Joan Penninkhof1, Sara Spadola2, Sebastiaan Breedveld3, Margreet Baaijens3, Nico Lanconelli4, Ben Heijmen3. 1. Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam, The Netherlands. Electronic address: j.penninkhof@erasmusmc.nl. 2. Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam, The Netherlands; Department of Physics and Astronomy, Alma Mater Studiorum, University of Bologna, Bologna, Italy. 3. Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam, The Netherlands. 4. Department of Physics and Astronomy, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
Abstract
PURPOSE AND OBJECTIVE: Propose a novel method for individualized selection of beam angles and treatment isocenter in tangential breast intensity modulated radiation therapy (IMRT). METHODS AND MATERIALS: For each patient, beam and isocenter selection starts with the fully automatic generation of a large database of IMRT plans (up to 847 in this study); each of these plans belongs to a unique combination of isocenter position, lateral beam angle, and medial beam angle. The imposed hard planning constraint on patient maximum dose may result in plans with unacceptable target dose delivery. Such plans are excluded from further analyses. Owing to differences in beam setup, database plans differ in mean doses to organs at risk (OARs). These mean doses are used to construct 2-dimensional graphs, showing relationships between: (1) contralateral breast dose and ipsilateral lung dose; and (2) contralateral breast dose and heart dose (analyzed only for left-sided). The graphs can be used for selection of the isocenter and beam angles with the optimal, patient-specific tradeoffs between the mean OAR doses. For 30 previously treated patients (15 left-sided and 15 right-sided tumors), graphs were generated considering only the clinically applied isocenter with 121 tangential beam angle pairs. For 20 of the 30 patients, 6 alternative isocenters were also investigated. RESULTS: Computation time for automatic generation of 121 IMRT plans took on average 30 minutes. The generated graphs demonstrated large variations in tradeoffs between conflicting OAR objectives, depending on beam angles and patient anatomy. For patients with isocenter optimization, 847 IMRT plans were considered. Adding isocenter position optimization next to beam angle optimization had a small impact on the final plan quality. CONCLUSION: A method is proposed for individualized selection of beam angles in tangential breast IMRT. This may be especially important for patients with cardiac risk factors or an enhanced risk for the development of contralateral breast cancer.
PURPOSE AND OBJECTIVE: Propose a novel method for individualized selection of beam angles and treatment isocenter in tangential breast intensity modulated radiation therapy (IMRT). METHODS AND MATERIALS: For each patient, beam and isocenter selection starts with the fully automatic generation of a large database of IMRT plans (up to 847 in this study); each of these plans belongs to a unique combination of isocenter position, lateral beam angle, and medial beam angle. The imposed hard planning constraint on patient maximum dose may result in plans with unacceptable target dose delivery. Such plans are excluded from further analyses. Owing to differences in beam setup, database plans differ in mean doses to organs at risk (OARs). These mean doses are used to construct 2-dimensional graphs, showing relationships between: (1) contralateral breast dose and ipsilateral lung dose; and (2) contralateral breast dose and heart dose (analyzed only for left-sided). The graphs can be used for selection of the isocenter and beam angles with the optimal, patient-specific tradeoffs between the mean OAR doses. For 30 previously treated patients (15 left-sided and 15 right-sided tumors), graphs were generated considering only the clinically applied isocenter with 121 tangential beam angle pairs. For 20 of the 30 patients, 6 alternative isocenters were also investigated. RESULTS: Computation time for automatic generation of 121 IMRT plans took on average 30 minutes. The generated graphs demonstrated large variations in tradeoffs between conflicting OAR objectives, depending on beam angles and patient anatomy. For patients with isocenter optimization, 847 IMRT plans were considered. Adding isocenter position optimization next to beam angle optimization had a small impact on the final plan quality. CONCLUSION: A method is proposed for individualized selection of beam angles in tangential breast IMRT. This may be especially important for patients with cardiac risk factors or an enhanced risk for the development of contralateral breast cancer.
Authors: Roberta Castriconi; Pier Giorgio Esposito; Alessia Tudda; Paola Mangili; Sara Broggi; Andrei Fodor; Chiara L Deantoni; Barbara Longobardi; Marcella Pasetti; Lucia Perna; Antonella Del Vecchio; Nadia Gisella Di Muzio; Claudio Fiorino Journal: Front Oncol Date: 2021-08-24 Impact factor: 6.244
Authors: Nienke Bakx; Hanneke Bluemink; Els Hagelaar; Jorien van der Leer; Maurice van der Sangen; Jacqueline Theuws; Coen Hurkmans Journal: Phys Imaging Radiat Oncol Date: 2021-04-28
Authors: M S Thomsen; M Berg; S Zimmermann; C M Lutz; S Makocki; I Jensen; M H B Hjelstuen; S Pensold; M P Hasler; M-B Jensen; B V Offersen Journal: Clin Transl Radiat Oncol Date: 2021-04-06