Caption: Figure 5: Comparison of Gray Values for Thinner Aluminum Step Wedges. D, V, and M indicate the Digora, VistaScan, and Megadixel detectors' values.
Caption: Figure 6: Comparison of Gray Values for Thicker Aluminum Step Wedges. D, V, and M indicate the Digora, VistaScan, and Megadixel detectors' values.
Contrast for the thinner phantom (only the aluminum step wedge) was evaluated according to the contrast-to-noise ratio (CNR), which is defined by the following equation:
The phantom used in the study was an aluminum step wedge and a plate.
Concerning the radiopacity of materials, the International Organization for Standardization has stated that radiopacity is evaluated using the aluminum step wedge technique with a range of 0.5-5.0 mm thickness at 0.5 mm increments at an accuracy of >98% purity and 0.05 mm variation in thickness .
(a) Aluminum step wedge with 0.5, 1.0, 1.5, 2.0, 2.5, and 3 mm thickness.
Caption: Figure 7: Comparison of the Contrast-to-Noise Ratio (CNR) for the Thinner Aluminum Step Wedge. (a) Exposure condition with only the aluminum step wedge.