# Feasibility of a Patient-Specific Bolus Using the Life-Casting Method for Radiation Therapy
## 3 Results
### In Vivo Dosimetry Using OSLD  
Table 2 displays the expected dose values in the treatment plan, the dose values measured using OSLD, and the %Diff between the two values. To minimize the setup errors introduced by the operator, the setup for all tests in this study was conducted using the ExacTracDynamic(r) system version 1.0 (Brainlab AG, Munich, Germany), a surface guided radiation therapy system. In the 3D-CRT plan, the patient-specific bolus showed a mean %Diff of 0.82 \(\pm\) 0.61% and a maximum %Diff of 1.69%. In contrast, when the SuperFlab bolus was used, the mean %Diff was measured as 1.10 \(\pm\) 0.61%, while the maximum %Diff was 2.00%. It is worth noting that the analysis of the three measurements for each point revealed a higher maximum standard deviation between the measurements obtained with the SuperFlab bolus (7 Gy) than with the patient-specific bolus (3 Gy).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{3}{c}{**3D-CRT**} & \multicolumn{2}{c}{**VMAT**} \\ \hline
**Dosimetric** & **Patient-Specific** & **SuperFlab** & **Patient-Specific** & **SuperFlab** \\
**Parameter** & **Bolus** & **Bolus** & **Bolus** & **Bolus** \\ \hline CL\_PTV & 0.31 & 0.31 & 0.94 & 0.93 \\ \hline HI\_PTV & 0.16 & 0.17 & 0.05 & 0.05 \\ \hline V\({}_{\rm 95\%\_PTV}\) (\%) & 92.2 & 91.3 & 100.0 & 99.8 \\ \hline V\({}_{\rm 20 Gy\_Lung}\) (\%) & 17.5 & 17.5 & 10.8 & 10.7 \\ \hline D\({}_{\rm mean\_Lung}\) (Gy) & 9.72 & 9.66 & 6.84 & 6.79 \\ \hline V\({}_{\rm 25 Gy\_Heart}\) (\%) & 8.50 & 8.45 & 1.13 & 0.97 \\ \hline D\({}_{\rm mean\_Heart}\) (Gy) & 5.92 & 5.82 & 4.84 & 4.71 \\ \hline \hline \end{tabular} Abbreviations: 3D-CRT, three-dimensional conformal radiation therapy; VMAT, volumetric modulated arc therapy; CI, conformity index; PTV, planning target volume; V\({}_{\rm 95\%\_}\) target coverage; HI, homogeneity index.  
\end{table}
Table 1: Dosimetric results for each plan.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**3D-CRT**} \\ \hline \multicolumn{6}{c}{Patient-Specific Bolus} & \multicolumn{6}{c}{SuperFlab Bolus} \\ \hline Point & Plan (cGy) & \begin{tabular}{c} OSLD \\ (cGy, Mean \(\pm\) SD) \\ \end{tabular} & \begin{tabular}{c} \%Diff \\ (\%) \\ \end{tabular} & Point & Plan (cGy) & \
\begin{tabular}{c} OSLD \\ (cGy, Mean \(\pm\) SD) \\ \end{tabular} &
\begin{tabular}{c} \%Diff \\ (\%) \\ \end{tabular} \\ \hline P1 & 189 & \(189\pm 1\) & 0.31 & P1 & 194 & 192 & 0.88 \\ \hline P2 & 202 & \(206\pm 3\) & 1.69 & P2 & 209 & \(213\pm 7\) & 2.00 \\ \hline P3 & 202 & \(202\pm 1\) & 0.20 & P3 & 198 & \(201\pm 2\) & 1.19 \\ \hline P4 & 204 & \(206\pm 2\)In the VMAT plan, utilizing the patient-specific bolus resulted in a mean %Diff of 3.42 \(\pm\) 1.01%. Conversely, employing the SuperFlab bolus yielded a higher mean %Diff of 7.19 \(\pm\) 1.90%. The maximum %Diff observed for the patient-specific bolus was 5.03%, whereas the maximum %Diff observed for the SuperFlab bolus was 10.1%. Moreover, considering the results of the three measurements, the maximum standard deviation between the measurements was higher with the SuperFlab bolus (14 cGy) than with the patient-specific bolus (8 cGy).