investigation on the performance of dose calibrators in nuclear medicine centers in Iran

To investigate the status of the nuclear medicine [NM] centers in Iran for the performance of dose calibrators, 18 out of 54 centers providing NM services in Iran were randomly selected and inspected in 1997. In the first phase of the study the selected centers were inspected for performing of quality control [QC] tests of dose calibrators. The linearity of the activity response, precision, accuracy, and the physical functions of the instruments, were studied. In the second phase of the study, carried out in 2006, 28 out of 75 NM centers were investigated for QC tests performance. The QC tests were performed by using standardized radio nuclides of Tc-99m and Cs-137 in the first phase, and Tc-99m and I-131 in the second phase of the studies. Standard procedures were used for carrying out the tests. According to the obtained results in the first phase of the study, 10 centers were found to be in unacceptable situation. Following this study, all the concerned NM centers were informed about the results, and at the same time the repair and adjustment of the dose calibrators were requested. In addition, the appropriate training courses along with the QC testing manuals were provided to the centers. Based on the data of the second phase of the study, only 6 NM centers were in unacceptable situation. The results indicated the effectiveness of the improvements carried out in the working procedures of the centers during interval between the two phases of investigation

Radon concentrations in public water supplies in Tehran and evaluation of radiation dose

Radon and its short-lived decay products in dwellings are recognized as the main sources of public exposure from the natural radioactivity. The tap water used for drinking and other household uses can make variable contributions to the indoor radon level. This study has provided data on radon concentrations in domestic water supplies in Tehran. Water samples were collected from various sources supplying domestic water in Tehran. Sample preparation for measuring waterborne radon by liquid scintillation counting was carried out in place. A modified sample preparation method providing higher measurement sensitivity was applied in this work. According to measurements, the mean 222Rn concentrations in groundwater and surface water supplies were 46.40 +/- 11.50 and 2.50 +/- 1.20 Bq.L-1, respectively. The mean radon concentration in tap water was 3.70 +/- 0.94 Bq.L-1. The annual total effective dose to adults due to waterborne radon in Tehran was estimated to be about 10 microSv. The radon concentrations in tap water actually used by people in Tehran are low enough and below the proposed limits in other countries

Personnel internal radiattion exposure to iodine-125 in a radioiodination laboratory: exposure levels and trends

Monitoring internal exposure of individuals handling significant amounts of iodine-125 [I-125] for iodination is of great importance. These individuals are potentially exposed to external contamination, and internal contamination through inhalation, ingestion and intact skin absorption, to I-125. Considering radiological toxicity of this radionuclide its monitoring in the workplace and workers is necessary for radiation protection purposes. Direct measurement of I-125 in thyroid of individuals, known as a common and reliable method, was applied in the framework of monitoring program. Intakes of I-125 by individuals and the associated effective doses were evaluated using thyroid monitoring results and recommended metabolic models. The monitoring results of the laboratory personnel for a period of 3 years are given and compared. According to the results, the intakes of I-125 by individuals in the early phase of laboratory operations were higher due to insufficient facilities and experience. Improvements in the radiation protection facilities of the laboratory and personnel including provision of personal respiratory protection devices resulted in significant reduction of I-125 intakes. According to 3 years results from the implementation of internal exposure monitoring program for personnel producing I-125 labeled compounds, the exposure levels of the personnel have contineously decreased due to improvements in working conditions and increasing of personnel experiences

survey of natural uraniumconcentrations in drinking water supplies in Iran

Measurement of back ground concentration of uranium in drinking water is very important for many reasons, specially, for human health. The uranium concentration in drinking water in many counties is a matter of concern for clinical and radioactive poisoning. Materials and The uranium concentration in drinking water is determined using laser flourimatric uranium analyzer. For this purpose after sampling, sample handling and sample preserving, sample preparation and treatment for reduction of organic matter, the concentration of uranium is measured. To determine the uranium concentrations in drinking water in Iran, nearly 200 water samples were collected from all sources supplying drinking water in 21 provincial centres in the country. The wells were found to be the main source for drinking water. Uranium in the samples was measured by a laser fluorimetry technique. According to results, the concentration values found in the wells ranged from 1.0 to 10.90 micro gL-1, while nearly 95% of the cities had uranium concentrations in the wells at less than 4.70 micro gL-1. Surface waters showed uranium concentrations in the range of 0.75 to 2.58 micro gL-1. The daily intake of uranium from drinking water was estimated to range from 2.04 to 21.80 micro gd-1, with the mean value of 5.44 micro gd-1. Highest uranium mean concentration of 10.9 micro gL-1 was found in Ardabil area where more studies should be done in that province in the future