Delivery of online adaptive magnetic resonance guided radiotherapy based on isodose boundaries

Votta, Claudio; Cusumano, D.; Boldrini, Luca; Dinapoli, N.; Placidi, L.; Turco, Gabriele; Antonelli, Marco; Pollutri, V.; Romano, Angela; Indovina, Luca; Valentini, Vincenzo

doi:10.1016/j.phro.2021.05.005

Cited by 6 publications

(1 citation statement)

References 34 publications

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“…The contours of target volume and a boundary structure are automatically deformed and transferred onto different cine MR frames. During the treatment session, the beam automatically shuts off, if a user-defined percentage of the volume of interest is outside of the user-defined boundary [ 57 ]. This method has increased delivery precision during both free-breathing and gated treatments with decreased toxicity for close tissues [ 58 ].…”

Section: Discussionmentioning

confidence: 99%

Magnetic resonance guided SBRT reirradiation in locally recurrent prostate cancer: a multicentric retrospective analysis

et al. 2023

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Aims Reirradiation of prostate cancer (PC) local recurrences represents an emerging challenge for current radiotherapy. In this context, stereotactic body radiation therapy (SBRT) allows the delivery of high doses, with curative intent. Magnetic Resonance guided Radiation Therapy (MRgRT) has shown promising results in terms of safety, feasibility and efficacy of delivering SBRT thanks to the enhanced soft tissue contrast and the online adaptive workflow. This multicentric retrospective analysis evaluates the feasibility and efficacy of PC reirradiation, using a 0.35 T hybrid MR delivery unit. Methods Patients affected by local recurrences of PC and treated in five institutions between 2019 and 2022 were retrospectively collected. All patients had undergone previous Radiation Therapy (RT) in definitive or adjuvant setting. Re-treatment MRgSBRT was delivered with a total dose ranging from 25 to 40 Gy in 5 fractions. Toxicity according to CTCAE v 5.0 and treatment response were assessed at the end of the treatment and at follow-up. Results Eighteen patients were included in this analysis. All patients had previously undergone external beam radiation therapy (EBRT) up to a total dose of 59.36 to 80 Gy. Median cumulative biologically effective dose (BED) of SBRT re-treatment was 213,3 Gy (103,1-560), considering an α/β of 1.5. Complete response was achieved in 4 patients (22.2%). No grade ≥ 2 acute genitourinary (GU) toxicity events were recorded, while gastrointestinal (GI) acute toxicity events occurred in 4 patients (22.2%). Conclusion The low rates of acute toxicity of this experience encourages considering MRgSBRT a feasibile therapeutic approach for the treatment of clinically relapsed PC. Accurate gating of target volumes, the online adaptive planning workflow and the high definition of MRI treatment images allow delivering high doses to the PTV while efficiently sparing organs at risk (OARs).

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Section: Discussionmentioning

confidence: 99%