{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T02:13:49Z","timestamp":1792635229078,"version":"4.5.0"},"reference-count":42,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2025,7,15]],"date-time":"2025-07-15T00:00:00Z","timestamp":1752537600000},"content-version":"vor","delay-in-days":14,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Medical Physics"],"published-print":{"date-parts":[[2025,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Lower production of  in water is a hallmark of ultra\u2010high dose rate (UHDR) compared to the conventional dose rate (CDR). However, the current computational models based on the predicted yield of  are the opposite of the experimental\u00a0data.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To present a multi\u2010scale formalism to reconcile the theoretical modeling and the experimental observations of  production and provide a mechanism for the suppression of  at\u00a0FLASH\u2010UHDR.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>An analytical model was constructed for the rate equation\u00a0in the production of  from \u2010radicals and used as a guide to propose a hypothetical geometrical inhomogeneity in the configuration of particles in the UHDR beams. A series of Monte Carlo (MC) simulations of the track structures was performed for a system of charged particles impinging the medium in the form of clusters and\/or\u00a0bunches.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The interplay of diffusion, reaction rates, and overlaps in track\u2010spacing contributes to a lower yield of  at UHDR versus CDR. This trend is reversed if spacing among the tracks becomes larger than a critical value, with a length scale that is proportional to the diffusion length of \u2010radicals modulated by a rate of decay due to recombination with other species, available within a track, and the space among the tracks. The latter is substantial in the suppression of the  population at UHDR relative to CDR. Under these conditions in the present MC setup, the reduction of  dose rate effect within 1 ms time\u2010scale is attributed mainly to several orders of magnitude earlier times, for example, 1 ns of the  reaction with \u2010radicals and negligible reaction with .<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Based on our analysis of the present work, at UHDR, the lower yield in  can be interpreted as a signature of bunching the particles in beams of ionizing radiation, and temporal correlations and time\u2010dependent chain of reactions. The beams enter the medium in closely packed clusters and form inhomogeneities in the track\u2010structure distribution. Thus, the MC simulations based on the assumption of uniformly distributed tracks are unable to explain the experimental\u00a0data.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/mp.17972","type":"journal-article","created":{"date-parts":[[2025,7,16]],"date-time":"2025-07-16T05:18:22Z","timestamp":1752643102000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["A Monte Carlo simulation framework for investigating the effect of inter\u2010track coupling on H2O2${\\rm H}_{2}{\\rm O}_{2}$ productions at ultra\u2010high dose rates"],"prefix":"10.1002","volume":"52","author":[{"given":"Ramin","family":"Abolfath","sequence":"first","affiliation":[{"name":"Department of Physics and Astronomy Howard University Washington District of Columbia USA"},{"name":"Department of Radiation Physics and Oncology University of Texas MD Anderson Cancer Center Houston Texas USA"},{"name":"Physics Department Sharif University of Technology Tehran Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sedigheh","family":"Fardirad","sequence":"additional","affiliation":[{"name":"Department of Physics Faculty of Science University of Guilan Rasht Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Houda","family":"Kacem","sequence":"additional","affiliation":[{"name":"The sector of radiobiology applied to radiotherapy, Radiation Oncology Department Geneva University Hospital Geneva Switzerland"},{"name":"LiRR\u2010 laboratory of innovation in radiobiology applied to radiotherapy, Faculty of Medicine University of Geneva Geneva Switzerland"},{"name":"Laboratory of Radiation Oncology, Radiation Oncology Service, Department of Oncology CHUV; Lausanne University Hospital and University of Lausanne Lausanne Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marie\u2010Catherine","family":"Vozenin","sequence":"additional","affiliation":[{"name":"The sector of radiobiology applied to radiotherapy, Radiation Oncology Department Geneva University Hospital Geneva Switzerland"},{"name":"LiRR\u2010 laboratory of innovation in radiobiology applied to radiotherapy, Faculty of Medicine University of Geneva Geneva Switzerland"},{"name":"Laboratory of Radiation Oncology, Radiation Oncology Service, Department of Oncology CHUV; Lausanne University Hospital and University of Lausanne Lausanne Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abbas","family":"Ghasemizad","sequence":"additional","affiliation":[{"name":"Department of Physics Faculty of Science University of Guilan Rasht Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,7,15]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1126\/scitranslmed.3008973"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2018.08.016"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1158\/1078\u20100432.CCR\u201017\u20103375"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1901777116"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2019.02.009"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2019.07.020"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.14253"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2019.03.028"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2019.07.004"},{"key":"e_1_2_9_11_1","unstructured":"KacemH.Oxygen contribution production and impact of reactive oxygen species after FLASH irradiation. Ph.D. Thesis.Lausanne;2023."},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2025.110942"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.17335"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.14548"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.14917"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.3389\/fphy.2023.1060910"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.3389\/fphy.2023.1215422"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1667\/RADE\u201022\u201000021.1"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1080\/09553002.2021.2004328"},{"key":"e_1_2_9_20_1","unstructured":"KirkegaardP BjergbakkeE OlsenJV.CHEMSIMUL: A chemical kinetics software package.Danmarks Tekniske Universitet Ris\u00f8 National laboratoriet for B\u00e6redygtig Energi. Denmark. Forskningscenter Risoe. Risoe\u2010R No. 1630(EN);chemsimul;2008.http:\/\/chemsimul.dk\/"},{"key":"e_1_2_9_21_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/abc93b"},{"key":"e_1_2_9_22_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/acb88a"},{"key":"e_1_2_9_23_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/acdc7d"},{"key":"e_1_2_9_24_1","doi-asserted-by":"publisher","DOI":"10.3390\/ijms26020571"},{"key":"e_1_2_9_25_1","unstructured":"AbolfathR FardiradS GhasemizadA.The effect of inter\u2010track coupling onH2O2${\\rm H}_{2}{\\rm O}_{2}$productions.https:\/\/doi.org\/10.48550\/arXiv.2403.16722"},{"key":"e_1_2_9_26_1","unstructured":"vanKampenNG.2007 Stochastic Processes in Physics and Chemistry 3rd edn. (Amsterdam: North\u2010Holland)."},{"key":"e_1_2_9_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.semradonc.2008.04.004"},{"key":"e_1_2_9_28_1","doi-asserted-by":"publisher","DOI":"10.2307\/3575434"},{"key":"e_1_2_9_29_1","doi-asserted-by":"publisher","DOI":"10.48550\/arXiv.physics\/0011071"},{"key":"e_1_2_9_30_1","doi-asserted-by":"publisher","DOI":"10.1140\/epjd\/e2019\u201090263\u20105"},{"key":"e_1_2_9_31_1","doi-asserted-by":"publisher","DOI":"10.1080\/095530097143149"},{"key":"e_1_2_9_32_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.13048"},{"key":"e_1_2_9_33_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejmp.2015.10.087"},{"key":"e_1_2_9_34_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.3476457"},{"key":"e_1_2_9_35_1","doi-asserted-by":"publisher","DOI":"10.1142\/S1793962310000122"},{"key":"e_1_2_9_36_1","doi-asserted-by":"publisher","DOI":"10.3390\/ijms22116023"},{"key":"e_1_2_9_37_1","doi-asserted-by":"publisher","DOI":"10.1088\/1361\u20106560\/ac69a6"},{"key":"e_1_2_9_38_1","doi-asserted-by":"publisher","DOI":"10.1063\/1.3071096"},{"key":"e_1_2_9_39_1","volume-title":"Quantum Field Theory","author":"Itzykson C","year":"1980"},{"key":"e_1_2_9_40_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-85184-1"},{"key":"e_1_2_9_41_1","doi-asserted-by":"publisher","DOI":"10.1140\/epjd\/s10053\u2010024\u201000928\u20101"},{"key":"e_1_2_9_42_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.elstat.2024.103982"},{"key":"e_1_2_9_43_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598\u2010022\u201023727\u20103"}],"container-title":["Medical Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/mp.17972","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T10:36:06Z","timestamp":1765190166000},"score":1,"resource":{"primary":{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/10.1002\/mp.17972"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7]]},"references-count":42,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2025,7]]}},"alternative-id":["10.1002\/mp.17972"],"URL":"https:\/\/doi.org\/10.1002\/mp.17972","archive":["Portico"],"relation":{},"ISSN":["0094-2405","2473-4209"],"issn-type":[{"value":"0094-2405","type":"print"},{"value":"2473-4209","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7]]},"assertion":[{"value":"2024-11-27","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-06-22","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-07-15","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e17972"}}