## 5 Conclusions  
To conclude, the main objective of this study was the automatic segmentation of OARs and prostate in the pelvic region and the construction of a TPS-readable RT structure set. The presented work compared different training strategies with an in-house dataset of 103 cases. The 2.5D ResAttU-Net was the optimal model compared to plain U-Net and Attention U-Net. The mean DSC for each organ in the test dataset was 0.84, 0.92, 0.88, 0.88, and 0.80 for the rectum, bladder, femoral head (right), femoral head (left), and prostate, respectively. Problems arose mainly related to the class imbalance, where the organs were not shown in each slice. The proposed model shows great potential to be adapted to different anatomical regions or additional organs in the pelvic region for radiation therapy planning, which requires a considerable amount of training samples. For future work, dosimetry analysis will be performed. The final tool for the pelvic region is clinically used in our institution and is available for any ViewRay Inc. MRIdian user. The source code for the project is available on GitHub. ([[https://github.com/manoskout/automatic_segmentation](https://github.com/manoskout/automatic_segmentation)]([https://github.com/manoskout/automatic_segmentation](https://github.com/manoskout/automatic_segmentation))) (accessed on 25 July 2023).  
Conceptualization, E.K., L.M., I.B. and A.L.; methodology, E.K., L.M., I.B. and A.L.; software, E.K. and E.M.; validation, E.K., L.M., I.B. and A.L.; formal analysis, I.B. and A.L.; investigation, E.K. and E.M.; data curation, L.M., L.A., C.J. and I.B.; writing, original draft preparation, E.K.; writing, review and editing, L.M., I.B. and A.L.; funding acquisition, A.L. All authors have read and agreed to the published version of the manuscript.  
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Organs**} & **Our Work** & **[PERSON] et al. [37]** & **[PERSON] et al. [40]** \\ \cline{2-4}  & **Dice \(\pm\) STD** & **Dice \(\pm\) STD** & **Dice \(\pm\) STD** \\ \hline \multirow{2}{*}{Rectum Bladder} & 0.84 \(\pm\) 0.10 & 0.82 \(\pm\) 0.05 & 0.78 \(\pm\) 0.07 \\  & 0.92 \(\pm\) 0.09 & 0.93 \(\pm\) 0.04 & 0.90 \(\pm\) 0.09 \\  & 0.88 \(\pm\) 0.08 & - & 0.90 \(\pm\) 0.02 \\  & 0.88 \(\pm\) 0.08 & - & 0.89 \(\pm\) 0.03 \\  & 0.80 \(\pm\) 0.15 & 0.85 \(\pm\) 0.07 & - \\ \hline \multicolumn{2}{c}{Sequence Protocol} & \multicolumn{1}{c}{SSFP} & \multicolumn{1}{c}{T2-weighted} & Multisequence \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison with recent works related to the pelvic region.  
**Institutional Review Board Statement:** This study was approved by the human subject ethics board of the Centre Georges-Francois Leclerc and was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2013. Moreover the study was in accordance to the GDPR (General Data Protection Regulation). All participants were given clear information about the study, and their non-opposition was obtained.  
**Data Availability Statement:** Ethical reasons prohibit the public availability of the dataset. However, it can be confidentially communicated to the reviewers and the Journal's Editor if necessary.  
**Conflicts of Interest:** The authors declare no conflict of interest.