ESTRO 2025 - Abstract Book

S2864

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

ESTRO 2025

Results:

The TR for Bg-LRT and HCP-LRT within ADC10%, ADC20%, ADC30%, ADC40%, and ADC50% are 15.442% vs. 3.420%, 11.069% vs. 2.886%, 9.200% vs. 2.884%, 8.005% vs. 3.053%, and 7.352% vs. 3.024%, respectively, all showing significant differences (p < 0.001). For TR GTV and PVDR GTV , Bg-LRT and HCP-LRT values are 2.721% vs. 2.403% and 2.754% vs. 1.476%, respectively, both showing significant differences (p < 0.05). The Dmean to OARs for Bg-LRT and HCP-LRT are as follows: heart 6.177 Gy vs. 6.236 Gy, stomach 8.712 Gy vs. 8.926 Gy, esophagus 8.722 Gy vs. 8.864 Gy, kidneys 5.812 Gy vs. 5.762 Gy, and duodenum 6.240 Gy vs. 6.597 Gy. These differences are not statistically significant (p > 0.05). Details are provided in Table 1. Conclusion: This study demonstrates the feasibility of biologically guided lattice arrangements for LRT. The proposed strategy enhances both the TR GTV and PVDR GTV , along with the TR in biologically targeted regions, potentially increasing tumor control rates. Additionally, the generated LRT plans maintain low doses to OARs, offering a novel perspective for LRT. References: [1] Jiang L, Li X, Zhang J, et al. Combined high-dose LATTICE radiation therapy and immune checkpoint blockade for advanced bulky tumors: the concept and a case report[J]. Front Oncol, 2020, 10: 548132. DOI: 10.3389/fonc.2020.548132. [2] Xu P, Wang S, Zhou J, et al. Spatially fractionated radiotherapy (Lattice SFRT) in the palliative treatment of locally advanced bulky unresectable head and neck cancer[J]. Clin Transl Radiat Oncol, 2024, 48: 100830. DOI: 10.1016/j.ctro.2024.100830. [3] Lawrence LSP, Chan RW, Chen H, et al. Diffusion-weighted imaging on an MRI-linear accelerator to identify adversely prognostic tumour regions in glioblastoma during chemoradiation. Radiother Oncol[J]. 2023, 188, 109873. DOI: 10.1016/j.radonc.2023.109873. Keywords: Spatially fractionated RT, functional imaging