A procedure that uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body. The x-ray machine scans the body in a spiral path. This allows more images to be made in a shorter time than with older CT methods. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly on the x-ray. Helical computed tomography also creates more detailed pictures and may be better at finding small abnormal areas inside the body. It may be used to help diagnose disease, plan treatment, or find out how well treatment is working. Also called spiral CT scan.