Reusable Syringe

The invention relates to a reusable syringe with a syringe body for receiving an ampoule. At the front end of the syringe body there is an opening which defines an axis along which a needle can be inserted. A plurality of holding segments are arranged around this axis and engage behind a needle carrier in the longitudinal direction. According to the invention, a holding segment designed as a thread part is movable in the radial direction. The invention further relates to a system composed of a reusable syringe, a needle carrier, and a container for used needles. Moreover, the invention includes an associated method for connecting and releasing a needle of a reusable syringe. The movable holding segment facilitates the release of the threaded connection of the needle carrier from the syringe body and makes the reusable syringe safer to use.