Keywords:
Physics, CT, Radiographers, Trauma
Authors:
T. Esaki, T. Kawashima; Shimotsuke City/JP
DOI:
10.26044/ecr2019/C-0129
Conclusion
HD FOV Pro had lower CT value and distortion than eFOV.
The eFOV significantly decreased CT value at offset 4 cm.
The algorithm used for eFOV is extrapolation.
Offset 4 cm was not properly extrapolated because sinogram was truncated because of bone at the boundary between FOV and Extended FOV.
However,
HD FOV Pro was presumed to be able to appropriately extrapolate even if sinogram was truncated due to the change of the extrapolation method.
The distortion by HD HOV Pro improved by up to 2.9% compared with eFOV.
However,
as with eFOV,
distortion increased due to offset the increase.
Distortion could be suppressed with Bolus.
Since the CT value of the boundary between the phantom and air is gradually converted to that of air in the extrapolation process,
the boundary is lost with the use of a bolus,
improving the CT value and distortion (Fig. 10).
In conclusion Compared to eFOV,
HD FOV Pro improves CT value reduction and distortion.
CT value and distortion are improved by Bolus even if HD FOV Pro is used.