S2031
Physics - Dose prediction/calculation, optimisation and applications for photon and electron planning
ESTRO 2026
caused by radiotherapy. Keywords: mass dosimetry, DMH, breast radiotherapy
Digital Poster 5126 Script-based automatization for lattice dosimetry planning in Raystation for tomotherapy Rafael Esteban Chona, Andres Felipe Castillo Radiotherapy, Clinica Mar Caribe, Santa Marta, Colombia Purpose/Objective: Given the iterative nature (both for contouring and planning) of the lattice technique, the goal of this project was to automate the sphere creation and placement following [1,2] as well as other ROI (region of interest) without sacrificing customization, using the scripting tools embedded on the Raystation TPS (treatment planning system). Furthermore, our method includes the creation of a dosimetric plan on a tomotherapy machine ready for fine tuning and
Figure 1. Automated plan created with 15 spheres. It took 20 minutes to complete, from the base PTV to a usable dosimetric plan.Finally, the plan is ready to be evaluated by the physicist or the radiation oncologist in case any fine tuning or adjustment is needed. Results: We tested this method on ten patients with different morphologies and geometries (including breast, head and neck, cervix). The planning time (from the contouring of the PTV and OAR by the clinician to having a viable plan) was reduced from one to two days, down to an hour, for a plan with 65 spheres and less time if the PTV has a smaller volume. Conclusion: We have successfully created an automatic method for contouring and planning for lattice plans for the Raystation TPS on a tomotherapy linac reducing the total time considerably while still allowing customization by the radio oncologist. This is of particular importance, as lattice candidate patients are often in urgent need of radiation treatment. References: 1. Duriseti S et al. Spatially fractionated SBRT (Lattice) for large tumors. Adv Radiat Oncol. 2021;6(3):100639. doi:10.1016/j.adro.2020.100639.2.Tucker WW et al. Script-based automatic grid placement for lattice SBRT. Phys Imaging Radiat Oncol. 2024;29:100549. doi:10.1016/j.phro.2024.100549.3.Chen M et al. Theoretical analysis of the thread effect in helical TomoTherapy. Med Phys. 2011;38(11):5945–60. doi:10.1118/1.3644842. Keywords: Lattice, Raystation, Tomotherapy.
clinical evaluation. Material/Methods:
First, the spheres are created as individual ROIs inside the PTV (Planning target volume) with a custom angle, following the distribution in [1] (figure 1). The user can freely move the union ROI of PTV_spheres, and the individual spheres will move accordingly. Auxiliary structures are then automatically created and the spheres are cropped with the PTV.
Figure 1. Sphere creation for a lesion of 3796 cc. Second, using the prescription data on the beamset, the pitch and jaw are chosen, a beam is created, based on the dose per fraction and the length of the PTV, according to [3]. Optimization objectives are created for each PTV sphere (based on the prescription dose), as well as other ROIs. The optimization algorithm is then executed (figure 2).
Digital Poster 5130 Simultaneous integrated boost in
hypofractionated left breast radiotherapy: VMAT versus 3D conformal for optimal heart subvolume sparing Raouia Ben Amor 1,2 , Ghada Bouguerra 1 , Syrine Lahiouel 1,2 , Siwar Abdessaied 1 , Zeineb Naimi 1,2 , Rihab Haddad 1 , Awatef Hamdoun 1 , Lotfi Kochbati 1,2
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