Människan har i alla tider varit utsatt för joniserande strålning. Kosmiskstrålning och naturligt radioaktiva nuklider i vår omgivning och i vår kropp ger ett årligtbidrag till den absorberade dosen i hela kroppen, som i genomsnitt för människorna påjorden uppgår till 1 mGy/år (1Gy = 1 J/kg). Det finns områden på jorden där stråldosenfrån naturlig strålning är 10-100 ggr större, jfr avsnittet "Vår strålningsmiljö".
I slutet av 1800-talet upptäckte Röntgen röntgenstrålningen och Becquerel den naturligaradioaktiviteten. Människan fick därmed för första gången tillgång till starka källor avjoniserande strålning. Dessa togs snabbt i bruk framförallt inom medicinsk röntgendiagnostikoch radioterapi. Man gjorde snart bittra erfarenheter av den joniserandestrålningens skadliga biologiska verkningar efter höga stråldoser. Fram till år 1922 hadec:a 100 radiologer dött av strålskador. Man insåg att något måste göras för att förbättraläget för personalen och år 1928 bildades ICRP (International Commission on RadiationProtection). ICRP ger ut rekommendationer för strålskydd, som ligger till grund förnationella lagar och förordningar över hela världen.
Den förhållandevis långa erfarenhet människan har av joniserande strålning och denlätthet med vilken även små stråldoser kan mätas har gett oss stränga normer vad gällerhanteringen av producerade strålkällor. Många har därför uppfattningen att joniserandestrålning är en exklusiv miljökomponent. Så är knappast fallet. Förutom att vi alltid varitnaturligt bestrålade finns det idag anledning att förmoda att den kemiska nedsmutsningenav miljön är ett långt allvarligare hot mot vårt välbefinnande än den nuvarandeanvändningen av producerade strålkällor. En rättvis bedömning av olika miljökomponenterkan endast göras den gång alla mäts med samma mått. Arbete med dennainriktning pågår med strålskydds-verksamheten som förebild.
The design and calibration of a small and simple instrument for measuring the ambient dose equivalent, H*(10), in photon fields is described. Comprising a thermoluminescence LiF dosemeter inside a 20 mm diameter PMMA sphere, it is capable of measuring the ambient dose equivalent with a nearly isotropic response. In the interval 0.1-100 mSv and for the energy range 30 keV to 1.25 MeV the energy response is within -31% and +15% relative to that of 137Cs gamma radiation (662 keV). In practical use, it is therefore sufficient to calibrate the instrument in a 137Cs gamma field using the corresponding conversion coefficient H*(10)/Kair taken from tabulations. The possibility of using the instrument to monitor the ambient dose equivalent for energies above 1.25 MeV is discussed and indicates that the range of applicability can be extended to 4.4 MeV with an energy response within -10% relative to 662 keV.
The use of UV/Vis spectroscopy in combination with partial least squares (PLS) regression for the simultaneous prediction of nitrate and non-purgeable organic carbon (NPOC) in groundwaters was evaluated. A model of high quality was obtained using first order derivative spectra in the range 200–300 nm. Inclusion of non-UV-absorbing constituents in the modeling procedure, i.e., chloride, sulfate, fluoride, total carbon (TC), inorganic carbon (IC), alkalinity, pH and conductivity was also evaluated. This model seemed to be useful for prediction of chloride, TC, IC, alkalinity and conductivity, while its ability to predict sulfate, fluoride and pH was poor. In conclusion, application of PLS regression, which requires neither filtration of samples nor addition of chemicals, is a promising alternative for fast interpretation of geochemical patterns of groundwater quality.
A method for rapid determination of plutonium isotopes in environmental samples with ultrasonic nebulisation and quadrupole ICP-MS detection was established. Techniques for sample dissolution, pre-concentration and chemical separation were evaluated and the optimal scheme outlined. Comparisons with α-spectrometry and high resolution ICP-MS confirmed the suitability of the method when applied to different environmental matrices within the global fallout concentration range in the northern hemisphere as well as more contaminated sites. Operational detection limits were 0.5–1.5 fg/l for fresh waters and 0.03–0.1 ng/kg for lake sediments and saline marsh sediments.
As a complement to the training of first responders in their preparedness for accidents and incidents involving radiation, a radiac simulation, called RadiaX, was developed. RadiaX has a threefold purpose; to teach (i) the handling of specific instruments, (ii) the proper procedures in missions and (iii) basic principles in radiation physics and radiation protection. The simulation is developed as a modification of Half-Life 2, a famous computer game.
Information about each X-ray examination, in a modern digitized X-ray department is generated and stored in a PACS. Appropriate conversion factors, e.g. E/DAP, can be applied to separate projections and summed to the total effective dose for each examination. The objectives of the work were (i) to investigate the accuracy and precision in the calculated effective dose (ii) to identify data for registration of (1) patient dose, (2) exposure data, and (3) patient information (iii) to make it possible to derive dose statistics on patient level for documentation of diagnostic standard doses, optimizations, constancy checks, and future epidemiological studies. The effective doses were calculated using Monte Carlo based computer programs or by using tabulations. Conversion factors were calculated for different levels of information and the individual effective dose was compared to the most precise estimation. The results suggest that the accuracy in the estimations of effective dose increases by added information about the patient (gender, size) and how the examination was performed.
With an unmanned helicopter (UAS), known as drones, equipped with a gamma spectrometer, one can achieve both a high spatial resolution and good range, and be able to approach a radioactive source closely. Linköping University, Sweden, is proposing a microdrone system that will fill a gap between man-portable measurement systems and full-sized airborne systems, complementing the car-driven measurement systems. The system may play a unique role in many of our contingency scenarios in terms of accessibility, versatility, efficiency, and is advantageous from the viewpoint of radiation protection as it can be controlled at a safe distance.
Dosimeters based on the Direct Ion Storage technology is used as the first approved electronic personal dosimeter in Sweden at the County Councils in Östergötland and Kalmar. TL dosimeters are replaced by DIS-1 dosimeters for all category A personnel at six hospitals with totally 300 dosimeter holders. The advantages are longer issue periods and instant read outs, appreciated by both the service and the holders
RadiaDroid is an Android application that simulates the portable radiation detector Intensimeter 28 civ. and uses virtual radioactive sources, defined by GPS coordinates, radionuclide and activity. The trainees load a scenario and search the exercise area for radioactivity. The locations of sources and safety perimeters are reported. Creation of scenarios is possible in the application, but is facilitated in a PC tool that also presents the reports and the dose to the trainee.
Inhalation exposure to uranium aerosols can be a concern in nuclear fuel fabrication. The ICRP provides default absorption parameters for various uranium compounds but also recommends determination of material-specific absorption parameters to improve dose calculations for individuals exposed to airborne radioactivity. Aerosol particle size influences internal dosimetry calculations in two potentially significant ways: the efficiency of particle deposition in the various regions of the respiratory tract is dependent on aerodynamic particle size, and the dissolution rate of deposited materials can vary according to particle size, shape, and porosity because smaller particles tend to have higher surface-to-volume ratios than larger particles. However, the ICRP model assumes that deposited particles of a given material dissolve at the same rate regardless of size and that uptake to blood of dissolved material normally occurs instantaneously in all parts of the lung (except the anterior portion of the nasal region, where zero absorption is assumed). In the present work, the effect of particle size on dissolution in simulated lung fluid was studied for uranium aerosols collected at the plant, and its influence on internal dosimetry calculations was evaluated. Size fractionated uranium aerosols were sampled at a nuclear fuel fabrication plant using portable cascade impactors. Absorption parameters, describing dissolution of material according to the ICRP Human Respiratory Tract Model, were determined in vitro for different size fractions using simulated lung fluid. Samples were collected at 16 time-points over a 100-d period. Uranium content of samples was determined using inductively coupled plasma mass spectrometry and alpha spectrometry. In addition, supplementary experiments to study the effect of pH drift and uranium adsorption on filter holders were conducted as they could potentially influence the derived absorption parameters. The undissolved fraction over time was observed to vary with impaction stage cut-point at the four main workshops at the plant. A larger fraction of the particle activity tended to dissolve for small cut-points, but exceptions were noted. Absorption parameters (rapid fraction, rapid rate, and slow rate), derived from the undissolved fraction over time, were generally in fair agreement with the ICRP default recommendations for uranium compounds. Differences in absorption parameters were noted across the four main workshops at the plant (i.e., where the aerosol characteristics are expected to vary). The pelletizing workshop was associated with the most insoluble material and the conversion workshop with the most soluble material. The correlation between derived lung absorption parameters and aerodynamic particle size (impactor stage cut-point) was weak. For example, the mean absorption parameters derived from impaction stages with low (taken to be <5 mu m) and large (>= 5 mu m) cut-points did not differ significantly. Drift of pH and adsorption on filter holders appeared to be of secondary importance, but it was found that particle leakage can occur. Undissolved fractions and to some degree derived lung absorption parameters were observed to vary depending on the aerodynamic size fraction studied, suggesting that size fractionation (e.g., using cascade impactors) is appropriate prior to conducting in vitro dissolution rate experiments. The 0.01-0.02 mu m and 1-2 mu m size ranges are of particular interest as they correspond to alveolar deposition maxima in the Human Respiratory Tract Model (HRTM). In the present work, however, the dependency on aerodynamic size appeared to be of minor importance, but it cannot be ruled out that particle bounce obscured the results for late impaction stages. In addition, it was noted that the time over which simulated lung fluid samples are collected (100 d in our case) influences the curve-fitting procedure used to determine the lung absorption parameters, in particular the slow rate that increased if fewer samples were considered.
The aim of this work was to determine mean absorbed doses to the unborn child in common conventional X-ray and computed tomography (CT) examinations and to find an approach for estimating foetal dose based on data registered in the Radiological Information System/Picture Archive and Communication System (RIS/PACS). The kerma-area product (KAP) and CT dose index (CTDIvol) in common examinations were registered using a human-shaped female dosimetry phantom. Foetal doses, Df, were measured using thermoluminescent dosimeters placed inside the phantom and compared with calculated values. Measured foetal doses were given in relation to the KAP and the CTDIvol values, respectively. Conversion factor Df/KAP varies between 0.01 and 3.8 mGy/Gycm2, depending on primary beam position, foetus age and beam quality (tube voltage and filtration). Conversion factors Df/CTDIvol are in the range 0.02 – 1.2 mGy/mGy, in which the foetus is outside or within the primary beam. We conclude that dose conversion factors based on KAP or CTDIvol values automatically generated by the RIS/PACS system can be used for rapid estimations of foetal dose for common examination techniques.
In the present study the distribution of uranium in single human hair shafts has been evaluated using two synchrotron radiation (SR) based micro X-ray fluorescence techniques; SR μ-XRF and confocal SR μ-XRF. The hair shafts originated from persons that have been exposed to elevated uranium concentrations. Two different groups have been studied, i) workers at a nuclear fuel fabrication factory, exposed mainly by inhalation and ii) owners of drilled bedrock wells exposed by ingestion of water. The measurements were carried out on the FLUO beamline at the synchrotron radiation facility ANKA, Karlsruhe. The experiment was optimized to detect U with a beam size of 6.8 μm × 3 μm beam focus allowing detection down to ppb levels of U in 10 s (SR μ-XRF setup) and 70 s (SR confocal μ-XRF setup) measurements. It was found that the uranium was present in a 10–15 μm peripheral layer of the hair shafts for both groups studied. Furthermore, potential external hair contamination was studied by scanning of unwashed hair shafts from the workers. Sites of very high uranium signal were identified as particles containing uranium. Such particles, were also seen in complementary analyses using variable pressure electron microscope coupled with energy dispersive X-ray analyzer (ESEM–EDX). However, the particles were not visible in washed hair shafts.
These findings can further increase the understanding of uranium excretion in hair and its potential use as a biomonitor.
Hair is evaluated and compared with urine as a biomonitor for human intake of uranium. Concentrations of U and U and the activity ratio between them are measured in the hair, urine, and drinking water of 24 drilled bedrock well water users in Östergötland, Sweden. The samples are measured with α-spectrometry after radiochemical preparation using liquid-liquid separation with tributylphosphate. The results show that there is a stronger correlation between the uranium concentrations in the drinking water of each subject and the hair of the subject (r = 0.50) than with the urine (r = 0.21). There is also a stronger correlation between the activity ratios of water and hair (r = 0.91) than between water and urine (r = 0.56). These results imply that hair may serve as a robust indicator of chronic uranium intake. One obvious advantage over sampling urine is that hair samples reflect a much longer excretion period: weeks compared to days. The absorbed fraction of uranium, the f value, is calculated as the ratio between the excreted amount of uranium in urine and hair per day and the daily drinking water intake of uranium. The f values stretch from 0.002 to 0.10 with a median of 0.023.
Scalp hair is evaluated and compared with urine as a potential biomonitor following inhalation intake of uranium. The samples were collected among eight workers at a nuclear fuel fabrication factory and the sample concentrations of 234U and 238U were analyzed by α-spectrometry after radiochemical preparation using a TBP-based liquidliquid separation method. Personal air samplers (PAS) filters were also analyzed for determination of inhaled uranium activity.
The results show that there is a large day-to-day variation (7-70 Bq d-1) of the inhaled 234U activity over a 6 week period. A large variation is also seen for the 234U activity concentration among 12 urine samples collected over a 12 week period; (2-50 mBq kg-1). Four hair samples from the same subject and period showed less variation (100-240 mBq g-1) as they reflect the average excretion over a longer period than the periodic urine samples.
The total inhalation intake and excretion in urine and hair was obtained for two study subjects over a 6 week period. The uranium inhalation to urine and hair factors finh,u and finh,h were 0.0014 and 0.0002 respectively, given by calculations based on the measured PAS, urine and hair data. It has been demonstrated that scalp hair could be a valuable complement to urine as biomonitor of uranium intake.
Realistic and reliable dose models are required to estimate the radiological risks to non-human biota, in regions contaminated by radioactivity. To facilitate detailed dose calculations, a graphical user interface has been developed to the Monte Carlo N-Particle Transport code (MCNP): the TADPOLE editor (Terrestrial and Aquatic Dose assessment Program for Organisms in their Local Environment). The editor is intended for site and biota specific analyses of absorbed dose from external γ- and β- radiation.
An experiment was performed in controlled, laboratory conditions as a first validation of the calculation models assigned by the editor. Measurements with TL-dosimeters yielded lower doses than was calculated by MCNP5 through the editor.
Pu239+240 concentrations and Pu-240/Pu-239 atom ratios in bottom sediments of the Yellow Sea, Korea Strait, East Sea (Sea of Japan), Sea of Okhotsk, and Northwest Pacific Ocean were determined. In coastal sediments near the Korean Peninsula, Pu239+240 concentrations varied from 0.02 to 1.72 Bq.kg(-1), and their Pu-240 /Pu-239 atom ratios from 0.15 to 0.24, with an average of 0.20+/-0.03. Pu-240/Pu-239 atom ratios of bottom sediments in the deep NW Pacific Ocean and its marginal seas(East,Okhotsk seas) were in the range of 0.15-0.23. A little elevated Pu-240/Pu-239 atom ratios in the bottom layer sediment may be due to Pu released into the environment during the pre-moratorium period, having high Pu-240 /Pu-239 atom ratios and low Pu-238/Pu239+240 activity ratios.
Plutonium isotopes and 241Am were studied in seawater and sediment from the East China Sea, the Yellow Sea, the East Sea/Sea of Japan, the Sea of Okhotsk, and the northwest Pacific Ocean, collected between 1993 and 1996 with the aim to contribute to better understanding the behaviour of plutonium and americium in the marine environment. 239,240Pu concentrations in surface water varied from 2.3 to 13 µBq l-1 in the East China Sea and from 3.5 to 9.4 µBq l-1 in the East Sea. The 239,240Pu vertical profiles in water showed a broad subsurface maximum between 500 and 1000 m with a range of 30-40 µBq l-1, and gradually decreased from 1000 m depth down to the seafloor. 241Am concentrations in surface water showed values from 1.1 to 2.2 µBq l -1 in the East Sea, from 1.0 to 3.1 µBq l-1 in the Sea of Okhotsk, and from 0.68 to 12.0 µBq l-1 in the northwest Pacific Ocean. The activity ratios of 241Am/239,240Pu in seawater showed values similar to the global fallout ratio, which suggests that the source of these radionuclides in the northwest Pacific Ocean is global fallout. However, the 241Am/239,240Pu activity ratios in sediment were found to be much higher (1.0-1.9) than the global fallout ratio (0.37), confirming that 241Am is scavenged from the water column more rapidly than 239,240Pu. The 239,240Pu inventories in the water column of the East Sea were from 0.98 to 93 Bq m-2 depending on water depth and sedimentation rates. The 241Am inventory in the water column east of Kamchatka was 6.3 ± 1.0 Bq m -2 and the sediment inventory in the Sea of Okhotsk was 16 ± 2 Bq m-2. 239,240Pu concentrations in sinking particles in the southwest Japan Basin were from 3.7 to 5.2 Bq kg-1 (dry weight) with fluxes of 0.19-4.50 mBq m-2 d-1 and at the Ulleung Basin from 2.4 to 3.7 Bq kg-1 (dry weight) with fluxes of 0.77-1.10 mBq m-2 d-1. The mean residence time of 239,240Pu in the water column of the East Sea derived from sediment trap data was 140 ± 20 years, 2-3 times less than in the Atlantic and Pacific oceans.
A national study was performed to investigate radiation doses and associated risks to patients during X-ray fluoroscopy-guided small intestinal biopsies in the investigation of coeliac disease. Thermoluminescent dosemeters (TLD) and questionnaires were sent to 42 of the 43 paediatric departments in Sweden performing these biopsies. During the study period (2 × 3 weeks) 257 biopsies were recorded, representing about 10% of annually performed paediatric investigations. The results show that the absorbed dose during biopsy ranged from 0.04 mGy to 23.8 mGy (mean 1.87 mGy). The fluoroscopy time ranged from 2 s to 663 s (mean 60 s). The collective dose from the procedure amounts to 4.7 manSv year-1. Thus, the annual excess cancer mortality, including severe hereditary effects, can be estimated at 0.6-0.7 cases per year. However, significant dose saving can be obtained by proper choice of sedation and biopsy equipment. © 2005 The British Institute of Radiology.
IAEA-MEL participated in five expeditions to the Kara Sea with the aim of assessing the radiological consequences of dumped radioactive wastes in the Novaya Zemlya Bays and Trough. The programme included sampling, in-situ underwater investigations, laboratory analyses of water, sediment and biota samples, the development of a marine radioactivity database, modelling and radiological assessment, the organization of intercomparison exercises and the evaluation of distribution coefficients. Radiometric investigations have shown that no radiologically significant environmental contamination has occurred. Leakages which have led to locally increased levels of radionuclides in sediment have only been observed in Stepovoy and Abrosimov Bays. Computer modelling results suggest that only radiological effects on local and regional scales may be of importance. The global radiological impact of the disposals in the Arctic Seas will be negligible.
A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The K-40, Cs-132, U-234 and Pu239+240 radionuclides were certified for this material, and information values for 12 other radionuclides (Sr-90, Tc-99, Pb-210 (Po-210), Ra-226, Ra-228, Th-228, Th-230, Th-232, U-235, U-238, Pu-239 and Pu-240) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes.
A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (H-3, K-40, Sr-90, Cs-137, U-234, U-235, U-238, Pu-238, Pu239+240 and Am-241) have been certified, and information values on massic activities with 95% confidence intervals are given for four radionuclides (Th-230, Th-232, Pu-239 and Pu-240). Results for less frequently reported radionuclides (Tc-99, Th-228, Np-237 and Pu-241) are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in water samples, for the development and validation of analytical methods and for training purposes. The material is available in 5 L units from IAEA (http://nucleus.iaea.org/rpst/index.htm).
A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) isdescribed and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu,239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six otherradionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np)and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of theanalysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. Thematerial is available from IAEA, Vienna, in 100 g units.r 2006 Elsevier Ltd. All rights reserved.
A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides in the environment, as well as for the development and validation of analytical methods and for training purposes. The material is available from IAEA in 100 g units.
Radon (222Rn) accumulation in water in relation to stable elements was studied for the purpose of determining factors influencing the transfer of 222Rn to and from water. In 72 groundwater samples, 222Rn and about 70 analytical parameters were analysed using radiometric and ICP-MS techniques. Using multivariate statistics (partial least squares), it was observed that 222Rn has a positive correlation with fluoride and uranium. The correlation with fluoride was further investigated by a laboratory time-scale experiment to measure the emanation of 222Rn from water as a function of fluoride, pH and carbonate. The transfer of 222Rn from water was measured by continuous monitoring in air in a closed loop set-up. It was observed that fluoride in water adhere or trap 222Rn preferably in acidic water (pH 3). It is suspected that natural physical processes (such as diffusion and microbubble phenomenon) are less effective to transport 222Rn in the presence of fluoride.
A new method for measuring 222Rn and 226Ra in water has been devised. It is based on exhaling radon to a void volume by continuous bubbling of air through the water. The exhaled radon is then transferred in a closed circuit to a modified radon gas pulse ionisation chamber for alpha-spectrometric measurements. About 86% of the radon in water is transferred from 0.75 l of water to the void volume (3.2 l). The set-up offers direct and specific 222Rn measurements for a wide range of concentrations and shows a low detection limit (LLD=45 mBq l−1 for 8 h counting time). Radium in water is measured, via radon, after sample storage for a month. The method was compared with gamma ray spectrometry for radon and for radium, the latter after pre-concentration by co-precipitation with MnO2 from 10 l water samples. An excellent agreement between the two techniques was obtained. As a part of a radon survey, the method was employed for analysis of drinking water from bedrock wells.
Natural radioactivity in drinking water from 328 drilled wells was studied in correlation to source parameters. Poor correlation to both aquifer geology and bedrock radioactivity was observed. Concentrations of 238U, 226Ra, 228Ra, 222Rn and 210Po in groundwater samples was in the ranges <0.027-5.3, <0.016-4.9, <0.014-1.24, 5-8105 and <0.05-0.947 Bq.l(-1) respectively. In about 80% of the sites the radon concentration exceeds the Nordic recommended exemption level for radon in drinking water and 15% of the sites exceed the action limit. The effective doses from ingestion were calculated and presented in association with geology. Doses due to ingestion ranged between 0.05 and 20.4 mSv.y(-1), where the average contribution from 222Rn amounted to 75%. In comparison, the effective doses from inhalation of indoor 222Rn ranged between 0.2 and 20 mSv.y(-1). The average contribution from inhalation of 222Rn in air to the total effective dose (ingestion+inhalation) was 58 +/- 22%, 73 +/- 18% and 77 +/- 16% (1 SD) for the age categories 1 y, 10 y and adults respectively.
This study describes approaches to create surface maps of radon in groundwater based on measurements of radon (222Rn) in drilled bedrock wells at unevenly distributed sites and uranium bedrock maps from the South East of Sweden, the Östergotland county (N 58°14’ – N 58°56’and E 14°53’ – E 16°06’), see figure 1. Geostatistical techniques of inverse distance weighted(IDW), kriging and cokriging were compared in terms of their interpolation power and correlation between the produced radon in the water layer and the bedrock uranium layer. The goal of these analyses and calculations is to improve our understanding concerning the factors influencing the transport of radon. Therefore, these interpolation techniques were investigated by optimizing parameters that are used in the specific interpolation. Using the IDW interpolator method at fixed radius enabled us to determine the linkage or search distances for auto correlation, and linkage between radon in water and bedrock. This method showed good agreement with the cokriging method when using uranium concentration as a secondary variable. Good interpolation layers (with least root mean square errors RMSE=232) were obtained by kriging. However, the kriged radon surface showed poor correlation with bedrock uranium layers. The best radon in waterlayer that match with uranium in bedrock layer was produced using IDW interpolator (RMSE=377, using all points). The correlation coefficient (R2) is 0.5 while for the kriging method the best correlation is R2 = 0.1. A compromise between the two approaches is demonstrated.
The aim of this study was to compare the radiation dose to patients during coronary angiography (CA) and coronary intervention (percutaneous transluminal coronary angioplasty, PTCA) by the femoral or radial artery access routes. A plane-parallel ionisation chamber, mounted on an under-couch X-ray tube (Siemens Coroskop TOP with an optional dose reduction system), recorded the dose-area product (DAP) to the patient from 40 coronary angiographies and 42 coronary interventions by the femoral route. The corresponding numbers for radial access were 36 and 24, respectively. Using a human-shaped phantom, conversion factors between maximum entrance surface dose and DAP were derived for CA and CA plus PTCA, respectively. The dose to the staff was measured with TL dosimeters for 22 examinations. Fluoroscopy time and DAP were significantly (p=0.003) larger using the radial access route for coronary angiography (7.5 min, 51 Gy cm2) than the corresponding values obtained from femoral access route (4.6 min, 38 Gy cm2. For CA plus PTCA the fluoroscopy time and DAP were larger for radial access (18.4 min, 75 Gy cm2) than for femoral access (12.5 min, 47 Gy cm2, p=0.013). In our experience, radial access did significantly prolong the fluoroscopy time and increase the patient doses.
PURPOSE: The aim of this retrospective study was to estimate risk organ doses and to estimate radiation risks during the imaging work-up and treatment for aneurysmal subarachnoid hemorrhage (SAH). METHODS: The imaging procedures comprised computed tomography and digital subtraction angiography studies for diagnosis or endovascular interventional procedures in 50 consecutive patients. Equivalent organ doses (H(T)) to skin, brain, eye lens, salivary glands, thyroid and oral mucosa were measured using thermoluminescence dosimeters in an anthropomorphic head phantom. Picture archiving and communication system (PACS) and radiological information system (RIS) records were analyzed and the frequency of each imaging procedure was recorded as well as the registered individual kerma-length product (P(KL)) and the kerma-area product (P(KA)). The doses were computed by multiplying the recorded P(KL) and P(KA) values by the conversion coefficients H(T)/P(KL) and H(T)/P(KA) from the head phantom. RESULTS: The mean fluoroscopy time, P(KL) and P(KA) were 38 min, 7269 mGy cm and 286 Gy cm(2), respectively. The estimated mean equivalent doses were as follows: skin 2.51 Sv, brain 0.92 Sv, eye lens 0.43 Sv and salivary glands 0.23 Sv. Maximum organ doses were 2.3-3.5 times higher than the mean. Interventional procedures contributed 66 % to skin dose, 55 % to brain dose and 25 % to eye lens dose. Of the patients with an estimated skin dose exceeding 6 Sv, only 1 developed temporary epilation. CONCLUSION: The risk for radiation-induced cancer for SAH patients is low (2-3 cases per 1,000 patients, of which 90 % are expected to be benign types) compared with the risk of tissue reactions on the head such as skin erythema and epilation (1 temporary epilation per 50 patients).
Purpose To assess patient skin and eye lens doses in interventional neuroradiology and to assess both stochastic and deterministic radiation risks. Methods Kerma–area product (P KA) was recorded and skin doses measured using thermoluminescence dosimeters. Estimated dose at interventional reference point (IRP) was compared with measured absorbed doses. Results The average and maximum fluoroscopy times were 32 and 189 min for coiling and 40 and 144 min for embolisation. The average and maximum P KA for coiling were 121 and 436 Gy cm2, respectively, and 189 and 677 Gy cm2 for embolisation. The average and maximum values of the measured maximum absorbed skin doses were 0.72 and 3.0 Sv, respectively, for coiling and 0.79 and 2.1 Sv for embolisation. Two out of the 52 patients received skin doses in excess of 2 Sv. The average and maximum doses to the eye lens (left eye) were 51 and 515 mSv (coiling) and 71 and 289 mSv (embolisation). Conclusion The ratio between the measured dose and the dose at the IRP was 0.44 ± 0.18 mSv/mGy indicating that the dose displayed by the x-ray unit overestimates the maximum skin dose but is still a valuable indication of the dose. The risk of inducing skin erythema and lens cataract during our hospital procedures is therefore small.
For assessment of external radiation doses to frogs in a wetland area contaminated with 137Cs, frog phantoms were constructed from polymethyl methacrylate (PMMA). The frog phantoms contained thermoluminescence (TL) chips and were used in situ at two study sites to measure doses. To test if higher doses are received by the sensitive skin of frogs, extra-thin TL chips were applied close to the surface of the frog phantoms. In addition, the measured doses were compared with those calculated on the basis of soil sample data from the wetland multiplied with dose-conversion coefficients from the US Department of Energy's RESRAD-BIOTA code and from the ERICA assessment tool. Measured doses were generally lower than those calculated to ellipsoids used to model frogs. Higher doses were measured at the frog phantoms' surfaces in comparison to inner parts at one of the two sites indicating that the frogs' thin skin could receive a higher radiation dose than expected. In the efforts to assure protection of non-human biota, in situ measurements with phantoms provide valuable dose information and input to dose models in site-specific risk assessments of areas contaminated with radionuclides. © 2008 Springer-Verlag.
Denna bok beskriver hur man ska hantera den svåra uppgiften att bedriva sjukvård på effektivast möjliga sätt i alla de olika typer av situationer där det akuta vårdbehovet överstiger vad som kan klaras med tillgängliga resurser. Den täcker hela omhändertagandekedjan från skadeområdet till definitiv behandling på sjukhus. Denna nya upplaga av Katastrofmedicin är en helt ny bok, utökad till innehållet och uppdaterad mot bakgrund av den omfattande utveckling som präglat detta ämnesområde sedan föregående upplaga.
Katastrofmedicin kan användas som både läromedel vid utbildning på alla nivåer och som en lättillgänglig handbok och vänder sig till såväl personal i prehospital vård som till läkare och sjuksköterskor på sjukhusens akutmottagningar och inom berörda specialiteter.
An intercomparison exercise on Rn-222 determination in groundwater was organized between eight Nordic laboratories. The individual laboratory results were in most cases within 20% of the median value and within reported uncertainties. Considering the particular difficulties in preparing, transporting and analyzing Rn-222, being a gaseous radionuclide, the results indicate a high analytical capability among the Nordic laboratories. In order to maintain a high analytical quality, similar intercomparisons will also be needed in the future.