Fig. 6.

Illustration of the model fit considering the 5-parameter model or 3-parameter model in phantom 3. (Left) The model fit to the data using all parameters: $C_1$, $C_2$, ${\delta }_1$, ${\delta }_2$ and $\alpha$ (with an error of 1.50%). (Right) The model fit to the data using a reduced number of parameters: $C_2$, ${\delta }_1$, and $\alpha$ (with an error of 1.78%). The parameter values can be seen in Tables 1 and 3