Table 2 BMD measurements based on spectral CT compared to a phantom containing four known concentrations of calcium hydroxyapatite (HA) (100, 200, 400, and 800 mg/cm3).
Measurement differences: | Phantom HA concentrations: | |||||||
|---|---|---|---|---|---|---|---|---|
800 mg/cm3 | 400 mg/cm3 | 200 mg/cm3 | 100 mg/cm3 | |||||
mg/cm3 | % | mg/cm3 | % | mg/cm3 | % | mg/cm3 | % | |
Exposure: | ||||||||
1000 mAs | +1.2 | +0.15% | −2.3 | −0.56% | −1.5 | −0.71% | +2.6 | +2.58% |
500 mAs | −0.3 | −0.03% | −3.5 | −0.87% | −1.3 | −0.61% | +3.5 | +3.49% |
250 mAs | +1.5 | +0.19% | −3.2 | −0.79% | −2.6 | −1.26% | +3.0 | +2.99% |
125 mAs | +13.2 | +1.63% | +2.0 | +0.51% | +3.1 | +1.49% | +4.8 | +4.79% |
50 mAs | +43.0 | +5.32% | +24.2 | +5.98% | +13.8 | +6.62% | +11.2 | +11.22% |
38 mAs | +53.1 | +6.56% | +26.7 | +6.58% | +18.4 | +8.83% | +14.8 | +14.84% |
