Collective Effective Dose Research Articles

Statistical characteristics of the collective dose

A statistical approach for estimating the yearly effective collective dose is proposed. The distribution law for the collective dose is proposed on the basis of the assumption that the distributions of the number of people in the controlled group and the individual irradiation dose are random. It is shown that the distribution law for the collective dose has a quasiexponential form and is characterized by an average value and a variance. It is shown for a statistical analysis of the multiyear data from individual dosimetric monitoring of workers at the Moscow Scientific and Industrial Association Radon that the hypothesis advanced is consistent with observations. Practical recommendations are given for calculating collective dose statistics. 3 figures. 8 references.

Organ doses, detriment and genetic risk from interventional vascular procedures in Málaga (Spain)

Nowadays, the radiological risk from simple X-ray procedures is well known. The purpose of this work has been to estimate the population risk from digital angiographic and interventional procedures and to compare it with the one from simple procedures in the same population. The population risk has been estimated according to the following quantities: genetically significant dose, somatic significant dose, collective effective dose, annual per caput effective dose and detriment. These have been estimated from dose area product and organ dose. Organ dose values were estimated with the Eff-Dose software. A population of 605 410 people were included in the study. In 1996, 1312 patients were to digital interventional vascular procedures in Malaga, and 159 of them were selected in this research project to obtain the dose area product and organ dose. The results obtained for the quantities evaluated are: genetically significant dose, 4.1 μGy; somatic significant dose, 0.9 mSv; collective effective dose, 11.65 person-Sv; annual per caput effective dose, 0.02 mSv and detriment, 0.65 radiogenic cancers per year. These procedures supply a high radiation dose, so they should have a greater contribution to population dose and risk than simple examinations. However, our results indicate just the opposite.

Stochastic risk estimate for barium radiological examinations in Malaga (Spain)

The aim of this research work has been the estimation of the stochastic risk for five barium examinations. The sample was the population attending the Radiological Service of the `Nuestra Señora de la Victoria' University Hospital, who had been treated with some barium examinations, set in five different groups: oesophagus tract, oesophagus-gastric-duodenal tract, intestinal tract, enteroclysis and double enema. To estimate the stochastic risk, it is necessary to know the organ dose. This can be calculated from the dose-area product which allows us to determine the effective dose using software. The dose-area product is the most suitable quantity to measure in these types of examination. We have evaluated the contribution that each procedure provides to the genetically significant dose, somatically significant dose, collective effective dose, annual effective dose `per capita' and detriment, which are useful for assessing the population risk of cancer or hereditary effects after x-ray exposure. The contribution to the genetically significant dose is 6.7 µGy, to the somatically significant dose 8.82 mSv-yr, 16.07 person-Sv for the collective effective dose, 0.03 mSv for the `per capita' annual effective dose and the annual aggregated detriment is 0.33.

Estimation of Absorbed Dose Rate and Collective Effective Dose Equivalent Due to Gamma Radiation from Selected Radionuclides in Soil in Ondo and Ekiti State, South-Western Nigeria

The concentrations of natural radionuclides, namely 40 K, 238 U and 232 Th, in surface soils in Ondo and Ekiti States, south-western Nigeria have been measured using a very sensitive gamma ray spectroscopic system consisting of a 760 mm × 760 mm NaI(TI) scintillation detector coupled to a Canberra Series 10 Plus multichannel analyser. The mean absorbed dose rate, annual effective dose equivalent and the collective effective dose equivalent in these states have been estimated from the measured concentrations of the radionuclides, which are 0.015 ± 0.008 μGy.h -1 , 18.4 μSv.y -1 and 73.6 man.Sv.y -1 respectively.

Collective dose estimates by the marine food pathway from liquid radioactive wastes dumped in the Sea of Japan

IAEA-MEL has been engaged in an assessment programme related to radioactive waste dumping by the former USSR and other countries in the western North Pacific Ocean and its marginal seas. This paper focuses on the Sea of Japan and on estimation of collective doses from liquid radioactive wastes. The results from the Japanese–Korean–Russian joint expeditions are summarized, and collective doses for the Japanese population by the marine food pathway are estimated from liquid radioactive wastes dumped in the Sea of Japan and compared with those from global fallout and natural radionuclides. The collective effective dose equivalents by the annual intake of marine products caught in each year show a maximum a few years after the disposals. The total dose from all radionuclides reaches a maximum of 0.8 man Sv in 1990. Approximately 90% of the dose derives from 137Cs, most of which is due to consumption of fish. The total dose from liquid radioactive wastes is approximately 5% of that from global fallout, the contribution of which is below 0.1% of that of natural 210Po.

Medical radiation exposures for diagnostic radiology in Malaysia.

The medical radiation usage for diagnostic radiology in Malaysia (a Level II country) for 1990-1994 is reported, enabling a comparison to be made for the first time with the United Nations Scientific Committee on the Effects of Atomic Radiation Report. In 1994, the number of physicians, radiologists, x-ray units, and x-ray examinations per 1,000 population was 0.45, 0.005, 0.065, and 183, respectively. (Level I countries had averages of 2.6, 0.072, 0.35, and 860, respectively). In 1994, a total of 3.6 million x-ray examinations were performed; the annual effective dose per capita to the population was 0.05 mSv, and the collective effective dose was 1,000 person-Sv. Chest examinations contributed 63% of the total. Almost all examinations experienced increasing frequency from 1990 to 1994 except for barium studies, cholecystography, and intravenous urography (-23%, -36%, -51%). These decreases are related to the increasing use of ultrasound and greater availability of fiberoptic endoscopy. Notable increases during the same period were observed in computed tomography (161%), cardiac procedures (190%), and mammography (240%). In order to progress from Level II to Level I status Malaysia needs to expand and upgrade radiological service in tandem with the health care development of the country.

Assessment of Dose Rate and Collective Effective Dose Equivalent Due to Terrestrial Gamma Radiation in the City of Lagos, Nigeria

The average annual effective dose equivalent and the collective effective dose equivalent have been determined from measurements of the concentrations of 40 K, 238 U and 232 Th in top soil in and around the city of Lagos using in situ γ spectrometry. The average outdoor absorbed dose rate was (0.041 ± 0.012) μGyh -1 resulting in an annual average effective dose equivalent of 50 μSv.y -1 . The collective effective dose equivalent to the population in the city is 2.84 x 10 2 man.Sv.y -1 .

Diagnostic Radiology in Norway from 1983 to 1993 - Examination Frequency and Collective Effective Dose to Patients

Radiological activity in Norway has been investigated by means of three surveys in 1983, 1988 and 1993. The patient doses from conventional X ray examinations were assessed from more than 5000 measurements of area-exposure at 50 hospitals, using conversion coefficients from the National Radiological Protection Board in the UK. The total collective effective dose (CED) to patients from diagnostic radiology in 1993, including contributions from computed tomography and mammography, was assessed to be about 3400 man.Sv (0.78 mSv per inhabitant). The total frequency of radiological examinations has increased from 641 to 710 per 1000 inhabitants during the past ten years. The most significant trend is the increase in CT examinations, now representing 7% of the total number of examinations, and 30% of the total CED from diagnostic radiology. Conventional examinations of the gastrointestinal tract are decreasing due to the introduction of other procedures, but these examinations still contributed 26% to the total CED in Norway.

Establishing protective long term measures after severe nuclear accidents using multiple criteria.

This paper proposes a methodology supporting decisions on protective measures following severe nuclear accidents and demonstrates its use. A multicriteria decision analysis approach is adopted where value tradeoffs are postponed until the very last stage of the decision process. All feasible solutions are implicitly considered and evaluated in the chosen criteria. Technically inferior solutions are excluded. Only the non-dominated or efficient solutions forming the "efficient frontier" are retained and presented to the decision makers. Implementation of inefficient solutions is in this way avoided. A choice among the efficient solutions, although it implies value tradeoffs among the multiple criteria, avoids the direct and apriori assessment of preferences. An interactive computer package has been developed with which the decision maker can choose a point on the efficient frontier in the consequence space and immediately see the corresponding alternative in the decision space. The methodology is demonstrated through an application on the choice among possible protective measures in contaminated areas of the former USSR after the Chernobyl accident using as criteria the collective effective life-time dose received by the population and the cost associated with each possible decision.

Collective Doses and Radiation Risks Due to Medical Diagnostic Exposures in Ukraine

Effective collective, mean population doses as well as radiation risks for the Ukrainian population and separate regions of Ukraine due to radiodiagnosis have been calculated. Data about the structure and the number of examinations and the age of the patients were used. Individual effective doses were determined according to ICRP Publication 60. It has been established that the frequency of diagnostic and prophylactic X ray examinations in 1994 was 600 per 1000 persons. The frequency of CT examinations was 2.8 per 1000 persons. That of diagnostic nuclear medicine examinations was 5 per 1000 persons. Effective collective dose to the patients due to X ray procedures was 26,250 in 1994, that of radionuclide examinations was 320 man.Sv. Mean population dose due to these examinations was about 0.5 mSv.y -1 . The levels of population exposure due to X ray examinations in Ukraine have decreased about twice during the past 10 years. The causes of this are reduction in the number of examinations (especially in the regions contaminated with radionuclides) and change in methods (reduction of the number of the main dose-forming fluoroscopy methods). Collective dose due to CT examinations was approximately 790 man.Sv, or 3% of the value for X ray diagnosis and 2.5 times more than for diagnostic nuclear medicine examinations. Radiation risks for the Ukrainian population caused by radiodiagnosis in 1994 were calculated: the total number of fatal and non-fatal cancers was 1116, the number of serious hereditary disturbances was 96.

Effective dose estimation for the population in Kragujevac due to the Chernobyl accident

The doses that inhabitants of Kragujevac received after the nuclear accident in Chernobyl are given in this paper. During April and May in 1986, the radionuclide content in rain water was determined by applying gamma spectroscopic analysis, and the exposure dose rate in air was measured. The results obtained are the basis for absorbed dose, effective dose and commitment dose calculations. The effective dose, that some individuals received for the first year after the accident, due to the external exposure was estimated to be 50 μSv. Thus, the collective effective dose commitment due to the external exposure for population in Kragujevac town amounts to 11.5 Sv man. The effective dose from internal radiation due to 131I and 137Cs was also estimated, and amounted to 195 μSv in the first year. The collective effective dose commitment, due to the internal exposure (for 50 years) will be 43 Sv man. The total effective dose commitment (50 years) will be 0.32 mSv, while the total collective effective dose commitment will be 54.5 Sv man.

A comparison of doses from 137Cs and 210Po in marine food: A major international study

Radioactivity levels of natural 210Po and anthropogenic 137Cs in sea water and biota (fish and shellfish) have been estimated for the FAO fishing areas on the basis of measurements carried out in recent years. Collective doses resulting from seafood consumption are calculated for each FAO area using radioactivity data for water and biota. Good agreement is observed between the results calculated by these two methods, with the exception of the doses from 210Po via shellfish consumption. The collective effective dose commitment from 137Cs in marine food in 1990 has been estimated at 160 man Sv with an uncertainty of 50%. The corresponding dose from 210Po is 30000 man Sv with an estimated uncertainty of a factor of 5. The results confirm that the dominant contribution to doses derives from natural 210Po in fish and shellfish and that the contribution from anthropogenic 137Cs (mainly originating from nuclear weapons tests) is negligible.

Internal Doses to Ukrainian Populations Using Dnieper River Water

The dynamics of internal doses from 137CS and 90Sr as a consequence of the use of Dnieper River water were calculated. Local peculiarities of municipal tap, irrigation, and fish consumption in the Ukraine were considered. The dynamics of 90Sr accumulation in human bone as a result of the use of Dnieper water is simulated. The dose predictions are based on de facto data and the stochastic forecast of radionuclide concentrations in Dnieper reservoirs. A large array of statistical data on the age-structures of exposed populations, food consumption rate, agricultural production, fish contamination, and site-specific parameters were used. Exposures are estimated for 12 regions of the Dnieper basin and the Crimea Republic. The maximal individual annual committed effective doses are 1.7 X 10(-5) and 2.7 X 10(-5) Sv from 90Sr and 137Cs, respectively, due to the use of water in 1986 by members of the population in the Kievska region. Commercial fishermen on the Kievska reservoir, who consumed 360 kg y(-1) of fish in 1986, received 4.7 X 10(-4) and 5 X 10(-3) Sv from 90Sr and 137Cs, respectively. The contributions to the collective (over 70 y) effective dose of irrigation, municipal tap water, and fish consumption for members of the general public, respectively, are 18%, 43%, 39% in the Kievska region; 8%, 25%, 67% in the Poltavska region; 50% 50%, 0% (no Dnieper fish consumed) in the Crimea Republic. The predicted contribution of 90Sr to collective dose resulting from the use of water is 80%. The collective dose to the population of the Dnieper regions (32.5 million people) is 3,000 person-Sv, due to the use of water.

Radiological impact from atmospheric releases of 226Ra from coal-fired power plants

Lignite contains naturally occurring radionuclides arising from the uranium and thorium series and also 40K. Lignite burning is, therefore, one of the sources of technologically enhanced exposure to man from natural radionuclides. Emissions from thermal power stations in gaseous and particulate form contain radioisotopes, such as 226Ra, which are discharged to the environment causing radiation exposures to the population. About 11672 M Bq of 226Ra per year are discharged to the environment from four coal-fired power plants, totalling 3.62 GW electrical energy, at the Valley of Ptolemais, Northern Greece, in which the combustion of 1.1 × 10 10 kg lignite is required to produce an electrical energy of 1 GW year. The collective effective dose equivalent commitment to lung tissue per unit power generated resulting from atmospheric releases of 226Ra was estimated to be 1.1 × 10 −2 manSv (GW year) −1, i.e. more than 15 times higher than that corresponding to a modern-type coal-fired power plant according to the UNSCEAR (1988) data.

Radioactivity concentrations in non-nuclear industries

Radiation and radionuclides are natural phenomena. Small quantities of radionuclides, for example, are always released into the environment when materials are burnt or heated. Large-scale conventional energy sources such as coal and nuclear power have been well investigated for many years with regard to the emission of radionuclides, while emissions from the combustion of peat and wood and from other non-nuclear industries have not been investigated to the same extent. For the nuclear industry in Sweden, the annual dose limit to the public arising from regulated outlets to air and water must not exceed 0.1 mSv year −1 and the global collective effective dose must not exceed 5 person Sv year −1 per GW. A proposed radiation limit for peat power plants in Sweden is also 0.1 mSv year −1. Like most human pursuits, power-generating and other industrial activities affect the environment negatively but the radiation hazard is generally small compared with other hazards and natural radiation.

137Cs Chernobyl fallout in Greece and its associated radiological impact

Right after the Chernobyl reactor accident, a systematic soil sampling and analysis programme was undertaken to detect and quantitatively analyse the long-lived radionuclides in the Chernobyl fallout in Greece. In the frame of this programme, 1242 soil samples of 1-cm thick surface soil were collected over Greece during the period May - November 1986. The samples were counted and analysed using Ge-detector setups for fission products from the Chernobyl fallout, which led to the mapping of 137Cs deposition in the form of a five-class histogram, extending between 0 – 150 kBq m −2, with boundaries defined by isolines of 5, 15, 35, 65, and 150 kBq m −2. To investigate the radiological impact of the 137Cs fallout on the Greek population, the computer code PABLM was run using as input the above isoline data. According to the results obtained, the total body collective effective dose commitment of the Greek population was estimated as 340 manSv over the first year after the accident and 8800 manSv over a period of 40 y. Concerning the 6000 inhabitants within the 65 kBqm −2 isoline, the results were 2 manSv over the first year after the accident and 55 manSv over a period of 40 y. The above radiological impact was compared to that due to fly ash releases from the Ptolemais Lignite Power Plants in northern Greece.

96/00946 Estimation of collective effective dose equivalent for the population due to airborne effluent from coal-fired power plants in China

96/00946 Estimation of collective effective dose equivalent for the population due to airborne effluent from coal-fired power plants in China

Chernobyl radioactivity in Turkish tea and its possible health consequences

Like several other European countries, Turkey has been affected by the radioactive clouds arising from the Chemobyl reactor accident. There were two major fronts. The first one affected the western parts of Turkey, namely Thrace, Istanbul and Western Black Sea coast, starting from April 30th 1986. The second cloud affected the Eastern Black Sea coast at the beginning of May 1986. In both regions the clouds left their radioactive content with the heavy rains. Eastern Sea coast is one of the regions receiving highest volume of rainfall almost all year round. However, after the accident, the rains loaded with radioactive contaminants felt just before the tea collection period and the contaminated tea leaves were collected without finding a chance for cleaning with following rains. All of the tea consumed by Turkish people grows on a very narrow coastal line along the Eastern Black Sea. In this study, the results of radioactivity measurement on Turkish tea are summarized. Although there were other affected products in the region, e.g., hazelnuts, tobacco, vegetables, their level of contamination and yearly consumption rates were not as significant as tea. Tea is the major hot beverage consumed by Turkish people of all ages, but unfortunately it turned out to be one of the heavily contaminated products of Turkey. The effect of brewing and rinsing with hot water on tea were also investigated in the present work. The dose estimates from the tea consumption was done following a different approach than previous studies. Instead of using the radioactivity data obtained by measuring only limited number of contaminated tea samples in our laboratories, the data reported by the Turkish Atomic Energy Agency Authority covering all the tea product of 1986 were used for dose estimates. In addition the collective effective dose equivalent in Turkey was estimated. Although in this study contamination only in one product, namely tea, was discussed, it turned out to be important as it was consumed by large populations in Turkey, so contributed to the doses significantly. Precautions to be taken were summarized, one simple precaution “rinsing of tea before brewing” was sufficient to remove half of the contamination from tea without any drawbacks.

Assessment of the Population Effective Doses from the Diagnostic Use of Radiopharmaceuticals in Taiwan

Effective doses from typical radiopharmaceutical examinations were evaluated using new conversion factors based on the latest recommendations of the ICRP. These doses have been combined with information on the frequency of examinations to estimate that the per caput annual effective dose and the annual collective effective dose to the Taiwanese population from all radiodiagnostic examinations involving radioactive labelled materials are about 30 μSv and 600 man.Sv, respectively. The results obtained are discussed in terms of the possible radiological impact of the exposures incurred from radiopharmaceuticals and compared with the 1993 UNSCEAR Report.

Radiation dose to the population of Slovak Republic from diagnostic nuclear medicine.

This study estimated the radiation exposure attributed to nuclear medicine examinations during the period of 1985 through 1992 in Slovak Republic. It was accomplished by survey of nuclear medicine facilities from 1987 to 1992. In addition, a detailed analysis of nuclear medicine practice was obtained for 1992. The mean effective dose equivalent per capita and per exam were 0.022 mSv and 3.8 mSv, respectively. The collective effective dose equivalent for 1992 was 110.7 person Sv. In conclusion, the practice of nuclear medicine produces a very low radiation dose per examination and per capita of population. The Slovak Republic appeared favorable in comparison to other countries in the judicious use of diagnostic nuclear medicine procedures.