ESTRO 2024 - Abstract Book

S5955

RTT - Treatment planning, OAR and target definitions

ESTRO 2024

This study demonstrates that MCO in Eclipse and RayStation resulted in some discrepancies. The discrepancy of the dose to clinical targets in Eclipse is smaller than that of RayStation. On the other hand, the rectal dose reduction of Eclipse shows a greater improvement than RayStation. The existence of pre-computed plan in Eclipse and calculation algorithm difference of the two planning systems could be possible causes of the discrepancies. Nonetheless, these discrepancies leaned towards a more clinically favorable outcome. Although RayStation MCO generated the final deliverable plans with better OARs sparing which could be attributed to insufficient dose boosting to PTV resulting in lower dose to nearby important organs, worse overall dose coverage to the targets is also noted. Radiotherapists should take these into account when selecting and applying MCO clinically. Future studies with more complex cancer cases and focusing on influence of multi-objectives selection in navigation should be conducted.

Keywords: Multi-Criteria Optimization, Prostate cancer

References:

[1] J. Xiao et al., “Multi-criteria optimization achieves superior normal tissue sparing in intensity-modulated radiation therapy for oropharyngeal cancer patients,” Oral oncology, vol. 80, pp. 74–81, 2018, doi: 10.1016/j.oraloncology.2018.03.020. [2] S. Zieminski, M. Khandekar, and Y. Wang, “Assessment of multi ‐ criteria optimization (MCO) for volumetric modulated arc therapy (VMAT) in hippocampal avoidance whole brain radiation therapy (HA ‐ WBRT),” Journal of applied clinical medical physics, vol. 19, no. 2, pp. 184–190, 2018, doi: 10.1002/acm2.12277. [3] A. Kyroudi et al., “Discrepancies between selected Pareto optimal plans and final deliverable plans in radiotherapy multi-criteria optimization,” Radiotherapy and oncology, vol. 120, no. 2, pp. 346–348, 2016, doi: 10.1016/j.radonc.2016.05.018.

956

Poster Discussion

Dutch multicenter comparison and robustness assessment of radiotherapy techniques for breast cancer

Kim Compagner, Tommi S Leijstra, Rik Westendorp, Tristan C.F. van Heijst

Isala, Radiotherapy, Zwolle, Netherlands

Purpose/Objective:

In the Netherlands, various radiation treatment techniques are applied for locally advanced breast carcinoma. We initiated a treatment planning comparison between eight Dutch radiotherapy (RT) departments, all using the same clinical treatment planning system (RayStation, RaySearch Laboratories). The main goal of this study was to gain insight into differences in treatment planning techniques, including a focus on how to minimize the impact of potential anatomical changes during treatment. Therefore, the robustness of photon radiation techniques with respect to displacements of the targets was investigated.