Effect of copper filtration on phantom DSA readings. Low-dose pediatric protocol, DSA 0.54 nGy/frame, field of view 22 cm, source–image distance 100 cm
| No of frames | Cu filter mm | Grid | DAP µGy.m2 | ESD mGy | Output kV |
| 15 | 0.1 | No | 53.8 | 6.1 | 70 |
| 15 | 0.2 | No | 40.6 | 4.6 | 69 |
| 15 | 0.3 | No | 31 | 3.5 | 71 |
| 15 | 0.6 | No | 18.3 | 2.1 | 75 |
| 15 | 0.9 | No | 13.6 | 1.6 | 80 |
| 15 | 0.1 | Yes | 76.9 | 8.8 | 73 |
| 15 | 0.2 | Yes | 53.4 | 6.1 | 74 |
| 15 | 0.3 | Yes | 40.9 | 4.7 | 76 |
| 15 | 0.6 | Yes | 24.8 | 2.8 | 80 |
| 15 | 0.9 | Yes | 17.9 | 2 | 85 |
Readings using a phantom in the anteroposterior plane and a low-dose pediatric protocol are tabulated with and without the grid. At first glance it would seem that more copper filtration is desirable to reduce DAP and ESD uniformly. However, the right-hand column illustrates the penalty of increasing kVp incurred with this adjustment in filtration, resulting in compromised image quality.
DAP, dose–area product; ESD, estimated skin doses.