Compression devices and mammography units using the same, and methods of using the same during imaging of a patient's breast are provided. The devices compress the breast against a bucky without the need for a traditional mammography unit compression paddle. The devices comprise at least one x-ray transparent inflatable chamber for containing a fluid, for example, a pressurized gas. In use, at least one surface of the chamber expands in the direction of the bucky. The devices secure the breast to the bucky by wrapping over the tube-side surface of the breast. Compressed air, for example, can be introduced, manually or automatically, to inflate the chamber. As the chamber expands, breast motion is limited and the breast is compressed against the surface of the bucky.