Endoscopic view of invasive procedures in narrow passages

Medical apparatus, comprising:

• a medical tool, which is configured to move within a passage in a body of a patient;
• a position sensing system, which is configured to track coordinates of the medical tool within the body;
• a display screen;
• and
• a processor, which is configured to:
• register the position sensing system and a three-dimensional (3D) computerized tomography (CT) image of at least a part of the body within a common frame of reference,
• receive input specifying a performance characteristic, a location, and orientation of at least one virtual camera within the common frame of reference, wherein the input specifying the performance characteristic comprises an instruction to enable the at least one virtual camera to begin to render and display a virtual endoscopic image only when the medical tool approaches the specified location, and
• render and display on the display screen the virtual endoscopic image, based on the 3D CT image, of the passage in the body from the specified location and orientation including an animated representation of the medical tool positioned in the virtual endoscopic image in accordance with the tracked coordinates.