Second cancer risk after radiation therapy of ependymoma using the flattening filter free irradiation mode of a linear accelerator

URN zum Zitieren dieses Dokuments:: urn:nbn:de:bvb:355-epub-376282
DOI zum Zitieren dieses Dokuments:: 10.5283/epub.37628

Alvarez Moret, Judit ; Obermeier, Tina ; Pohl, Fabian ; Loeschel, Rainer ; Koelbl, Oliver ; Dobler, Barbara

Lizenz: Creative Commons Namensnennung 4.0 International
PDF
(657kB)

Veröffentlichungsdatum dieses Volltextes: 24 Aug 2018 10:04

Alternative Links zum Volltext:DOI Verlag Verlag

Details

Vorschau

Indiziert in

Bibliographische Daten exportieren

Zusammenfassung

Zusammenfassung

Pediatric patients suffering from ependymoma are usually treated with cranial or craniospinal three-dimensional (3D) conformal radiotherapy (3DCRT). Intensity-modulated techniques spare dose to the surrounding tissue, but the risk for second malignancies may be increased due to the increase in low-dose volume. The aim of this study is to investigate if the flattening filter free (FFF) mode allows reducing the risk for second malignancies compared to the mode with flattening filter (FF) for intensity-modulated techniques and to 3DCRT. A reduction of the risk would be advantageous for treating pediatric ependymoma. 3DCRT was compared to intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) with and without flattening filter. Dose volume histograms (DVHs) were compared to evaluate the plan quality and used to calculate the excess absolute risk (EAR) to develop second cancer in the brain. Dose verification was performed with a two-dimensional (2D) ionization chamber array and the out-of-field dose was measured with an ionization chamber to determine the EAR in peripheral organs. Delivery times were measured. Both VMAT and IMRT achieved similar plan quality in terms of dose sparing in the OAR and higher PTV coverage as compared to 3DCRT. Peripheral dose in low-dose region, which is proportional to the EAR in organs located in this region, for example, gonads, bladder, or bowel, could be significantly reduced using FFF. The lowest peripheral EAR and lowest delivery times were hereby achieved with VMAT(FFF). The EAR calculated based on DVH in the brain could not be reduced using FFF mode. VMAT(FFF) improved the target coverage and homogeneity and kept the dose in the OAR similar compared to 3DCRT. In addition, delivery times were significantly reduced using VMAT(FFF). Therefore, for radiotherapy of ependymoma patients, VMAT(FFF) may be considered advantageous for the combination of Elekta Synergy linac and Oncentra External Beam planning system used in this study.

Nur für Besitzer und Autoren: Kontrollseite des Eintrags

Downloadstatistik

Altmetric

Alternative Statistik (altmetrics)

Weitere Literatur (mittels CORE)

Details

Vorschau

Indiziert in

Bibliographische Daten exportieren

Zusammenfassung

Zusammenfassung

Downloadstatistik

Downloads

Alternative Statistik (altmetrics)

Weitere Literatur (mittels CORE)

Universitätsbibliothek