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Ab Azar N.,Iran Nuclear Regulatory Authority | Babakhani A.,Islamic Azad University at Tehran | Broumandnia A.,Islamic Azad University at Tehran | Sepanloo K.,Iran Nuclear Regulatory Authority
Radiation Measurements | Year: 2016

Overlapping object detection and counting is a challenge in image processing. A new method for detecting and counting overlapping circles is presented in this paper. This method is based on pattern recognition and feature extraction using "neighborhood values" in an object image by implementation of image processing techniques. The junction points are detected by assignment of a value for each pixel in an image. As is shown, the neighborhood values for junction points are larger than the values for other points. This distinction of neighborhood values is the main feature which can be utilized to identify the junction points and to count the overlapping tracks. This method can be used for recognizing and counting charged particle tracks, blood cells and also cancer cells. The method is called "Track Counting based on Neighborhood Values" and is symbolized by "TCNV". © 2016 Elsevier Ltd. All rights reserved.


PubMed | Nuclear Science and Technology Research Institute, Iran, Iran Nuclear Regulatory Authority and Islamic Azad University at Tehran
Type: Journal Article | Journal: Radiation and environmental biophysics | Year: 2016

An in vitro study of the dose responses of human peripheral blood lymphocytes was conducted with the aim of creating calibrated dose-response curves for biodosimetry measuring up to 4 Gy (0.25-4 Gy) of gamma radiation. The cytokinesis-blocked micronucleus (CBMN) assay was employed to obtain the frequencies of micronuclei (MN) per binucleated cell in blood samples from 16 healthy donors (eight males and eight females) in two age ranges of 20-34 and 35-50 years. The data were used to construct the calibration curves for men and women in two age groups, separately. An increase in micronuclei yield with the dose in a linear-quadratic way was observed in all groups. To verify the applicability of the constructed calibration curve, MN yields were measured in peripheral blood lymphocytes of two real overexposed subjects and three irradiated samples with unknown dose, and the results were compared with dose values obtained from measuring dicentric chromosomes. The comparison of the results obtained by the two techniques indicated a good agreement between dose estimates. The average baseline frequency of MN for the 130 healthy non-exposed donors (77 men and 55 women, 20-60 years old divided into four age groups) ranged from 6 to 21 micronuclei per 1000 binucleated cells. Baseline MN frequencies were higher for women and for the older age group. The results presented in this study point out that the CBMN assay is a reliable, easier and valuable alternative method for biological dosimetry.


Bavarnegin E.,Guilan University | Fathabadi N.,Iran Nuclear Regulatory Authority | Vahabi Moghaddam M.,Guilan University | Vasheghani Farahani M.,Iran Nuclear Regulatory Authority | And 3 more authors.
Journal of Environmental Radioactivity | Year: 2013

Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m-2 h-1. The 226Ra, 232Th and 40K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of 226Ra, 232Th and 40K content varied from below the minimum detection limit up to 86,400 Bq kg-1, 187 Bq kg-1 and 1350 Bq kg-1, respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. © 2012 Elsevier Ltd.


Mianji F.A.,Nuclear Science and Technology Research Institute, Iran | Diba J.K.,Iran Nuclear Regulatory Authority | Babakhani A.,Nuclear Science and Technology Research Institute, Iran
Radiation Protection Dosimetry | Year: 2014

Unrecognised pregnancy during radioisotope therapy of thyroid cancer results in hardly definable embryo/fetus exposures, particularly when the thyroid gland is already removed. Sources of such difficulty include uncertainty in data like pregnancy commencing time, amount and distribution of metastasized thyroid cells in body, effect of the thyroidectomy on the fetus dose coefficient etc. Despite all these uncertainties, estimation of the order of the fetus dose in most cases is enough for medical and legal decision-making purposes. A model for adapting the dose coefficients recommended by the well-known methods to the problem of fetus dose assessment in athyrotic patients is proposed. The model defines a correction factor for the problem and ensures that the fetus dose in athyrotic pregnant patients is less than the normal patients. A case of pregnant patient undergone post-surgical therapy by I-131 is then studied for quantitative comparison of the methods. The results draw a range for the fetus dose in athyrotic patients using the derived factor. This reduces the concerns on under-or over-estimation of the embryo/fetus dose and is helpful for personal and/or legal decision-making on abortion. © The Author 2014.


Mianji F.,Nuclear Science and Technology Research Institute, Iran | Pooya S.M.H.,Nuclear Science and Technology Research Institute, Iran | Zakeri F.,Nuclear Science and Technology Research Institute, Iran | Dashtipour M.R.,Iran Nuclear Regulatory Authority
Journal of Radiological Protection | Year: 2016

The Iran Nuclear Regulatory Authority has investigated overexposure cases in industrial radiography over a period of three years. Radiographers with thermoluminescence dosimeter (TLD) records of more than 4 mSv in any 2 month routine monitoring period were asked to fll in a questionnaire explaining their points of view of the reasons for such relatively high doses. The responses showed that more than 50% of the radiographers did not agree with their recorded TLD doses, although the majority of the alternative explanations were weak. The main causes of overexposures were found to be diffcult working conditions and ignoring safety principles while accidents or device failures were a minor contribution. Also, there was poor correlation between the TLDs and direct reading dosimeters worn by the radiographers, indicating that personal monitoring instructions were not being implemented appropriately. © 2016 IOP Publishing Ltd Printed in the UK.


Hosseini Pooya S.M.,Iran Nuclear Regulatory Authority | Hosseini Pooya S.M.,Nuclear Science and Technology Research Institute, Iran | Taheri M.,Iran Nuclear Regulatory Authority
Applied Radiation and Isotopes | Year: 2013

Based upon the steady flow method, a setting has been introduced for fast calibration of almost all types of active and passive radon detectors. In this method, a traceable radon reference flow-through sources is connected to a portable rectangular cubic transparent chamber (volume of 50. L) which is completely sealed and has 6 valves on its sides. The initializing calibration times are less than 150. min by this chamber. The radon concentration in the chamber is in consistent with the source activity. The Best Measurement Capability (BMC) of the method has been calculated less than 5% at 68% confidence level. As well by using grab-sampling method, the difference of radon concentration of different points in the chamber was measured less than 1.2%. So the flow-through sources can be developed for a fast calibration of almost all types of the radon monitors with an acceptable uncertainty using this calibration setting. © 2012.


Pooya S.M.H.,Nuclear Science and Technology Research Institute, Iran | Dashtipour M.R.,Iran Nuclear Regulatory Authority | Enferadi A.,Iran Nuclear Regulatory Authority | Orouji T.,Iran Nuclear Regulatory Authority
Journal of Environmental Radioactivity | Year: 2015

A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure.In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year.The maximum average dose equivalent value measured was approximately 70 μSv/month for Tehran city. Also, the average dose values obtained were less than 40 μSv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 μSv/month for the higher elevation cities.The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR. © 2015 Elsevier Ltd.


PubMed | Iran Nuclear Regulatory Authority, Tehran University of Medical Sciences and Nuclear Science and Research Institute
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2016

Recent data suggest that knowledge of radiation exposures among physicians is inadequate. This study, therefore, aimed to evaluate their knowledge of the radiation doses their patients received and awareness of associated biological risks of radiation exposure. A questionnaire in multiple-choice format consisted of four sections with a total of 10 questions based on the literature review. A total of 136 questionnaires were returned from 69 general practitioners and 67 physicians in various specialties from 10 different hospitals in the capital city of Tehran, Iran. Fifty-four percent of general practitioners and twenty-five percent of specialties declared that they are not aware of biological risks of radiation exposure. Fifty-six percent of physicians did not know the correct definition of absorbed dose. Only 33% of physicians knew the dose exposure of a chest X-ray and only 31% knew the approximate doses of various procedures relative to a chest X-ray. Forty-seven percent of physicians incorrectly distinguished the stochastic effects of radiation from the deterministic effects, and thirty-eight of physicians did not know the organs of the body that are most sensitive to ionizing radiation. Only 23.5% of physicians were aware of the one in 2000 risk of induction of fatal carcinoma from computed tomography of the abdomen. Seventy-nine percent of physicians incorrectly underestimated the contribution of nuclear and radiological tests in exposure of an average person. The mean score of the specialties trended toward being more accurate than general practitioners (4.181.28 vs. 3.891.46, respectively, from a potential accurate total score of 9), but these differences were not statistically significant. Among specialists, orthopedics had the highest scores. The present study demonstrated the limited knowledge of radiation exposures among general practitioners and specialists and a need to improve their knowledge by means of targeted training and re-education.


PubMed | Nuclear Science and Technology Research Institute, Iran, Iran Nuclear Regulatory Authority and Tehran University of Medical Sciences
Type: | Journal: Radiation protection dosimetry | Year: 2016

Industrial radiography is the process of using either gamma-emitting radionuclide sources or X-ray machines to examine the safety of industrial materials. The average annual effective dose in industrial radiography is one of the highest among radiation workers. The aim of this study was to investigate the cytogenetic effects of ionizing radiation in the peripheral blood lymphocytes of 60 industrial radiographers and 40 non-exposed individuals as the control group by using cytokinesis-block micronucleus (CBMN) assay. Totally, the frequencies of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) were significantly higher in the industrial radiographers than in the controls (p=0.000). The mean MN frequency per 1000 binucleated cells in the industrial radiographers with last 5-y radiation dose of >100 mSv was significantly higher than those with 100 mSv (34.8112.7 vs. 26.337.94, p=0.024). The effect of age was observed in the control group and subjects with the age of >30 y showed significantly higher MN frequency compared with the subjects with the age of 30 y (9.453.71 vs. 6.813.05, p=0.02). No obvious trend of increased MN as a function of either duration of employment or age or smoking status was observed in the industrial radiographers. The results show the increased levels of cytogenetic damages in the industrial radiographers. Even the workers exposed to the permissible doses are subjected to elevated frequencies of DNA damages. These findings confirm the importance of cytogenetic biomonitoring program beside physical dosimetry, surveying radiation safety of equipment and periodic training of workers for improvement of safety and radiation protection.


PubMed | Nuclear Science and Technology Research Institute, Iran and Iran Nuclear Regulatory Authority
Type: | Journal: Journal of environmental radioactivity | Year: 2015

A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70Sv/month for Tehran city. Also, the average dose values obtained were less than 40Sv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55Sv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR.

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