ESTRO 2024 - Abstract Book

S3613

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Figure 2: the V95% for each plan type against PTV volume for each patient case. The line y=x is plotted to indicate the theoretical performance of a perfectly conformal margin plan.

Conclusion:

Both Robust and Probabilistic treatment plans can achieve equivalent CTV coverage whilst significantly reducing the mean brain dose and the volume of healthy tissue irradiated to 95% of the prescription. Probabilistic planning may give scope for improving CTV coverage in the region of adjacent OARs however the probabilistic method did not always achieve the requested confidence level of OAR tolerance. Robust optimisation achieves a similar improvement over margins as probabilistic planning with a much shorter optimisation time.

Keywords: Probabilistic planning, robust optimisation

References:

1 M.-C. Biston, S. Chiavassa, V. Grégoire, J. Thariat, and T. Lacornerie, “Time of PTV is ending, robust optimization comes next,” Cancer/Radiothérapie, vol. 24, no. 6, pp. 676–686, Oct. 2020, doi: 10.1016/j.canrad.2020.06.016.

2 J. Unkelbach et al., “Robust radiotherapy planning,” Phys. Med. Biol., vol. 63, no. 22, p. 22TR02, Nov. 2018, doi: 10.1088/1361-6560/aae659.

3 L. P. Kaplan et al., “Plan quality assessment in clinical practice: Results of the 2020 ESTRO survey on plan complexity and robustness,” Radiotherapy and Oncology, vol. 173, pp. 254–261, Aug. 2022, doi: 10.1016/j.radonc.2022.06.005.

4 R. Bohoslavsky, M. G. Witte, T. M. Janssen, and M. van Herk, “Probabilistic objective functions for margin-less IMRT planning,” Phys. Med. Biol., vol. 58, no. 11, pp. 3563–3580, Jun. 2013, doi: 10.1088/0031-9155/58/11/3563.

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Poster Discussion

KB plan prediction model for whole breast irradiation: an international inter-consortium experience