Fig 4.17: Multi-slice with conventional systems
The spiral, or helical CT was developed to overcome these problems by acquiring data as the table position is moved continuously through the scanner as shown in Fig 4.18. The trajectory of the X-ray beam through the patient traces out a spiral, or helix; hence the name. This technique represented a very significant advance in CT because it allowed scan times for a complete chest abdominal study to be reduced from about 10 min to 1 min. In addition, a full-three dimensional volume dataset could be acquired.