[en] The IDQBRN/CTEx has a Cs-137 research irradiator to promote research development in the field of material irradiation, assisting in obtaining data and scientific publications in the area. Currently, tests are being conducted with pellets and plates of materials placed at the base of the irradiator chambers, requiring verification of the absorbed dose to water in the central areas of the chambers, where the plates and pellets are positioned, ensuring the dose delivered in processes, as well as ensuring a corresponding average value for each material positioned within this measured area. By using the Fricke chemical dosimeter, it was possible to determine that for the central position closest to the door of the upper chamber of the irradiator, the highest absorbed dose in water found in the measurements conducted was a value of 5.10% above the expected value compared to the last dosimetry performed with a ceric-cerous sulfate chemical dosimeter. The results show that using the Fricke dosimeter it was possible to characterize the irradiator obtaining complete dosimetry and doses according to the positioning of the material within the chamber to subsequently create a simulator that could be used for dosimetry of the irradiation volume. (author)

[en] The IDQBRN/CTEx has a Cs-137 research irradiator whose purpose is to promote the development of research in the area of irradiation of materials, assisting in the acquisition of data and scientific publications in the area. Because it is used for research, it is necessary to verify the distribution of dose point in the irradiator chambers. The purpose of this work is to carry out a five-point dosimetry of each irradiator chamber, using the Fricke chemical dosimeter. This dosimeter is used worldwide in several areas of medical and industrial physics, presenting relevant characteristics such as low cost, uncertainties of less than 3% in industrial applications, in addition to being an absolute and primary dosimeter. Dosimetry was performed in the IDQBRN/CTEx irradiator drawers where the materials to be irradiated are placed in the research irradiator chambers. (author)

No abstract available

[en] Full text: The developments in the diagnosis, and treatment techniques for the breast cancer (BC), which include chemotherapy and/or radiotherapy, increased the patients survival rates for this type of cancer, increasing the chances of late effects due to the treatment. A mammogram is an exam that uses ionizing radiation and aims to obtain radiographic images of the breast for the detection of early stages breast cancer. Considering that during interaction of the radiation with the mammary tissue, important biomolecules ionization and subsequent destabilization may occur, the use of ionizing radiation in health care must be justified (1-5). Most studies concerning the effects using low dose radiation focus, mainly, the alterations in the DNA molecule (6-8). Elemental alterations may be associated with changes in the enzymatic activities of the cell. Our purpose was to quantify the trace elements in the two different cell lines: human breast tumor cells MCF-7 and non-tumor cells MCF-10 after the exposure of doses used for mammograms, considering low breast density (9 mGy) and high breast density (18 Gy), subjected to doses used in mammography and compare the results between those groups. Our study indicated some changes in the concentration of certain elements such as Ca, Fe, Cr and Zn in different tumor cell lines, after different treatments, using the TXRF method. We are trying to identify the potential mechanism of how ionizing radiation can activate cellular targets associated with tumor progression (9-12). MCF-7 and MCF-10 cells were irradiated with doses of 17 mGy and 2Gy in a conventional mammography equipment (Siemens). From the resulting solutions, 5 μL were pipetted on the quartz reflectors used for TXRF analysis. These results can help to better understand the mechanisms involved in the neoplastic transformations, enzymatic alterations, and biomolecules destabilization that may occur after a breast screening. (author)

[en] Fricke dosimetry for blood irradiators has been studied by the LCR/UERJ group for 5 years. Irradiation of blood and its components is currently practiced with the main objective of preventing graft versus host disease in immunodeficient patients associated with transfusion, with irradiation of blood bags being the most effective method to prevent this disease. The phantom designed by the group was designed to solve the national demand for dosimetry for blood irradiators. The tissue-equivalence between Fricke and water and the dose distribution provided throughout the reservoir, simulating a canister in a real irradiation situation, with maximum occupancy of blood bags in its volume, bring safety and effectiveness to the technique. The results obtained with the Fricke dosimeter were compared with the doses calculated by the physicist responsible for different blood centers and 3 phantoms and the reproducibility of the dosimetric sets were tested. The biggest dose difference presented between the 3 phantoms for the central doses was 3.57%. The type A uncertainty obtained from the reproducibility between the 3 phantoms was 2.06%

[en] This study aimed to compare the results of dosimetry performed on blood irradiators with the Fricke dosimeter by the Radiological Sciences Laboratory group (LCR/UERJ) with the results of dosimetry performed with alanine by the High Dose Dosimetry Laboratory (LDA/IPEN). /CNEN). The two laboratories performed the measurements at the Blood Center of Rio de Janeiro (HEMORIO), using the phantom patented by the LCR/UERJ. The results showed an agreement of 2.2% between the dose averages in the central region of the phantom with both systems. This work presents the preliminary results without including minor corrections that are being defined through Monte Carlo simulations, to allow the calculation of the final uncertainty in continuation of this work

No abstract available

[en] The Fricke dosimeter is the most used liquid chemical dosimeter. High dose rate (HDR) brachytherapy using 192Ir sources is an important treatment option and it has been shown to be a feasible option for the absorbed dose standard. One of the parameters used to determine the absorbed dose at the Fricke solution is the G-value. This parameter is crucial and can be defined as the number of molecules of Fe+3 produced per Joule of energy absorbed in the solution. Few authors have determined the G-value for energies below the 60Co. Most part of papers on the literature compare the G-value to 60Co and different beam qualities. The G-value for energies lower than Co-60 are not well defined, some authors obtained it through calorimetric measurements and others the G(Fe3+) was obtained from the empirical formalism based on the primary products and Linear energy transfer (LET) values. The present work aim to determinate the G-value for 192Ir HDR using a new setup elaborated by Radiological Sciences Laboratory group (LCR/UERJ-Rio de Janeiro State University, Rio de janeiro, Brazil). It was performed using a HDR brachytherapy using 192Ir source (GammaMed Plus HDR 232, Varian) at Radiotherapy department of HUCFF - Hospital Universitário Clementino Fraga Filho, Rio de Janeiro, Brazil. The results showed a good statistical response to doses about 22 Gy and dose rates of and the G value calculated was 1.5607·10-6 Plus- Minus Sign·0.0669·10-6 mol.J-1 and type A uncertanty 0.96%.

[en] In the last decades, studies showed that the exposure to low doses of ionizing radiation of the body could sense and activate the cell signaling pathways needed to respond to any induced cellular damage. This procedure reduces cell killing compared with a single dose of high radiation dose. Damage to the vasculature can affect the function of most body organs by restricting blood flow and oxygen to tissues; however, the heart and brain are of main concern. The precise relationship between long-term health effects and low-dose exposures remain poorly understood. Biological markers are powerful tools that can be used to determine dose- response relationships and to estimate risk, especially when dealing with, the effects of low dose exposures in humans. These markers should be specific, sensitive, as well as easy and fast to quantify. Various types of biologic specimens are potential candidates for identifying biomarkers but blood has the advantage of being minimally invasive to obtain. In this study, we propose to apply total reflection X-ray fluorescence to quantify possible chemical elemental concentration (sulfer, iron, zinc, potassium and calcium) changes in blood and heart tissues of Wistar rats after total body irradiation with low (0.1 Gy) and high (2.5 Gy) doses. The fluorescence measurements were carried out at the X-ray Fluorescence beamline in the Brazilian Synchrotron Light Laboratory. The results showed that the irradiated animals with low doses have significant alterations in blood and cardiac tissue when compared with animals that received high doses of radiation. Taken together the analysis of all the elements, we can observe that the radiation induced oxidative stress may be the leading cause for alteration of the elemental level in the studied samples.

[en] Recently some developments in a large number of investigative techniques have been made with the objective to obtain a micrometer spatial resolution imaging of elemental concentrations. The X-ray microfluorescence analysis (µXRF) is one of those techniques which is based on the localized excitation of a small area on the surface of sample, providing information of all elements contained in the material under study. Breast cancer is the most common malignancy in Brazilian women. The main treatment strategies for the breast cancer are surgery and chemotherapy. As bone loss is one of the possible chemotherapy side effects, in this work was used μXRF technique on femoral head samples of female Wistar rats to evaluate Ca, Fe and Zn concentrations in order to investigate possible elemental changes in bone caused by the chemotherapy. Fifteen female rats were divided randomly in groups (five rats each). G1 group received doses of doxorubicin/cyclophosphamide drugs and G2 group was treated with docetaxel/cyclophosphamide drugs. µXRF measurements were carried out at the X-ray XRF beamline in the Brazilian Synchrotron Light Laboratory. The results showed significant decrease especially in Ca concentrations when comparing the treated groups with the control group. - Highlights: • One of the side effects caused by chemotherapy drugs is a significant bone loss. • Metals in human provide insights into individual exposure and/or disease. • We applied μXRF in samples of Wistar rats to evaluate the elemental concentrations.