The intensity of the reflective ultrasonic signals is used to determine {HEAD ~ the location} of {TAIL ~ a preselected body structure} 
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The intensity of the reflective ultrasonic signals is used to determine { HEAD ~ the location } of { TAIL ~ a preselected body structure }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL