TABLE II.
The CT numbers measured from the physically acquired ACR phantom image, “commercial,” and the CT numbers measured from the simulated ACR phantom image, “forward projection.” Unit: HU. The air, acrylic, bone, polyethylene, and solid water materials are provided by inserts in Module 1 of ACR phantom.
| Air | Acrylic | Bone | Polyethylene | Solid water | ||
|---|---|---|---|---|---|---|
| 80 kV | Commercial | −987 | 102 | 1178 | −111 | 3 |
| Forward projection | −988 | 103 | 1180 | −112 | 4 | |
| 100 kV | Commercial | −987 | 115 | 980 | −93 | 2 |
| Forward projection | −988 | 116 | 981 | −94 | 2 | |
| 120 kV | Commercial | −987 | 121 | 868 | −83 | 3 |
| Forward projection | −987 | 121 | 868 | −82 | 4 | |
| 140 kV | Commercial | −985 | 125 | 797 | −75 | 3 |
| Forward projection | −985 | 126 | 796 | −76 | 4 |