Keywords:
Radiation physics, Radioprotection / Radiation dose, Cone beam CT, CT, Dosimetry, Physics, Radiation safety, Quality assurance
Authors:
A. Schegerer1, U. Lechel1, M. Ritter2, G. Weisser2, C. Fink3, G. Brix1; 1Neuherberg/DE, 2Mannheim/DE, 3Celle/DE
DOI:
10.1594/ecr2013/C-1998
Results
On average,
the same local skin doses of 10.6 mGy were measured in the axial plane of the central ray for the high-contrast protocol of CBCT and MSCT (130 kV; 110 mAsreference,
16x0.6 mm,
CTDIvol=7.79 mGy).
However,
there were local dose maxima in case of CBCT exceeding the average dose by ~30% (s.
Fig.
2)
Effective doses were determined from organ doses considering ICRP Publication 60 [1].
For the different acquisition protocols used in this study,
effective doses ranged from 0.52 mSv to 5.2 mSv for the MSCT and from 0.35 mSv to 20 mSv for the CBCT.
The effective dose to receive the same CNR at both CT systems depends on the reconstruction kernel used for MSCT.
For a soft and medium-hard reconstruction kernel,
the dose was statistically lower than that applied at the CBCT.
The difference increases for increasing CNR (s.
Fig.
3).
In contrast,
for hard reconstruction kernels,
the dose at the MSCT has strongly to be increased to receive the CNR of the CBCT.