{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T22:07:09Z","timestamp":1787695629211,"version":"build-2784847793"},"reference-count":28,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2024,12,20]],"date-time":"2024-12-20T00:00:00Z","timestamp":1734652800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2025,4]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>In radiotherapy, body contour inaccuracies may compromise the delineation of adjacent structures and affect calculated dose. Here, we evaluate the un\u2010editable body contours auto\u2010generated by Ethos versions 1.0 (v1) and 2.0 (v2) treatment planning softwares for two simulated cases: weight\u2010loss and bolus application, particularly important for head and neck radiotherapy patients.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A 3D\u2010printed target structure was secured to the neck of an anthropomorphic phantom and sequentially covered with silicone boluses of uniform thickness, providing cases for bolus application (0.5 and 1\u00a0cm) and weight\u2010loss (2.0, 1.5, 1.0, 0.5, and 0\u00a0cm). HyperSight CBCT images of the phantom were acquired to simulate the online adaptation process. Baseline body contours were manually produced and compared to those auto\u2010generated in Ethos v1 (synthetic CTs) and Ethos v2 (synthetic CTs and direct calculation on HyperSight CBCTs). Additionally, the target volume D95% dose metric for weight\u2010loss adapted plans generated by the Ethos v2 were analyzed as a function of surface layer thickness.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The Ethos v1 body contour did not adapt adequately for the weight\u2010loss image set [mean absolute volume deviation from baseline (MAD)\u00a0=\u00a0205 cm<jats:sup>3<\/jats:sup>]. The weight\u2010loss synthetic CT and HyperSight CBCT volumes in Ethos v2 were comparable to manually generated contours (MAD\u00a0=\u00a034 and 46\u00a0cm<jats:sup>3<\/jats:sup><jats:sub>,<\/jats:sub> respectively); however, the bolus Hypersight CBCT body contour intersected the outer edge of the phantom (MAD\u00a0=\u00a0157\u00a0cm<jats:sup>3<\/jats:sup>). The D95% deviation from the planned dose decreased by up to 10% when using the Ethos v2 adapted plan for the weight\u2010loss scenario.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Contours in Ethos v1 rely on reference contours and deformable registration algorithms, whereas Ethos v2 does not. Hence, Ethos v2 is preferred for cases involving weight change. A tight\u2010fitted air gap\u2010free bolus is critical for achieving accurate body contours for Ethos v2 Hypersight CBCTs.<\/jats:p><\/jats:sec>","DOI":"10.1002\/acm2.14587","type":"journal-article","created":{"date-parts":[[2024,12,20]],"date-time":"2024-12-20T17:39:04Z","timestamp":1734716344000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Body contour adaptation for weight\u2010loss and bolus for head and neck radiotherapy on Ethos version 2.0 and HyperSight: Synthetic CT versus direct calculation"],"prefix":"10.1002","volume":"26","author":[{"given":"Abby","family":"Yashayaeva","sequence":"first","affiliation":[{"name":"Department of Physics and Atmospheric Sciences Dalhousie University  Halifax Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R. 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