOOVERCOME THE DIFFICULTIES ENCOUNTERED IN WORKING AND MACHINING MULTIPHASE ALLOY TUBES, A COMBINATION OF MECHANICAL AND CHEMICAL METHODS WILL BE USED. A COMPOSITE ROD CONSISTING OF AN EXPENDABLE METAL CORE SURROUNDED BY A BIOCOMPATIBLE TITANIUM ALLOY OUTER SHEATH ISTO BE CONSOLIDATED INTO A SOLID ROD. THIS WILL ALLOW THE COMPOSITE TO BE WORKED TO FINAL WIRE SIZE BY COMMON DEFORMATION PROCESSING PROCEDURES SUCH AS SWAGING AND DRAWING. RATHER THAN MACHINE THE DESIRED HOLE IN THE ROD, THE CENTER IS TO BE CHEMICALLY REMOVED TO PRODUCE A HOLLOW NEEDLE TUBE OF BIOCOMPATIBLE MATERIAL.