Aras, SerhatÖzkanli, SeymaErdem, EsraGokalp, SevtapErdoğan, Ceren Ezgi2024-07-122024-07-1220230969-80431872-980010.1016/j.apradiso.2023.1108232-s2.0-85153535736https://doi.org/10.1016/j.apradiso.2023.110823https://hdl.handle.net/20.500.12415/6827The aim of this study is to analyze the effect on histopathological changes and Ki-67 expression levels of Flat-tening Filter (FF) and Flattening Filter Free (FFF) beams to investigate the radiobiological mechanisms under-lying laryngeal cancer (LCa) post-radiotherapy (RT) on mice models. Forty adult NOD SCID gamma (NSG) mice models were randomly divided into four groups; the sham, LCa, FF -RT and FFF-RT groups. The head and neck region of mice in FF-RT and FFF-RT groups (LCa plus RT groups) were irradiated with a single dose of 18 Gy at 400 MU/min and 1400 MU/min. The NSG mice received radiotherapy 30 days after tumor transplantation and sacrificed 2 days after radiotherapy for analysis of histopathology pa-rameters and K-67 expression levels. Comparing the LCa, FF-RT and FFF-RT groups with the sham group, statistically significant differences were observed in histopathological parameters depending on tumor tissue and dose rate (p < 0.05). When the his-topathological effects of FF-RT beam on LCa tissue were compared with FFF-RT beam, it was observed that statistically significant differences occurred (p < 0.05). Comparing the LCa group with the sham group, it was observed that the Ki-67 level affected significantly depending on the development of cancer (p < 0.01). It was concluded that FF and FFF beams caused significant changes in the histopathological parameters and Ki -67 expression levels. When the effects of FFF beam on Ki-67 levels, cell nucleus and cytoplasmic findings were compared with FF beam, significant radiobiological differences were observed.eninfo:eu-repo/semantics/closedAccessRadiotherapyFlattening Filter FreeLaryngeal CancerHistopathologyKi-67Article37116260Q3197WOS:000988062500001N/A