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Table 2 Phantom measurements.

From: Investigation of the usability of conebeam CT data sets for dose calculation

  1F 4F IMRT plan
Correction strategy 6 MV 18 MV 6 MV 18 MV 10 MV
(a) CBCT, S10F0      
HU-DpCT 19.9% ± 2.5% 15.5% ± 2.1% 19.5% ± 0.7% 14.7% ± 0.5% 8.8% ± 6.3%
HU-DS10F0 4.2% ± 1.2% 2.6% ± 0.9% 1.8% ± 0.3% 2.1% ± 0.3% 0.8% ± 0.8%
(b) CBCT, M20F1      
HU-DpCT 18.4% ± 3.7% 13.7% ± 2.4% 12.7% ± 1.0% 11.6% ± 0.5% 6.8% ± 5.6%
HU-DM20F1 2.6% ± 0.7% 1.9% ± 0.9% 3.2% ± 0.7% 1.1% ± 0.3% 1.0% ± 1.1%
  1. Comparison of dose calculation based on planning CT and CBCT with different correction strategies for the different test plans (1F, 4F and IMRT) for phantom studies acquired with different presets: (a) collimation S10 and no filter (S10F0) and (b) collimation M20 and bow tie filter (M20F1). The standard table (HU-DpCT) was created based on the CT and densities values of the planning CT phantom scan. The phantom based tables HU-DM20F1, HU-DS10F0 were based on the CBCT phantom data sets acquired M20F1 and S10F0, respectively. The mean difference between the dose in the planning CT and the CBCT is given in percentage of the dose based on the planning CT.