Low-dose Radiation Research Articles

Effects of Continuous Prenatal Low Dose Rate Irradiation on Neurobehavior, Hippocampal Cellularity, Messenger RNA and MicroRNA Expression on B6C3F1 Mice.

Epidemiological, experimental, and ecological data have indicated the controversial effect of in utero chronic low dose rate (<6 mGy/h) with accumulative low (≤100 mGy) or high (>100 mGy) dose radiation exposure. Our main goal of this study was to examine if different low dose rates of chronic pre- and/or post-natal radiation exposure with accumulative high doses could induce hippocampal cellular, mRNA, and miRNA changes leading to neuropsychiatric disorders. The comprehensive mouse phenotypic traits, organ weight, pathological, and blood mRNA and miRNA changes were also studied. Using different approaches including SmithKline, Harwell, Imperial College, Royal Hospital, Phenotype Assessment (SHIRPA), neurobehavioral tests, pathological examination, immunohistochemistry, mRNA and miRNA sequencing, and real-time quantitative polymerase chain reaction (qRT-PCR) validation, we found that in prenatally irradiated (100 mGy/d for 18 days with an accumulative dose of 1.8 Gy) 1-year-old mice, no cellular changes, including immature neurons in the subgranular zone, mature neurons and glial cells in the hilus of the dentate gyrus and development of cognitive impairment, neuropsychiatric disorders, occurred. However, a significant reduction in body weight and mass index (BMI) was indicated by the SHIRPA test. A reduced exploratory behavior was shown by an open field test. Organ weights showed significant reductions in the testes, kidneys, heart, liver and epididymides with no abnormal pathology. mRNA and miRNA sequencing and qRT-PCR validation revealed the upregulation of Rubcnl and Abhd14b, and downregulation of Hspa1b, P4ha1, and Banp genes in both the hippocampus and blood of mice prenatally irradiated with 100 mGy/d. Meanwhile, downregulation of miR-448-3p and miR1298-5p in the hippocampus, miR-320-3p, miR-423-5p, miR-486b-5p, miR-486b-3p, miR-423-3p, miR-652-3p, miR-324-3p, miR-181b-5p, miR-let-7b, and miR-6904-5p in the blood was induced. The target scan revealed that Rubcnl is one of the miR-181b-5p targets in the blood. We, therefore, concluded that prenatal chronic irradiation with a low dose rate of 100 mGy/d and accumulative dose of 1.8 Gy or below might not induce significant adverse health effects on the offspring. Further study of different low dose rate radiation exposures with accumulative high doses may provide threshold doses for authorities or regulators to set new radiation safety guidelines to replace those extrapolated from acute high dose/dose rate irradiation to reduce unnecessary emergency evacuation or spending once a nuclear accident or leakage occurs.

Feasibility of Remotely Controlled Capsule to Enable Directionality and Higher Dose Rates for Conventional Low Dose Rate Brachytherapy Using Topas

With low dose radiation (LDR) brachytherapy, thus far, only low dose rates could be used with low energy level radiation sources at 30 keV or less due to the risk of radiation to healthy cells, tissue, and organs. The radiation seeds are placed in the location of the tumor and is left in the body for the total dose to be continuously administered throughout the decay period of the radiation seed. However, the amount of time to deliver the total dose can take up to several months depending on the type of radiation source, tumor size and location, due to the low dose rate of <2 Gy/hr. In contrast, high dose radiation (HDR) is defined as a dose delivered at a rate >12 Gy/hr, although usually much higher, often in excess of 1 Gy/min, with a higher energy radiation source close to 0.5 MeV.For the first time, a remotely controllable, implanted radiation capsule is introduced, to enable a very high dose rate of 10 Gy/min for 30 keV I-125 radiation source. Until now, this combination of low energy and high dose rate for implanted radiation seeds for LDR was not possible due to the risk of radiation. The implantable capsule is designed to control this risk of radiation by remotely controlling the opening of the capsule hole. In the open case, the high dose rate of I-125 is delivered for a duration of 1 minute and then closed to stop emission.For feasibility, a simulation study was conducted using TOPAS for Monte Carlo simulation of radiotherapy. In the top right figures, a cylindrical capsule of height 6 mm, diameter 3 mm, and wall thickness 0.9 mm is designed using gold to contain the radiation and prevent leakage radiation. An opening of 30 degrees was made in the middle of the capsule wall where the radiation was to be emitted. For the radiation source, a 30 keV I-125 was used with a specific activity of 6.42 x 1014 Bq/gram. With a wall thickness of 0.9 mm, calculations showed that 4.4 micrograms of I-125 was needed to increase the source activity for 1.454 x 1020 Bq per second for a high dose rate of 10 Gy/min.The yellow and red colors in the capsule are both gold with wall thickness of 0.9 mm. The red portion of the cylinder is where the 30 degree opening was defined. The green lines show the paths of the radiation particles.TOPAS simulation results successfully show that the capsule contains the radiation and the only direction of radiation is through the defined opening in the capsule. The bottom three graphs show the x, y, and z plane cuts showing a directional radiation beam that drops in intensity, from a range of 1.0 to 0, over distance and slightly widens over distance.To control the opening and closing of the hole in the radiation capsule, an inner cylinder and outer cylinder is used, where the inner cylinder can move up and down. A permanent magnet is attached to the bottom of the inner cylinder and an electromagnet is attached to the base at the bottom of the capsule. An implantable inductive coil receives an AC current from the external inductive coil, which is rectified using a diode and capacitor circuit. This DC current powers the electromagnet, which repels the inner cylinder, moving it up to align the windows of the inner and outer cylinders. This alignment opens the hole and radiation is emitted towards the target tumor. After the dose is delivered, the current is turned off, which turns off the electromagnet. With no repelling force from the electromagnet, the permanent magnet reattaches itself to the base, and the inner cylinder slides down and the windows are no longer aligned. This blocks the radiation from being emitted. The dimensions of the capsule and the windows depend on the radiation source and tumor size. Micromachining and micro 3D printing techniques can be applied for fabrication of the device.In conclusion, a feasibility study using TOPAS demonstrated that a 0.9 mm gold wall with a hole can contain a very high source activity of I-125 radiation for a very high dose rate of 10 Gy/min and emit a directional beam through the hole. A remotely controllable capsule can enable a high dose rate with LDR brachytherapy that combines the advantages of LDR and HDR, which is minimum radiation risk and minimum treatment time, simultaneously. Potential applications for this is intracavitary cancer treatment such as esophageal or cervical cancer. Figure 1

Long-Term, Non-Invasive Detection of Low-Dose Ionizing Radiation Exposure

Ionizing radiation induces complex changes in cells and tissues. The conventional approach to biological dosimetry has been to integrate physical and clinical measurements to optimize dose assessment. Molecular biodosimetry is an effective strategy to monitor radiation exposure and hematologic, cytogenetic, protein and transcript-based approaches have been developed to increase dose estimation accuracy. However, these approaches are invasive, time-consuming, have limited effectiveness over time, and importantly do not accurately inform on low dose radiation exposures. Therefore, novel, non-invasive, biomarkers are required that can overcome these limitations. We developed a pipeline that employs Fourier transform infrared (FTIR) spectroscopy in the mid-infrared spectrum to identify a signature of low dose ionizing radiation exposure in mouse ear pinnae over time. Two cohorts of C57BL/6J and one cohort of BALB/c mice were followed for ninety days after total body X-ray exposures of 10, 50, 100 or 200 cGy. The stratum corneum layer of the ear pinnae were repeatedly measured with attenuated total reflectance - focal plane array (ATR-FPA)-FTIR at 5, 14, 21, 49 and 90 days after radiation exposure. We found statistically significant discriminative power for all doses and all tested time-points out to 90 days after exposure. Classification accuracy was maximized when testing 14 days after exposure (specificity > 0.9 with a sensitivity threshold of 0.9) and dropped by roughly 30% sensitivity at 90 days. Since only hundreds of samples were required to learn highly discriminative signatures, developing human-relevant diagnostic capabilities is likely feasible and this non-invasive procedure points toward future non-invasive biodosimetry applications at population scales.

Site-specific cancer mortality after low level exposure to ionizing radiation: Findings from an update of the International Nuclear Workers Study (INWORKS).

A major update to the International Nuclear Workers Study was undertaken that allows us to report updated estimates of associations between radiation and site-specific solid cancer mortality. A cohort of 309,932 nuclear workers employed in France, the United Kingdom, and United States were monitored for external radiation exposure and associations with cancer mortality were quantified as the excess relative rate (ERR) per gray (Gy) using a maximum likelihood and a Markov chain Monte Carlo method (to stabilize estimates via a hierarchical regression). The analysis included 28,089 deaths due to solid cancer, the most common being lung, prostate, and colon cancer. Using maximum likelihood, positive estimates of ERR per Gy were obtained for stomach, colon, rectum, pancreas, peritoneum, larynx, lung, pleura/mesothelioma, bone and connective tissue, skin, prostate, testis, bladder, kidney, thyroid, and residual cancers; negative estimates of ERR per Gy were found cancers of oral cavity and pharynx, esophagus, and ovary. A hierarchical model stabilized site-specific estimates of association, including for lung (ERR per Gy=0.65; 95% credible interval [CrI]: 0.24, 1.07), prostate (ERR per Gy=0.44; 95% CrI: -0.06, 0.91), and colon cancer (ERR per Gy=0.53; 95% CrI: -0.07, 1.11). The results contribute evidence regarding associations between low dose radiation and cancer.

A novel material for radiation detection application of zinc bismuth lithium borotellurite glass doped with Dy2O3

Radiation detection glass with the following chemical composition B2O3–TeO2–Li2O3–Bi2O3–ZnO doped with Dy2O3 where x = 0.00, 0.10, 0.50, 1.00, 1.50 and 2.00 mol%, was developed for the characterization of physical properties such as density, molar volume (Vm), and refractive index, optical absorption, luminescence, CIE's diagram, and radiation detection properties. The density and refractive index of glass samples increase with the increase of Dy2O3 composition. The optical property of glass shows eight strongest peaks from 6H15/2 centering at 263 nm (4I13/2 + 4F7/2), 298 nm (4G11/2), 357 nm (4I15/2), 803 nm (6F5/2), 897 nm (6F7/2), 1090 nm (6H7/2 + 6F9/2), 1272 nm (6F11/2 + 6H9/2) and 1671 nm (6H11/2), respectively. The emission peaks are r (4F9/2), 481 nm (6H15/2), 575 nm (6H13/2), 664 nm (6H11/2), and 751 nm (6H9/2) under excited at 453 nm (4F9/2), respectively. The excitation peaks under emission at 575 nm from 6H15/2 centering at 350 nm (6P7/2), 365 nm (4P3/2), 388 nm (4K17/2), 425 nm (4G11/2), 453 nm (4I15/2), and 471 nm (4F9/2) respectively. The study of luminescence characteristics, which includes emission, excitation, and CIE diagrams, reveals white emission bands that coincide with the CIE diagram. Furthermore, measuring the parameters of the thermoluminescence dosimeter (TLD) recorded with a heating rate of 5 °C/s in the temperature up to a maximum of 400 °C yields good results in low dose radiation detection. Based on all the results, it was determined that this glass can be a candidate for radiation detection materials in the future.

Radioactivity concentration of 14C in the air of 14C urea breath test rooms and the resulting internal dose to medical staff

ObjectiveTo monitor the radioactivity concentration of 14C in the air of rooms used to perform 14C urea breath tests, and evaluate the contamination status of 14C released during such tests, and assess the occupational health risk to medical staff working in such areas. Methods14CO2 in air was absorbed from the air and turned into calcium carbonate through a chemical reaction. Then, calcium carbonate was prepared into a suspension in a low-potassium glass vial. The sample was analyzed using a low-background liquid scintillation counter. ResultsThe radioactivity concentrations of 14C in air of the breath-test rooms in hospitals and physical examination institutions range from 1.35 to 18.41 Bq/m3. The annual committed dose for medical staff was estimated to be between 2.01 × 10−2 and 2.74 × 10−1 μSv. ConclusionsOur results reveal a significant increase of 14C radioactivity concentration in the air of breath-test rooms, but the resulting committed dose is much lower than the limits prescribed by the International Commission on Radiological Protection (ICRP). However, the potential risk of long-term exposure to low-dose radiation should be paid more attention.

Early and Late Effects of Low-Dose X-ray Exposure in Human Fibroblasts: DNA Repair Foci, Proliferation, Autophagy, and Senescence.

The effects of low-dose radiation exposure remain a controversial topic in radiation biology. This study compares early (0.5, 4, 24, 48, and 72 h) and late (5, 10, and 15 cell passages) post-irradiation changes in γH2AX, 53BP1, pATM, and p-p53 (Ser-15) foci, proliferation, autophagy, and senescence in primary fibroblasts exposed to 100 and 2000 mGy X-ray radiation. The results show that exposure to 100 mGy significantly increased γH2AX, 53BP1, and pATM foci only at 0.5 and 4 h post irradiation. There were no changes in p-p53 (Ser-15) foci, proliferation, autophagy, or senescence up to 15 passages post irradiation at the low dose.

Effects of low-dose gamma radiation on DNA measured using a quartz tuning fork sensor

Despite the expected direct effects of radiation on DNA through its direct interaction with the biomolecule, research indicates that radiation also interacts with the DNA’s environment, resulting in indirect effects. Therefore, in this study, we explored the feasibility of using the quartz tuning fork (QTF) sensor system in biomedical applications, specifically in detecting DNA damage caused by low doses of gamma radiation, directly and indirectly. We differentiated between direct and indirect damage by analyzing the fork’s resonance frequency changes. This experiment was divided into three stages: before, during, and after irradiation. Each stage involved samples of pure DNA and DNA in a 60-µL aqueous solution, evaluated under identical conditions. Before irradiation, we measured frequency shifts (Δf) over a 20-min period, resulting in values of 19.34, 20.25, and 7.6 Hz for water, DNA, and DNA in water, respectively. Subsequently, the samples were irradiated with cesium-137 for the specified duration, resulting in frequency shifts of ∼ 39.21, 28.37, and 41.23 Hz for the same conditions. Our investigations showed an increase in Δf from 20.25 to 28.3 Hz at doses ranging from 7.5 to 30 µGy for pure DNA. Interestingly, DNA in aqueous solution exhibited hypersensitivity to radiation, with frequency shifts ranging from 7.6 to 41.23 Hz. Furthermore, we observed a significant difference in frequency shift after irradiation between pure DNA and DNA in water, with shifts of ∼ 70.75–98.45 Hz and 56.32–79.28 Hz for DNA and DNA in water, respectively. This result indicates a significant increase in DNA damage in aqueous environments, driven by the generation of active hydroxyl radicals (OH−), resulting in base damage and an associated increase in strand breaks. Consequently, our research indicates a lack of substantial direct impact on DNA repair owing to the absence of a conducive postirradiation environment. Therefore, QTF is a valuable biomarker for radiation sensitivity and is promising for future applications as a mass-sensitive biosensor.

Low-dose radiation promotes high-fat diet-induced atherosclerosis by activating cGAS signal pathway

BackgroundAtherosclerosis (AS) is the most prevalent cardiovascular disease, with an exceptionally high burden. High-fat diet (HFD) is a popular diet behavior, whereas low-dose radiation (LDR) is an environmental physical factor. There is evidence to suggest that an HFD may exacerbate the onset of atherosclerosis. Whether the combination effect of HFD and LDR would have potential on atherosclerosis development remains incompletely unclear. MethodsIn this study, ApoE−/− mice were used as atherosclerosis model animals to investigate the combination effects of HFD and LDR (10 × 0.01Gy, or 20 × 0.01Gy) on vascular lesions. Doppler ultrasound imaging, H&E staining, oil red O staining, western blotting, and immunohistochemistry (IHC) were used to assess the pro-atherosclerotic effects. LC-MS was used to detect the non-targeted lipidomic. ResultsLong-term exposure of low-dose radiation at an accumulated dose of 0.2Gy significantly increased the occurrence of vascular stiffness and the aortic lesion in ApoE−/− mice. The synergistic effect of HFD and LDR was observed in the development of atherosclerosis, which might be linked to both the dysbiosis of lipid metabolism and the stimulation of the inflammatory signaling system. Moreover, LDR but not HFD can activate the cGAS-STING signaling through increasing the yield of cytosolic mitochondrial DNAs as well as the expression of cGAS protein. The activation of cGAS-STING signal triggers the release of IFN-α/-β, which functions as an inflammatory amplifier in the formation of atherosclerotic plaque. ConclusionThe current study offers fresh insights into the risks and mechanism that underlie the development of atherosclerosis by LDR, and there is a combination effect of LDR and HFD with the involvement of cGAS-STING signal pathway.

Developing a novel radiosensitive metal ion-loaded PVA/NBT film as medical low-dose X-ray dosimeter

The hazards associated with ionizing radiation exposure has spurred the advancement of reliable and precise dosimetry techniques. Currently, there still lacks a viable and efficient dosimetry methods for measuring radiation expo-sure within low dosage ranges. This raises a concern in certain domains, such as radiodiagnostics and practitioners that employ low-dose X-ray radiation. Hence, this study aims to produce PVA/NBT film dosimeters that are capable in effectively detecting low dosages of X-ray radiation. Moreover, PVA/NBT films loaded by various metal ions will also be studied. The films were synthesized by the solvent casting method. The films were subjected to X-ray irradiation with a dosage ranging from 0 to 2.626 mGy. The films were further examined through EDX analysis, UV–Vis spectroscopy, optical density measurement, FTIR spectroscopy, and SEM analysis. It was observed that X-ray radiation exposure caused a broadening in the UV–Vis absorbance spectrum, which enhances its light absorption capability and making it more opaque. Furthermore, the careful selection of metal ion enhanced the film's ability in detecting X-ray radiation. Silver-loaded films were proven to significantly enhance the linearity and sensitivity of the PVA/NBT dosimeter film. These findings showed that silver-loaded PVA/NBT films exhibit a promising prospect for further applications in the domain of medical radiation.

Study of Radiosensitivity and Induction of Radiation Adaptive Response in Peripheral Blood Lymphocytes of Patients with Oncological Diseases Using the Micronuclear Test.

Radiosensitivity to low and medium doses of X-ray radiation and the ability to induce a radiation adaptive response (RAR) of lymphocytes during in vitro irradiation of peripheral blood of patients with cancer were studied. The criterion for cytogenetic damage was the frequency of micronuclei (MN) in cytochalasin-blocked binucleate lymphocytes in culture. It was found that the spontaneous level of cytogenetic damage in the lymphocytes of patients was 2.6 times higher than in healthy volunteers, and there was also significant interindividual variability in values compared to the control cohort. There were no differences in mean values for radiosensitivity to low and medium doses of X-ray between the study groups. There was no correlation between the spontaneous level of MN in lymphocytes and the radiosensitivity of individuals in both groups. RAR was induced with the same frequency and to the same extent in lymphocytes from both patients and healthy individuals.

Investigation of intra-fractionated range guided adaptive proton therapy: I. On-line PET imaging and range measurement

Objective. Develop a prototype on-line positron emission tomography (PET) scanner and evaluate its capability of on-line imaging and intra-fractionated proton-induced radioactivity range measurement. Approach. Each detector consists of 32 × 32 array of 2 × 2 × 30 mm3 Lutetium–Yttrium Oxyorthosilicate scintillators with single-scintillator-end readout through a 20 × 20 array of 3 × 3 mm2 Silicon Photomultipliers. The PET can be configurated with a full-ring of 20 detectors for conventional PET imaging or a partial-ring of 18 detectors for on-line imaging and range measurement. All detector-level readout and processing electronics are attached to the backside of the system gantry and their output signals are transferred to a field-programable-gate-array based system electronics and data acquisition that can be placed 2 m away from the gantry. The PET imaging performance and radioactivity range measurement capability were evaluated by both the offline study that placed a radioactive source with known intensity and distribution within a phantom and the online study that irradiated a phantom with proton beams under different radiation and imaging conditions. Main results. The PET has 32 cm diameter and 6.5 cm axial length field-of-view (FOV), ∼2.3–5.0 mm spatial resolution within FOV, 3% sensitivity at the FOV center, 18%–30% energy resolution, and ∼9 ns coincidence time resolution. The offline study shows the PET can determine the shift of distal falloff edge position of a known radioactivity distribution with the accuracy of 0.3 ± 0.3 mm even without attenuation and scatter corrections, and online study shows the PET can measure the shift of proton-induced positron radioactive range with the accuracy of 0.6 ± 0.3 mm from the data acquired with a short-acquisition (60 s) and low-dose (5 MU) proton radiation to a human head phantom. Significance. This study demonstrated the capability of intra-fractionated PET imaging and radioactivity range measurement and will enable the investigation on the feasibility of intra-fractionated, range-shift compensated adaptive proton therapy.

Improving Cytogenetic Surveillance in Radiology Workers Exposed to Low-Dose Radiation in Africa: A Call to Action

Radiation exposure is an occupational hazard for diagnostic and interventional radiology workers, potentially leading to chromosomal damage and increased cancer risk. This review explores the status of cytogenetic monitoring of radiation exposure among radiology workers in Africa. Monitoring of Radiation Exposure in Diagnostic and Interventional Radiology Workers in Ghana and Africa provides a crucial examination of radiation safety practices within the Ghanaian and Africa healthcare sector. We recovered existing literature on the cytogenetic surveillance conducted on radiology workers in Ghana and Africa stressing on the impact and/or significance of cytogenetic monitoring programmes. In these studies, mostly mathematical modeling and physical methods were used to estimate and extrapolate risks of exposure to ionizing radiation. Additionally, we discuss the challenges and opportunities for implementing cytogenetic monitoring programmes in Africa particularly Ghana and provide recommendations for future research and occupational health policies. This review attempts to bridge the gap between physical and biological dosimetry in surveillance studies. It addresses the significant gap in cytogenetic monitoring among diagnostic and interventional radiology workers in Africa. It highlights the importance of cytogenetic surveillance for early detection of radiation-induced genetic damage, assesses the current practices, and provides a recommendation and a roadmap for establishing robust monitoring programmes. This work would contribute significantly to the understanding of occupational radiation safety issues in the healthcare sector of Africa. It also offers a comprehensive examination of the challenges and opportunities in implementing cytogenetic monitoring programmes.

Establishment and activity of the planning and acting network for low dose radiation research in Japan (PLANET): 2016-2023.

The Planning and Acting Network for Low Dose Radiation Research in Japan (PLANET) was established in 2017 in response to the need for an all-Japan network of experts. It serves as an academic platform to propose strategies and facilitate collaboration to improve quantitative estimation of health risks from ionizing radiation at low-doses and low-dose-rates. PLANET established Working Group 1 (Dose-Rate Effects in Animal Experiments) to consolidate findings from animal experiments on dose-rate effects in carcinogenesis. Considering international trends in this field as well as the situation in Japan, PLANET updated its priority research areas for Japanese low-dose radiation research in 2023 to include (i) characterization of low-dose and low-dose-rate radiation risk, (ii) factors to be considered for individualization of radiation risk, (iii) biological mechanisms of low-dose and low-dose-rate radiation effects and (iv) integration of epidemiology and biology. In this context, PLANET established Working Group 2 (Dose and Dose-Rate Mapping for Radiation Risk Studies) to identify the range of doses and dose rates at which observable effects on different endpoints have been reported; Working Group 3 (Species- and Organ-Specific Dose-Rate Effects) to consider the relevance of stem cell dynamics in radiation carcinogenesis of different species and organs; and Working Group 4 (Research Mapping for Radiation-Related Carcinogenesis) to sort out relevant studies, including those on non-mutagenic effects, and to identify priority research areas. These PLANET activities will be used to improve the risk assessment and to contribute to the revision of the next main recommendations of the International Commission on Radiological Protection.

Radiation Chemistry and Radiation Research: A History from the Beginning to the Platinum Edition.

At the dawn of the 20th Century, the underlying chemistry that produced the observed effects of ionizing radiation, e.g., X rays and Radium salts, on aqueous solutions was either unknown or restricted to products found postirradiation. For example, the Curies noted that sealed aqueous solutions of Radium inexplicably decomposed over time, even when kept in the dark. By 1928 there were numerous papers describing the phenomenological effects of ionizing radiation on a wide variety of materials, including the irradiated hands of early radiologists. One scientist who became intensely interested in these radiation effects was Hugo Fricke (Fricke Dosimetry) who established a laboratory in 1928 dedicated to studies on chemical effects of radiation, the results of which he believed were necessary to understand observed radiobiological effects. In this Platinum Issue of Radiation Research (70 years of continuous publication), we present the early history of the development of radiation chemistry and its contributions to all levels of mechanistic radiobiology. We summarize its development as one of the four disciplinary pillars of the Radiation Research Society and its Journal, Radiation Research, founded during the period 1952-1954. In addition, the work of scientists who contributed substantially to the discipline of Radiation Chemistry and to the birth, life and culture of the Society and its journal is presented. In the years following 1954, the increasing knowledge about the underlying temporal and spatial properties of the species produced by various types of radiation is summarized and related to its radiobiology and to modern technologies (e.g., pulsed radiolysis, electron paramagnetic resonance) which became available as the discipline of radiation chemistry developed. A summary of important results from these studies on Radiation Chemistry/Biochemistry in the 20th and 21st Century up to the present time is presented. Finally, we look into the future to see what possible directions radiation chemistry studies might take, based upon promising current research. We find at least two possible directions that will need radiation chemistry expertise to ensure proper experimental design and interpretation of data. These are FLASH radiotherapy, and mechanisms underlying the effects of low doses of radiation delivered at low dose rates. Examples of how radiation chemists could provide beneficial input to these studies are provided.

Ag-Pt@BSA bimetallic nanoparticles for breast cancer radiation treatment dose augmentation

Cancer has traditionally been treated with surgery and chemotherapy. Radiation therapy (RT) is a branch of oncology based on radiation therapy that can be used alone or in combination with surgery and chemotherapy to achieve local control of breast cancer. Radiosensitizers make tumor cells more responsive and sensitive to ionizing radiation, consequently facilitating production of free radicals and hastening DNA damages. Stages I to III of breast cancer is managed with curative intent with multimodality treatment including radiotherapy. The current cancer therapies in particular radiotherapy have a high risk of serious side effects to the healthy tissues and do not guarantee remission. In response to this challenge, the present study developed bovine serum albumin capped platinum and silver nanoparticles (Ag-Pt@BSA NPs), a bimetallic radiosensitizer, which is a remedy to the aforementioned issue. This research makes use of a nanoplatform that contains two high-Z nanoparticles— Pt and Ag. A variety of methods were used to fully characterize the developed Ag-Pt@BSA NPs. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), UV–Vis, X-ray diffractometery (XRD) and energy-dispersive X-ray spectroscopy (EDS) techniques were used to investigate the physical and chemical features of designed bimetallic nanoradiosensitizer. The Ag-Pt@BSA naoradiosensitizer was proven to have successfully prepared by FTIR, XRD and EDX. According to the DLS result, the hydrodynamic size of the NPs is 35.42 nm, and the average diameter in the TEM image is around 7.8 ± 2.6 nm. The initial hydrodynamic size Ag-Pt@BSA was around 35 nm and within the storage time its size remained below 40 nm which indicating the unique colloidal stability of fabricated nanoradiosensitizers. The zeta potential of Ag-Pt@BSA radio-enhancement was determined to be approximately −17.9 mV, providing additional support for the nanoparticles’ colloidal stability. The results showed that the utilization of Ag-Pt@BSA NPs in conjunction with X-ray irradiation could substantially enhance the effectiveness of cancer therapy. This is supported by research, examining a series of in vitro tests including reactive oxygen species generation (ROS), cell viability, apoptosis and colony formation assay. Furthermore, the dosage-dependent radiosensitizing ability of the Ag-Pt@BSA NPs was also observed in the apoptosis and MTT assay against 4 T1 cells by increasing the localized radiation dosage. Ag-Pt@BSA NPs could be a potential radio-enhancer agent against breast cancers and, by extension, other cancers, since it multiplies the therapeutic effect of low-dose radiation while reducing the damage to normal tissues compared to high-dose radiation therapy. Increasing the concentration of Ag-Pt@BSA NPs and the dosage of X-ray irradiation boosted the radiosensitizing capacity in a dose-dependent way.

Reparative effects after low-dose radiation exposure: Inhibition of atherosclerosis by reducing NETs release

ObjectiveThe cardiovascular system effects of environmental low-dose radiation exposure on radiation practitioners remain uncertain and require further investigation. The aim of this study was to initially investigate and explore the mechanisms by which low-dose radiation may contribute to atherosclerosis through a multi-omics joint comprehensive basic experiment. MethodsWe used WGCNA and differential analyses to identify shared genes and potential pathways between radiation injury and atherosclerosis sequencing datasets, as well as tissue transcriptome immune infiltration level extrapolation and single-cell transcriptome data correction using the CIBERSORT deconvolution algorithm. Animal models were constructed by combining a high-fat diet with 5 Gy γ-ray whole-body low-dose ionizing radiation. The detection of NETs release was validated by enzyme-linked immunosorbent assay. ResultsAnalysis reveals shared genes in both datasets of post-irradiation and atherosclerosis, suggesting that immune system neutrophils may be a key node connecting radiation to atherosclerosis. NETs released by neutrophil death can influence the development of atherosclerosis. Animal experiments showed that the number of neutrophils decreased (P < 0.05) and the concentration of NETs reduced after low-dose radiation compared with the control group, and the concentration of NETs significantly increased (P < 0.05) in the HF group. Endothelial plaques were significantly increased in the high-fat feed group and significantly decreased in the low-dose radiation group compared with the control group. ConclusionsLong-term low-dose ionizing radiation exposure stimulates neutrophils and inhibits their production of NETs, resulting in inhibition of atherosclerosis.

Radiotherapy and Testicular Function: A Comprehensive Review of the Radiation-Induced Effects with an Emphasis on Spermatogenesis.

This comprehensive review explores the existing literature on the effects of radiotherapy on testicular function, focusing mainly on spermatogenic effects, but also with a brief report on endocrine abnormalities. Data from animal experiments as well as results on humans either from clinical studies or from accidental radiation exposure are included to demonstrate a complete perspective on the level of vulnerability of the testes and their various cellular components to irradiation. Even relatively low doses of radiation, produced either from direct testicular irradiation or more commonly from scattered doses, may often lead to detrimental effects on sperm count and quality. Leydig cells are more radioresistant; however, they can still be influenced by the doses used in clinical practice. The potential resultant fertility complications of cancer radiotherapy should be always discussed with the patient before treatment initiation, and all available and appropriate fertility preservation measures should be taken to ensure the future reproductive potential of the patient. The topic of potential hereditary effects of germ cell irradiation remains a controversial field with ethical implications, requiring future research.

699 Gender Inequality in Orthopaedic Radiation Protection: An Audit

Abstract Aim The literature demonstrates an increased prevalence of breast cancer in female orthopaedic surgeons compared to the population baseline. One contributor to this alarming statistic may be exposure to frequent low-dose radiation inherent to orthopaedics. The British Orthopaedic Association (BOA) has emphasised the importance of wearing lead aprons that provide adequate coverage, especially of the axillary region in women. To assess the availability of vests that fulfil such criteria, an audit of the lead aprons available at our local adult tertiary centre was undertaken. Method Lead protective equipment used by the orthopaedic theatres were documented by type, size, and brand. Data collection occurred prior to theatre activity requiring lead use, to ensure all equipment was present. Results 115 pieces of equipment were identified - 43 standard vests, 9 tabard gowns with side coverage, 4 tabard gowns without side coverage, 48 skirts and 11 thyroid covers. Vests, skirts, and tabard gowns ranged from XS (n=4), S (n=21), M (n=15), L (n=46), to XL (n=12), unidentifiable size (n=6). Vests, skirts and tabard gowns ranged from several different brands including Xenolite Male (n=45), Xenolite Female (n=29) and Kenex (n=23). No boleros, high axilla vests, or vests with wings/sleeves/axillary shields, were identified. Conclusions This audit demonstrated inadequate adherence to BOA recommendations and a lack of size diversity. With increasing numbers of women in orthopaedics, there is a need to raise more awareness and address this safety concern to mitigate a larger concerning trend.

Role of Olive Leaf Extract, Mesenchymal Stem Cells or Low Radiation Dose in Alleviating Hepatic Injury in Rats.

This study was conducted to determine the efficacy of mesenchymal stem cells (MSCs) or low-dose gamma radiation (LDR) on liver injury compared to the effect of olive leaf extract as a hepatoprotective agent. Rats were allocated into six groups; group I served as the negative control. Group II received 5% dextran sodium sulfate (DSS) in its drinking water for 1 week. Group III was injected with a single dose of 1 × 106 bone marrow-derived mesenchymal stem cells (BM-MSCs) intravenously. Group IV was treated as in group III after 5% DSS treatment. Group V was given 5% DSS, followed by olive leaf extract (OLE) (1000mg/ kg, oral). Group VI: 5% DSS for 1 week, then was exposed to low-dose gamma radiation (LDR) (0.05Gy). Rats treated with OLE, BM-MSCs, or exposed to LDR exerted significant alleviation in all hepatic biomarkers, significant enhancements in oxidative stress parameters, and improvements in inflammatory biomarkers Interleukin-1 beta (IL-1β) and Interferon gamma (INF-γ) hepatic contents compared with those of the DSS group. Histological pictures emphasized the biochemical findings. BM-MSCs might be a valuable therapeutic approach to overcome hepatic injury. Exposure to LDR provided protective mechanisms that allow the body to survive better.