A compact radar system for detecting displacement of an internal organ of a patient in a medical scanner. The system includes at least one transmitting antenna and at least one receiving antenna located in a bed arrangement that supports the patient. In particular, the receiving antenna is located a predetermined distance from a patient reference location to enable detection of electromagnetic energy reflected from a region of the internal organ undergoing asymmetric displacement. The system further includes a radar energizing system that energizes the transmitting and receiving antennas wherein the transmitting antenna irradiates a volume of the patient's body that includes the internal organ. In addition, the receiving antenna detects the reflected electromagnetic energy from the region of the internal organ undergoing asymmetric displacement to enable determination of inhalation and exhalation by the patient.
