ESTRO 2024 - Abstract Book

S5468

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

The results indicate there was overall good agreement between groups suggesting CBCT can be adequate for treatment verification without fiducials for MRI-derived CTVs. Whilst the k-value for the long suggests poor agreement, this value was not significant.

Keywords: MRI, PACE B, Radiotherapy

References:

[1] Schmidt, D. R. et al., 2020. A prospective comparison of MRI-planned versus CT-planned radiotherapy for prostate cancer. Journal of Clinical Oncology, pp. 312-312.

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Clinical and geometric results of lung SBRT implementation

Maria Calderó Torra 1 , Iñigo González Lizarraga 2 , Germán Valtueña Peydró 1 , Alejandro Barranco López 2 , Carla Sánchez Cortés 3 , Miriam López Mata 1 1 Hospital Clínico Universitario Lozano Blesa, Radiation oncology department, Zaragoza, Spain. 2 Hospital Clínico Universitario Lozano Blesa, Radiophysics, Zaragoza, Spain. 3 Hospital Universitario de Toledo, Radiation oncology department, Toledo, Spain

Purpose/Objective:

The main objective of this study is to perform a detailed evaluation of clinical and geometric data after the implementation of lung SBRT treatment at our center. The secondary endpoints are: to assess the acute toxicity of radiotherapy treatment in these patients; to determine the magnitude of positioning errors in the 6 degrees of freedom and calculate the margin resulting in PTV for an adapted protocol in lung cancer patients; and to evaluate dispersion of geometric data from initial CBCTs performed during lung SBRT.

Material/Methods:

Longitudinal analytical observational study collecting a pool of patients treated with SBRT of the lung at the Hospital Clínico Universitario Lozano Blesa in Zaragoza from the implementation of this technique in February 2021 until the January 1, 2023. Retrospective data collection has been carried out on the three CBCTs performed for the treatment of these patients: two before irradiation (initial CBCT and verification CBCT) and one final CBCT. For each image set, geographic loss volume was measured by subtracting the PTV from the planning CT and the lung volume on the post-treatment CBCT.