{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T16:41:12Z","timestamp":1792514472695,"version":"4.5.0"},"reference-count":22,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T00:00:00Z","timestamp":1792454400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T00:00:00Z","timestamp":1792454400000},"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":[[2026,11]]},"abstract":"Abstract<\/jats:title>\n \n Background<\/jats:title>\n Treating multiple brain metastases simultaneously with single\u2010isocenter multi\u2010target (SIMT) stereotactic radiosurgery (SRS) can streamline treatment planning and delivery. However, it can also result in targets at large distances from the isocenter, increasing sensitivity to rotational setup errors and requiring wider collimator leaves. Grouping the targets and treating each group with its own plan retains the practical benefits of SIMT SRS while mitigating the concerns of targets at large distances off\u2010isocenter.<\/jats:p>\n <\/jats:sec>\n \n Purpose<\/jats:title>\n This work presents a prototype of a newly integrated treatment planning pipeline that automatically clusters targets into groups and subsequently optimizes a plan for each group simultaneously. Treatment scenarios featuring varying numbers of isocenters were compared.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n Twenty\u2010nine treatment courses for patients receiving SRS for 3\u201315 brain metastases were retrospectively analyzed. Multiple treatment scenarios were prepared for each patient\u2010course by grouping targets into 1\u20135 isocenters using k\u2010means clustering. PTV margins were added using two methods, one with a magnitude that varied with distance to the isocenter, and a second with a constant 1\u2010mm magnitude. A non\u2010clinical, command\u2010line version of the Brainlab Elements Multiple Brain Mets SRS software was used to optimize plans within each scenario simultaneously. Cumulative doses were analyzed in terms of geometric values (target distances to isocenter, total PTV volume), dosimetric values (volume of normal brain (brain\u2010GTVs) receiving 5, 8, 10, 12, and 18\u00a0Gy (V\n 5Gy<\/jats:sub>\n , V\n 8Gy<\/jats:sub>\n , V\n 10Gy<\/jats:sub>\n , V\n 12Gy<\/jats:sub>\n , and V\n 18Gy<\/jats:sub>\n )), and logistical values (number of Monitor Units (MUs)). A representative sample of 69% of plans with variable margins was reviewed by clinical SRS experts.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n As the number of isocenters increased, distances from the targets to the isocenters decreased, and the proportion of targets within a given distance increased. For example, 36%, 77%, 94%, 99%, and 100% of targets were within 4\u00a0cm of the isocenter for 1\u20135 isocenters, respectively. For the variable margin method, the total PTV volume relative to the single\u2010isocenter scenario had a median decrease of 17.5, 24.3, 31.6, and 37.8% for 2\u20135 isocenters, respectively. Similarly, the relative change in the normal brain dose metrics decreased with increasing number of isocenters (e.g. V\n 12Gy<\/jats:sub>\n decreased 20.1, 26.2, 36.2, and 40.9%, respectively). The relative change in dose metrics at each level was found to have a linear relationship with that of the total PTV volume (e.g. V\n 12Gy<\/jats:sub>\n ,\n R<\/jats:italic>\n 2<\/jats:sup>\n \u00a0=\u00a00.81). For the constant margin method, total PTV volume remained constant, but normal brain dose metrics still decreased due to the grouping and simultaneous plan optimization alone (e.g. V\n 12Gy<\/jats:sub>\n decreased 6.4, 10.5, 15.1, and 17.1%). Regarding logistical values, the number of MUs increased with each additional isocenter for both margin methods, but at a rate slower than proportional to the number of isocenters. Of the evaluated plans, nearly all (97.7%) were clinically acceptable without modification.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n The SIMT SRS treatment planning pipeline presented here features automatic grouping of targets followed by automatic dose optimization of up to five isocenters. By quantifying the geometric, dosimetric, and logistical effects of adding isocenters, this pipeline can empower clinicians to make resource\u2010conscious treatment decisions optimal for each patient.<\/jats:p>\n <\/jats:sec>","DOI":"10.1002\/acm2.70869","type":"journal-article","created":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T15:51:51Z","timestamp":1792511511000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Geometric and dosimetric effects of an automated clustering and plan optimization pipeline for multiple brain metastasis radiosurgery"],"prefix":"10.1002","volume":"27","author":[{"given":"Adam D.","family":"Yock","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology Vanderbilt University Medical Center Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5460-2099","authenticated-orcid":false,"given":"Guozhen","family":"Luo","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Vanderbilt University Medical Center Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sean","family":"All","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Vanderbilt University Medical Center Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Austin N.","family":"Kirschner","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Vanderbilt University Medical Center Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cornelis","family":"Kamerling","sequence":"additional","affiliation":[{"name":"Brainlab SE Munich Bavaria Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,20]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijrobp.2009.05.029"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.prro.2011.12.003"},{"issue":"3","key":"e_1_2_10_4_1","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1016\/j.ijrobp.2015.07.2262","article-title":"Single\u2010isocenter multiple\u2010target stereotactic radiosurgery: risk of compromised coverage","volume":"93","author":"Roper J","year":"2015","journal-title":"International Journal of Radiation Oncology \u2022 Biology \u2022 Physics"},{"issue":"3","key":"e_1_2_10_5_1","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/j.prro.2015.10.010","article-title":"Physics considerations for single\u2010isocenter, volumetric modulated arc radiosurgery for treatment of multiple intracranial 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