A biopsy device includes a housing body, and a cannula assembly having a first elongate cannula and a second elongate cannula coaxial with the first elongate cannula. The second elongate cannula has a side wall and a lumen. The side wall has a vacuum side port in fluid communication with the lumen. A vacuum source is positioned in the housing body. The vacuum source has a chamber side wall, which may define a CT-shaped volume, and has a chamber vacuum port. A seal is interposed in sealing engagement between the chamber vacuum port and the second elongate cannula. A trigger slide assembly is configured to move the second elongate cannula to align the vacuum side port of the second elongate cannula with the chamber vacuum port of the vacuum source to supply vacuum from the vacuum source to the lumen of the second elongate cannula. The trigger slide assembly is operated so that a first movement of the slider body retracts the cannula assembly a first distance to latch the cannula assembly in the retracted position and to compress the cannula drive spring； a second movement of the slider body retracts the cannula assembly a second distance cumulative with the first distance to align the vacuum side port of the elongate cannula with the chamber vacuum port of the vacuum source to supply vacuum from the vacuum source to the second lumen of the elongate cannula； and a third movement of the slider body in a distal direction releases the proximal latch mechanism such that the cannula drive spring decompresses to propel the cannula assembly in the distal direction.
