SONTU’s virtual dual-energy subtraction function is applied in the posteroanterior(PA) view chest imaging. The images of both bone and soft tissue can be obtained from one single exposure that allows minimum radiation exposure for the patient, and lowers the wear and tear on the equipment. The soft-tissue image is valuable for a better diagnosis of the lesions behind the ribs, such as pulmonary nodules and pulmonary infection; while images of bone are more suitable for examinations with PICC (peripherally inserted central catheter).