TABLE IV.
Errors between calculated and ion chamber measured dose for the spine case. The baseline calculation error for uncorrected CT imaging is listed as well as the absolute change in calculation error when CT artifact reduction methods are used (o-mar, gsi, and mars), when metal kernels are used (MK), and when artifact reduction and metal kernels are used together for the dose calculation. Positive results indicate increased errors (i.e., worse performance).
| Chamber 1 | Chamber 2 | Average | |
|---|---|---|---|
| Baseline % errora | 4.3% | 2.0% | 3.2% |
| Absolute change in % error | |||
| o-mar | +0.7 | +0.1 | +0.4 |
| gsi 140 keV | +0.7 | −0.4 | +0.2 |
| mars 140 keV | +1.4 | +2.7 | +2.1 |
| MK | +0.1 | −0.3 | −0.1 |
| O-MAR + MK | +0.9 | −0.1 | +0.4 |
| GSI + MK | +0.8 | −0.5 | +0.2 |
| MARS + MK | +1.4 | +2.7 | +2.1 |
a
Average % error based on two uncorrected CT imaging methods (GE 120 kVp and Philips 120 kVp).