Lazzeroni, M.Ureba Sánchez, Ana MaríaRosenberg, V.Schäfer, H.Rühle, A.Baltas, D.Toma-Dasu, I.Grosu, A. L.2025-06-252025-06-252024-05-20Lazzeroni, M., Ureba Sánchez, A.M., Rosenberg, V., Schäfer, H., Rühle, A., Baltas, D.,...,Grosu, A.L. (2024). Evaluating the impact of a rigid and a deformable registration method of pre-treatment images for hypoxia-based dose painting. Physica medica, 122. https://doi.org/10.1016/j.ejmp.2024.103376.1120-17971724-191xhttps://hdl.handle.net/11441/174673Purpose To assess the impact of rigid and deformable image registration methods (RIR, DIR) on the outcome of a hypoxia-based dose painting strategy. Materials and methods Thirty head and neck cancer patients were imaged with [18F]FMISO-PET/CT before radiotherapy. [18F]FMISO-PET/CT images were registered to the planning-CT by RIR or DIR. The [18F]FMISO uptake was converted into oxygen partial pressure (pO2) maps. Hypoxic Target Volumes were contoured on pO2 maps for the deformed (HTVdef) and non-deformed (HTV) cases. A dose escalation strategy by contours, aiming at 95 % tumour control probability (TCP), was applied. HTVs were characterised based on geometry-related metrics, the underlying pO2 distribution, and the dose boost level. A dosimetric and radiobiological evaluation of selected treatment plans made considering RIR and DIR was performed. Moreover, the TCP of the RIR dose distribution was evaluated when considering the deformed [18F]FMISO-PET image as an indicator of the actual target radiosensitivity to determine the potential impact of an unalignment. Results Statistically significant differences were found between HTV and HTVdef for volume-based metrics and underlying pO2 distribution. Eight out of nine treatment plans for HTV and HTVdef showed differences on the level 10 %/3 mm on a gamma analysis. The TCP difference, however, between RIR and the case when the RIR dose distribution was used with the deformed radiosensitivity map was below 2 pp. Conclusions Although the choice of the CTplan-to-PET registration method pre-treatment impacts the HTV localisation and morphology and the corresponding dose distribution, it negligibly affects the TCP in the proposed dose escalation strategy by contours.application/pdf8 p.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/HypoxiaDose paintingImage registrationinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1016/j.ejmp.2024.103376