Radiation research最新文献

{"title":"Protective Effects and Mechanisms of Astragaloside on Microwave Radiation-induced Cardiac Injury.","authors":"Xueyan Zhang, Li Zhao, Shaohua Hu, Congcong Miao, Ji Dong, Jing Zhang, Binwei Yao, Yan Lv, Ruiyun Peng","doi":"10.1667/RADE-23-00103.1","DOIUrl":"10.1667/RADE-23-00103.1","url":null,"abstract":"<p><p>This study explores the potential protective effects and mechanisms of astragaloside (AST) on microwave radiation-induced cardiac injury. Rats and H9c2 cells were irradiated with S-band microwave to induce in vivo and in vitro cardiac injury models. In irradiated rats, experiments such as electrophysiological examination, serum biochemical analysis, hematoxylin and eosin (H&E) staining, transmission electron microscopy (TEM), western blot, and immunohistochemical staining were performed after AST were administrated for 7 and/or 14 days. In irradiated H9c2 cells that were pretreated with 1-Azakenpaullone (glycogen synthase kinase-3β inhibitor) or AST, experiments such as TEM, cell counting kit-8 assay, western blot, tetramethylrhodamine methylester staining, and determination of reactive oxygen species (ROS), adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) were performed. In vivo results showed that at 7 days after exposure, microwave radiation-induced severe cardiac injury (as evidenced by abnormal electrocardiograms and cardiac tissue structure, increased serum myocardial enzyme activities and Ca2+ concentration) and lower level of phosphorylation of glycogen synthase kinase-3β (p-GSK-3βSer9). All these changes were reversed after AST treatment. The results of in vitro experiments showed that microwave radiation induced a lower level of p-GSK-3βSer9, more mitochondrial permeability transition pore (mPTP) opening and more serious mitochondrial dysfunction (characterized by increased intracellular ROS production, decreased intracellular ATP synthesis and MMP decline) in H9c2 cells. All these changes were reversed by 1-Azakenpaullone and AST pretreatment. The findings suggest that AST could shield against microwave radiation-induced cardiac injury by promoting the phosphorylation of GSK-3βSer9, thereby inhibiting mPTP opening and restoring mitochondrial function. This study offers valuable insights into potential therapeutic strategies for mitigating the adverse effects of microwave radiation on cardiac health.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"142-154"},"PeriodicalIF":2.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143256423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculations of Mean Quality Factors and Their Implications for Organ-specific Relative Biological Effectiveness (RBE) in Analysis of Radiation-related Risk in the Atomic Bomb Survivors.","authors":"Shota Shimizu, Tatsuhiko Sato, Sachiyo Funamoto, Richard Sposto, Harry M Cullings, Akira Endo, Stephen D Egbert, Michiaki Kai","doi":"10.1667/RADE-24-00199.1","DOIUrl":"10.1667/RADE-24-00199.1","url":null,"abstract":"<p><p>Past and current estimates of relative biological effectiveness (RBE) from the cohort analyses of atomic bomb survivors suggested not only that RBE may be much higher than those assessed by the United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) and International Commission on Radiological Protection (ICRP), but also that RBE may differ by organ and organ depth. This is at least partly due to how the ratio of neutron to gamma-ray dose changes with organ depth because of the more rapid attenuation of neutrons in tissue. Additionally, the RBE estimates from Life Span Study (LSS) data depend on the total dose and the neutron/gamma ratio. To further examine this issue, we calculated the mean quality factor based on Linear Energy Transfer (LET) distributions for representative organs and exposure scenarios of A-bomb survivors using Particle and Heavy Ion Transport code System (PHITS) simulation and the radiation quality factor [Q(L) relationship] defined by ICRP, as well as the Quality Factor (QF) function defined by the National Aeronautics and Space Administration (NASA). This is done in the context of the adult male phantom of the J45 series, which was created to precisely reproduce the anatomy of the Japanese population in 1945. We also investigate the depth dependence of the mean quality factors in the International Commission on Radiation Units and Measurements (ICRU) sphere irradiated by mono-energetic neutrons. Both the results from the human phantom, and from the ICRU sphere phantom suggest that the mean quality factors are approximately 15 and independent of the organ type, body depth, city and ground range when the contributions from the secondary γ rays are excluded from the neutron doses. We also discuss reasons that RBE estimates from cohort analyses are generally much larger than those based on the mean quality factors.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":"203 3","pages":"155-162"},"PeriodicalIF":2.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143573708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Partial-body Models of Radiation Exposure.","authors":"M Sproull, K Camphausen","doi":"10.1667/RADE-24-00189.1","DOIUrl":"10.1667/RADE-24-00189.1","url":null,"abstract":"<p><p>The events of 9/11 sparked a revitalization of civil defense in the U.S. for emergency planning and preparedness for future radiological or nuclear event scenarios and specifically for mass casualty medical management of radiation exposure and injury. Research in medical countermeasure development in the form of novel pharmaceuticals to treat radiation injury and new radiation biodosimetry diagnostics, primarily focused on development of research models of uniform total-body irradiation (TBI). With the success of those models, it was recognized that most radiation exposures in the field will involve non-uniform heterogeneous irradiations and many partial-body or organ-specific irradiation models have been utilized. This review examines partial-body models of irradiations developed in the last decade for heterogeneous radiation exposures and organ-specific radiation exposure patterns. These research models have been used to further our understanding of radiation injury, novel medical countermeasures and biodosimetry diagnostics in development for future radiological and nuclear event scenarios.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"129-141"},"PeriodicalIF":2.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11973700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143383169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lifetime Risks for Lung Cancer due to Occupational Radon Exposure: A Systematic Analysis of Estimation Components.","authors":"M Sommer, F Heinzl, P Scholz-Kreisel, D Wollschläger, C Heumann, N Fenske","doi":"10.1667/RADE-24-00060.1","DOIUrl":"10.1667/RADE-24-00060.1","url":null,"abstract":"<p><p>Lifetime risk estimates play a key role in many areas of radiation research. Here, the focus is on the lifetime excess absolute risk (LEAR) for dying from lung cancer due to occupational radon exposure based on uranium miners cohort studies. The major components in estimating LEAR were systematically varied to investigate the variability and uncertainties of results. Major components of the LEAR calculation are baseline mortality rates for lung cancer and all causes of death, risk model and exposure scenario. Sex-averaged mortality rates were chosen from a mixed Euro-American-Asian population, in addition to mortality rates to represent heavy and light smokers. Seven radon-related lung cancer risk models derived from different uranium miners cohorts were compared. As exposure scenarios, occupational exposure of two working level months (WLM) from age 18-64 years was considered, and three scenarios from the German uranium miners cohort. Further components were modified in sensitivity analyses. The LEAR was compared to other lifetime risk measures. With a range from less than 0.6 × 10-4 to over 8.0 × 10-4, LEAR per WLM estimates were influenced heavily by the choice of risk models. Notably, mortality rates, particularly lung cancer mortality rates, had a strong impact on LEAR per WLM across all models. The LEAR per WLM exhibited only low variation to changes in exposure scenarios for all risk models, except for the BEIR VI model fitted on the pooled 11 miners study. All assessed lifetime risk measures displayed a monotonically increasing relationship between exposure and lifetime risk at low to moderate exposures, with minor differences between ELR, REID, and LEAR (all per WLM). RADS yields the largest lifetime risk estimates in most situations. There is substantial variation in LEAR per WLM estimates depending on the choice of underlying calculation components. Reference populations and mortality rates should be selected with care depending on the application of lifetime risk calculations. The explicit choice of the lifetime risk measure was found to be negligible. These findings should be taken into consideration when using lifetime risk measures for radiation protection policy purposes.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"175-187"},"PeriodicalIF":2.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dose Build-up of High-energy 1H and 4He Ions in Standard, Innovative and In Situ Shielding Materials for Space Radiation: Measurements and Simulations.","authors":"Francesca Luoni, Uli Weber, Alica Karin Lang, Moritz Westermayer, Felix Horst, Marcello Baricco, Luca Bocchini, Martina Giraudo, Giovanni Santin, Christoph Schuy, Marco Durante, Daria Boscolo","doi":"10.1667/RADE-24-00244.1","DOIUrl":"10.1667/RADE-24-00244.1","url":null,"abstract":"<p><p>Galactic cosmic rays (GCR) are among the biggest hindrances to crewed space exploration. The ions contributing the most to fluence and absorbed dose in free space are 1H and 4He. In addition, their contribution to dose equivalent increases behind thick shields. In this work, the results of depth-dose measurements performed with high-energy 1H and 4He ions (2 GeV and 480 MeV 1H, and 430 MeV/u 4He) in structural (aluminum alloy), standard (PMMA and high-density polyethylene), innovative (lithium hydride) and in situ (Moon regolith simulant) shielding materials are presented. A strong dose build-up effect, due to target fragments and secondary protons, is observed in the first part of the Bragg curve for all the tested ion beams. The experimental results are compared to the Monte Carlo simulation tools most used for radiation protection in space, i.e., different physics lists of Geant4, PHITS, and FLUKA.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"163-174"},"PeriodicalIF":2.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143383167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of Glutamine Synthetase on the Sensitivity to Radiotherapy of Hepatocellular Carcinoma.","authors":"Yuan He, Huihan Yu, Yijun Lu, Chen Zhou, Yu Tian, Tianwei Song, Dandan Wang, Zhiyou Fang, Zhi Zhang, Hongzhi Wang, Junchao Qian","doi":"10.1667/RADE-22-00181.1","DOIUrl":"https://doi.org/10.1667/RADE-22-00181.1","url":null,"abstract":"<p><p>The objective of this study was to investigate the relationship between radiotherapy sensitivity, glutamine synthetase (GS), and oxidative stress (OS) in human hepatocellular carcinoma (HCC) cells. HCC cells were X-ray irradiated, and the effect of glutamine synthetase inhibition on the proliferative capacity of HCC cells was examined using the CCK-8 colony formation assay. Real-time quantitative PCR assays were used to detect the effect of L-methionine sulfoximine (MSO) on cellular glutamine synthetase expression levels and the efficiency of glutamine synthetase knockdown in HepG2 cells. Glutamine synthetase activity assay kit was used to detect the viability of glutamine synthetase in cells and tissues. Oxidative stress production was assayed using an oxidative stress assay kit. Subcutaneous xenografts were used to detect the effects of L-methionine sulfoximine and radiation on tumor growth in vivo. The results showed that the apparent cell proliferation capacity of HCC cells after glutamine synthetase inhibition was significantly reduced after radiotherapy, which was closely related to the increased production of oxidative stress after radiotherapy. Furthermore, the results of animal experiments also showed that the combination of L-methionine sulfoximine and radiation induced a stronger tumor suppressive effect and that L-methionine sulfoximine could act as a radiosensitizer after radiotherapy.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143123320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmacokinetic and Metabolomic Studies with BBT-059 in Nonhuman Primates Exposed to Total-Body Gamma Radiation.","authors":"Alana D Carpenter, Yaoxiang Li, Issa Melendez Miranda, Stephen Y Wise, Oluseyi O Fatanmi, Sarah A Petrus, Christine M Fam, Sharon J Carlson, George N Cox, Amrita K Cheema, Vijay K Singh","doi":"10.1667/RADE-24-00219.1","DOIUrl":"10.1667/RADE-24-00219.1","url":null,"abstract":"<p><p>BBT-059 is a long-acting PEGylated interleukin-11 analog that has been shown to have hematopoiesis-promoting and anti-apoptotic attributes, and is being studied as a radiation countermeasure for the hematopoietic acute radiation syndrome (H-ARS). This potential countermeasure has been demonstrated to enhance survival in irradiated mice. To investigate the toxicity and safety profile of this agent, 14 nonhuman primates (NHPs, rhesus macaques) were administered two different doses of BBT-059 subcutaneously 24 h after 4 Gy total-body irradiation and were monitored for the next 60 days postirradiation. Blood samples were investigated for the pharmacokinetics and pharmacodynamics of this agent and its effects on complete blood counts, cytokines, vital signs, and metabolomics. No adverse health effects were observed in either treatment group. Radiation-induced metabolomic dysregulation was observed in both treatment groups, and BBT-059 afforded some short-term radiomitigation. A few pathways were commonly dysregulated by radiation exposure including steroid hormone biosynthesis pathways, fatty acid activation, and glycerophospholipid metabolism. Notably, radiation-induced dysregulation to the linoleate metabolism pathway was significantly mitigated by either dose of BBT-059. In brief, this study suggests that BBT-059 has a good safety profile in irradiated NHPs and that its development as a medical countermeasure for U.S. Food and Drug Administration approval for human use should be continued.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"83-95"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142954075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contribution of Nuclear Fragmentation to Dose and RBE in Carbon-Ion Radiotherapy.","authors":"Shannon Hartzell, Fada Guan, Giuseppe Magro, Paige Taylor, Phillip J Taddei, Christine B Peterson, Stephen Kry","doi":"10.1667/RADE-24-00164.1","DOIUrl":"10.1667/RADE-24-00164.1","url":null,"abstract":"<p><p>Variable relative biological effectiveness (RBE) of carbon radiotherapy may be calculated using several models, including the microdosimetric kinetic model (MKM), stochastic MKM (SMKM), repair-misrepair-fixation (RMF) model, and local effect model I (LEM), which have not been thoroughly compared. In this work, we compared how these four models handle carbon beam fragmentation, providing insight into where model differences arise. Monoenergetic and spread-out Bragg peak carbon beams incident on a water phantom were simulated using Monte Carlo. Using these beams, input parameters for each model (microdosimetric spectra, DNA double-strand break yield, kinetic energy spectra, physical dose fragment contributions) were calculated for each contributing carbon beam fragment (hydrogen, helium, lithium, beryllium, boron, secondary carbon, primary carbon, electrons, and \"other\"). Scored input parameters for each fragment were used to calculate linear (α) and quadratic (β) parameters according to each model, which were combined with reference α and β values and absorbed physical dose to calculate RBE. Contributions from secondary fragments were found to exceed 30% of the total physical dose. Using identical beam parameters, the four models produced not only different RBE values but also different RBE trends. In all models, RBE was highest for secondary carbon ions. Beyond secondary carbons, the RBE magnitude typically increased with the atomic number of the fragment, but RBE trends differed dramatically by model and beamline region (entrance, spread-out Bragg peak, and tail). Variations in fragment RBE were large enough to be apparent in biological dose predictions. This study demonstrated that fragmentation is a nonnegligible consideration in carbon radiotherapy. Our findings identified differences in RBE among specific fragments and the four models, contributing to variability in the total biological dose across models. Because these findings emphasize differences in how various models handle carbon beam fragments, greater care should be taken in characterization of secondary fragments in particle therapy.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"96-106"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143041526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Acute and Protracted Gamma Irradiation Effects During Perinatal Development in Beagle Dogs.","authors":"Shayenthiran Sreetharan, Stephanie Puukila, Christine Lalonde, Jake Pirkkanen, Gayle E Woloschak, Tatjana Paunesku, Antone L Brooks, Fiona E McNeill, Christopher Thome, Douglas R Boreham, Simon J Lees, Sujeenthar Tharmalingam, T C Tai","doi":"10.1667/RADE-24-00080.1","DOIUrl":"10.1667/RADE-24-00080.1","url":null,"abstract":"<p><p>Ionizing radiation exposure during perinatal development can produce various biological effects on the developing offspring. These effects are dependent on a number of factors, including total dose, dose rate and the developmental processes occurring at the time of irradiation. The present study conducted an analysis of historical radiobiological archived data involving 60Co-gamma irradiation of beagle dogs at specific periods of prenatal or postnatal development. The original studies were performed at two sites where animals were exposed to a single, acute dose of 0.2 or 1.0 Gy at six different stages of perinatal development or with protracted exposures ranging from 0.004 to 0.35 Gy per day, over multiple days of gestation. A number of outcomes were investigated after perinatal irradiation including changes in sex ratio, survival probability, disease incidence and growth of animals, based on collected size and weight measurements of animals and different tissues. Protracted irradiations with doses up to 0.35 Gy per day did not significantly affect survival in animals when irradiated prenatally, although significant increases in the incidence of neoplasms and diseases related to the cardiovascular and urogenital system were observed at the time of death. Dogs irradiated at a dose rate of 0.10 Gy per day, with the irradiations continuing after birth and resulting in the accumulation of large total doses, were observed to have chronic radiation syndrome symptoms based on pathologies related to the hematopoietic system. Acute irradiation with 0.2 and 1.0 Gy resulted in changes of different body or tissue sizes measured in animals terminally, with changes detected after irradiation at all tested prenatal and postnatal time points, with the exception of irradiation at 365 days after birth. The present analysis provides new information regarding the biological effects of ionizing radiation during perinatal development in offspring in the unique mammalian study model of the beagle dog.</p>","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"73-82"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143029456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Departures from Linearity in the Dose Response for Japanese Atomic Bomb Survivor Solid Cancer Mortality and Cancer Incidence Data and Assessment of Low-Dose Extrapolation Factors.","authors":"Mark P Little, Nobuyuki Hamada, Harry M Cullings","doi":"10.1667/RADE-24-00202.1","DOIUrl":"10.1667/RADE-24-00202.1","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Although leukemia in the Japanese atomic bomb survivor data has long exhibited upward curvature, until recently this appeared not to be the case for solid cancer. It has been suggested that the recently observed upward curvature in the dose response for the Japanese atomic bomb survivor solid cancer mortality data may be accounted for by flattening of the dose response in the moderate dose range (0.3-0.7 Gy). To investigate this, the latest version available of the solid cancer mortality and incidence datasets (with follow-up over the years 1950-2003 and 1958-2009 respectively) for the Life Span Study cohort of atomic bomb survivors was used to assess possible departures from linearity in the moderate dose range. Linear-spline models were fitted, also up to 6th order polynomial models in dose (higher order polynomials tended not to converge). The organ dose used for all solid cancers was weighted dose to the colon. There are modest indications of departures from linearity for the mortality data, whether using polynomial or linear-spline models. Use of the Akaike information criterion (AIC) suggests that the optimal model for the mortality data is given by a 5th order polynomial in dose. There is borderline significant (P = 0.071) indication of improvement provided by a linear-spline model in the mortality data. The low-dose extrapolation factor (LDEF), which measures the degree of overestimation of low-dose linear slope by the linear slope fitted over some specified dose range, is generally between 1.1-2.0 depending on the dose range, with upper confidence limits that sometimes exceed 10; although LDEF &lt; 1 for the lowest dose range (&lt;0.5 Gy), there are substantial uncertainties, with an upper confidence limit that exceeds 1.6. There are generally only modest indications of departures from linearity for the solid cancer incidence data, whether using polynomial or linear-spline models. In contrast to the mortality data, there are much weaker indications of improvement in fit provided by higher order polynomials, and only weak indications (P &gt; 0.2) of improvement provided by linear-spline models. Nevertheless, use of AIC suggests that the optimal model for the incidence data is given by a 3rd order polynomial. LDEF evaluated over various dose ranges is generally between 1.2-1.4 with upper confidence limits that generally exceed 1.6; although LDEF &lt; 1 for the lowest dose range (&lt;0.5 Gy), there are substantial uncertainties, with an upper confidence limit that substantially exceeds 2.0. In summary, the evidence we have presented for higher order powers than the second in the dose response is not overwhelmingly strong, and is to some extent dependent on dose range. A feature of the dose response, which is reflected in the higher-order polynomials fitted to the data, is a leveling off or even a downturn in the response at doses &gt;2 Gy. The linear-quadratic model is very widely used for modeling of dose response, and has been widely used in radiothe","PeriodicalId":20903,"journal":{"name":"Radiation research","volume":" ","pages":"115-127"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142972104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}