I want to take picture of a coronary Stent (used as an implant in heart Artery) of 2.75mm dia and 20mm length?

I have a canon 60D and have only one kit lens of 18-200. This final output of image is needed for a brochure where the image size on the A4 brochure will be approx 7" in length and proportionately in height. Hence the sharpness and focus must be very good, this stent looks like a spring. I have a manto tripod. Can anyone suggest what I can do. I tried the canon EF50mm f2.5macro, but in it the rear part is blurred. Thanks in advance