The helical scanning CT unit, in which an X-ray tube continuously rotates at the rate of one revolution per second with constant movement of the table on which the patient is placed, was clinically tested in scanning of upper abdomen. Quality of the images obtained was equal to that of conventional CT. The images were particularly good at an X-ray beam width of 5 mm and table movement of 5 mm/sec with scan parameters of 120 kvp, 200 mA. Because of limitation of the X-ray tube capacity. X-ray beam width of 5 mm and table movement of 10 mm/sec with scan parameters of 120 kvp, 150 m, would be the most appropriate clinically. Application of the helical scanning CT will result in examination times shorter than in the case of conventional high-resolution CT and be obtained images at early vascular enhancement phase through the whole scanning area, so that it can be expected to be extremely useful in clinical diagnosis involving upper abdomen.