ESTRO 2024 - Abstract Book

S5952

RTT - Treatment planning, OAR and target definitions

ESTRO 2024

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4. Moody, A.M., Mayles, W.P., Bliss, J.M. et al. (1994) The influence of breast size on late radiation effects and association with radiotherapy dose inhomogeneity. Radiother Oncol, 33(2), 106-112.

5. Chua, J.Z., Lim, L.H., Pang, E.P.P., Kusumawidjaja, G. (2023) Use of immobilisation bra for daily setup of patients with pendulous breasts undergoing radiotherapy. Strahlenther Onkol. Online ahead of print.

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Digital Poster

Mitigation of Electron Streaming Effect in thoracic Radiation Treatments using chin and neck bolus

Antonio Lozano Serrano 1 , Beatriz Sanchez Vilela 1 , Patricia Arroyo Corral 1 , Daniel Camacho Martinez 1 , Inmaculada Navarro Domenech 1 , Beatriz Deben Mendez 1 , Concepcion Huertas Martinez 2 , Carlos Luis Ferrer Gracia 2 , Rosa Morera Lopez 1 1 Hospital Universitario La Paz, Radiation Oncology, Madrid, Spain. 2 Hospital Universitario La Paz, Medical Physics, Madrid, Spain

Purpose/Objective:

The electron streaming effect (ESE) is a characteristic of the magnetic resonance linear accelerators (MR-Linac). ESE is a dose enhancement seen at the interface between different media, generated when radiation is delivered in the magnetic field. It affects the dose distribution and modifies the path of scattered secondary electrons. In thoracic radiation treatments (RT), the magnetic resonance field can significantly increase the dose in these areas, so it is important to protect them to avoid secondary toxicity. The aim of this study is to test the patient’s protection against scattered secondary electrons generated by the ESE, using a bolus in the chin and neck.

Material/Methods:

This is a case report of a sternum metastasis treated with Stereotactic body radiotherapy (SBRT) on a MR-Linac, Elekta Unity. In order to protect the chin a neck tissue, a 1cm thick bolus sheet was prepared covering the patient´s neck and chin, where the dose accumulation due to the ESE was greater.