{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T18:11:38Z","timestamp":1785521498158,"version":"3.56.0"},"reference-count":27,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2023,2,27]],"date-time":"2023-02-27T00:00:00Z","timestamp":1677456000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100011681","name":"Geothermal Technologies Office","doi-asserted-by":"publisher","award":["DE\u2010AC02\u201076SF00515"],"award-info":[{"award-number":["DE\u2010AC02\u201076SF00515"]}],"id":[{"id":"10.13039\/100011681","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Medical Physics"],"published-print":{"date-parts":[[2023,5]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>A preclinical MV\u2010energy photon FLASH radiotherapy system is being designed at Stanford and SLAC National Accelerator Laboratory. Because of the higher energy and dose rate compared to conventional kV\u2010energy photon laboratory\u2010scale irradiators, adequate shielding in a stand\u2010alone cabinet form factor is more challenging to achieve. We present a Monte Carlo simulation of multilayered shielding for a compact self\u2010shielding system without the need for a radiation therapy\u00a0vault.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A multilayered shielding approach using multiple alternating layers of high\u2010Z and low\u2010Z materials is applied to the self\u2010shielded cabinet to effectively mitigate the secondary radiation produced and to allow the device to be housed in a Controlled Radiation Area outside of a radiation vault. The multilayered shielding approach takes advantage of the properties of high\u2010Z and low\u2010Z radiation shielding materials such as density, cross\u2010section, atomic number of the shielding elements, and products of radiation interactions within each layer. The Monte Carlo radiation transport code, FLUKA, is used to simulate the total effective dose produced by the\u00a0operation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The multilayered shielding designs proposed and simulated produced effective dose rates significantly lower than monolayer designs with the same total material thickness at the regulatory boundary; this is accomplished through the manipulation of the locations where secondary radiation is produced and reactions due to material properties such as neutron back reflection in hydrogen. Borated polyethylene at 5 wt% significantly increased the shielding performance as compared to regular polyethylene, with the magnitude of the reduction depending upon the order of the shielding\u00a0material.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The multilayered shielding provides a path for shielding preclinical FLASH systems that deliver MV\u2010energy bremsstrahlung photons. This approach promises to be more efficient with respect to the shielding material mass and space claim as compared to shielded vaults typically required for clinical radiation therapy with MV\u00a0photons.<\/jats:p><\/jats:sec>","DOI":"10.1002\/mp.16290","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T15:39:38Z","timestamp":1676302778000},"page":"3055-3065","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Monte Carlo simulation of shielding designs for a cabinet form factor preclinical MV\u2010energy photon FLASH radiotherapy system"],"prefix":"10.1002","volume":"50","author":[{"given":"Andrew","family":"Rosenstrom","sequence":"first","affiliation":[{"name":"Nuclear &amp; Radiological Engineering &amp; Medical Physics Program Georgia Institute of Technology Atlanta Georgia USA"},{"name":"Radiation Protection Department SLAC Menlo Park California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mario","family":"Santana\u2010Leitner","sequence":"additional","affiliation":[{"name":"Radiation Protection Department SLAC Menlo Park California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sayed H.","family":"Rokni","sequence":"additional","affiliation":[{"name":"Radiation Protection Department SLAC Menlo Park California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad","family":"Shumail","sequence":"additional","affiliation":[{"name":"Technology Innovation Department SLAC Menlo Park California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sami","family":"Tantawi","sequence":"additional","affiliation":[{"name":"Technology Innovation Department SLAC Menlo Park California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaheen","family":"Dewji","sequence":"additional","affiliation":[{"name":"Nuclear &amp; Radiological Engineering &amp; Medical Physics Program Georgia Institute of Technology Atlanta Georgia USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"suffix":"Jr.","given":"Billy W.","family":"Loo","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology and Stanford Cancer Institute Stanford University School of Medicine Stanford California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2023,2,27]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1126\/scitranslmed.3008973"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/abaa28"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijrobp.2020.03.028"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.15442"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.3390\/cancers13164244"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijrobp.2021.07.1703"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijrobp.2021.11.020"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2018.08.016"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2021.11.004"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/abf2fa"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevAccelBeams.23.092001"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2019.05.005"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1667\/RADE\u201020\u201000095"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1088\/1757\u2010899X\/555\/1\/012008"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijhydene.2015.12.208"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.apradiso.2018.05.009"},{"key":"e_1_2_8_18_1","unstructured":"Neutron Contamination from Medical Electron Accelerators. 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