A closed-loop system for cryosurgery is provided. The system comprises: a closed-loop flow path for a cryofluid at cryogenic temperatures, said closed-loop flow path having a nominal pressure throughout and including a first section and a second section； a pump positioned in the second section of the closed-loop flow path for circulating said cryofluid in said closed-loop flow path； a heat exchanger coupled to a heat sink and positioned in the first section of the closed-loop flow path for cooling said cryofluid in the first section of the closed-loop flow path to cryogenic temperatures； a recuperator in said closed-loop flow path, the recuperator positioned between the first section and the second section, said recuperator configured for transferring thermal energy between said cryofluid in said second section and said cryofluid at cryogenic temperatures in said first section, the second section having an operating temperature substantially greater than cryogenic temperatures； one or more cryoneedles positioned in the first section of the closed-loop flow path, each cryoneedle configured to provide a cryotherapy； and one or more flow control devices positioned in the second section of the closed-loop flow path, each flow control device configured for selectively enabling and disabling a flow of said cryofluid at cryogenic temperatures between said closed-loop flow path and one or more of the cryoneedles.La présente invention concerne un système en boucle fermée pour la cryochirurgie comprenant un cryofluide à des températures cryogéniques circulant dans une voie de circulation en boucle fermée. L'invention concerne également une pompe, conçue pour fonctionner à des températures cryogéniques, qui fait circuler le cryofluide dans la voie de circulation en boucle fermée. La voie de circulation en boucle fermée comprend un échangeur de chaleur couplé à une source froide conçue pour refroidir le cryofluide dans la voie de circulation en boucle fermée à des températures
