Table 1.
Mean attenuation values and SD of the test object materials at different tube voltages and CTDIvol dose levels
| Tube voltage | 120 kVp | 100 kVp | 80 kVp | |||
|---|---|---|---|---|---|---|
|
| ||||||
| Acrylic (120 HU) | EID | PCD | EID | PCD | EID | PCD |
| 3.0 mGy | 119.1±1.3 | 118.1±0.1 | 111.1±1.6 | 110.2±0.1 | 99.0±1.4 | 99.3±0.2 |
| 1.5 mGy | 119.4±1.6 | 118.4±0.2 | 111.0±2.1 | 110.2±0.1 | 98.8±1.6 | 99.0±0.1 |
| 0.75 mGy* | 118.7±1.5 | 118.3±0.2 | 110.4±1.4 | 110.1±0.2 | 99.1±1.4 | 99.3±0.1 |
| P-value | 0.79 | 0.06 | 0.57 | 0.81 | 0.93 | 0.98 |
|
| ||||||
| Water (0 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -8.0±1.5 | -4.1±0.1 | -8.5±1.5 | -4.2±0.2 | -7.9±1.5 | -4.3±0.4 |
| 1.5 mGy | -8.3±1.5 | -3.7±0.3 | -8.7±1.6 | -4.7±0.4 | -8.7±1.8 | -4.9±0.3 |
| 0.75 mGy* | -8.7±1.6 | -4.1±0.3 | -10.5±1.9 | -6.9±0.21,2 | -9.8±.1.7 | -7.3±0.21,2 |
| P-value | 0.51 | 0.56 | 0.12 | <0.001 | 0.10 | <0.001 |
|
| ||||||
| Emphysema foam (-937 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -936.8±2.0 | -936.9±0.1 | -937.6±1.2 | -936.9±0.1 | -937.8±1.3 | -937.0±0.1 |
| 1.5 mGy | -940.5±1.4 | -937.2±0.2 | -940.2±2.8 | -936.8±0.2 | -940.2±1.2 | -937.0±0.2 |
| 0.75 mGy* | -943.7±1.61,2 | -937.0±0.2 | -943.2±1.41 | -936.9±0.2 | -942.6±3.41 | -937.2±0.1 |
| P-value | <0.001 | 0.24 | <0.001 | 0.60 | 0.005 | 0.14 |
|
| ||||||
| Lung foam (-856 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -857.6±1.3 | -857.7±0.2 | -857.0±1.7 | -857.7±0.3 | -857.8±1.4 | -857.5±0.2 |
| 1.5 mGy | -861.2±2.21 | -857.6±0.4 | -861.4±1.41 | -857.7±0.2 | -860.7±1.41 | -857.7±0.4 |
| 0.75 mGy* | -863.0±1.61 | -857.4±0.2 | -862.5±1.51 | -857.6±0.2 | -864.2±1.81,2 | -857.7±0.4 |
| P-value | <0.001 | 0.11 | <0.001 | 0.39 | <0.001 | 0.27 |
|
| ||||||
| 12-lb NIST foam (-824 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -823.5±1.5 | -823.3±0.2 | -824.7±1.8 | -823.5±0.1 | -824.6±1.3 | -823.3±0.2 |
| 1.5 mGy | -820.6±1.61 | -823.7±0.2 | -821.0±1.51 | -823.5±0.1 | -820.7±1.41 | -823.4±0.4 |
| 0.75 mGy* | -816.8±2.31 | -823.6±0.2 | -818.2±1.31 | -823.4±0.1 | -818.2±1.01 | -823.3±0.4 |
| P-value | <0.001 | 0.05 | <0.001 | 0.39 | <0.001 | 0.73 |
|
| ||||||
| GGN foam (-703 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -702.1±2.0 | -701.7±0.5 | -701.1±1.6 | -701.5±0.4 | -701.6±1.0 | -701.4±0.2 |
| 1.5 mGy | -698.9±2.4 | -701.5±0.4 | -698.3±1.2 | -701.5±0.4 | -698.9±1.51 | -701.6±0.2 |
| 0.75 mGy* | -696.4±2.51 | -701.0±0.4 | -696.2±1.41 | -701.4±0.3 | -696.7±2.11,2 | -701.1±0.6 |
| P-value | 0.002 | 0.07 | <0.001 | 0.82 | <0.001 | 0.43 |
|
| ||||||
| Air (-1000 HU) | EID | PCD | EID | PCD | EID | PCD |
|
| ||||||
| 3.0 mGy | -999.6±2.9 | -995.8±0.1 | -998.7±1.2 | -995.9±0.1 | -999.3±1.7 | -995.7±0.5 |
| 1.5 mGy | -999.3±2.2 | -995.8±0.5 | -998.7±1.6 | -995.8±0.1 | -999.0±1.7 | -995.7±0.1 |
| 0.75 mGy* | -999.0±1.9 | -995±0.2 | -998.9±1.4 | -995.8±0.1 | -998.8±1.4 | -995.5±0.2 |
| P-value | 0.69 | 0.59 | 0.83 | 0.19 | 0.61 | 0.47 |
1
post hoc Bonferroni corrected testing <0.05 versus 120 kVp;
2
post hoc Bonferroni corrected testing <0.05 versus 100 kVp.
*
0.97 mGy for 120 kVp.