TABLE 5
Requirements for Metal Particulate Agents in CT: Required Number Would Scale Inversely with Density
| Diameter of particle containing metal (nm) |  for specific metal at specific keV | Particles per cm3 to be detected | Particles per cell to be detected |
|---|---|---|---|
| 100 | 0.002 for gadolinium at 60 keV | 4 × 1010 | 40 per cell |
| 1,000 | 0.002 for gadolinium at 60 keV | 4 × 107 | 1 every 25 cells |
| 10,000 | 0.002 for gadolinium at 60 keV | 4 × 104 | 1 every 25,000 cells |
| 100 | 0.006 for iron at 30 keV | 12 × 1010 | 120 per cell |
| 1,000 | 0.006 for iron at 30 keV | 12 × 107 | 1 every 8 cells |
| 10,000 | 0.006 for iron at 30 keV | 12 × 104 | 1 every 8,000 cells |
| 100 | 0.001 for lead at 30 keV | 2 × 1010 | 20 per cell |
| 1,000 | 0.001 for lead at 30 keV | 2 × 107 | 1 every 50 |
| 10,000 | 0.001 for lead at 30 keV | 2 × 104 | 1 every 50,000 cells |