Fig. 2.

Explanation of the method used to quantify the measure of the perturbation $m={\langle A/A_0\rangle }_{x_i{z}_i}$ produced by a target inclusion with respect to a reference perturbation. The figure refers to a semi-infinite medium with ${\mu }_s^{\prime }=1{\mathrm{mm}}^{-1}$ ; the source is at (0,0,0) and the receiver at (30,0,0) mm. The target object is a sphere of $1000{\mathrm{mm}}^3$, with $\mathrm{\Delta }{\mu }_a=0.02{\mathrm{mm}}^{-1}$. The reference object is a totally absorbing sphere of $1{\mathrm{mm}}^3$. The numbers $A$ and $A_0$, which are reported in the tables, are the areas under the curve.