Comparison of Rhenium and Iodine as Contrast Agents in X-Ray Imaging

Table 5

Relative average absorbed dose.

X-ray tube potential (kVp)	Amount of additional filtration (mm of Cu)	Mean energy (keV)	Relative current	Relative average absorbed dose
50	0	31.8	10.2	7.0
80	0	42.4	2.8	2.2
120	0	53.7	1.6	1.4
120	0.1	59.0	1.3	1.2
120	0.3	64.9	1.1	1.1
120	0.5	68.1	1.0	1.0
120	1	74.1	0.9	0.9
120	1.5	78.4	0.8	0.9

Using Monte Carlo, the average absorbed dose in a 30 × 30 × 20 cm³ Solid Water® cuboid was calculated at 50, 80, and 120 kVp. The effect of the addition of copper filters with thicknesses between 0.1 and 1.5 mm was also investigated. The average absorbed dose was considered to be 1 at 120 kVp in the presence of a 0.5 mm thick copper filter. The table also shows the mean energy of the X-ray beam incident on the phantom, which is similar to the experimental values within 10%. The relative current is the scaling factor utilized to equalize the number of photons in the transmitted X-ray beam, which was set to 8.5 × 10⁵ (i.e., the number of photons produced at 120 kVp in the presence of a 0.5 mm thick copper filter).