A Comprehensive Dosimetric and Plan Quality Evaluation of Non-coplanar VMAT With Flattening Filter-free Versus Flattened Beams for Hippocampal-Avoidance Whole-Brain Radiotherapy: A Multi-Platform Study on Elekta Infinity and UIH uRT-Linac Systems

Technology in Cancer Research & Treatment · Published 2026-07-01 · DOI 10.1177/15330338261467841

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Authors (4)

Xiao-long Cheng, Lu Zhang, Long Sun, Wen-liang Yu

Abstract

Introduction Hippocampal-avoidance whole-brain radiotherapy (HA-WBRT) effectively reduces neurocognitive decline in patients with brain metastases, but evidence from direct multi-platform comparisons remains limited. This study addresses the gap by comparing two mainstream radiotherapy systems for non-coplanar VMAT (NCVMAT) with flattening filter-free (FFF) and flattened (FF) beams. Methods A retrospective dosimetric cohort study was conducted on 22 consecutive patients. Four plan types were created: MC-NCVMAT (Elekta Infinity/Monaco) FFF/FF and UT-NCVMAT (UIH uRT-linac 506c/uRT-TPOIS) FFF/FF. Dosimetry, organ-at-risk (OAR) sparing, efficiency, and plan quality metric (PQM) were evaluated. Identical constraints were applied across platforms. Results UT-NCVMAT showed significantly better homogeneity, conformity, and OAR sparing than MC-NCVMAT. FFF beams outperformed FF in hippocampal protection. UT-NCVMAT reduced beam-on time and planning time by 44%. The 16-item PQM score was significantly higher in the UIH group. Post-hoc power analysis confirmed sample adequacy. Conclusion The UIH uRT-TPOIS system with NCVMAT FFF may offer superior dosimetry, efficiency, and clinical feasibility for HA-WBRT. The PQM model may serve as a reliable tool for standardized plan evaluation. Further multi-center validation is warranted.

Abstract from DOAJ. Public domain (CC0 1.0).

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Publication details

Year
2026

Citation

Cheng, X., Zhang, L., Sun, L., et al. (2026). A Comprehensive Dosimetric and Plan Quality Evaluation of Non-coplanar VMAT With Flattening Filter-free Versus Flattened Beams for Hippocampal-Avoidance Whole-Brain Radiotherapy: A Multi-Platform Study on Elekta Infinity and UIH uRT-Linac Systems. Technology in Cancer Research & Treatment. https://doi.org/10.1177/15330338261467841

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