Scanning Single Section-‘Step and Shoot’ mode

The routine use of a CT scanner requires only few scan modes. These can be operated with a wide range of parameter stings. A routine examination simply requires taking a survey radiograph for orientation over the anatomy question, selecting slices or scan region s and scanning them in sequential or in spiral CT mode

Sequential partial scan examination may become more important for cardiac imaging with very fast cone beam scanners. A minimum scan range of 180⁰ plus the fan angle is required to measure all line integrals at least once in fans beam geometry (Parker, 1982). This means, example .that prospectively triggered scans of the heart can be taken in about 0,24 s on a 0.35 s rotation scanner , such as the Toshiba Aquilion One. In most cases this yields scans essentially free of motion artefact in the diastolic phase.

Depending on the total collimation 1 to 4 scans are necessary. The total scan time is significantly higher than in spiral scanning and transition zones may show discontinuities due to breathing motion or changes in heart frequency heart phase selective imaging will be  discussed in the further in next post. 

The step wise scanning of volumes by successive section scans, frequently termed as step and shoots approach can be applied to other organs or anatomical ranges. Its suffers from the disadvantages mentioned above,, in particular whenever patient motion may be involved