{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T15:22:56Z","timestamp":1778685776330,"version":"3.51.4"},"reference-count":27,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T00:00:00Z","timestamp":1756425600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T00:00:00Z","timestamp":1756425600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2025,9]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Extending the source\u2010to\u2010surface distance (SSD) is an effective approach to cover a large irradiation area in electron beam therapy for large planning target volumes (PTVs). However, the accuracy of dose calculations at extended SSDs has not been fully validated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>This study evaluated the dose calculation accuracy of the electron Monte Carlo (eMC) algorithm implemented in Varian's Eclipse radiation therapy planning system (RTPS) under extended SSD conditions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Simulations were conducted using Eclipse version 13.6 for 6, 12, and 18 MeV electron beams, with SSDs ranging from 100 to 140 cm. A 25 cm \u00d7 25 cm applicator and a virtual water phantom were utilized to compute percent depth dose (PDD), off\u2010axis ratio (OAR), and output factor (OPF). The calculated values were compared with measured data and independent Monte Carlo (MC) simulations performed using Particle and Heavy Ion Transport System (PHITS), referred to as PHITS\u2010MC in this study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The eMC algorithm achieved high accuracy along the central axis, with PDD deviations within 2 mm and OPF differences within 3% across all SSDs, including 140 cm. However, eMC exhibited increasing deviations in OAR field size (&gt;3 mm) at SSD \u2265 120 cm. A detailed parameter\u2010based analysis further revealed underperformance in OAR calculations at field peripheries for low\u2010energy beams (6 MeV), compared with PHITS\u2010MC.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The findings delineate the performance and limitations of the eMC algorithm under extended SSD conditions. These limitations should be considered in algorithm evaluation and quality assurance processes. The results provide guidance for algorithm assessment and may serve as a foundation for future studies to explore its clinical relevance in large\u2010field electron beam therapy.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/acm2.70237","type":"journal-article","created":{"date-parts":[[2025,8,30]],"date-time":"2025-08-30T01:36:20Z","timestamp":1756517780000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Evaluation of electron Monte Carlo algorithm accuracy for dose calculations in extended source\u2010to\u2010surface distances electron beam therapy"],"prefix":"10.1002","volume":"26","author":[{"given":"Naohito","family":"Ono","sequence":"first","affiliation":[{"name":"Department of Radiological Technology Juntendo University Shizuoka Hospital  Izunokuni Shizuoka Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Makoto","family":"Omiya","sequence":"additional","affiliation":[{"name":"Department of Radiological Technology Juntendo University Shizuoka Hospital  Izunokuni Shizuoka Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manami","family":"Sugiyama","sequence":"additional","affiliation":[{"name":"Department of Radiological Technology Juntendo University Shizuoka Hospital  Izunokuni Shizuoka Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masaki","family":"Oshima","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Juntendo University, Graduate School of Medicine  Bunkyo\u2010ku Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,8,29]]},"reference":[{"key":"e_1_2_10_2_1","unstructured":"International Commission on Radiation Units and Measurements (ICRU).Radiation Dosimetry: Electrons with Initial Energies Between 1 and 50 MeV. ICRU Report No. 21;1972."},{"key":"e_1_2_10_3_1","unstructured":"International Commission on Radiation Units and Measurements (ICRU).Radiation Dosimetry: Electron Beams with Energies Between 1 and 50 MeV. ICRU Report No. 35;1984."},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v10i3.2834"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v16i3.5036"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v14i2.4062"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.596695"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v12i4.3392"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.5021\/ad.2015.27.1.53"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1093\/jrr\/rrv031"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.3125820"},{"key":"e_1_2_10_12_1","unstructured":"Varian Medical Systems.Eclipse Photon and Electron Algorithms Reference Guide.2015."},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031\u20109155\/55\/16\/S11"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v16i3.4636"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejmp.2016.05.005"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031\u20109155\/51\/11\/007"},{"key":"e_1_2_10_17_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v9i4.2811"},{"key":"e_1_2_10_18_1","unstructured":"Varian Medical Systems. 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