Table 1.
Energy spectra of a Ra-223 vial with MEGP and HEGP
| Energy peak | Relative detector sensitivity with HEGP to MEGP collimator | Relative peak height to that at 84 keV with HEGP | % decrease in sensitivity by attenuation medium | |||
|---|---|---|---|---|---|---|
| Attenuation medium (−) | Attenuation medium (+)a | Attenuation medium (−) | Attenuation medium (+)a | MEGP | HEGP | |
| 84 | 99.5 | 98.3 | NA | NA | 2.9 | 2.3 |
| 154 | 70.2 | 74.1 | 29.3 | 31.2 | 3.4 | 1.1 |
| 269 | 69.8 | 69.9 | 18.9 | 18.8 | 4.3 | 4.1 |
| 351 | 52.0 | 56.8 | 11.2 | 12.0 | 5.5 | 0.9 |
| 402 | 47.5 | 46.4 | 8.8 | 8.8 | 2.4 | 4.1 |
aCT value of a chamber containing attenuation medium enclosing the vial was 350 HU
NA not applicable, MEGP medium-energy general purpose, HEGP high-energy general purpose