a disposable biopsy unit includes a biopsy needle unit and a pump . the biopsy needle unit includes a carrier , a biopsy needle and a cutting sheath . the carrier is configured to mount the biopsy needle and the cutting sheath . the cutting sheath is configured to move along a longitudinal axis relative to the biopsy needle . the pump has an elongate cylinder and a plunger . the plunger is configured to be movable inside the elongate cylinder in a first direction from a distal end of the elongate cylinder to a proximal end of the elongate cylinder to generate a vacuum and configured to be movable inside the elongate cylinder in a second direction from the proximal end of the elongate cylinder to the distal end of the elongate cylinder to build up pressure . the distal end of the elongate cylinder is coupled in fluid communication with the biopsy needle .