S1833
Physics - Dose prediction/calculation, optimisation and applications for photon and electron planning
ESTRO 2026
carcinoma in the era of image-guided radiotherapy. Front Oncol. 2021 Sep 20;11:753908. doi:10.3389/fonc.2021.753908.2.Gómez D, Cahlon O, Mechalakos J, Lee N. An investigation of intensity- modulated radiation therapy versus conventional two- dimensional and 3D-conformal radiation therapy for early stage larynx cancer. Radiat Oncol. 2010;5:74. doi:10.1186/1748-717X-5-74.3. Muzaffar K, Collins SL, Labropoulos N, Baker WH. A prospective study of the
Oncology*Biology*Physics. Keywords: Probabilistic treatment planning
Digital Poster 1402
carotid sparing in early-stage laryngeal cancer: a dosimetric comparison between 3DCRT, IMRT, and VMAT Mizada M. Mohamed, Karen Gonzalez, Maholy Paredes, Daneli Ruiz Centro Universitario Contra El Cancer, Hospital Universitario Dr. Jose Eleuterio Gonzalez, Monterrey, Mexico Purpose/Objective: To compare carotid artery dosimetry in patients with early-stage laryngeal cancer treated with 3DCRT, IMRT, and VMAT. Material/Methods: A retrospective comparative study was conducted on 20 patients with stage I–II laryngeal carcinoma treated at the University Hospital “Dr. José Eleuterio González”. Radiotherapy plans were generated using 3DCRT, IMRT, and VMAT. Maximum dose (Dmax), mean dose (Dmean), and V35 and V50 were recorded for both carotid arteries. Statistical analysis included ANOVA or Friedman tests, with p ≤ 0.05 considered significant. Results: Mean carotid dose was significantly lower with IMRT (21.5 Gy) and VMAT (18.9 Gy) compared with 3DCRT (33.7 Gy; p < 0.001). Likewise, V35 and V50 were substantially reduced with IMRT and VMAT (p < 0.001). Dmax was higher with 3DCRT (68.1 Gy) versus IMRT (61.6 Gy) and VMAT (62.0 Gy). Planning target volume (PTV) coverage remained equivalent across all techniques.
effects of irradiation on the carotid artery. Laryngoscope. 2000;110(11):1811-1814. doi:10.1097/00005537-200011000-00012. Keywords: Laryngeal cancer, carotid sparing, dosimetric
Digital Poster 1413 Dosimetric evaluation of dose fall-off in
neoadjuvant ultrahypofractionated radiotherapy with simultanous integrated boost for soft tissue sarcomas Nina Gercek 1 , Elena Kyryschuk 1 , Justus Kaufmann 1 , Stephanie Göller 1 , Sophia Drabke 1 , Liv-Annebritt Weimer 1 , Anna Sabrina Schunn 1 , Frank Traub 2 , Heinz Schmidberger 1 1 Department of Radiation Oncology, University Medical Center, Mainz, Germany. 2 Department of Orthopaedics and Trauma Surgery, University Medical Center, Mainz, Germany Purpose/Objective: To test feasibility and dosimetric evaluation of dose fall-off beyond tumor margins in the planned tumor bed when applying neoadjuvant ultrahypofractionated radiotherapy (RT) with a simultanous integrated boost (SIB) for soft tissue sarcomas (STS) of the extremities. Material/Methods: In this study, we conducted a retrospective analysis of 10 patients with histologically confirmed STS of the extremities, who underwent neoadjuvant conventionally fractionated RT (25 × 2,0 Gy) between 2021 and 2023. For each patient we created eight volumetric-modulated-arc-therapy treatment plans of 25 Gy in five fractions, with dose escalation within the macroscopic tumor volume (PTV_Boost) using a SIB of 6,0 Gy / 6,5 Gy / 7,0 Gy and 7,5 Gy per fraction, respectively. For each dose escalation, we calculated two plan variations with- and without - skin - protection. We performed a dosimetric comparison of the dose fall-off beyond tumor margins in the planned tumor bed and dose distribution within PTV_Boost. Results: The mean tumor volume was 552cm ³ (Range 53,2– 2935cm ³ ). The dose fall-off 5mm outside of PTV_Boost in PTV_low in plans without - skin - protection was - 2,2±0,4 Gy and in plans with - skin - protection -1,5±0,5
Conclusion: IMRT and VMAT significantly decrease radiation exposure to the carotid arteries without compromising target coverage. This dosimetric advantage may translate into reduced late vascular and cerebrovascular risk, supporting the preferential use of advanced techniques in early-stage laryngeal cancer. References: 1.Gupta A, Wong KH, Newbold K, Bhide S, Nutting C, Harrington KJ. Early-stage glottic squamous cell
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