International Journal of Radiation Research

en Experimental insights into high background radiation: reduced cancer risks in a murine model study Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: Natural background radiation varies geographically and has potential implications for cancer development. High-level natural radiation areas (HLNRAs), like Ramsar, Iran, offer unique opportunities to study the biological effects of radiation exposure. This study investigates the relationship between high background radiation and tumor progression in a murine model. Materials and Methods: Thirty-two C57BL/6 mice were exposed to varying levels of natural radiation (0.097 μSv/h to 9.24 μSv/h) for two months, simulating conditions in Ramsar. Mice were divided into four groups based on radiation intensity. After exposure, 1106 B16-F10 melanoma cells were injected subcutaneously, and tumor growth was monitored for 24 days. Tumor morphology was assessed using Magnetic Resonance Imaging (MRI), and survival rates were recorded. Statistical analyses included mixed-model and Kaplan-Meier methods. Results: Tumor volume and growth rates were significantly reduced in groups exposed to the highest radiation levels (100X Bkg). Mice in this group also exhibited the highest survival rates (100%) compared to the control group (55.6%). Tumor reduction and disintegration were observed, especially in female mice, suggesting a potential protective effect of elevated radiation exposure against melanoma progression. Conclusion: Findings challenge the Linear No-Threshold (LNT) model by demonstrating that high background radiation may not correlate with increased cancer risk. Instead, elevated radiation levels appear to confer protective effects against tumor growth in this murine model. These results highlight the need to reassess radiation safety standards and explore the complex interplay between radiation and cancer biology.</div> Background radiation, Radioactivity, Melanoma, Mice. 987 994 http://ijrr.com/browse.php?a_code=A-10-1-1425&slc_lang=en&sid=1 S.M.J. Mortazavi 7900319475328460032454 7900319475328460032454 No Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran M. Arshadi 7900319475328460032455 7900319475328460032455 No Department of Medical Physics and Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran B.F. Baha'addini Baigy Zarandi 7900319475328460032456 7900319475328460032456 No Department of, Pharmacology School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran J.S. Welsh 7900319475328460032457 7900319475328460032457 No Department of Radiation Oncology, Edward Hines Jr VA Hospital, Hines, IL, United States H. Mozdarani 7900319475328460032458 7900319475328460032458 No Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran M. Haghani 7900319475328460032459 7900319475328460032459 No Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran N. Jooyan 7900319475328460032460 7900319475328460032460 No Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran S. Nematollahi 7900319475328460032461 7900319475328460032461 No Noncommunicable Diseases Research Center, Bam University of Medical Sciences, Bam, Iran A.A. Fallah 7900319475328460032462 7900319475328460032462 No Department of Medical Physics and Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran A. Mortazavi 7900319475328460032463 7900319475328460032463 No MVLS College, The University of Glasgow, Glasgow, Scotland, UK Z. Farshidfar 7900319475328460032464 7900319475328460032464 No Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran N. Azarpira azarpiran@sums.ac.ir 7900319475328460032465 7900319475328460032465 Yes Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran L. Sihver 7900319475328460032466 7900319475328460032466 No Department of Informatics and Engineering Systems, College of Engineering and Computer Science, University of Texas Rio Grande Valley, TX, USA