Abstract: The present disclosure provides a system and method for scanning a subject. The method includes determining reference dimensions, along the width direction of the table, of the subject on the table at positions along the moving direction of the table; dividing, based on the reference dimensions, the subject into at least one region along the moving direction of the table, the at least one region including at least one of a first region or a second region; and controlling a relative motion between the detector and the table to perform scanning on the at least one region in sequence along the moving direction of the table. During scanning one of the at least one region, the detector moves along the width direction of the table relative to the table.