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| Main Authors: | , , , , , , , , |
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| Format: | Artículo Open Access |
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Wiley
2026
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| Online Access: | https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.70310 |
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| author | Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano |
| author_facet | Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano |
| collection | Wiley Open Access |
| contents | Small field dosimetry on a ring‐shape Linac machine with a dual‐layer MLC Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano Medical Physics Abstract Background The Varian Halcyon linac, equipped with a dual‐layer MLC and a single 6 MV FFF beam, is increasingly used for treatments involving small target volumes. The accuracy of dose calculation for small static fields on this platform remains a matter of concern. Purpose This study investigates the dosimetric accuracy of small static fields generated by the Halcyon dual‐layer MLC and to evaluate their modeling in Eclipse through Acuros XB versions 16.1, 18.0, and 18.1. Methods On‐axis field out put factors (FOFs) were measured for square and rectangular fields (0.5–4 cm) according to TRS‐483, using the equivalent square field formalism by Fogliata. Measurements with microDiamond and microSilicon detectors were compared with Acuros XB calculations in Eclipse versions 16.1, 18.0, and 18.1. Profiles and penumbrae were analyzed, and a clinical single‐lesion brain VMAT plan was evaluated. Results The two detectors agreed within ± 0.5%. Differences from vendor Representative Beam Data were 1.1%–1.8% for 1 cm fields. Acuros XB v.16.1 underestimated FOFs by up to –27% for 0.5 × 0.5 cm 2 , while v.18.x agreed within ∼2%. Y ‐direction penumbrae were larger for proximal bank or groove edges, not fully modeled in TPS. In the clinical case investigated, 50% of control points had fields < 1 cm, with central underdosage in v.16.1. Conclusion Acuros XB ≥ 18.x improves small‐field accuracy for Halcyon, although Y‐penumbra modeling remains incomplete. Constraints on minimum field sizes during treatment optimization are important to ensure high accuracy in treatment delivery. 10.1002/mp.70310 http://onlinelibrary.wiley.com/termsAndConditions#vor |
| doi_str_mv | 10.1002/mp.70310 |
| format | Artículo Open Access |
| id | wiley_oa_10_1002_mp_70310 |
| institution | Wiley Open Access |
| license_str_mv | http://onlinelibrary.wiley.com/termsAndConditions#vor |
| publishDate | 2026 |
| publisher | Wiley |
| record_format | wiley_oa |
| spellingShingle | Small field dosimetry on a ring‐shape Linac machine with a dual‐layer MLC Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano Medical Physics Small field dosimetry on a ring‐shape Linac machine with a dual‐layer MLC Antonella Fogliata Antonella Stravato Francesca Dusi Sebastiano Menna Elisa Pilloni Flavio Vincenzo Quaranta Luca Vellini Marco Fusella Davide Cusumano Medical Physics Abstract Background The Varian Halcyon linac, equipped with a dual‐layer MLC and a single 6 MV FFF beam, is increasingly used for treatments involving small target volumes. The accuracy of dose calculation for small static fields on this platform remains a matter of concern. Purpose This study investigates the dosimetric accuracy of small static fields generated by the Halcyon dual‐layer MLC and to evaluate their modeling in Eclipse through Acuros XB versions 16.1, 18.0, and 18.1. Methods On‐axis field out put factors (FOFs) were measured for square and rectangular fields (0.5–4 cm) according to TRS‐483, using the equivalent square field formalism by Fogliata. Measurements with microDiamond and microSilicon detectors were compared with Acuros XB calculations in Eclipse versions 16.1, 18.0, and 18.1. Profiles and penumbrae were analyzed, and a clinical single‐lesion brain VMAT plan was evaluated. Results The two detectors agreed within ± 0.5%. Differences from vendor Representative Beam Data were 1.1%–1.8% for 1 cm fields. Acuros XB v.16.1 underestimated FOFs by up to –27% for 0.5 × 0.5 cm 2 , while v.18.x agreed within ∼2%. Y ‐direction penumbrae were larger for proximal bank or groove edges, not fully modeled in TPS. In the clinical case investigated, 50% of control points had fields < 1 cm, with central underdosage in v.16.1. Conclusion Acuros XB ≥ 18.x improves small‐field accuracy for Halcyon, although Y‐penumbra modeling remains incomplete. Constraints on minimum field sizes during treatment optimization are important to ensure high accuracy in treatment delivery. 10.1002/mp.70310 http://onlinelibrary.wiley.com/termsAndConditions#vor |
| title | Small field dosimetry on a ring‐shape Linac machine with a dual‐layer MLC |
| topic | Medical Physics |
| url | https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.70310 |