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PubMed1991

[Results of studies on the effect of radiologic contamination after the Czernobyl catastrophe and prophylactic iodine on thyroid morphology and function of inhabitants of North-East Poland].

The results of the investigations of radioactive contamination after the Chernobyl catastrophe and subsequent iodine prophylaxis on the thyroid gland function and morphology in Northeast Poland. The aim of the study was to determine whether kalium iodine in one dose during radioactive contamination in Poland limited the radioactive dose in the thyroid gland and if significant disadvantageous side-effects in the intrathyroid and extrathyroid occurred. Additionally during the studies we tried to determine if radioactive iodine contamination which occurred in the region of the Medical Academy in Białystok caused an increase in thyroid disease. It is interesting to note the different results obtained after radioactive contamination with the results from the investigations in this same territory in 1983-1985. In 1983-1985, before the Chernobyl catastrophe, 6,921 persons in Northeast Poland were investigated. In 1986-1988, immediately after the disaster 4,010 persons were investigated. The main study according to grant No MZ-XVII was carried out in three provinces: Białystok, Suwałki and Olsztyn. In this investigation 10,011 persons born before April 26, 1986 and after January 1, 1936 participated, 5,789 townspeople and 4,222 villagers, 3,987 children up to 16 years of age it the time of the disaster 1,973 boys and 2,009 girls; 6,024 adults 2,509 men and 3,516 women were drawn from a register. Committed doses to the thyroid in the investigated region were one of the highest in Poland and depended on age group and were depended on time of prophylaxis non proportional. Iodine prophylaxis was provided mainly with one dose of Lugol solution about 90%, 95% children and 30% adults took iodine. The majority of the population (53.3%-74%) were given iodine in April. From May 1st to 5th 23.0-43.4% received iodine, but after May 5th very few persons. Iodine was well tolerated, but Lugol Solution was better tolerated than other kinds of iodine. Only 241 (4.4%) cases had side effects, mainly vomiting (143), symptoms such as stomach ache, diarrhea, dyspnoe, skinrash etc. in lesser numbers. 12% (29 persons) were seen by a physician. In the investigated population were 200 pregnant women aged 19-40 years of which the majority (177) delivered full term healthy babies. Only 1 interrupted pregnancy and 7 had spontaneous abortion. Changes in the thyroid were noticed by 187 persons (2.3%-11.7%) most of which were enlargement of the thyroid, but only a few were confirmed by a physician. In the studied population from 1989 to 1990 over 30% of the population had struma.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed2004

Foliar contamination of Phaseolus vulgaris with aerosols of 137Cs, 85Sr, 133Ba and 123mTe: influence of plant development stage upon contamination and rain.

As part of a requirement to improve the assessment of the impact of radioactive fallout on consumed agricultural products, bean plants at four development stages (seedlings, preflowering, late flowering and mature plants) were contaminated by dry deposition of (137)Cs, (85)Sr, (133)Ba and (123m)Te aerosols. The influence of two rain scenarios and of the development stage upon contamination on interception, retention, and translocation to pods was studied. Interception of the four radionuclides was almost identical and varied from 30 to 60% with increasing development stage. The most important rain parameter was the time which elapsed between contamination and the first rain. Whatever the development stage, rain washed off more cesium from the leaves when it occurred 2 days after the deposit (37% at the seedling stage, for example) rather than later on (6 days, 27%), due to rapid migration of Cs in the plant. The first rain washed off nearly 40% of Ba whatever the scenario. For later stages, Sr and Ba were more washed off by heavy weekly rains than by weak twice-a-week rains, perhaps because of the Sr/Ba-contaminated material loss associated with wash off (desquamation of cuticles). Te showed little wash off (less than 5%). Wash off decreased with an older development stage for a weak rain intensity, due to the superimposition of leaves. Heavy rains removed this shelter effect. At harvest, rain effect was no longer detectable as foliar activity was similar for both rain scenarios. Translocation factors (TF) for strontium and barium increased from 6 x 10(-3) to 1 x 10(-1) with the plant development stage upon contamination, whereas those for cesium remained almost unchanged between 2 x 10(-1) and 4 x 10(-1). Flowering is the most critical stage towards residual contamination in pods at harvest, with the exception of direct deposit on pods at the mature stage (TF values are one order of magnitude higher). TF value for Te was 6.5 x 10(-2) and was due to direct deposit. Modelling reflected the trends, through the differential values of the wash off and absorption coefficients, of what was reported for experimental results.

Aerosols↗
PubMed1999

Radiation safety with breast sentinel node biopsy.

BACKGROUND: Sentinel lymph node biopsy with Technetium 99m sulfur colloid (Tc99m) is an evolving technique that offers the potential for improved staging of breast cancer with decreased morbidity. However, the use of radioactive materials in the operating room generates significant concern about radiation exposure. The purpose of this study was to evaluate radiation exposure to operating room personnel, pathologist, and equipment from specimens during breast sentinel lymph node biopsy. METHODS: Twenty patients were injected with 0.7 to 1.1 mCi of Tc99m sulfur colloid 1.5 to 3 hours before sentinel lymph node biopsy. A calibrated Geiger counter was used to measure dose rates from the breast injection site before skin incision (n = 20), lumpectomy specimens (n = 8), and sentinel nodes (n = 20) at distances of 3, 30, and 300 cm. This represented exposure to the surgeon's hands, surgeon's torso, and scrub nurse, respectively. Exposure to the pathologist's hands and torso was represented as dose-rate measurements from lumpectomy and nodal specimens. The operative instruments, trash receptacles, suction canisters, pathology slides, and cryostat machines were measured at 3 cm at the conclusion of each procedure. Specimens or equipment emitting radiation doses equal to background levels (0.04 mRem/h) were exempt from special handling and disposal. RESULTS: The highest exposure rate was to the surgeon's hands from the breast injection site before skin incision (34.25 mRem/h). Exposure to the surgeon's torso measured 1.33 mRem/h, and exposure to the scrub nurse's torso measured 0.15 mRem/h from the injection site. Exposure to the pathologist's hands was 18.62 and 0.06 mRem/h from the lumpectomy specimen and sentinel node, respectively. Exposure to the pathologist's torso measured 0.34 and 0.04 mRem/h from the lumpectomy specimen and sentinel node, respectively. One hundred percent of lumpectomy specimens measured above the exempt level. Thirty-two of 46 (70%) sentinel lymph nodes emitted radiation equal to the exempt background level. Seventeen of 20 trash receptacles (85%) and 4 of 12 (33%) suction canisters measured equal to background levels. All operative instruments, pathology slides, and cryostat machines were equal to background levels. CONCLUSIONS: Radiation exposure to operating room personnel, pathologists, and operative equipment during a breast sentinel node biopsy using Tc99m is minimal. A primary surgeon can perform 2,190 hours, a scrub nurse 33,333 hours, and a pathologist 14,705 hours of procedural work before surpassing Occupational Safety and Health Administration limits. Operative instruments, pathology slides, and cryostat machines do not require special handling. All lumpectomy specimens should be stored for decontamination until the dose rate equals background levels. Intraoperative dose-rate monitoring allows selective decontamination of nodal specimens, trash receptacles, and suction canisters, which decreases disposal time and cost.

Air Pollutants, Radioactive↗
PubMed2003

Influences of parameter uncertainties within the ICRP-66 respiratory tract model: particle clearance.

Quantifying radiological risk following the inhalation of radioactive aerosols entails not only an assessment of particle deposition within respiratory tract regions but a full accounting of clearance mechanisms whereby particles may be translocated to adjacent respiratory tissue regions, absorbed to blood, or released to the gastrointestinal tract. The model outlined in ICRP Publication 66 represents to date one of the most complete overall descriptions of particle deposition and clearance, as well as localized radiation dosimetry, within the respiratory tract. In this study, a previous review of the ICRP-66 deposition model is extended to the study of the subsequent clearance model. A systematic review of the clearance component within the ICRP 66 respiratory tract model was conducted in which probability density functions were assigned to all input parameters for both 239PuO2 and 238UO2/238U3O8. These distributions were subsequently incorporated within a computer code LUDUC (Lung Dose Uncertainty Code) in which Latin hypercube sampling techniques are used to generate multiple (e.g., 1,000) sets of input vectors (i.e., trials) for all model parameters needed to assess mechanical clearance and particle dissolution/absorption. Integral numbers of nuclear disintegrations, U(s), in various lung regions were shown to be well-described by lognormal probability distributions. Of the four extrathoracic clearance compartments of the respiratory tract, uncertainties in U(s), expressed as the ratio of its 95% to 5% confidence levels, were highest within the LN(ET) tissues for 239PuO2 (ratio of 50 to 130) and within the ET(seq) tissues for 238UO2/238U3O8 (ratio of 12 to 50). Peak uncertainties in U(s) in these respiratory regions occurred at particle sizes of approximately 0.5-0.6 microm where uncertainties in ET2 particle deposition fractions accounted for only approximately 10% of the total U(s) uncertainty for 239PuO2, and only approximately 30% of the total U(s) uncertainty for 238UO2/238U3O8 (the remainder is attributed to the clearance model alone). Of the eight clearance compartments within the thoracic regions of the respiratory tract, and for particle sizes below approximately 5 microm, uncertainties in U(s) were highest within the LN(TH) tissues for 239PuO2 (ratio of 60 to 80) and within the BB(seq) tissues for 238UO2/238U3O8 (ratio of 20 and 60). At particle sizes exceeding approximately 5 microm in aerodynamic diameter, peak uncertainties in U(s) are noted for the AI, bb(seq), and bb1 clearance compartments. As the particle size approaches 10 microm in size, uncertainties in U(s) within these three thoracic tissue regions approach a factor of 1,000 and are dominated by corresponding uncertainties in particle deposition.

Aerosols↗
PubMed1991

Health effects of radon exposure. Report of the Council on Scientific Affairs, American Medical Association.

The consensus of scientists is that exposure to radon is hazardous, but disagreement exists about the effects of lower radon concentrations. Studies of underground miners have indicated that the risk of lung cancer increases in proportion to the intensity and duration of exposure to radon, and a recent authoritative report (BEIR IV) has concluded that estimates based on those studies are appropriate for estimating risks for occupants of homes. The BEIR IV report concluded that smoking cigarettes increases the risk of lung cancer associated with radon. Average radon levels in US homes range from 0.055 to 0.148 Bq/L (1.5 to 4 pCi/L), depending on the circumstances of measurement. Few studies have investigated health outcomes in occupants of homes with high radon levels. In advising patients about reducing the risks associated with radon, physicians should consider the costs, as well as the benefits, of remedial actions, and they should emphasize that, by far, the best way to avoid lung cancer is to stop smoking.

Air Pollutants, Radioactive↗
PubMed1973

Nuclear fuel hazards.

Explore the source record for details and available documents.

Air Pollution, Radioactive↗
PubMed1987

Smoking and radon.

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Air Pollutants↗
PubMed1999

Latency analysis in epidemiologic studies of occupational exposures: application to the Colorado Plateau uranium miners cohort.

BACKGROUND: Latency effects are an important factor in assessing the public health implications of an occupational or environmental exposure. Usually, however, latency results as described in the literature are insufficient to answer public health related questions. Alternative approaches to the analysis of latency effects are warranted. METHODS: A general statistical framework for modeling latency effects is described. We then propose bilinear and exponential decay latency models for analyzing latency effects as they have parameters that address questions of public health interest. Methods are described for fitting these models to cohort or case-control data; statistical inference is based on standard likelihood methods. APPLICATION: A latency analysis of radon exposure and lung cancer in the Colorado Plateau uranium miners cohort was performed. We first analyzed the entire cohort and found that the relative risk associated with exposure increases for about 8.5 years and thereafter decreases until it reaches background levels after about 34 years. The hypothesis that the relative risk remains at its peak level is strongly rejected (P < 0.001). Next, we investigated the variation in the latency effects over subsets of the cohort based on attained age, level and rate of exposure, and smoking. Age was the only factor for which effect modification was demonstrated (P = 0.014). We found that the decline in effect is much steeper at older ages (60+ years) than younger. CONCLUSION: The proposed methods can provide much more information about the exposure-disease latency effects than those generally used.

Air Pollutants, Radioactive↗
PubMed1999

Radiation safety in the cardiac catheterization laboratory: operational radiation safety.

The goal of the catheterization laboratory radiation safety program is to facilitate invasive cardiology while simultaneously reducing staff risks to an acceptable level. Achieving this goal requires a balance between the value of catheterization to the patient and the associated radiation risk to the staff. This article introduces the principles of radiation protection as applied in the catheterization laboratory. Prudent conformance to these principles will appropriately reduce radiation risk. Cathet. Cardiovasc. Intervent. 47:347-353, 1999.

Air Pollution, Radioactive↗
PubMed1991

Seasonal indoor radon variations related to precipitation.

Indoor radon concentrations show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, in northern Virginia, the summer of 1988 was wetter than the summer of 1987. Consequently, the regional indoor radon during the summer of 1988 was about 30% higher than during the summer of 1987, and indoor radon during the summer of 1988 actually exceeded the indoor radon level of the 1987-1988 winter.

Air Pollutants, Radioactive↗
PubMed2002

Revealed preference valuation compared to contingent valuation: radon-induced lung cancer prevention.

This paper explores and compares two tools of economic valuation, revealed preference and contingent valuation, with the purpose of ultimately informing the use of two methods of economic evaluation, CEA and CBA. The valuation methods are applied to empirical data for radon-induced lung cancer prevention. However, only the single bound CV and the subjective revealed preference estimates have overlapping confidence intervals, indicating that they do have external validity as assessed by convergent validity. The revealed preference subjective risk valuation was (180 pounds sterling (144 pounds sterling, 247 pounds sterling)) and the single bounded contingent valuation estimate was (269 pounds sterling (201 pounds sterling, 343 pounds sterling)).

Air Pollutants, Radioactive↗
PubMed2003

TP53 mutations in workers exposed to occupational carcinogens.

In some cases, evidence exists that exogenous carcinogenic exposures contribute to the mutation spectrum of the TP53 gene (p53) in human cancers. Although the clearest examples come from dietary and environmental sources, only a restricted number of papers have concentrated specifically on TP53 mutations in tumors from workers exposed to occupational carcinogens. In populations exposed to dietary aflatoxin B1 with liver cancer (AFB1) and ultraviolet (UV)-radiation with skin cancer, a single specific-looking TP53 mutation has been described in some of the tumors. Whether these fingerprints in the TP53 gene can be used to reveal an occupational etiology remains to be shown. In other cases, although differences in the TP53 mutation spectrum exist, they are more diffuse and difficult to interpret at this point. For instance, cigarette smoking seems to induce long-lasting molecular footprints in TP53. However, their use to rule out other occupational exposures as etiological factors in occupational cancers is still very questionable, especially due to the putative synergistic effects of cigarette smoke with other carcinogens. Although interesting implications of possible typical mutation spectra among cancers with other occupational etiologies exist, the data are scanty and await further development of TP53 mutation databases.

Air Pollutants, Radioactive↗
PubMed2004

Risk of lung cancer and residential radon in China: pooled results of two studies.

Studies of radon-exposed underground miners predict that residential radon is the second leading cause of lung cancer mortality; however, case-control studies of residential radon have not provided unambiguous evidence of an association. Owing to small expected risks from residential radon and uncertainties in dosimetry, large studies or pooling of multiple studies are needed to fully evaluate effects. We pooled data from 2 case-control studies of residential radon representing 2 large radon studies conducted in China. The studies included 1050 lung cancer cases and 1996 controls. In the pooled data, odds ratios (OR) increased significantly with greater radon concentration. Based on a linear model, the OR with 95% confidence intervals (CI) at 100 Becquerel/cubic-meter (Bq/m(3)) was 1.33 (1.01,1.36). For subjects resident in the current home for 30 years or more, the OR at 100 Bq/m(3) was 1.32 (1.07,1.91). Results across studies were consistent with homogeneity. Estimates of ORs were similar to extrapolations from miner data and consistent with published residential radon studies in North American and Europe, suggesting long-term radon exposure at concentrations found in many homes increases lung cancer risk.

Aged↗
PubMed1994

Childhood cancer incidence in relation to distance from the former nuclear testing site in Semipalatinsk, Kazakhstan.

Rates of childhood cancer between 1981 and 1990 in the 4 administrative zones of Kazakhstan were studied to assess the relationship, if any, with distance from nuclear testing sites. Risk of various cancers among children aged 14 years or younger were estimated in relation to distance from (1) a site where testing in air was performed before 1963, (2) a site where underground testing took place thereafter, and (3) a reservoir, known as "Atom Lake," created by 4 nuclear explosions in 1965. Risk of acute leukaemia rose significantly with increasing proximity of residence to the testing areas, although the absolute value of the risk gradient was relatively small. The relative risk for those living less than 200 km from the air-testing site was 1.76 compared with those living 400 km or more away from the site. Similar relative risks were observed for the underground site and "Atom Lake." There was also some evidence of increased risk of brain tumours in association with proximity to the test sites. In 2 of the 4 zones studied, there was substantial regional variation in acute leukaemia rates which was not attributable to distance from the test site. The findings may be affected by potential confounders, notably urban/rural status and ethnic factors.

Adolescent↗
PubMed2002

On the potential of measurement error to induce differential bias on odds ratio estimates: an example from radon epidemiology.

It is well established that odds ratios estimated by logistic regression are subject to bias if exposure is measured with error. The dependence of this bias on exposure parameter values, particularly for multiplicative measurement error, and its implications in epidemiology are not, however, as fully acknowledged. We have been motivated by a German West case-control study on lung cancer and residential radon, where restriction to a subgroup exhibiting larger mean and variance of exposure than the entire group has shown higher odds ratio estimates as compared to the full analysis. By means of correction formulae and simulations, we show that bias from additive classical type error depends on the exposure variance, not on the exposure mean, and that bias from multiplicative classical type error depends on the geometric standard deviation (in other words on the coefficient of variation of exposure), but not on the geometric mean of exposure. Bias from additive or multiplicative Berkson type error is independent of exposure distribution parameters. This indicates that there is a potential of differential bias between groups where these parameters vary. Such groups are commonly compared in epidemiology: for example when the results of subgroup analyses are contrasted or meta-analyses are performed. For the German West radon study, we show that the difference of measurement error bias between the subgroup and the entire group exhibits the same direction but not the same dimension as the observed results. Regarding meta-analysis of five European radon studies, we find that a study such as this German study will necessarily result in smaller odds ratio estimates than other studies due to the smaller exposure variance and coefficient of variation of exposure. Therefore, disregard of measurement error can not only lead to biased estimates, but also to inconsistent results and wrongly concluded effect differences between groups.

Air Pollutants, Radioactive↗
PubMed1993

Synthetic cancer variables and the construction and testing of synthetic risk maps.

Cancer cluster investigations are usually univariate in nature; they focus on a particular cancer, such as leukaemia, and attempt to determine whether excess risk is associated with a suspected cancer-causing agent. Although several causes of death (such as leukaemia, lymphoma, Hodgkin's) may be considered, the approach is univariate because the causes of death are analysed sequentially and independently of one another. This approach is consistent with a one-cause one-effect model. Rarely, however, is the action of a carcinogen manifested at only one body site, and correlations among causes of death are the norm rather than the exception. A multiple effects model is therefore appropriate, and the multivariate nature of cancer mortality data should be exploited when exploring geographic pattern in cancer risks. This paper describes such an approach. We construct maps based on a principal components analysis of cancer mortality rates from different geographic areas. The resulting principal components are called synthetic cancer variables (SCVs), and maps of the SCV scores are synthetic risk maps (SRMs). These maps quantify geographic variation in cancer risk at several body sites simultaneously, and may be analysed for (1) spatial structure and (2) geographic association with potential risk factors. As an example, we use synthetic risk maps to determine whether high-risk counties in Illinois cluster near nuclear facilities. Much work remains to be done, but synthetic cancer risk maps appear to be a useful tool for quantifying geographic pattern and multivariate structure in cancer mortality.

Air Pollutants, Radioactive↗
PubMed2001

Radon levels in abandoned metalliferous mines, Devon, southwest England.

Radon levels underground in two abandoned mines in Devon, United Kingdom, are reported and analyzed. Extremely high levels have been noted, 7,100,000 Bq m(-3) being the highest level recorded. This is approximately 89 times higher than the highest published radon level for caves and mines in Devon and Cornwall, England, which is 80,000 Bq m(-3). These levels have significant health implications for both casual and occupational mine explorers.

Air Pollutants, Radioactive↗