Medical devices using an expandable body to deliver a therapeutic agent. In one particular embodiment, the medical device comprises a tubular catheter and an inner expandable body (e.g., a scaffolding) contained within the catheter. The inner expandable body is connected to a core wire for advancing or retracting the inner body. The inner body may be advanced to exit out of the catheter or retracted to withdraw the inner body back into the catheter. This particular embodiment further comprises a sheath on the outside of the interior of the catheter. The sheath carries a plurality of capsules that contain a therapeutic agent. The therapeutic agent is delivered by pushing the core wire to advance the inner body, which expands against the sheath, causing the capsules on the sheath to be compressed against body tissue such that the therapeutic agent is released.