Table 2. Comparison of errors in NC, 5D, and RMP model predictions between 4DCT1 and 4DCT2.
| Prediction error (mm) | t Test P value | ||||
|---|---|---|---|---|---|
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|
|
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| Points | Model | Mean | SD | vs NC | vs 5D |
| All points | NC | 2.0 | 2.8 | - | - |
| 5D | 1.2 | 1.7 | .004 | - | |
| RMP | 1.2 | 1.8 | .002 | .72 | |
| Left points | NC | 2.1 | 3.0 | - | - |
| 5D | 1.3 | 1.7 | .003 | - | |
| RMP | 1.2 | 1.8 | .002 | .57 | |
| Right points | NC | 2.0 | 2.4 | - | - |
| 5D | 1.1 | 1.5 | .004 | - | |
| RMP | 1.3 | 1.7 | .013 | .09 | |
Abbreviations: BP = breathing pattern; 4DCT1 = first 4-dimensional computed tomography scan; 4DCT2 = second 4-dimensional computed tomography scan; 5D = 5-dimensional; NC = noncorrected; RMP = respiratory motion perturbation.
No significant difference was found between the 5D and RMP models using the Student t test (n = 800).