CT-Dose-Index of Standard-CT corresponds to CT-Dose-Effect-Index of Spiral-CT. Spiral-CT provides a continuous data acquisition with well balanced dose profiles. Increasing pitch reduces radiation dose and nevertheless an unbroken reconstruction of scanned volume is possible. In contrast to Standard-CT, small parts at both ends of the volume scan are not reconstructed. Volume-Dose-Index therefore is elevated in short scan times but corresponds to that of Standard-CT in long scan times. 1 mm slices cause more radiation exposure due to their broadened dose profiles.