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Radiation and Environmental Biophysics

Atiyeh Ebrahimi-Khankook, Alireza Vejdani-Noghreiyan
Nowadays, Monte Carlo calculations are commonly used for the evaluation of dose distributions and dose volume histograms in eye brachytherapy. However, currently available eye models have simple geometries, and main substructures of the eye are either not defined in details or not distinguished at all. In this work absorbed doses of eye substructures have been estimated for eye plaque brachytherapy using the most realistic eye model available, and compared with absorbed doses obtained with other available eye models...
June 7, 2018: Radiation and Environmental Biophysics
Branko Petrinec, Marina Poje Sovilj, Dinko Babić, Tomislav Meštrović, Igor Miklavčić, Vanja Radolić, Denis Stanić, Branko Vuković, Marko Šoštarić
A study of the environmental radioactivity in the Kopački Rit Nature Park, Croatia, is presented. This wildlife reserve is part of the Middle Danube River Basin, and it is exposed to various pollutants due to a number of human activities in the surroundings, where there is a nuclear power plant and also urban centres and areas of intense agricultural production. Results for the activity concentrations of soil and surface water samples do not indicate any elevated radioactivity level, which is confirmed by on-site measurements of ambient dose rate equivalent...
June 5, 2018: Radiation and Environmental Biophysics
Vladimir Spielmann, Wei Bo Li, Maria Zankl
Internal dosimetry after incorporation of radionuclides requires standardized biokinetic and dosimetric models. The aim of the present work was to identify the parameters and the components of the models which contribute most to dosimetric uncertainty. For this a method was developed allowing for the calculation of the uncertainties of the absorbed dose coefficients. More specifically, the sampling-based regression method and the variance-based method were used to develop and apply a global method of sensitivity analysis...
August 2018: Radiation and Environmental Biophysics
Rowida Abdalla, Amr Omar, Kareem Eid
The purpose of this study was to evaluate the ability of radiographic densitometry in detecting the early demineralization of human enamel and cementum in irradiated and non-irradiated teeth. Sixty extracted teeth were divided into two groups: irradiated group and non-irradiated group. After irradiation, the groups were subjected to demineralization-remineralization (PH) cycling. Radiographic densitometric measurements (gray values) of a selected area of interest in the enamel and in the cementum of each tooth were performed at baseline and after PH cycling...
August 2018: Radiation and Environmental Biophysics
Iwona Słonecka, Krzysztof Łukasik, Krzysztof W Fornalski
The present paper proposes two methods of calculating components of the dose absorbed by the human body after exposure to a mixed neutron and gamma radiation field. The article presents a novel approach to replace the common iterative method in its analytical form, thus reducing the calculation time. It also shows a possibility of estimating the neutron and gamma doses when their ratio in a mixed beam is not precisely known.
August 2018: Radiation and Environmental Biophysics
Esmail Jafari, Mehrosadat Alavi, Fatemeh Zal
The goal of this study was to evaluate the protective and mitigative effect of vitamin C on oxidative stress in differentiated thyroid cancer (DTC) patients ablated with radioiodine. 58 DTC patients selected for radioactive iodine therapy (RAIT) with 5550 MBq 131 Iodine were divided into four groups. Group 1 (control group) consisted of patients who underwent RAIT routinely. Other patients received 1500 mg vitamin C daily 2 days after (group 2), 2 days before to 2 days after (group 3) and 2 days before RAIT (group 4)...
August 2018: Radiation and Environmental Biophysics
Simon P Keam, Twishi Gulati, Cristina Gamell, Franco Caramia, Gisela Mir Arnau, Cheng Huang, Ralf B Schittenhelm, Oded Kleifeld, Paul J Neeson, Scott G Williams, Ygal Haupt
Transcriptional dosimetry is an emergent field of radiobiology aimed at developing robust methods for detecting and quantifying absorbed doses using radiation-induced fluctuations in gene expression. A combination of RNA sequencing, array-based and quantitative PCR transcriptomics in cellular, murine and various ex vivo human models has led to a comprehensive description of a fundamental set of genes with demonstrable dosimetric qualities. However, these are yet to be validated in human tissue due to the scarcity of in situ-irradiated source material...
August 2018: Radiation and Environmental Biophysics
Kentaro Ariyoshi, Tomisato Miura, Kosuke Kasai, Nakata Akifumi, Yohei Fujishima, Mitsuaki A Yoshida
Although evidence suggests that ionizing radiation can induce the bystander effect (radiation-induced bystander effect: RIBE) in cultured cells or mouse models, it is unclear whether the effect occurs in cells of wild animals. We investigated medium-mediated bystander micronucleus (MN) formation and DNA damage in un-irradiated cells from a large Japanese field mouse (Apodemus speciosus). We isolated four clones of A. speciosus embryonic fibroblasts (A603-1, A603-2, A603-3, and A603-4) derived from the same mother, and examined their radiation sensitivity using the colony-forming assay...
August 2018: Radiation and Environmental Biophysics
Xue-Lei Tian, Xue Lu, Jiang-Bin Feng, Tian-Jing Cai, Shuang Li, Mei Tian, Qing-Jie Liu
Chromosome damage is related to DNA damage and erroneous repair. It can cause cell dysfunction and ultimately induce carcinogenesis. Histone acetylation is crucial for regulating chromatin structure and DNA damage repair. Ionizing radiation (IR) can alter histone acetylation. However, variations in histone acetylation in response to IR exposure and the relationship between histone acetylation and IR-induced chromosome damage remains unclear. Hence, this study investigated the variation in the total acetylation levels of H3 and H4 in human lymphocytes exposed to 0-2 Gy 60 Co γ-rays...
August 2018: Radiation and Environmental Biophysics
Roula Ajrouche, Candice Roudier, Enora Cléro, Géraldine Ielsch, Didier Gay, Jérôme Guillevic, Claire Marant Micallef, Blandine Vacquier, Alain Le Tertre, Dominique Laurier
Radon is the second leading cause of lung cancer after smoking. Since the previous quantitative risk assessment of indoor radon conducted in France, input data have changed such as, estimates of indoor radon concentrations, lung cancer rates and the prevalence of tobacco consumption. The aim of this work was to update the risk assessment of lung cancer mortality attributable to indoor radon in France using recent risk models and data, improving the consideration of smoking, and providing results at a fine geographical scale...
August 2018: Radiation and Environmental Biophysics
P Vivek Vardhan, Lata Israni Shukla
The present article focuses on the influence of gamma irradiation and post-irradiation storage conditions on FT-IR spectra of 1 mm thick polystyrene irradiated with 51, 77 and 129 kGy. The increase in amplitude corresponding to 3600, 3400 and 2100 cm- 1 stretching frequencies clearly showing the formation of O-H and C=O bonds (~ 25%). On prolonged storage (2160 h) in the dark, there is an increase in O-H group (~ 28%). The electron cloud facilitates the formation of hydroxyl group in irradiated polystyrene...
August 2018: Radiation and Environmental Biophysics
Ewa M Nowosielska, Aneta Cheda, Robert Zdanowski, Sławomir Lewicki, Bobby R Scott, Marek K Janiak
Tritium is a potentially significant source of internal radiation exposure which, at high levels, can be carcinogenic. We evaluated whether single intraperitoneal injection of BALB/c and C57BL/6 mice with tritiated water (HTO) leading to exposure to low (0.01 or 0.1 Gy) and intermediate (1.0 Gy) cumulative whole-body doses of β radiation is immunosuppressive, as judged by enhancement of artificial tumour metastases, functioning of NK lymphocytes and macrophages, circulating cytokine's levels, and numbers of bone marrow, spleen, and peripheral blood cells...
August 2018: Radiation and Environmental Biophysics
Vadim V Chumak, Sergiy V Klymenko, Horst Zitzelsberger, Christina Wilke, Lyudmila A Rybchenko, Elena V Bakhanova
The Chernobyl reactor accident in 1986 has caused significant exposure to ionizing radiation of the Ukrainian population, in particular clean-up workers and evacuees from the exclusion zones. A study aiming at the discovery of radiation markers of the breast cancer was conducted from 2008 to 2015 within a collaborative project by HZM, LMU, and NRCRM. In this study, post-Chernobyl breast cancer cases both in radiation-exposed female patients diagnosed at age less than 60 from 1992 to 2014 and in non-exposed controls matched for residency, tumor type, age at diagnosis, TNM classification as well as tumor grading were investigated for molecular changes with special emphasis to copy number alterations and miRNA profiles...
May 2018: Radiation and Environmental Biophysics
Sabine Hoffmann, Chantal Guihenneuc, Sophie Ancelet
Exposure measurement error can be seen as one of the most important sources of uncertainty in studies in epidemiology. When the aim is to assess the effects of measurement error on statistical inference or to compare the performance of several methods for measurement error correction, it is indispensable to be able to generate different types of measurement error. This paper compares two approaches for the generation of Berkson error, which have recently been applied in radiation epidemiology, in their ability to generate exposure data that satisfy the properties of the Berkson model...
May 2018: Radiation and Environmental Biophysics
Pingyan Jin, Huijuan Feng, Wei Ouyang, Juqing Wu, Pan Chen, Jing Wang, Yungang Sun, Jialang Xian, Liuhua Huang
Postoperative 131 I treatment for differentiated thyroid cancer (DTC) can create a radiation hazard for nearby persons. The present prospective study aimed to investigate radiation dose rates in 131 I-treated DTC patients to provide references for radiation protection. A total of 141 131 I-treated DTC patients were enrolled, and grouped into a singular treatment (ST) group and a repeated treatment (RT) group. The radiation dose rate of 131 I-treated patients was measured. The rate of achieving discharge compliance and restricted contact time were analyzed based on Chinese regulations...
May 2018: Radiation and Environmental Biophysics
Natalia M Espector, Agustina Portu, Gustavo A Santa Cruz, Gisela Saint Martin
The analysis of the distribution and density of nuclear tracks forming an autoradiography in a nuclear track detector (NTD) allows the determination of 10 B atoms concentration and location in tissue samples from Boron Neutron Capture Therapy (BNCT) protocols. This knowledge is of great importance for BNCT dosimetry and treatment planning. Tissue sections studied with this technique are obtained by cryosectioning frozen tissue specimens. After the slicing procedure, the tissue section is put on the NTD and the sample starts drying...
May 2018: Radiation and Environmental Biophysics
Malgorzata Lysek-Gladysinska, Anna Wieczorek, Anna Walaszczyk, Karol Jelonek, Artur Jozwik, Monika Pietrowska, Wolfgang Dörr, Dorota Gabrys, Piotr Widlak
The aim of the study was to investigate long-term effects of radiation on the (ultra)structure and function of the liver in mice. The experiments were conducted on wild-type C57BL/6J and apolipoprotein E knock-out (ApoE-/- ) male mice which received a single dose (2 or 8 Gy) of X-rays to the heart with simultaneous exposure of liver to low doses (no more than 30 and 120 mGy, respectively). Livers were collected for analysis 60 weeks after irradiation and used for morphological, ultrastructural, and biochemical studies...
May 2018: Radiation and Environmental Biophysics
Nikolay Sirota, Elena Kuznetsova, Irina Mitroshina
Comparative studies of the level of DNA damage induced in vitro by X-rays (0-8 Gy) or hydrogen peroxide (0-300 µM) in cells of blood, spleen, and bone marrow of mice and in blood cells of frogs and humans were performed using the alkaline comet assay. For both agents, the levels of induced DNA damage in leucocytes/splenocytes of mice were higher than those in blood cells of frogs and humans, while in human leucocytes, they were comparable with those in frog blood cells. The rate of DNA repair in frog blood cells was very slow...
May 2018: Radiation and Environmental Biophysics
Zhila Rajaee, Samideh Khoei, Seied Rabi Mahdavi, Marzieh Ebrahimi, Sakine Shirvalilou, Alireza Mahdavian
The aim of this study was to investigate the effect of hyperthermia, 6 MeV electron radiation and combination of these treatments on cancer cell line DU145 in both monolayer culture and spheroids enriched for prostate cancer stem cells (CSCs). Flowcytometric analysis of the expression of molecular markers CD133+ /CD44+ was carried out to determine the prostate CSCs in cell line DU145 grown as spheroids in serum-free medium. Following monolayer and spheroid culture, DU145 cells were treated with different doses of hyperthermia, electron beam and combination of them...
May 2018: Radiation and Environmental Biophysics
C Rodriguez, M Carpano, P Curotto, S Thorp, M Casal, G Juvenal, M Pisarev, M A Dagrosa
Boron neutron capture therapy (BNCT) for aggressive tumors is based on nuclear reaction [10 B (n, α) 7 Li]. Previously, we demonstrated that BNCT could be applied for the treatment of undifferentiated thyroid carcinoma. The aim of the present study was to describe the DNA damage pattern and the repair pathways that are activated by BNCT in thyroid cells. We analyzed γH2AX foci and the expression of Ku70, Rad51 and Rad54, main effector enzymes of non-homologous end joining (NHEJ) and homologous recombination repair (HRR) pathways, respectively, in thyroid follicular carcinoma cells...
May 2018: Radiation and Environmental Biophysics
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