An applicator is provided, for manipulating one or more catheters carrying a radiation generating device, for delivering a radiation field to a target, the applicator having a proximal end and a distal end. The applicator includes: a spring mechanism at least one catheter grasper for grasping one or more catheters carrying a radiation generating material, the catheter grasper being attached to the spring mechanism and a sheath, for covering at least a portion the spring mechanism. The spring mechanism is designed for being retracted within the sheath, in a closed configuration of the applicator. The spring mechanism is designed for being released into a predetermined arrangement when moved out of a distal end of the sheath, in an open configuration of the applicator. The applicator is designed to be repeatedly switched between the closed configuration and the open configuration.
