In a method and an apparatus for conducting minimally-invasive procedures involving heart valves at least one multi-access articulated x-ray imaging robot is employed that allows a radiation detector carried by the robot to be moved in arbitrary paths, such as in circle, an ellipse, or along a spiral, around a patient in order to generate multiple projection exposures of the relevant region of the patient during the procedure. An image processor reconstructs a 3D image from the projection exposures substantially in real time during the procedure, and the 3D image is displayed to operating personnel during the procedure.