Pose of a probe is detected in x-ray medical imaging. Since the TEE probe is inserted through the esophagus of a patient, the pose is limited to being within the esophagus. The path of the esophagus is determined from medical imaging prior to the intervention. During the intervention, the location in 2D is found from one x-ray image at a given time. The 3D probe location is provided by assigning the depth of the esophagus at that 2D location to be the depth of the probe. A single x-ray image may be used to determine the probe location in 3D, allowing for real-time pose determination without requiring space to rotate a C-arm during the intervention.