Ratchet-slide handle and system for fiducial deployment

A medical device handle configured for controlled incremental lengthwise stylet advancement through a cannula, the handle comprising:

• an elongate outer handle body defining a longitudinal handle lumen;
• an elongate cannula attached directly or indirectly to a distal end of the handle body, the cannula defining a longitudinal cannula lumen in mechanical communication with the handle lumen;
• a rack member, including a plurality of longitudinally-aligned, laterally protruding and depressible, retractable, and/or foldable teeth, where the rack member is disposed within the handle lumen;
• a stylet extending distally from the rack member into the cannula lumen;
• and
• a pair of actuation members with a portion of the actuation members engaging against one of or between two or more of the plurality of teeth, where actuating of the actuation members by moving the actuation members longitudinally relative to the handle along a handle slot of predetermined length is effective to move the rack member distally by a predetermined lengthwise increment.