Table 2.
Materials used for contrast-to-noise ratio measurements
| Material | Density (103 kg m−3) |
|---|---|
| Air | 0.00 |
| Low-density polyethylene | 0.92 |
| Polytetrafluoroethylene | 2.16 |
| Aluminium | 2.70 |
| Polymethyl methacrylatea | 1.19 |
a
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