## 2 Materials and Methods
### Analysis Procedure  
Other physical parameters were evaluated for tissues and TMMs. Among them, we used the NIST database to calculate the mass attenuation coefficient (\(\mu/\rho\)) and the mass energy absorption coefficient (\(\mu_{en}/\rho\)) according to the additivity rule [21] as follows:  
\[\frac{\mu}{\rho}=\sum_{i}w_{i}(\frac{\mu}{\rho})_{i} \tag{5}\] \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{**Elemental Composition**} & \multicolumn{3}{c}{\(Z_{eq}\)} \\ \cline{3-5}  & & **0.5** & **5** & **15** \\ \hline Adipose & H(12.001), C(64.005), N(0.800), O(22.902), Na(0.050), Mg(0.002) & 6.67 & 5.374 & 5.348 \\  & P(0.016), S(0.070), Cl(10.20), K(0.030), Ca(0.002), Fe(0.002) & & & \\ AD1 & H(8.359), C(69.133), N(2.360), O(16.938), F(3.070), Cl(0.140) & 6.713 & 5.656 & 5.619 \\ AD2 & H(11.180), C(53.310), O(35.510) & 6.914 & 5.635 & 5.597 \\ AD3 & H(14.370), C(85.630) & 5.928 & 4.742 & 4.705 \\ \hline Bone & H(3.392), C(15.509), N(3.972), O(44.128), Na(0.060), Mg(0.210) & 14.08 & 10.49 & 10.44 \\  & P(10.206), S(0.310), Ca(22.213) & & & \\ CB1 & Al(100.000) & 13 & 13 & 13 \\ CB2 & H(4.840), C(38.436), Cl(56.724) & 14.51 & 11.38 & 11.32 \\ CB3 & H(3.100), C(31.260), N(0.990), O(37.570), Cl(0.050), Ca(27.030) & 14.27 & 10.11 & 10.06 \\ CB4 & C(24.020), F(75.980) & 8.653 & 8.251 & 8.243 \\ CB5 & H(4.686), O(56.630), P(10.867), K(27.817) & 14.11 & 10.94 & 10.88 \\ \hline Fat & H(12.210), C(76.080), O(11.710) & 6.007 & 5.127 & 5.111 \\ FA1 & H(14.369), C(85.607), O(0.004), Sb(0.020) & 6.382 & 4.749 & 4.71 \\ FA2 & H(11.701), Li(3.48), C(72.748), O(12.071) & 6.775 & 5.09 & 5.076 \\ FA3 & H(11.840), C(77.320), O(18.40) & 6.774 & 5.141 & 5.126 \\ \hline Lung & H(10.134), C(10.237), N(2.866), O(75.752), Na(0.184), Mg(0.007) & 8.153 & 6.576 & 6.547 \\  & Al(0.001), P(0.082), S(0.225), Cl(0.266), K(0.194), Ca(0.010) & & & \\  & Fe(0.041), Zn(0.001) & & & \\ LU1 & H(5.741), C(73.947), N(2.010), O(18.142), Sb(0.160) & 9.129 & 5.873 & 5.821 \\ LU2 & H(6.000), C(51.440), N(4.290), O(30.720), Al(7.550) & 8.231 & 6.536 & 6.511 \\ LU3 & H(10.100), B(8)), C(79.200), O(10.120), S(1910), Zn(0.670) & 8.843 & 5.325 & 5.298 \\ \hline Muscle & H(10.200), C(12.300), N(3.500), O(72.893), Na(0.080) & 8.075 & 6.534 & 6.506 \\  & Mg(0.020), P(0.200), S(0.500), K(0.300), Ca(0.007) & & & \\ MU1 & H(8.830), C(64.450), N(4.050), O(20.350), Cl(2.240), Sb(0.080) & 8.908 & 5.843 & 5.79 \\ MU2 & H(8.871), C(66.817), N(3.100), O(21.132), Sb(0.080) & 8.037 & 5.63 & 5.593 \\ MU3 & H(5.740), C(77.460), Cl(6.800) & 6.438 & 5.771 & 5.73 \\ MU4 & H(10.200), C(12.101), N(3.540), O(74.250) & 7.505 & 6.459 & 6.435 \\ MU5 & H(5.549), C(75.573), O(18.878) & 6.526 & 5.827 & 5.783 \\ MU6 & H(11.430), C(65.580), O(9.220), Mg(13.480), Ca(0.290) & 8.287 & 5.891 & 5.833 \\ MU7 & H(13.401), C(77.799), O(3.500), Mg(3.860), Tl(1.440) & 8.436 & 5.274 & 5.247 \\ MU8 & H(9.750), C(63.160), N(0.940), O(16.020), Al(9.600), Cl(0.530) & 8.437 & 6.06 & 6.045 \\ MU9 & H(8.119), C(58.344), N(1.780), O(18.638), Mg(13.029), Cl(0.090) & 8.316 & 6.338 & 6.317 \\ MU10 & H(9.799), C(63.683), N(12.379), O(14.139) & 6.364 & 5.48 & 5.452 \\ MU11 & H(14.860), C(85.140) & 5.902 & 4.706 & 4.67 \\ MU12 & H(8.051), C(59.986), O(31.963) & 6.918 & 5.843 & 5.796 \\ MU13 & H(7.74), C(92.26) & 6.301 & 5.284 & 5.267 \\ MU14 & H(10.2), C(76.8), N(3.6), O(5.9), F(1.7), Ca(1.8) & 8.043 & 5.489 & 5.456 \\ MU15 & H(9.654), C(87.489), N(0.06), O(0.473), S(1.539) & 8.42 & 5.407 & 5.377 \\ MU16 & H(11.19), O(88.81) & 7.72 & 6.505 & 6.478 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Percentage elemental composition and equivalent atomic number (for three photon energies in MeV) of studied tissues and their mimicking material candidates. where \(w_{i}\) represents the fraction by weight of the \(i\)th element of the material.