Figure 1.
The CT scans of the Cheese phantom reconstructed with the standard algorithm Qr40, acquired at 120 kVp: (a) without metal inserts; (b) with the stainless-steel insert with a nominal density of 8 g/cm3; (c) with the titanium insert with a nominal density of 4.51 g/cm3.
Figure 1.
The CT scans of the Cheese phantom reconstructed with the standard algorithm Qr40, acquired at 120 kVp: (a) without metal inserts; (b) with the stainless-steel insert with a nominal density of 8 g/cm3; (c) with the titanium insert with a nominal density of 4.51 g/cm3.
Figure 2.
The CT scan of the CIRS phantom simulating the pelvis region with the contouring of the prostate (red), seminal vescicles (pink), bladder (light blue), and rectum (orange). (a) Transverse plan; (b) sagittal plan; (c) coronal plan.
Figure 2.
The CT scan of the CIRS phantom simulating the pelvis region with the contouring of the prostate (red), seminal vescicles (pink), bladder (light blue), and rectum (orange). (a) Transverse plan; (b) sagittal plan; (c) coronal plan.
Figure 3.
The CT scans (transverse sections) of the Cheese phantom reconstructed with the standard algorithm Qr40 at 120 kVp: (a) without metal inserts; (b) with the stainless-steel insert; (c) with the titanium insert. Structures of the targets (prostate in red and vescicles in pink) and organs at risk (bladder in light blue and rectum in orange) are visible at the center of each phantom. The density override in the brown ROI of figure (a) allows two ideal phantoms to be obtained, simulating the presence of the stainless-steel insert and the titanium insert, respectively, but without artifacts. The override of densities was also conducted in the metallic ROIs of the other CT scans (b,c).
Figure 3.
The CT scans (transverse sections) of the Cheese phantom reconstructed with the standard algorithm Qr40 at 120 kVp: (a) without metal inserts; (b) with the stainless-steel insert; (c) with the titanium insert. Structures of the targets (prostate in red and vescicles in pink) and organs at risk (bladder in light blue and rectum in orange) are visible at the center of each phantom. The density override in the brown ROI of figure (a) allows two ideal phantoms to be obtained, simulating the presence of the stainless-steel insert and the titanium insert, respectively, but without artifacts. The override of densities was also conducted in the metallic ROIs of the other CT scans (b,c).
Figure 4.
Isodoses, expressed as percentages of the dose to the prostate (100% = 70 Gy), on: (a) the ideal phantom simulating the stainless-steel insert (SRP); (b) the ideal phantom simulating the titanium insert (TRP); (c) the standard reconstruction of the CT scans of the Cheese phantom acquired at 120 kVp with the stainless-steel insert; (d) the standard reconstruction of the CT scans of the Cheese phantom acquired at 120 kVp with the titanium insert.
Figure 4.
Isodoses, expressed as percentages of the dose to the prostate (100% = 70 Gy), on: (a) the ideal phantom simulating the stainless-steel insert (SRP); (b) the ideal phantom simulating the titanium insert (TRP); (c) the standard reconstruction of the CT scans of the Cheese phantom acquired at 120 kVp with the stainless-steel insert; (d) the standard reconstruction of the CT scans of the Cheese phantom acquired at 120 kVp with the titanium insert.
Figure 5.
A representative scheme of the dose calculation procedure.
Figure 5.
A representative scheme of the dose calculation procedure.
Figure 6.
(a) The mean calibration curves at densities up to 1.82 g/cm3 associated with the three different convolution kernels (Qr40 on the left, DD in the middle, and DD + iMAR on the right) used during the reconstruction of the Cheese phantom CT scans with or without the metal inserts. Curves associated with each kVp value, given a convolution kernel, were obtained by averaging the mean HU (or HUDD) value in each ROI over the acquisitions with and without the metal inserts in the Cheese phantom, at the same kVp value. (b) The mean calibration curves at densities ranging from 1.82 g/cm3 to 8 g/cm3 associated with the three different convolution kernels (Qr40 on the left, DD in the middle, and DD + iMAR on the right) used during the reconstruction of the Cheese phantom CT scans with the metal inserts.
Figure 6.
(a) The mean calibration curves at densities up to 1.82 g/cm3 associated with the three different convolution kernels (Qr40 on the left, DD in the middle, and DD + iMAR on the right) used during the reconstruction of the Cheese phantom CT scans with or without the metal inserts. Curves associated with each kVp value, given a convolution kernel, were obtained by averaging the mean HU (or HUDD) value in each ROI over the acquisitions with and without the metal inserts in the Cheese phantom, at the same kVp value. (b) The mean calibration curves at densities ranging from 1.82 g/cm3 to 8 g/cm3 associated with the three different convolution kernels (Qr40 on the left, DD in the middle, and DD + iMAR on the right) used during the reconstruction of the Cheese phantom CT scans with the metal inserts.
Figure 7.
The absolute difference in HU or HUDD between the average calibration curve corresponding to the acquisition at 80 kVp and the average calibration curve corresponding to the acquisition at 140 kVp, for each set of curves related to each reconstruction algorithm. The curve related to the DD reconstruction (DD) matched the curve related to the combined reconstruction DD + iMAR.
Figure 7.
The absolute difference in HU or HUDD between the average calibration curve corresponding to the acquisition at 80 kVp and the average calibration curve corresponding to the acquisition at 140 kVp, for each set of curves related to each reconstruction algorithm. The curve related to the DD reconstruction (DD) matched the curve related to the combined reconstruction DD + iMAR.
Figure 8.
Absolute maximum differences in dose, expressed as percentage of the dose to the prostate (100% = 70 Gy), between the dose distribution calculated on the DD reconstruction of the CT scan of the Cheese phantom acquired with the stainless-steel insert at 120 kVp and the dose distribution calculated on the ideal phantom simulating the presence of the stainless-steel phantom SRP). Green and blue shading corresponds to maximum differences of −0.5% and 0.5%, respectively. The analysis was made with MIM Maestro® and differences are reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 120 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Figure 8.
Absolute maximum differences in dose, expressed as percentage of the dose to the prostate (100% = 70 Gy), between the dose distribution calculated on the DD reconstruction of the CT scan of the Cheese phantom acquired with the stainless-steel insert at 120 kVp and the dose distribution calculated on the ideal phantom simulating the presence of the stainless-steel phantom SRP). Green and blue shading corresponds to maximum differences of −0.5% and 0.5%, respectively. The analysis was made with MIM Maestro® and differences are reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 120 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Figure 9.
The absolute maximum differences in dose, expressed as the percentage of the dose to the prostate (100% = 70 Gy), between the dose distributions calculated on the DD reconstructions of the CT scans of the Cheese phantom with the stainless-steel insert acquired at 100 kVp and 140 kVp, respectively. Blue shading corresponds to maximum differences of 0.5%. The analysis was conducted with MIM Maestro® and differences were reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 100 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Figure 9.
The absolute maximum differences in dose, expressed as the percentage of the dose to the prostate (100% = 70 Gy), between the dose distributions calculated on the DD reconstructions of the CT scans of the Cheese phantom with the stainless-steel insert acquired at 100 kVp and 140 kVp, respectively. Blue shading corresponds to maximum differences of 0.5%. The analysis was conducted with MIM Maestro® and differences were reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 100 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Figure 10.
The absolute maximum differences in dose, expressed as percentage of the dose to the prostate (100% = 70 Gy) between the dose distributions calculated on the DD reconstruction of the CT scan of the Cheese phantom with the stainless-steel insert acquired at 120 kVp using the correct calibration curve and the calibration curve related to the acquisition at 80 kVp, respectively. Blue shading corresponds to maximum differences of 0.5%. The analysis was conducted with MIM Maestro® and the differences were reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 120 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Figure 10.
The absolute maximum differences in dose, expressed as percentage of the dose to the prostate (100% = 70 Gy) between the dose distributions calculated on the DD reconstruction of the CT scan of the Cheese phantom with the stainless-steel insert acquired at 120 kVp using the correct calibration curve and the calibration curve related to the acquisition at 80 kVp, respectively. Blue shading corresponds to maximum differences of 0.5%. The analysis was conducted with MIM Maestro® and the differences were reported on the DD reconstruction of the Cheese phantom acquired with the stainless-steel insert at 120 kVp (axial section on the left, sagittal section at the upper right corner, and coronal section at the lower right corner).
Table 1.
A list of the equivalent materials of the inserts used in the Cheese phantom, with the correspondent nominal mass densities.
Table 1.
A list of the equivalent materials of the inserts used in the Cheese phantom, with the correspondent nominal mass densities.
Equivalent Material | Density (g/cm3) |
---|
LN-300 Lung | 0.300 |
LN-450 Lung | 0.490 |
Adipose | 0.942 |
Breast | 0.979 |
Solid Water | 1.018 |
Brain | 1.053 |
Liver | 1.095 |
Inner Bone | 1.139 |
B-200 Bone | 1.152 |
CB2-30% | 1.334 |
CB2-50% | 1.562 |
Cortical Bone | 1.824 |
Titanium | 4.510 |
Stainless-steel | 8.000 |
Table 2.
The mean HU in the selected cylindrical ROIs in the Cheese phantom with inserts of densities ranging from 0.30 g/cm3 to 8 g/cm3. Data were divided on the basis of the kVp used during the acquisition of the image, on the basis of the reconstruction algorithm (Qr40, DD or the combined algorithm DD + iMAR), and on the basis of the metal insert placed in the phantom. The combined algorithm DD + iMAR was used only for CT scans acquired with the metal inserts.
Table 2.
The mean HU in the selected cylindrical ROIs in the Cheese phantom with inserts of densities ranging from 0.30 g/cm3 to 8 g/cm3. Data were divided on the basis of the kVp used during the acquisition of the image, on the basis of the reconstruction algorithm (Qr40, DD or the combined algorithm DD + iMAR), and on the basis of the metal insert placed in the phantom. The combined algorithm DD + iMAR was used only for CT scans acquired with the metal inserts.
| Convolution Kernel |
---|
Qr40 | DD | DD + iMAR |
---|
80 kVp | 100 kVp | 120 kVp | 140 kVp | 80 kVp | 100 kVp | 120 kVp | 140 kVp | 80 kVp | 100 kVp | 120 kVp | 140 kVp |
---|
Metal Insert | Insert Name | Density (g/cm3) | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean | HU Mean |
---|
None | LN-300 Lung | 0.30 | −710 ± 15 | −713 ± 15 | −712 ± 14 | −711 ± 15 | −714 ± 11 | −717 ± 11 | −715 ± 10 | −714 ± 11 | - | - | - | - |
LN-450 Lung | 0.49 | −511 ± 18 | −512 ± 15 | −513 ± 15 | −516 ± 17 | −520 ± 14 | −519 ± 12 | −520 ± 12 | −522 ± 14 | - | - | - | - |
Adipose | 0.94 | −115 ± 11 | −102 ± 10 | −95 ± 8 | −90 ± 10 | −118 ± 7 | −105 ± 7 | −97 ± 5 | −92 ± 7 | - | - | - | - |
Breast | 0.98 | −57 ± 11 | −52 ± 9 | −48 ± 8 | −46 ± 12 | −61 ± 7 | −55 ± 6 | −51 ± 5 | −48 ± 7 | - | - | - | - |
Solid Water | 1.02 | 9 ± 12 | 4 ± 9 | 3 ± 9 | 1 ± 13 | 7 ± 7 | 3 ± 6 | 2 ± 5 | 0 ± 9 | - | - | - | - |
Brain | 1.05 | 4 ± 14 | 16 ± 9 | 23 ± 11 | 28 ± 10 | 2 ± 9 | 15 ± 6 | 22 ± 7 | 27 ± 6 | - | - | - | - |
Liver | 1.10 | 84 ± 15 | 80 ± 9 | 78 ± 12 | 77 ± 11 | 80 ± 77 | 77 ± 6 | 76 ± 7 | 74 ± 6 | - | - | - | - |
Inner Bone | 1.14 | 314 ± 15 | 253 ± 12 | 220 ± 11 | 196 ± 10 | 106 ± 5 | 107 ± 4 | 108 ± 4 | 107 ± 4 | - | - | - | - |
B-200 Bone | 1.15 | 328 ± 15 | 263 ± 10 | 233 ± 13 | 209 ± 11 | 112 ± 4 | 113 ± 3 | 116 ± 4 | 114 ± 4 | - | - | - | - |
CB2-30% | 1.33 | 621 ± 15 | 525 ± 11 | 471 ± 11 | 438 ± 16 | 226 ± 7 | 235 ± 6 | 243 ± 6 | 250 ± 7 | - | - | - | - |
CB2-50% | 1.56 | 1151 ± 23 | 952 ± 13 | 847 ± 13 | 776 ± 15 | 448 ± 13 | 447 ± 9 | 453 ± 9 | 455 ± 9 | - | - | - | - |
Cortical Bone | 1.82 | 1734 ± 28 | 1449 ± 22 | 1269 ± 1163 | 1163 ± 18 | 719 ± 14 | 712 ± 13 | 703 ± 10 | 703 ± 10 | - | - | - | - |
Titanium | LN-300 Lung | 0.30 | −708 ± 16 | −710 ± 14 | −712 ± 15 | −710 ± 14 | −713 ± 12 | −714 ± 11 | −716 ± 11 | −713 ± 11 | −716 ± 11 | −716 ± 11 | −717 ± 11 | −715 ± 11 |
LN-450 Lung | 0.49 | −513 ± 20 | −515 ± 16 | −516 ± 16 | −58 ± 16 | −521 ± 16 | −521 ± 13 | −521 ± 13 | −522 ± 13 | −522 ± 19 | −521 ± 13 | −521 ± 14 | −522 ± 13 |
Adipose | 0.94 | −114 ± 12 | −101 ± 9 | −94 ± 11 | −89 ± 8 | −118 ± 8 | −104 ± 6 | −97 ± 8 | −92 ± 6 | −118 ± 7 | −104 ± 6 | −97 ± 8 | −92 ± 6 |
Breast | 0.98 | −51 ± 18 | −48 ± 9 | −44 ± 11 | −42 ± 11 | −58 ± 12 | −53 ± 6 | −48 ± 7 | −46 ± 7 | −61 ± 10 | −54 ± 6 | −49 ± 7 | −46 ± 7 |
Solid Water | 1.02 | 14 ±18 | 7 ± 10 | 4 ± 9 | 4 ± 13 | 10 ± 12 | 4 ± 6 | 2 ± 6 | 3 ± 9 | 7 ± 10 | 2 ± 6 | 0 ± 6 | 1 ± 9 |
Brain | 1.05 | 5 ± 12 | 17 ± 9 | 24 ± 8 | 28 ± 8 | 3 ± 8 | 16 ± 6 | 23 ± 5 | 27 ± 6 | 2 ± 8 | 15 ± 6 | 23 ± 5 | 28 ± 6 |
Liver | 1.10 | 85 ± 13 | 79 ± 9 | 77 ± 9 | 77 ± 10 | 80 ± 9 | 77 ± 6 | 75 ± 6 | 75 ± 6 | 80 ± 8 | 77 ± 6 | 75 ± 6 | 75 ± 6 |
Inner Bone | 1.14 | 310 ± 16 | 251 ± 11 | 217 ± 10 | 195 ± 9 | 106 ± 5 | 107 ± 4 | 107 ± 4 | 107 ± 4 | 106 ± 5 | 107 ± 4 | 108 ± 4 | 107 ± 4 |
B-200 Bone | 1.15 | 323 ± 15 | 263 ± 9 | 228 ± 9 | 208 ± 9 | 111 ± 5 | 113 ± 3 | 113 ± 3 | 114 ± 4 | 111 ± 4 | 113 ± 3 | 112 ± 3 | 115 ± 4 |
CB2-30% | 1.33 | 623 ± 18 | 525 ± 11 | 470 ± 10 | 438 ± 14 | 228 ± 8 | 236 ± 6 | 243 ± 6 | 250 ± 6 | 228 ± 8 | 237 ± 6 | 243 ± 6 | 250 ± 7 |
CB2-50% | 1.56 | 1136 ± 21 | 949 ± 12 | 839 ± 11 | 775 ± 14 | 445 ± 12 | 448 ± 9 | 450 ± 8 | 456 ± 9 | 448 ± 12 | 449 ± 9 | 451 ± 8 | 456 ± 9 |
Cortical Bone | 1.82 | 1718 ± 30 | 1430 ± 21 | 1269 ± 19 | 1150 ± 16 | 719 ± 16 | 708 ± 12 | 708 ± 11 | 699 ± 9 | 728 ± 16 | 712 ± 13 | 711 ± 12 | 701 ± 10 |
Titanium | 4.51 | 13,021 ± 468 | 9891 ± 282 | 8059 ± 213 | 6953 ± 172 | 11,539 ± 429 | 8826 ± 245 | 7249 ± 186 | 6306 ± 149 | 11,541 ± 433 | 8828 ± 249 | 7251 ± 188 | 6308 ± 152 |
St. steel | LN-300 Lung | 0.30 | −700 ± 15 | −701 ± 15 | −705 ± 15 | −712 ± 17 | −706 ± 11 | −705 ± 12 | −709 ± 12 | −716 ± 13 | −708 ± 12 | −717 ± 11 | −716 ± 11 | −719 ± 12 |
LN-450 Lung | 0.49 | −525 ± 18 | −513 ± 20 | −516 ± 27 | −516 ± 17 | −531 ± 11 | −518 ± 16 | −522 ± 21 | −520 ± 14 | −533 ± 11 | −524 ± 23 | −525 ± 27 | −523 ± 22 |
Adipose | 0.94 | −111 ± 11 | −97 ± 15 | −91 ± 12 | −87 ± 15 | −115 ± 10 | −100 ± 10 | −94 ± 8 | −90 ± 10 | −115 ± 9 | −105 ± 6 | −98 ± 6 | −91 ± 7 |
Breast | 0.98 | −52 ± 11 | −42 ± 33 | −42 ± 19 | −42 ± 15 | −58 ± 10 | −48 ± 22 | −47 ± 12 | −46 ± 10 | −61 ± 9 | −55 ± 14 | −50 ± 9 | −48 ± 7 |
Solid Water | 1.02 | 13 ± 12 | 18 ± 38 | 16 ± 28 | 5 ± 15 | 10 ± 9 | 15 ± 30 | 13 ± 22 | 3 ± 11 | 7 ± 9 | 4 ± 13 | 3 ± 9 | 0 ± 7 |
Brain | 1.05 | 5 ± 14 | 15 ± 16 | 25 ± 10 | 28 ± 13 | 3 ± 9 | 14 ± 11 | 24 ± 6 | 28 ± 8 | 2 ± 9 | 12 ± 8 | 22 ± 6 | 26 ± 7 |
Liver | 1.10 | 85 ± 15 | 78 ± 13 | 78 ± 13 | 77 ± 12 | 80 ± 9 | 74 ± 8 | 74 ± 8 | 73 ± 7 | 80 ± 9 | 76 ± 6 | 76 ± 6 | 75 ± 6 |
Inner Bone | 1.14 | 310 ± 15 | 247 ± 15 | 215 ± 11 | 196 ± 14 | 106 ± 9 | 106 ± 5 | 107 ± 4 | 108 ± 5 | 106 ± 8 | 107 ± 4 | 107 ± 4 | 109 ± 5 |
B-200 Bone | 1.15 | 322 ± 15 | 261 ± 14 | 229 ± 12 | 208 ± 12 | 111 ± 9 | 112 ± 5 | 112 ± 5 | 115 ± 5 | 111 ± 8 | 113 ± 4 | 114 ± 4 | 115 ± 4 |
CB2-30% | 1.33 | 623 ± 15 | 529 ± 23 | 481 ± 25 | 436 ± 15 | 228 ± 9 | 239 ± 9 | 249 ± 11 | 249 ± 7 | 228 ± 8 | 238 ± 10 | 247 ± 12 | 250 ± 8 |
CB2-50% | 1.56 | 1137 ± 23 | 944 ± 18 | 847 ± 18 | 770 ± 12 | 445 ± 8 | 446 ± 11 | 454 ± 11 | 454 ± 8 | 447 ± 7 | 451 ± 10 | 457 ± 10 | 457 ± 8 |
Cortical Bone | 1.82 | 1718 ± 28 | 1405 ± 25 | 1242 ± 23 | 1150 ± 22 | 719 ± 7 | 698 ± 13 | 693 ± 11 | 701 ± 13 | 728 ± 6 | 718 ± 14 | 713 ± 14 | 711 ± 12 |
St. steel | 8.00 | 27,708 ± 2217 | 19,552 ± 2640 | 17,790 ± 1188 | 15,464 ± 670 | 25,596 ± 2560 | 18,691 ± 2472 | 17,175 ± 1107 | 14,988 ± 625 | 25,591 ± 2303 | 18,682 ± 2488 | 17,170 ± 1116 | 14,989 ± 631 |
Table 3.
The absolute and percentage differences in terms of HU or HUDD, for each non-metallic ROI, between the pairs of images acquired at the same kVp value and reconstructed with the same algorithm but one with and one without metal inserts (stainless-steel or titanium) in the phantom. For data related to the combined algorithm (DD + iMAR), variations were investigated with respect to the images acquired at different kVp without metallic materials and reconstructed with the DD convolution kernel.
Table 3.
The absolute and percentage differences in terms of HU or HUDD, for each non-metallic ROI, between the pairs of images acquired at the same kVp value and reconstructed with the same algorithm but one with and one without metal inserts (stainless-steel or titanium) in the phantom. For data related to the combined algorithm (DD + iMAR), variations were investigated with respect to the images acquired at different kVp without metallic materials and reconstructed with the DD convolution kernel.
| Convolution Kernel |
---|
Qr40 | DD | DD + iMAR |
---|
80 kVp | 100 kVp | 120 kVp | 140 kVp | 80 kVp | 100 kVp | 120 kVp | 140 kVp | 80 kVp | 100 kVp | 120 kVp | 140 kVp |
---|
Metal Insert | Insert Name | Density (g/cm3) | dHU | % | dHU | % | dHU | % | dHU | % | dHUDD | % | dHUDD | % | dHUDD | % | dHUDD | % | dHUDD | % | dHUDD | % | dHUDD | % | dHUDD | % |
---|
Titanium | LN-300 Lung | 0.30 | 2 | 0 | 3 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 2 | 1 | 1 | 0 | 0 | 0 | 2 | 1 | 1 | 0 | 2 | 1 | 1 | 0 |
LN-450 Lung | 0.49 | 2 | 0 | 3 | 1 | 2 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 1 | 0 | 0 | 0 |
Adipose | 0.94 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Breast | 0.98 | 6 | 1 | 5 | 0 | 4 | 0 | 4 | 0 | 3 | 0 | 3 | 0 | 2 | 0 | 3 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 2 | 0 |
Solid Water | 1.02 | 4 | 0 | 3 | 0 | 1 | 0 | 3 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
Brain | 1.05 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
Liver | 1.10 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
Inner Bone | 1.14 | 3 | 0 | 2 | 0 | 3 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
B-200 Bone | 1.15 | 6 | 0 | 0 | 0 | 5 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 0 | 0 |
CB2-30% | 1.33 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
CB2-50% | 1.56 | 15 | 1 | 3 | 0 | 8 | 0 | 1 | 0 | 3 | 0 | 1 | 0 | 2 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 2 | 0 | 1 | 0 |
Cortical Bone | 1.82 | 16 | 1 | 19 | 1 | 0 | 0 | 13 | 0 | 1 | 0 | 4 | 0 | 5 | 0 | 4 | 0 | 10 | 0 | 0 | 0 | 8 | 0 | 2 | 0 |
St.steel | LN-300 Lung | 0.30 | 10 | 3 | 12 | 4 | 6 | 2 | 1 | 0 | 8 | 3 | 11 | 4 | 6 | 2 | 2 | 1 | 6 | 2 | 0 | 0 | 1 | 0 | 5 | 2 |
LN-450 Lung | 0.49 | 14 | 3 | 1 | 0 | 2 | 0 | 0 | 0 | 11 | 2 | 1 | 0 | 2 | 0 | 2 | 0 | 12 | 3 | 5 | 1 | 6 | 1 | 1 | 0 |
Adipose | 0.94 | 4 | 0 | 5 | 1 | 3 | 0 | 3 | 0 | 2 | 0 | 4 | 0 | 2 | 0 | 2 | 0 | 3 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
Breast | 0.98 | 6 | 1 | 10 | 1 | 6 | 1 | 4 | 0 | 3 | 0 | 7 | 1 | 3 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
Solid Water | 1.02 | 4 | 0 | 14 | 1 | 13 | 1 | 4 | 0 | 2 | 0 | 12 | 1 | 11 | 1 | 3 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
Brain | 1.05 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 3 | 0 | 1 | 0 | 1 | 0 |
Liver | 1.10 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Inner Bone | 1.14 | 3 | 0 | 5 | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
B-200 Bone | 1.15 | 6 | 0 | 2 | 0 | 4 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
CB2-30% | 1.33 | 2 | 0 | 4 | 0 | 10 | 1 | 2 | 0 | 2 | 0 | 4 | 0 | 6 | 0 | 0 | 0 | 2 | 0 | 2 | 0 | 4 | 0 | 0 | 0 |
CB2-50% | 1.56 | 15 | 1 | 8 | 0 | 0 | 0 | 6 | 0 | 3 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 4 | 0 | 4 | 0 | 2 | 0 |
Cortical Bone | 1.82 | 16 | 1 | 44 | 2 | 27 | 1 | 12 | 1 | 1 | 0 | 14 | 1 | 9 | 0 | 2 | 0 | 10 | 0 | 6 | 0 | 10 | 1 | 8 | 0 |
Table 4.
The absolute and percentage differences (percentage differences between brackets) in the HU or HUDD between the average calibration curve corresponding to the acquisition at 80 kVp and the average calibration curve corresponding to the acquisition at 140 kVp, for each set of curves related to each reconstruction algorithm.
Table 4.
The absolute and percentage differences (percentage differences between brackets) in the HU or HUDD between the average calibration curve corresponding to the acquisition at 80 kVp and the average calibration curve corresponding to the acquisition at 140 kVp, for each set of curves related to each reconstruction algorithm.
Insert Name | Density (g/cm3) | Convolution Kernel |
---|
| | Qr40 | DD | DD + iMAR |
---|
| | Abs dHU (dHU%) | Abs dHU (dHU%) | Abs dHU (dHU%) |
---|
LN-300 Lung | 0.30 | 5 (2) | 3 (1) | 5 (2) |
LN-450 Lung | 0.49 | 0 (0) | 3 (1) | 5 (1) |
Adipose | 0.94 | 24 (3) | 26 (3) | 25 (3) |
Breast | 0.98 | 10 (1) | 12 (1) | 14 (1) |
Solid Water | 1.02 | 9 (1) | 7 (1) | 7 (1) |
Brain | 1.05 | 23 (2) | 24 (2) | 25 (2) |
Liver | 1.10 | 7 (1) | 6 (0) | 6 (0) |
Inner Bone | 1.14 | 116 (10) | 1 (0) | 2 (0) |
B-200 Bone | 1.15 | 116 (10) | 3 (0) | 3 (0) |
CB2-30% | 1.33 | 185 (23) | 22 (2) | 22 (2) |
CB2-50% | 1.56 | 368 (21) | 9 (0) | 9 (1) |
Cortical Bone | 1.82 | 569 (26) | 18 (1) | 22 (1) |
Titanium | 4.51 | 6068 (76) | 5233 (72) | 5234 (72) |
Stainless-steel | 8.00 | 12,243 (74) | 10,608 (66) | 10,602 (66) |
Table 5.
The gamma indices obtained from the comparation of dose distributions calculated on the images acquired at 120 kVp, with the acceptability criteria of 2% in dose and 2 mm in space. Each distribution considered in the comparisons was identified by the image on which it was calculated (i.e., by the type of algorithm used to reconstruct it (Qr40, DD, DD + iMAR) and by the type of metal insert placed in the Cheese phantom (titanium, steel, or none)).
Table 5.
The gamma indices obtained from the comparation of dose distributions calculated on the images acquired at 120 kVp, with the acceptability criteria of 2% in dose and 2 mm in space. Each distribution considered in the comparisons was identified by the image on which it was calculated (i.e., by the type of algorithm used to reconstruct it (Qr40, DD, DD + iMAR) and by the type of metal insert placed in the Cheese phantom (titanium, steel, or none)).
| | Qr40 |
---|
| | SRP/TRP | Steel | Titanium |
---|
Qr40 | Steel | 100% | - | - |
Titanium | 100% | - | - |
DD | Steel | 100% | 100% | - |
Titanium | 100% | - | 100% |
DD + iMAR | Steel | 100% | 100% | - |
Titanium | 100% | - | 100% |
Table 6.
The maximum differences in dose, expressed as percentages of the prostate dose (70 Gy), derived from the comparation of the dose distributions on the images acquired at 120 kVp, performed with MIM Maestro®. Each distribution considered in the comparisons was identified by the image on which it was calculated (i.e., by the type of algorithm used to reconstruct it (Qr40, DD, DD + iMAR) and by the type of metal insert inserted in the phantom (titanium, steel, or none)).
Table 6.
The maximum differences in dose, expressed as percentages of the prostate dose (70 Gy), derived from the comparation of the dose distributions on the images acquired at 120 kVp, performed with MIM Maestro®. Each distribution considered in the comparisons was identified by the image on which it was calculated (i.e., by the type of algorithm used to reconstruct it (Qr40, DD, DD + iMAR) and by the type of metal insert inserted in the phantom (titanium, steel, or none)).
| | Qr40 |
---|
| | SRP/TRP | Steel | Titanium |
---|
Qr40 | Steel | 2.6% | - | - |
Titanium | 1.6% | - | - |
DD | Steel | 0.5% | 1.6% | - |
Titanium | 0.5% | - | 0.5% |
DD + iMAR | Steel | 0.5% | 1.6% | - |
Titanium | 0.5% | - | 0.5% |