Just tell your doc that the next time they jab you that you want to keep the needle. With a little luck, after they finish laughing and you explain why, they will feel sorry for you and give you a clean one.
Find out what caliber they are and then find the tubing that is closest to that size inside when converted to 1/72 scale. Then find some brass tubing that is slightly bigger diameter then the hypodermic is on the outside and you can slide the hypo tubing into the brass tubing as I did, glue it with CA and you are all set. [:D] [;)]
Mike