## 4 Results
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**US System** & **Probe** & \multicolumn{2}{c}{**AdSTM (mm)**} & \multicolumn{2}{c}{**TTM [18] (mm)**} & \multicolumn{2}{c}{**Observers (mm)**} \\ \hline \hline \multirow{8}{*}{A} & \multirow{3}{*}{L} & set 1 & \(36\pm 3\) & 4.3 & \(35\pm 2\) & 2.9 & \(39\pm 3\) & 4.3 \\ \cline{3-8}  & & set 2 & \(38\pm 2\) & 2.9 & \(38\pm 3\) & 4.3 & \(37\pm 3\) & 4.3 \\ \cline{2-8}  & & set 1 & \(152\pm 3\) & 1.7 & \(154\pm 6\) & 3.3 & \(138\pm 12\) & 6.7 \\ \cline{2-8}  & & set 2 & \(141\pm 2\) & 1.1 & \(124\pm 2\) & 1.1 & \(128\pm 6\) & 3.3 \\ \cline{2-8}  & & set 1 & \(101\pm 5\) & 2.8 & \(105\pm 4\) & 2.2 & \(107\pm 10\) & 5.6 \\ \cline{2-8}  & & set 2 & \(106\pm 3\) & 1.7 & \(86\pm 2\) & 1.1 & \(97\pm 7\) & 3.9 \\ \hline \multirow{8}{*}{B} & \multirow{3}{*}{L} & set 1 & \(43\pm 2\) & 2.9 & \(40\pm 3\) & 4.3 & \(40\pm 3\) & 4.3 \\ \cline{2-8}  & & set 2 & \(42\pm 2\) & 2.9 & \(40\pm 2\) & 2.9 & \(40\pm 2\) & 2.9 \\ \cline{2-8}  & & set 1 & \(99\pm 2\) & 1.1 & \(84\pm 3\) & 1.7 & \(83\pm 6\) & 3.3 \\ \cline{2-8}  & & set 2 & \(89\pm 2\) & 1.1 & \(78\pm 3\) & 1.7 & \(77\pm 7\) & 3.9 \\ \cline{2-8}  & & set 1 & \(120\pm 2\) & 1.1 & \(113\pm 5\) & 2.8 & \(109\pm 8\) & 4.4 \\ \cline{2-8}  & & set 2 & \(102\pm 2\) & 1.1 & \(100\pm 4\) & 2.2 & \(98\pm 10\) & 5.6 \\ \hline \multirow{8}{*}{C} & \multirow{3}{*}{L} & set 1 & \(46\pm 2\) & 2.9 & \(39\pm 2\) & 2.9 & \(41\pm 4\) & 5.7 \\ \cline{2-8}  & & set 2 & \(48\pm 2\) & 2.9 & \(47\pm 2\) & 2.9 & \(48\pm 3\) & 4.3 \\ \cline{2-8}  & & set 1 & \(151\pm 6\) & 3.3 & \(142\pm 5\) & 2.8 & \(143\pm 8\) & 4.4 \\ \cline{2-8}  & & set 2 & \(140\pm 2\) & 1.1 & \(142\pm 6\) & 3.3 & \(135\pm 5\) & 2.8 \\ \cline{2-8}  & & set 1 & \(124\pm 2\) & 1.1 & \(99\pm 2\) & 1.1 & \(118\pm 14\) & 7.8 \\ \cline{2-8}  & & set 2 & \(118\pm 9\) & 5.0 & \(120\pm 5\) & 2.8 & \(112\pm 13\) & 7.2 \\ \hline \multirow{8}{*}{D} & \multirow{3}{*}{L} & set 1 & \(43\pm 2\) & 2.7 & \(28\pm 2\) & 2.7 & \(37\pm 4\) & 5.4 \\ \cline{2-8}  & & set 2 & \(40\pm 2\) & 2.7 & \(28\pm 2\) & 2.7 & \(35\pm 2\) & 2.7 \\ \cline{2-8}  & & set 1 & \(107\pm 2\) & 1.1 & \(-1\) & \(-1\) & \(81\pm 8\) & 4.3 \\ \cline{1-1} \cline{2-8}  & & set 2 & \(104\pm 2\) & 1.1 & \(61\pm 3\) & 1.6 & \(96\pm 6\) & 3.3 \\ \cline{1-1} \cline{2-8}  & & set 1 & \(138\pm 6\) & 3.1 & \(78\pm 3\) & 1.6 & \(130\pm 7\) & 3.7 \\ \cline{1-1} \cline{2-8}  & & set 2 & \(141\pm 2\) & 1.0 & \(86\pm 2\) & 1.0 & \(138\pm 7\) & 3.7 \\ \hline \hline \end{tabular}  
* L = linear array probe; C = convex array probe, V = vector/phased array probe. Results are reported in terms of mean \(\pm\) SD (\(\mu\pm\)) (\(\mu\)). The percentage error is expressed with respect to the field of view (\(\%_{\text{FOV}}=100\) (\(\sigma/\text{FOV}\))) whose values are reported in Table 2. 1 Missing outcome.  
\end{table} 
Table 4: DOP outcomes for different US diagnostic systems. Figure 1: Depth of penetration for A and B diagnostic systems equipped with linear L, convex C, vector V probes tested in sets 1 and 2. DOP\({}_{\#1}\) and DOP\({}_{\#2}\) were evaluated through the AdSTM and the TTM [18], respectively, while DOP\({}_{\#3}\) was assessed by naked eye. DOP values are represented with related error bars due to the total uncertainties reported in Table 4.  
Figure 2: Depth of penetration for C and D diagnostic systems equipped with linear L, convex C, vector V probes tested in sets 1 and 2. DOP\({}_{\#1}\) and DOP\({}_{\#2}\) have been evaluated through the AdSTM and the TTM [18], respectively, while DOP\({}_{\#3}\) was assessed by naked eye. DOP values are represented with related error bars due to the total uncertainties reported in Table 4.  
Furthermore, the only missing outcome reported in Table 4 was due to the TTM impossibility of retrieving a DOP value for the convex probe in set 1 configuration, despite the highest STC setting.