An imaging apparatus comprising a patient table configured for supporting a lying patient, comprising a gurney and a base, wherein said gurney can slide between two extreme positions with respect to said base in a direction longitudinal to the gurney itself, comprising an electrically supplied motoreducer controlled by a control unit, configured to slide said table along at least one spatial axis, comprising a sliding lock/unlock system, said sliding lock/unlock system is a mechanical system independent from the electrical supply, manually controlled by a handle which is actuated by a human operator and wherein said lock/unlock system comprises two opposing elements (17, 18) wherein said first and second opposing elements are mounted on a shaft and adapted to rotate independently of each other, and wherein at least one of said elements is axially movable in the direction of insertion and disconnection of the two said elements by a movement mechanism in the axial direction of the said insertion elements; said lock/unlock system is provided with two brackets, a first fixed bracket and a second mobile bracket; and wherein at a first end of the handle, opposed to a second end configured to be grabbed by said human operator, said handle is provided with a spring pin which engages alternatively: - In an insertion hole located in the fixed bracket, blocking the system in a position wherein the motion of the motoreducer is transmitted; - In a dis-insertion hole located in the fixed bracket blocking the system in a position wherein the motion of the motoreducer is idle; said lock/unlock system comprises a proximity sensor recognizing the axial position of the handle: when said spring pin is inserted in said insertion hole, said sensor is active and adapted to communicate to the control unit of the radiographic apparatus that said gurney is moved in an automatic way; and while when said handle is extracted from said insertion hole, said sensor is inactive, and adapted to signal to said control unit that the motoreducer is idle; and wherein X-ray emission of the imaging apparatus is blocked by the control unit when said lock/unlock system is in its dis-insertion position. wherein said lock/unlock system comprises two opposing elements (17, 18) wherein said first and second opposing elements are mounted on a shaft and adapted to rotate independently of each other, and wherein at least one of said elements is axially movable in the direction of insertion and disconnection of the two said elements by a movement mechanism in the axial direction of the said insertion elements; said lock/unlock system is provided with two brackets, a first fixed bracket and a second mobile bracket; and wherein at a first end of the handle, opposed to a second end configured to be grabbed by said human operator, said handle is provided with a spring pin which engages alternatively: - In an insertion hole located in the fixed bracket, blocking the system in a position wherein the motion of the motoreducer is transmitted; - In a dis-insertion hole located in the fixed bracket blocking the system in a position wherein the motion of the motoreducer is idle; - In an insertion hole located in the fixed bracket, blocking the system in a position wherein the motion of the motoreducer is transmitted; - In a dis-insertion hole located in the fixed bracket blocking the system in a position wherein the motion of the motoreducer is idle; said lock/unlock system comprises a proximity sensor recognizing the axial position of the handle: when said spring pin is inserted in said insertion hole, said sensor is active and adapted to communicate to the control unit of the radiographic apparatus that said gurney is moved in an automatic way; and while when said handle is extracted from said insertion hole, said sensor is inactive, and adapted to signal to said control unit that the motoreducer is idle; and wherein X-ray emission of the imaging apparatus is blocked by the control unit when said lock/unlock system is in its dis-insertion position.