Radiation Biology

The purpose of this publication is to offer general guidance to medical personnel in a hospital setting regarding the handling of patients with common injuries complicated by the presence of radioactive contamination and of patients who have been exposed to a high level of radiation.

This guide provides an overview of radiation, its basic effects on the body, the types of accidents that can produce contaminated and/or exposed patients, and an explanation of how accidents involving radiation differ from other Hazardous Materials incidents. Also included is a section that deals with the effects of exposure, contains information on etiology, clinical manifestations, and classifications of severe radiological injuries. The intent is to provide background information on the more serious aspects of radiation exposure, but not to be a definitive treatment guide or
replace expert technical advice. It also addresses the practical aspects of handling the contaminated and/or exposed patient in an emergency situation, including recommendations on the precautions that should be observed in treating such cases.

The hematopoietic system is among the most radiosensitive systems in the human organism. Cellular responses to ionizing radiation, regardless of dose magnitude, share common regulatory mechanisms, particularly in the control of oxidative stress. Oxidative stress plays a critical role in cellular senescence and in the dysregulation of stem cell proliferative capacity. Exposure to high doses of ionizing radiation (≥ 1 Gy) leads to significant physiological consequences, with severity increasing proportionally with dose. Acute hematopoietic syndrome, a subsyndrome of acute radiation syndrome, typically manifests following exposure to doses between 2 and 6 Gy. Clinical symptoms emerge within hours postexposure, progressively exacerbating due to severe impairment of hematopoietic organs, vasculature, and bone marrow. Prompt diagnosis and therapeutic intervention are essential for mitigating disease progression and facilitating recovery. Conversely, prolonged exposure to low doses of ionizing radiation is associated with delayed stochastic effects, often manifesting long after initial exposure. Although these effects do not exhibit a direct dose-response relationship, the risk of long-term hematopoietic dysfunction increases with cumulative radiation dose. In all cases, ionizing radiation exposure necessitates comprehensive biodosimetric assessment, precise dose estimation, early diagnosis, and the implementation of effective therapeutic strategies. This review aims to examine systematically the comparative effects of highand low-dose ionizing radiation on the hematopoietic system, with a particular emphasis on the molecular mechanisms influencing stem cell function and the potential clinical pathologies that may arise.

Objectives: This review aims to trace the historical narrative surrounding the low dose effects of radiation on the immune system and how our understanding has changed from the beginning of the 20th century to now. The particular focus is on the non-targeted effects (NTEs) of low dose ionizing radiation (LDIR) which are effects that occur when irradiated cells emit signals that cause effects in the nearby or distant non-irradiated cells known as radiation induced bystander effect (RIBE). Moreover, radiation induced genomic instability (RIGI) and abscopal effect (AE) also regarded as NTE. This was prompted by our recent discovery that ultraviolet A (UVA) photons are emitted by the irradiated cells and that these photons can trigger NTE such as the RIBE in unirradiated recipients of these photons. Given the well-known association between UV radiation and the immune response, where these biophotons may pose as bystander signals potentiating processes in deep tissues as a consequence of LDIR, it is timely to review the field with a fresh lens. Various pathways and immune components that contribute to the beneficial and adverse types of modulation induced by LDR will also be revisited. Conclusion: There is limited evidence for LDIR induced immune effects by way of a non-targeted mechanism in biological tissue. The literature examining low to medium dose effects of ionizing radiation on the immune system and its components is complex and controversial. Early work was compromised by lack of good dosimetry while later work mainly looks at the involvement of immune response in radiotherapy. There is a lack of research in the LDIR/NTE field focusing on immune response although bone marrow stem cells and lineages were critical in the identification and characterization of NTE where effects like RIGI and RIBE were heavily researched. This may be in part, a result of the difficulty of isolating NTE in whole organisms which are essential for good immune response studies. Models involving inter organism transmission of NTE are a promising route to overcome these issues.

Accidents involving human exposure to radiation can cause severe health effects which may require extensive medical resources. Particularly in mass-casualty events, the rapid identification and classification of potentially overexposed individuals into medical treatment groups is of prime importance. For this purpose, clinical signs and symptoms and biological dosimetry methods are the two main approaches for assessing radiation exposure in situations where no dosimetry badge was worn. The dicentric chromosome assay (DCA) is considered the “gold standard” method for biological dosimetry after an acute radiation exposure. However, several novel techniques are emerging which may be faster and have a higher throughput than the DCA and could thus become valuable dosimetric tools in the future. This comprehensive study was organized under the umbrella of the NATO Research Task Group RTG-033 “Radiation Bioeffects and Countermeasures” in order to compare the performance of the two most val...

Purpose: In the framework of RENEB, several biodosimetry exercises were conducted analyzing different endpoints. Among them, the analysis of translocations is considered the most useful method for retrospective biodosimetry due to the relative stability of their frequency with post irradiation time. The aim of this study was to harmonize the accuracy of translocation-based biodosimetry within the RENEB consortium. Materials and methods: An initial telescoring exercise analyzing FISH metaphase images was done to harmonize chromosome aberration descriptions. Then two blind intercomparison exercises (IE) were performed, by sending irradiated blood samples to each partner. Samples were cultured and stained by each partner using their standard protocol and translocation frequency was used to produce dose estimates. Results: The coefficient of variation in the 1st IE (CV ¼ 0.34) was higher than in the 2nd IE (CV ¼ 0.16 and 0.23 in the two samples analyzed), for the genomic frequency of total translocations. Z-score analysis revealed that eight out of 10 and 17 out of 20 dose estimates were satisfactory in the 1st and 2nd IE, respectively. Conclusions: The results obtained indicate that, despite the problems identified in few partners, which can be corrected, the RENEB consortium is able to carry out retrospective biodosimetry analyzing the frequency of translocations by FISH.

Interest in deep space exploration underlines the needs to investigate the effects of exposure to combined sources of space radiation. The lung is a target organ for radiation, and exposure to protons and heavy ions as radiation sources may lead to the development of degenerative disease and cancer. In this study, we evaluated the pro-fibrotic and epigenetic effects of exposure to protons (150 MeV/nucleon, 0.1 Gy) and heavy iron ions ( 56 Fe, 600 MeV/nucleon, 0.5 Gy) alone or in combination (protons on Day 1 and 56 Fe on Day 2) in C57BL/6 male mice 4 weeks after irradiation). Exposure to 56 Fe, proton or in combination, did not result in histopathological changes in the murine lung. At the same time, combined exposure to protons and 56 Fe resulted in pronounced molecular alterations in comparison with either source of radiation alone. Specifically, we observed a substantial increase in the expression of cytokine Il13, loss of expression of DNA methyltransferase Dnmt1, and reactivation of LINE-1, SINE B1 retrotransposons, and major and

N owadays radiotherapy and adjuvant endocrine therapy represent a standard treatment option in management of breast cancer. Melatonin exerts oncostatic actions on human breast cancer cells. Therefore, the purpose of this study was to investigate the effects of a combination of radiotherapy and melatonin on human breast cancer cells. Radiation inhibited MCF-7 cell proliferation in a dose-dependent manner, and pretreatment with melatonin one week before radiation led to a significantly decrease of cell proliferation compared with radiation alone. Melatonin pretreatment also decrease G2-M phase arrest compared with radiation alone, with a higher percentage of cells in G0-G1 phase and a lower percentage of cells in S phase. Regarding double-strand DNA break repair proteins, melatonin led to a significantly greater decrease in RAD-51 and DNA-PKcs mRNA gene expression compared with radiation alone. Melatonin pretreatment also upregulated the tumor suppressor p53. We have also demonstrated that melatonin pretreatment induced a greater decrease in aromatase and sulfatase, two main enzymes involved in the tumoral synthesis of estrogens, compared with radiation alone. Therefore, melatonin reduces active estrogens levels at tumoral cell. This is an important finding since anti-estrogens and anti-aromatase drugs have potential application with radiotherapy. Our findings suggest that melatonin may act as a radiaosensitizer in breast cancer cells by inhibiting tumor alestrogen production, decreasing cell proliferation, inducing cell cycle arrest and down-regulating proteins involved in double-strand DNA break repair through its regulatory action on p53. Thus, these results may have high translational potential for the adjuvant therapy in breast cancer patients.

E xposure of radiation leads to cell death and also leads to cancer. Compare to other toxicants, ionizing radiation is especially challenging because contaminated animals cannot be definitively identified without the use of specialized detection equipment. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of high and low levels of radiation that may ultimately result in ionization radiation exposure to both human and non-human biota. The present study was conducted to investigate the radioprotective efficacy of Spirulina through feed in comparison with standard compound Silymarin (500 mg/kg) and Spirulina (cyanobacterium). The species Pangasius sutchi exposed to Gamma Radia-tions (60Co), at the dosage of LD50 and LD70 from the source of 60Co. Blood samples were collected at the differentperiod of time 2nd day, 4th day, 8th day, 16th day and 28th day and analyzed micronucleus assay. The abnormalities were observed as micronuclei, cytoplasmic bridge, cytoplasmic division, vacuolated cytoplasm, binucleated, lobed cell, enucleated and trinucleated cells. And no single base pair DNA damage has been observed in erythrocytes after different time intervals, by doing single cell gel electrophoresis. Furthermore research is needed in this study to determine the actual mechanism of radioprotection of Spirulina for the application as radioprotective agent.

Personalized medicine is revolutionizing cancer treatment by tailoring therapeutic strategies to the unique genetic, epigenetic, and molecular characteristics of individual patients. Traditional "one-size-fits-all" approaches to cancer care are increasingly being replaced by precision-driven interventions that enhance efficacy, reduce adverse effects, and improve patient outcomes. This review explores recent advances in personalized cancer medicine, focusing on the integration of genetic profiling, epigenetic modifications, and pharmacogenomics in clinical oncology. Genomic technologies such as next-generation sequencing have enabled the identification of somatic mutations, gene fusions, and copy number variations that drive tumorigenesis, providing actionable targets for therapies. Epigenetic alterations, including DNA methylation, histone modifications, and non-coding RNAs, are also being recognized as critical regulators of gene expression in cancer, offering new biomarkers for diagnosis, prognosis, and therapeutic response. Meanwhile, pharmacogenomics, the study of how genetic variation affects drug metabolism and response, allows clinicians to optimize drug selection and dosing based on a patient's genetic makeup, minimizing toxicity and maximizing therapeutic benefit. The integration of these molecular insights is paving the way for a comprehensive, systems biology approach to cancer treatment. Despite notable progress, challenges remain, including the complexity of tumor heterogeneity, the dynamic nature of epigenetic changes, and limited access to genomic testing in some settings. Nevertheless, ongoing research and technological advancements continue to expand the clinical utility of personalized medicine. New tools enabled by liquid biopsy or integrative multi-omics platforms improve early detection as well as monitoring of treatment. Yet, problems remain, such as tumor heterogeneity, dynamic epigenetic changes, and equitable access to advanced diagnostics. This review synthesizes the current state of knowledge and emerging trends in personalized oncology, highlighting the transformative impact of genetic, epigenetic, and pharmacogenomic approaches in shaping the future of cancer therapy.

The description of the biological effects of ionizing radiation requires a good knowledge of the dose deposition processes at both the cellular and molecular scales. However, the specific behavior of subkeV electrons which deposit their energy in nanometric volumes, remains poorly described [1]. Moreover, theoretical calculations have shown that ionizing the K-shell electrons of metal ions in solution can lead to large local production of radical and slow electron species [2]. Irradiating solutions containing metal ions, such as Mg, with monochromatic X-rays around their K edges could thus allow to investigate this process. Hydroxyl radical quantification was conducted through OH scavenging by benzoate to form the fluorescent hydroxybenzoate [3]. Liquid water samples were first irradiated in a static cell with monochromatic soft X-rays (0.2-1.4 keV) at the Metrologie beamline (SOLEIL synchrotron, France). Yields of OH radicals exhibit a minimum around 1.5 keV, in good agreement with...

Purpose: Humans are increasingly exposed to ionizing radiation (IR). Both low (<100 mGy) and high doses can cause stochastic effects, including cancer; whereas doses above 100 mGy are needed to promote tissue or cell damage. 10-15% of radiotherapy (RT) patients suffer adverse reactions, described as displaying radiosensitivity (RS). Sensitivity to IR's stochastic effects is termed radiosusceptibility (RSu). To optimize radiation protection we need to understand the range of individual variability and underlying mechanisms. We review the potential mechanisms contributing to RS/RSu focusing on RS following RT, the most tractable RS group. Conclusions: The IR-induced DNA damage response (DDR) has been well characterized. Patients with mutations in the DDR have been identified and display marked RS but they represent only a small percentage of the RT patients with adverse reactions. We review the impacting mechanisms and additional factors influencing RS/RSu. We discuss whether RS/RSu might be genetically determined. As a recommendation, we propose that a prospective study be established to assess RS following RT. The study should detail tumor site and encompass a well-defined grading system. Predictive assays should be independently validated. Detailed analysis of the inflammatory, stress and immune responses, mitochondrial function and life style factors should be included. Existing cohorts should also be optimally exploited.

Ensuring the integrity of the reactor pressure vessel (RPV) during the operating life of nuclear reactors is of paramount importance, and hence the harmful effects of irradiation on the steels of the RPVs have been extensively studied especially the irradiation embrittlement effects. However, improvements in the calculation methods are still necessary to further reduce the discrepancy between calculations and experiments. This study was performed to examine the neutron fluence and respective rate of displacement per atom (DPA), an important parameter describing the irradiation-induced damage, in the VVER-1000 RPV steel based on the criticality calculation, instead of the common fixed source approach, with the MCNP6 Monte Carlo code, and identify the most sensitive locations in the VVER-1000 RPV. The MCNP6 modeling of the VVER-1000 reactor was verified against the OpenMC calculations in addition to the confirmation of the convergence of the effective neutron multiplication factor and the Shannon entropy of the fission source distribution in the MCNP6 criticality calculations to ensure reliable tally results of the neutron fluence. Consequently, the maximum neutron fluence in the VVER-1000 RPV was found at the positions adjacent to the peripheral fuel assemblies, and the respective DPA rate was analyzed in correlation with the neutron fluence and energy spectrum.

India is a mega-diversity country with rich cultural and natural heritages. Its geographical diversity reflects its rich biodiversity; the fact that 10% of all known species of organisms inhabit India is enough to establish this.
Desert is an ecosystem of harsh climatic extremes of both hot and cold across the year. Indian desert (Thar) is in the west and boasts richness in both floral and faunal diversity. Electromagnetic radiations have a wide range of energies,and they are broadly classified into two categories, namely ionizing radiation, and non-ionizing radiation. Exposure to radiation can have mutagenic effects on humans as well as other biota. Mode of exposure to radiation can vary from being natural to artificial, and consequently their respective effects are of different magnitudes.Two case studies have been taken to study the effects of large scale exposure of electromagnetic radiations on wildlife. Chernobyl nuclear power plant accident (April 1986, in former USSR) was one such event which has been widely studied over its impact on society and wildlife. Fukushima nuclear accident Japan) was yet another accident of similar kind and effects. Effects of high rate of absorption of radiation showed high mortality and tissue necrosis in vegetation, while low to moderate absorption led suppression of growth. Among invertebrates, radiation absorption widely affected reproductive success, although diversity initially fell after the Chernobyl accident, but it was restored to about its 80% in the following years. Chernobyl Exclusion Zone was created to contain the spread of radiation in 1986, till date it has not been inhabited by humans. Although, radiation exposure bore harmful effects, but removal of humans has led Chernobyl Exclusion Zone (CEZ) to become an example of how ecosystems can thrive when human interference becomes minimal. This review article is an attempt to assess the impact of natural and man-made nuclear disasters on wildlife and how the radiations are impacting the fauna of the Thar.

The King's College London (KCL) rst X-ray microprobe (MKI) and the third generation microfocus X-ray sources (MKIII) are intended to be used for various applications including the study of physical and biological interactions at the atomic and molecular scales. The microfocus ultra-soft X-ray sources (MKI and MKIII) with interchangeable targets will provide a superior spatial resolution (a focal spot a few hundreds of nanometres in diameter can be achieved) and the control of the dose delivered to irradiated cells. This will require characterization of the spectra and intensities of the source, measurements of the focus intensities and spot sizes of suitable X-ray optics such as zone plates, grazing incidence microstructured optical arrays and multilayer mirrors.

Mammographic density (MD) is a strong risk factor for breast cancer. It is altered by exogenous endocrine treatments, including hormone replacement therapy (HRT) and Tamoxifen. Such agents also modify breast cancer (BC) risk. However, the biomolecular basis of how systemic endocrine therapy modifies MD and MD-associated BC risk is poorly understood. This study aims to determine whether our xenograft biochamber model can be used to study the effectiveness of therapies aimed at modulating MD, by examine the effects of Tamoxifen and oestrogen on histologic and radiographic changes in high and low MD tissues maintained within the biochamber model. High and low MD human tissues were precisely sampled under radiographic guidance from prophylactic mastectomy fresh specimens of high-risk women, then inserted into separate vascularized murine biochambers. The murine hosts were concurrently implanted with Tamoxifen, oestrogen or placebo pellets, and the high and low MD biochamber tissues maintained in the murine host environment for three months, before the high and low MD biochamber tissues were harvested for histologic and radiographic analyses. The radiographic density of high MD tissue maintained in murine biochambers was decreased in Tamoxifen-treated compared to oestrogen-treated mice (p=0.02). Tamoxifen treatment of high MD tissue in SCID mice led to a decrease in stromal (p=0.0088), and an increase in adipose (p=0.023) percent areas, compared to placebo-treated mice. No histologic or radiographic differences were observed in low MD biochamber tissue with any treatment. High MD biochamber tissues maintained in mice implanted with Tamoxifen, oestrogen or placebo pellets had dynamic and measurable histologic compositional and radiographic changes. This further validates the dynamic nature of the MD xenograft model, and suggests the biochamber model may be useful for assessing the underlying molecular pathways of Tamoxifen-reduced MD, and in testing of other pharmacologic interventions in a preclinical model of high MD.

Background: The sources of radioactivity in the environment have natural, terrestrial and extraterrestrial, and anthropogenic origins. Plants may get radioactive nuclides in two ways: (i) by the deposition of radioactive fallout, (ii) by absorption from the soil. Materials and Methods: The Concentrations of the natural radionuclides (226Ra, 228Ra, 40K) and the artificial radionuclide (137Cs) in leek and parsley in Tehran province-Iran were determined using HPGe. Also the effective dose due to the ingestion of such vegetables by the population of Tehran province was studied. Results: The average value of radionuclide concentrations in parsley samples were measured 177.69 ± 12.47 mBq kg-1 fresh for 226Ra; 349.62 ± 28.42 mBq kg -1 fresh for 228 Ra; 187364.6 mBq kg -1 fresh for 40K. The average value of radionuclide concentrations in leek samples were measured 94.31 ± 6.46 mBq kg -1 fresh for 226 Ra; 207.47 ± 19.46 mBq kg -1 fresh for 228Ra; 174555 ± 1704.21 mBq kg-1 fresh for 40K. The ...

Companies and organizations around the world spend massive amounts of money each year to discover, predict, and remediate failures within engineered systems. By doing so, these groups save lives, reduce costs, and maintain their reputations. However, to effectively and efficiently perform these tasks, companies and organizations rely on individuals with specialized knowledge in a variety of topics related to failure. This knowledge is often acquired through years of academic and onthe-job training centered around the review of scientific documentation such as books, reports, manuals, and peerreviewed publications. The loss of this knowledge through employee attrition can be detrimental to a group as knowledge is often difficult to reacquire. The aggregation and representation of known failure mechanisms for engineered materials could aid in the sharing of knowledge, the acquisition of knowledge, and the discovery of failure causes, reducing the risk of failure. Thus, the current work proposes the Adverse Outcome Pathway for Engineered Systems (AOP-ES) framework, an extension of the Adverse Outcome Pathway used in toxicology. The AOP-ES is designed to document failure knowledge enabling knowledge transfer and the prediction of failures of novel engineered materials based on the performance of similar materials. This paper introduces the AOP-ES framework and its key elements alongside the principles that govern the framework. An application of the framework is presented and additional benefits are explored.

Purpose: Technological advancement in the treatment of cancer together with early detection and diagnosis have considerably improved the survival of breast cancer patients. On the other hand, the potential of patients developing side effects from cancer treatment are not negligible. Despite the progress that has been made in terms of early diagnosis, therapy, and survival, including improvements in the chemotherapeutic agents, radiation and molecular targeted therapies, cardiotoxicity of cancer therapy is still cause for concern. Radiation therapy for breast cancer is associated with increased risk of heart disease and myocardial infarction. Furthermore, the association of radiation therapy to chemotherapy is an important aspect to be considered in the development of cardiac disease, as this could play an additional role as a risk factor. Besides the heart effect, other side effects can be observed in the bone, ovary, uteri, and other organs. This paper aims to review the recent literature to present the current understanding of side effects associated with breast cancer treatment. The focus is on recent preclinical studies that have assessed potential changes in different organs that may be injured after breast cancer treatment, both due to both radiation and chemotherapy agents. Conclusion: Radiation-induced heart disease is one important side effect that must be considered during the treatment planning and patient follow-up. The cardiac damage can be potentialized when chemotherapy is associated to radiotherapy, and the literature findings indicate that heart fibrosis plays an important role at the radio-chemotherapy induced cardiac damage. Literature findings also showed important side effects at the bone, that can lead to ospeoporosis, due to the decrease of calcium, after radio or chemotherapy treatments. This decrease could be explained by the ovarian failure observed at rats after chemotherapy treatment. It is of great importance to acknowledge the complications originating from the treatment, so that new strategies can be developed. In this way, it will be possible to minimize side effects and improve the patients' quality of life.

Purpose: Heavy ion and proton brain irradiations occur during space travel and in Hadron therapy for cancer. Heavy ions produce distinct patterns of energy deposition in neuron cells and brain tissues compared to X-rays leading to large uncertainties in risk estimates. We make a critical review of findings from research studies over the last 25 years for understanding risks at low dose. A large number of mouse and rat cognitive testing measures have been reported for a variety of particle species and energies for acute doses. However tissue reactions occur above dose thresholds and very few studies were performed at the heavy ion doses to be encountered on space missions (<0.04 Gy/y) or considered dose-rate effects, such that threshold doses are not known in rodent models. Investigations of possible mechanisms for cognitive changes have been limited by experimental design with largely group specific and not subject specific findings reported. Persistent oxidative stress and activated microglia cells are common mechanisms studied, while impairment of neurogenesis, detriments in neuron morphology, and changes to gene and protein expression were each found to be important in specific studies. Future research should focus on estimating threshold doses carried out with experimental designs aimed at understating causative mechanisms, which will be essential for extrapolating rodent findings to humans and chronic radiation scenarios, while establishing if mitigation are needed.

Background Chemoradiotherapy complications has always been of great concern to both clinicians and patients during the course of treatment. The purpose of the present study was to examine the effectiveness of oral famotidine on the reduction of hematologic complications of patients with esophageal and gastric cardia cancers undergoing radiotherapy. Methods A single-blind controlled trial was conducted on 60 patients with esophageal and cardia cancers, who were undergoing chemoradiotherapy. Patients were randomly assigned to 2 groups with 30 patients to receive either 40 mg of oral famotidine (daily and 4 h before each session) or placebo. Complete blood count with differential, platelet counts, and hemoglobin levels were obtained weekly during treatment. The main outcome variables were lymphocytopenia, granulocytopenia, thrombocytopenia, and anemia. Results The findings indicated a significant effect of famotidine on reduction of thrombocytopenia among intervention group compared to...

Background: After radiation therapy (RT), some health hazards including DNA damages may occur where melatonin can play a protective role due to free radical generation. On the other hand, serious accidental overexposures may occur during RT due to nuclear accidents which necessitate the need for study on exposure to high-dose radiations during treatments. Objective: The aim of this study was to study the expression level of two genes in non-homologous end joining (NHEJ) pathways named Xrcc4 and Xrcc6 (Ku70) in order to examine the effect of melatonin on repair of DNA double-strand breaks (BSBs) caused by 8Gy ionizing radiation. Methods: One hundred eight male Wistar rats were irradiated with a whole body gamma radiation dose of 8Gy with or without melatonin pretreatments. They were divided into six different groups of control, 100 mg/kg melatonin alone, 8Gy irradiation alone, vehicle alone, vehicle plus 8Gy irradiation and 100 mg/kg melatonin plus 8Gy irradiation. Peripheral blood s...

Introduction Quality control (QC) techniques are used in monitoring and maintenance of the components of an x-ray system. QC of radiology devices plays a significant role in reduction of medication dose and optimization of image quality. This study aimed to conduct QC tests on randomly selected radiology devices, installed in diagnostic imaging departments of Iran. Materials and Methods In total, quality control tests were conducted on 51 conventional radiology devices installed in 20 cities of Iran in order to assess the accuracy of peak kilovoltage  (kVp), exposure time, exposure linearity and reciprocity, reproducibility of exposure and determination of half-value layer (HVL) using a calibrated Mult-O-Meter. Results In this study, 38.6% of devices had intolerable variance of kVp accuracy. The results of 34.5% of devices were out of the acceptable limits in exposure time accuracy test. In 46.7% and 53.1% of devices, variance was greater than the acceptable range for exposure linea...

Objective(s): Radiotherapy is one of the most effective modalities of cancer therapy, but clinical responses of individual patients varies considerably. To enhance treatment efficiency it is essential to implement an individual-based treatment. The aim of present study was to identify the mechanism of intrinsic apoptosis pathway on radiosensitivity and normal tissue complications caused by the radiotherapy. Materials and Methods: Peripheral blood mononuclear cells from ten breast cancer patients were exposed to 6MV X-rays to deliver 1 and 2 Gy. Expression levels of Bax, Bcl-2, and Bax/Bcl-2 ratio were examined by relative quantitative RT-PCR. All the patients received similar tangential irradiation of the whole breast and conventional fractionation. Skin dosimetry was done by GAFChromic EBT-3 film and clinical radiosensitivity was determined using the acute reactions to radiotherapy of the skin according to Radiation Therapy Oncology Group score. All statistical analyses were perfor...

In a longitudinally designed study, we tested whether an isoflavone enriched soy extract (SE) stimulated peak bone gain in rats during growth and maturity so as to confer better bone conserving effect after ovariectomy with concurrent treatment discontinuation. Weaned female rats were given SE or vehicle for 12-weeks and bone parameters were recorded (baseline). One group was then ovariectomized (OVx) and the other group sham operated. Vehicle group after OVx was given 17b-estradiol (E2) or continued with vehicle (OVx + vehicle). SE group after OVx was given vehicle (SEV). After 12-weeks, all groups were killed (endpoint). At baseline, SE group had greater cortical bone parameters over control. At endpoint, SEV group displayed significant bone conservation which was comparable to OVx + E2 group. Data suggest that SE enhanced peak bone accrual that supported skeletal preservation post-OVx on a par with E2 supplementation, not withstanding SE withdrawal at OVx.

Field experiments were conducted at Nubareia Agricultural Research Station Farm on a calcareous soil under drip irrigation system to study the effect of adding humic acid (20 g/l) as well as foliar application with putrescine (1.0 mg/l), novavol (2.5 ml/l) and vegimax (0.2 ml/l) on growth, yield and its components as well as chemical composition of snap bean plants cv. Paulista. The obtained results indicated that, application of humic acid, novavol or vegimax significantly increased all of the studied growth characters, i.e. plant height, number of leaves and branches/plant, leaf area as well as dry weight of shoots and roots at both samples. However, putrescine did not show a clear trend for various studied growth characters. Moreover, addition of humic acid as well as foliar application by novavol, putrescine and vegimax significantly increased yield and its components, i.e. total green pod yield, number of pods/plant, pods weights/plant, average pod weight and pod diameter at both pickings. Plant pigments, i.e. chlorophyll a, total chlorophyll and caroenoids concentrations either in leaves or pods significantly increased at both samples when the plants treated with humic acid, novavol and vegimax. In shoots, P, K, Ca, Mg, Zn and Fe concentrations significantly increased at both samples with all studied applications. Meanwhile in pods, addition of humic acid significantly affected on N, K, Fe and Cu concentrations, whereas foliar application with novavol and vegimax significantly improved N, K, Mg, Zn, Mn and Fe concentration at both pickings. On the other hand, application of any treatments significantly decreased Na and Cl concentrations in both shoots and pods at both samples. Results also showed that all studied applications significantly increased some organic compounds, i.e. total sugar, total free amino acids and total soluble phenols concentrations at both of shoots and pods in both samples as well as protein concentration in pods. Meanwhile, all studied applications significantly decreased pods bending % and fiber content in pods at both pickings as well as pod humidity % and nitrate concentrations with humic acid, putrescine and vegimax treatments. [

This study compares the capabilities of three different passive collimation devices to produce micrometer-sized beams for proton and alpha particle beams (1.7 MeV and 5.3 MeV respectively): classical platinum TEM-like collimators, straight glass capillaries and tapered glass capillaries. In addition, we developed a Monte-Carlo code, based on the Rutherford scattering theory, which simulates particle transportation through collimating devices. The simulation results match the experimental observations of beam transportation through collimators both in air and vacuum. This research shows the focusing effects of tapered capillaries which clearly enable higher transmission flux. Nevertheless, the capillaries alignment with an incident beam is a prerequisite but is tedious, which makes the TEM collimator the easiest way to produce a 50 lm microbeam.

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Sulforaphane, present in cruciferous vegetables such as broccoli, is a dietary anticancer agent. Sulforaphane, added 2 or 20 h following phytohemaglutinin stimulation to cultured peripheral blood lymphocytes of individuals accidentally exposed to mixed and ␤-radiation, reduced the micronucleus frequency by up to 70%. Studies with whole blood cultures obtained from healthy volunteers confirmed the ability of sulforaphane to ameliorate -radiation-induced genotoxicity and to reduce micronucleus induction by other DNA-damaging anticancer agents, such as bleomycin and doxorubicin. This reduction in genotoxicity in lymphocytes treated at the G 0 or G 1 stage suggests a role for sulforaphane in modulating DNA repair. Sulforaphane also countered the radiation-induced increase in lymphocyte HDAC activity, to control levels, when cells were treated 2 h after exposure, and enhanced histone H4 acetylation status. Sulforaphane post-irradiation treatment enhanced the CD 34 + Lin -cell population in culture. Sulforaphane has therapeutic potential for management of the late effects of radiation.

Psoralea corylifolia Linn., an Indian medicinal plant exhibited good antioxidant, antitumoral and immunomodulatory activities and excellent ex vivo radical scavenging capacity, which are relevant to radioprotection and uses in medicine. By the present research for the first time using EPR spectroscopy we report our investigations on “real time” levels of Ascorbate radicals (Asc . ) and ROS production in organs of mice treated by Psoralea corylifolia Linn. and its biodistribution in the same organs. For the present study BALB/c mice were injected i.p. with compound (40 mg/kg), dissolved in saline. Mice were dissected at the different time intervals post injection and tissues from liver, kidneys and pancreas were homogenates in cold PBS solution and tested for organ allocation of the drug. Tissue homogenates in DMSO and DMSO solution of the spin trap N-tert-butyl-alpha-phenylnitrone (PBN) were prepared for determination of the ascorbate radicals level and for ROS products level, corre...

Globally, amongst all the factors threatening the existence of landcover in the biosphere, agriculture and urbanization plays the most potent role aside from the natural factor of climate. The study examines the effect of human factors on vegetal cover and identifies the drivers of the changes within the area councils of the FCT over a period of three decades. The need to conserve limited natural resources is threaten by the effect of increased population and their continuous anthropogenic activities on this limited resource, thus the vegetation cover which represents an important natural resource for both humans and other species is lost due to reckless and unsustainable usage. Using geospatial techniques, the magnitude of human activities of development is assessed as it affects vegetation cover. The results of the analysis show a tremendous impact of anthropogenic activities as the landcover continue to deplete from 1987 – 2016. Human impacts were identified as the major driver o...

Reactive Oxygen Species are chemically unstable molecules generated during aerobic respiration, especially in the electron transport chain. ROS are involved in various biological functions; any imbalance in their standard level results in severe damage, for instance, oxidative damage, inflammation in a cellular system, and cancer. Oxidative damage activates signaling pathways, which result in cell proliferation, oncogenesis, and metastasis. Since the last few decades, mesenchymal stromal cells have been explored as therapeutic agents against various pathologies, such as cardiovascular diseases, acute and chronic kidney disease, neurodegenerative diseases, macular degeneration, and biliary diseases. Recently, the research community has begun developing several anti-tumor drugs, but these therapeutic drugs are ineffective. In this present review, we would like to emphasize MSCs-based targeted therapy against pathologies induced by ROS as cells possess regenerative potential, immunomodulation, and migratory capacity. We have also focused on how MSCs can be used as next-generation drugs with no side effects.

A new design for a y-ray C om pton scatterin g spectrom eter is presented. The spectrom eter uses an an n u lar geom etry th a t is th e inversion of th e an n u lar geom etry used in earlier experim ents w ith am ericium y-rays. A small source is placed d irectly in fro n t of th e d etecto r so th a t it is th e d etecto r and n o t th e source th a t provides th e annulus. M easurem ents of th e C om pton profile of alum inium are used to evalu ate th e new design. F o r sm all sam ples it is possible to increase th e in ten sity by a facto r of up to 104 while m aintaining th e resolution. This should m ake it possible to o btain accurate d a ta for m any com pounds th a t could n o t previously be studied because of th e difficulties associated w ith obtaining large single crystals.

В последните години биодозиметричните методи за анализ на поета доза йонизираща радиация, се наложиха в европейската практика. Основни методи за биодозиметрия са дицентричен хромозомен анализ (наличие на дицентрични хромозоми), тест за наличие на микронуклеус в двуядрени клетки, FISH анализ (флуоресцентна in situ хибридизация), преждевременна хромозомна кондензация (PCC) и др. НИЛ по радиобиология и радиационна защита, ВМА-София, е в етап на разработване на два основни метода за биодозиметрия (дицентричен хромозомен анализ и тест за наличие на микронуклеус в двуядрени клетки). Първият метод се използва за оценка на риска от развитие на късни, стохастични ефекти при хронично, продължително, нискодозово облъчване. Следващият етап ще бъде интегриране на двата метода, като рутинна диагностика на поета висока доза при радиационен инцидент или оценка на риска при пациенти с онкологични заболявания.
Целта на настоящото изследване е да се оптимизират двата биодозиметрични метода за нуждите на НИЛ по РЗР, ВМА МБАЛ-София.
След направен детайлен анализ и преглед на двата методи, приоритет се дава на дицентричният хромозомен анализ. Избран е като най-точен, бърз и високоефективен метод за анализ на поета висока доза йонизираща радиация или за оценка на риска от развитие на късни, стохастични ефекти, при нискодозово, продължително облъчване. Тестът за анализ на микронуклеус в двуядрени клетки е добър метод за потвърждаване на резултатите, получени от дицентричния хромозомен анализ.
Биодозиметричната оценка на погълната доза йонизираща радиация, е висококвалифицирана дейност. Включва екип от професионалисти, правилен подбор на приложимите методи и предварителна оптимизация на процеса.

To determine the effective dose equivalent of the public in Iran due to 222Rn and its daughters (218po and 214po) from natural radiation environment, a national radon monitoring program was developed at the Radiation Protection Department of the Atomic Energy Organization of Iran (AEOI). The AEOI passive radon diffusion dosimeters were applied in this program. About 250 dosimeters applled in about 206 randomly selected houses in some regions of Iran including Ramsar Ca high natural radiation area), Tehran, Babolsar and Gonabad have been processed and analyzed for radon level evaluatlon. The polycarbonate foils have been electrochemically etched using our new design of multl-chamber electrochemlcal etching system applylng our optimized ECE conditions. The mean radon levels in the above cities were determined to be respectlvely 578~ 80, 88 and 84 Bq.m -~, leading to average effective dose equlyalents of 17.6, 2.44, 2.68 2.56 mSv/year. Gamma dosimetry were also carried out with TLD and film badge in houses of high natural radiation areas of Ramsar together with Rn dosimetem. Some houses were found with vary high gamma and Rn exposures. In this paper, some preliminary results of such measurements are reported and discussed.

The potential annual effective doses of the public in Ramsar and its elevated level natural radiation areas (ELNRA) from the external and internal exposures received indoors and outdoors were determined. This paper only reports the potential annual effective doses from the external exposure, the rate of which was measured in 1000 locations outdoors and in 800 locations indoors, 200 in ENLRA and 600 in low level natural radiation areas (LLNRA). An SPP2 Scintillometer, a Reuter-Stokes pressurized ionization chamber and a SAPOS system of an environmental early warning network were used for measuring the exposure rates. The distribution of the absorbed dose rates in air, indoors and outdoors, with their mean values were determined. The absorbed dose rates in the air outdoors range from 0.08 to 20 mGy h À 1 with occasional higher values up to 100 mGy h À 1 over some hot spots. The isodose and topological exposure rate maps of the region were drawn. The cosmic ray dose rate of 32 nGy h À 1 was measured over the Caspian Sea using the pressurized ionization chamber. The absorbed dose rates in the air indoors range from 0.01 to 30 mGy h À 1 with occasional higher values up to 105 mGy h À 1 on the wall of one room in a house in Talesh Mahalleh. The topological map of the exposure rates over the wall is also reported. As expected, Talesh Mahalleh showed the highest potential effective public doses from terrestrial radiation. The potential annual effective doses of the public in ELNRA range from 0.6 to 131 mSv with a mean value of 6 mSv, and in LLNRA, these range from 0.6 to 1.5 mSv with a mean value of 0.7 mSv. The distributions of percent population in different annual effective dose intervals in Ramsar and its ELNRA were also obtained. The mean potential annual effective doses in ELNRA are about 10 times higher than those in ELNRA, but some individual effective doses are about 200 times higher than the mean of LLNRA. The results are reported and discussed.

Purpose: To evaluate the effects of polyethylene glycol (PEG) 6000 pretreatment on growth and physiological responses of eukaryotic microalga Chlorella vulgaris exposed to ionizing irradiation. The microalgal cells pretreated with different PEG concentrations (0, 5, 10 and 20%) and then exposed to 300 Gray gamma irradiation at a dose rate of 0.5 G Gray.s -1 . The various growth and physiological parameters including algal growth, cell size, the degree of electrolyte leakage (EL) and lipid peroxidation, the content of pigments and proline and the activity of antioxidant enzymes under gamma-free or 300 Gray gamma irradiation conditions were examined. The results showed that PEG stimulated a higher growth and cell size under both stressfree and gamma-stress conditions. The maximum growth and cell size was reported when the algae was pretreated with 10% PEG. A relative increase of catalase activity was observed in all samples after exposing to gamma irradiation. However, the highest value recorded for the gamma-radiated algae pretreated with 10% PEG. In the absence of PEG, gamma irradiation induced a significant reduction in ascorbate peroxidase activity, but with PEG pretreatment, the enzyme activity remained constant or even increased after gamma irradiation. On the other hand, although gamma irradiation stress generally suppressed the activity of superoxide dismutase in all cells, pretreating the algae with PEG could diminish this suppressing effect at all applied concentrations. Compared to the PEG-free controls, a lower rate of chlorophylls and membrane integrity loss was shown in the PEG-treated algae when exposed to gamma stress. Total carotenoid content in PEG-treated algae was also similar under both gamma-free and gamma-A c c e p t e d M a n u s c r i p t radiated conditions. A PEG-independent increase in proline accumulation was reported under gamma irradiation treatment. Conclusions: Overall, the results suggested that PEG pretreatment could improve gammairradiation tolerance in C. vulgaris probably by stimulating a range of enzymatic and nonenzymatic reactive oxygen species (ROS) scavenging systems. The microalgae may also consume PEG to break down and use it as an alternative source of carbon during stress which should be further studied in details.

Purpose: To evaluate the effects of polyethylene glycol (PEG) 6000 pretreatment on growth and physiological responses of eukaryotic microalga Chlorella vulgaris exposed to ionizing irradiation. The microalgal cells pretreated with different PEG concentrations (0, 5, 10 and 20%) and then exposed to 300 Gray gamma irradiation at a dose rate of 0.5 G Gray.s -1 . The various growth and physiological parameters including algal growth, cell size, the degree of electrolyte leakage (EL) and lipid peroxidation, the content of pigments and proline and the activity of antioxidant enzymes under gamma-free or 300 Gray gamma irradiation conditions were examined. The results showed that PEG stimulated a higher growth and cell size under both stressfree and gamma-stress conditions. The maximum growth and cell size was reported when the algae was pretreated with 10% PEG. A relative increase of catalase activity was observed in all samples after exposing to gamma irradiation. However, the highest value recorded for the gamma-radiated algae pretreated with 10% PEG. In the absence of PEG, gamma irradiation induced a significant reduction in ascorbate peroxidase activity, but with PEG pretreatment, the enzyme activity remained constant or even increased after gamma irradiation. On the other hand, although gamma irradiation stress generally suppressed the activity of superoxide dismutase in all cells, pretreating the algae with PEG could diminish this suppressing effect at all applied concentrations. Compared to the PEG-free controls, a lower rate of chlorophylls and membrane integrity loss was shown in the PEG-treated algae when exposed to gamma stress. Total carotenoid content in PEG-treated algae was also similar under both gamma-free and gamma-A c c e p t e d M a n u s c r i p t radiated conditions. A PEG-independent increase in proline accumulation was reported under gamma irradiation treatment. Conclusions: Overall, the results suggested that PEG pretreatment could improve gammairradiation tolerance in C. vulgaris probably by stimulating a range of enzymatic and nonenzymatic reactive oxygen species (ROS) scavenging systems. The microalgae may also consume PEG to break down and use it as an alternative source of carbon during stress which should be further studied in details.

This report is an update on Program Area Committee 1 (PAC 1) of National Council on Radiation Protection and Measurements activities during the past year. Highlights include an update on the reports on radiation dose limits for the lens of the eye and relative biological effectiveness on low linear energy transfer radiations as related to energies. In addition, ongoing reports on the relevance of the linear no-threshold model and a phase 2 study on space radiation effects on the central nervous system were discussed. New topics for future work of PAC 1 include considerations of cardiovascular effects, dose and dose-rate effectiveness factors, and tissue factors.

The number of proton therapy facilities and the clinical usage of high energy proton beams for cancer treatment has substantially increased over the last decade. This is mainly due to the superior dose distribution of proton beams resulting in a reduction of side effects and a lower integral dose compared to conventional X-ray radiotherapy. More recently, the usage of metallic nanoparticles as radiosensitizers to enhance radiotherapy is receiving growing attention. While this strategy was originally intended for X-ray radiotherapy, there is currently a small number of experimental studies indicating promising results for proton therapy. However, most of these studies used low proton energies, which are less applicable to clinical practice; and very small gold nanoparticles (AuNPs). Therefore, this proof of principle study evaluates the radiosensitization effect of larger AuNPs in combination with a 200 MeV proton beam. CHO-K1 cells were exposed to a concentration of 10 μg/ml of 50 n...

An understanding of the "bioavailability" of disseminated radiocontaminants is a necessary adjunct in order to tailor treatment and to calculate dose. A simple test has been designed to predict the bioavailability of different actinide forms likely to be found after dissemination of radioactive elements by dispersal devices or nuclear reactor incidents. Plutonium (Pu) or Americium (Am) nitrate or MOX (U,PuO 2 ) are immobilized in culture wells using a static gel phase simulating biological compartments (lung, wound, etc.). Gels are incubated in a fluid phase representing physiological media (plasma, sweat, etc.). Transfer of radionuclide from static to fluid phase reflects contaminant bioavailability. After 48 h of incubation in physiological saline, Am transfer from static to fluid phase was greater than for Pu (70% vs. 15% of initial activity). Transfer of Pu or Am was markedly less from the oxide form of the two elements (1% Am and 0.05% Pu transferred). Medium representing intracellular lysosomal fluid (pH 4) increased transfer of Pu and Am, whereas culture medium including serum reduced actinide transfer. Actinide transfer was also reduced by elements of the extracellular matrix present in the static gel phase. Increasing DTPA concentrations (5 to 500 mM) to the fluid phase significantly enhanced transfer of Pu and Am. Although this agarose gel cannot fully represent in vivo complexity, this simple test can be used to investigate and predict the behavior in vivo of radiocontaminants to support medical treatments and medical forensic investigations.

To evaluate skin penetration and retention of americium (Am) and plutonium (Pu), in different chemical forms relevant to the nuclear industry and to treatment by chelation. Percutaneous penetration of different Am and Pu forms were evaluated using viable pig skin with the Franz cell diffusion system. The behavior of the complex Pu-tributyl phosphate (Pu-TBP), Am or Pu complexed to the chelator Diethylene triamine pentaacetic acid (DTPA) and the effect of dimethyl sulfoxide (DMSO) was assessed. Radioactivity was measured in skin and receiver compartments. Three approaches were used to visualize activity in skin including the recent iQID technique for quantification. Transfer of Am was 24-fold greater than Pu and Pu-TBP complex penetration was enhanced by 500-fold. Actinide-DTPA transfer was greater than the Am or Pu alone (17-fold and 148-fold, respectively). The stratum corneum retained the majority of activity in all cases and both DMSO and TBP enhanced skin retention of Am and Pu,...

Cs released from the TEPCO’s Fukushima Dai-ichi Nuclear Power Plant accident has a long half-life of about 30 years, it is necessary to monitor the distribution and its radioecological impact over the long term. Mountainous forests, which accounts for about 70% of Fukushima Prefecture, tend to be a sink of radiocesium contamination rather than a source for the contamination of other ecosystems. An understanding of the environmental dynamics of radiocesium in various forest conditions is important issue under the situation which the return of evacuated residents is in progress.