Levente Varga, Ádám Gáldi, Domonkos Szegedi, András Herein, Dóra Pulugor, István Nahaji, László Gesztesi, Kliton Jorgo, Zoltán Takácsi Nagy, Csaba Polgár, Zsuzsa Kocsis, Tibor Major, Péter Ágoston
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引用次数: 0
Abstract
Introduction: External radiation therapy for bladder cancer requires large planning target volumes (PTVs) due to the daily anatomy of the bladder. Online adaptive radiotherapy (oART) can reduce the PTV by considering daily anatomical changes.
Patients and methods: We performed oART in 8 patients with muscle-invasive bladder cancer between June 10, 2022, and April 14, 2023, on an Ethos linear accelerator (Varian, Palo Alto, USA). Using the 496 cone-beam computed tomography (CBCT) images of the fractions, we retrospectively compared the differences in volumetric changes between oART and image-guided and intensity-modulated radiotherapy (IGRT/IMRT). According to our local protocol, for oART, a patient-specific PTV margin was created based on the intrafractional clinical target volume (CTV) changes observed during the first three fractions.
Results: The average duration of treatment was 14.8 min (range 7-49 min). The average volume of the PTV with oART and IGRT/IMRT was 296.8 cm3 (range 114.5-810.4 cm3) and 416.5 cm3 (range 188.2-991.3 cm3), respectively, representing a 30% reduction with oART. This new technique resulted in an average reduction of 43.9% in the volume of unnecessarily irradiated healthy tissues. Geometrical miss of the CTV occurred in 13 fractions with IGRT/IMRT, with an average of 9.4 cm3 of missed volume (range 0.4-56.4 cm3, standard deviation [SD] 15.73), for oART in 7 fractions, with an average missed volume of 4 cm3 (range 0.4-21.2 cm3, SD: 7.6).
Conclusion: The use of patient-specific margins in oART allows for reduction of the PTV and dose to healthy tissues while achieving equal or better target coverage.
期刊介绍：
Strahlentherapie und Onkologie, published monthly, is a scientific journal that covers all aspects of oncology with focus on radiooncology, radiation biology and radiation physics. The articles are not only of interest to radiooncologists but to all physicians interested in oncology, to radiation biologists and radiation physicists. The journal publishes original articles, review articles and case studies that are peer-reviewed. It includes scientific short communications as well as a literature review with annotated articles that inform the reader on new developments in the various disciplines concerned and hence allow for a sound overview on the latest results in radiooncology research.
Founded in 1912, Strahlentherapie und Onkologie is the oldest oncological journal in the world. Today, contributions are published in English and German. All articles have English summaries and legends. The journal is the official publication of several scientific radiooncological societies and publishes the relevant communications of these societies.
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