The Chernobyl accident resulted in a number of cases of thyroid cancer in females under the age of 20 y. Many of these individuals were treated with surgical removal of the thyroid gland followed by 131I ablation of residual thyroid tissue. Epidemiologic evidence demonstrates that 131I treatment for thyroid cancer or hyperthyroidism in adult women confers negligible risk of breast cancer. However, comparable data for younger women do not exist. Studies of external radiation exposure indicate that, for radiation exposures of as low as 0.2-0.7 Gy, the risk of breast cancer is greater for infant and adolescent female breast tissues than for adult female breast tissues. METHODS: The effective half-time of 131I measured in athyrotic patients was used together with the OLINDA/EXM computer code to estimate doses to breast tissue in 10-y-old, 15-y-old, and young adult females from ablation treatment. RESULTS: The dose to pediatric and young adult female breast tissue associated with a 5.6-GBq (150 mCi) ablation treatment may range from 0.35 to 0.55 Gy, resulting in a lifetime risk of breast cancer ranging from 2-4 cases per 100 such individuals exposed and a lifetime risk of solid tumors ranging from 8 to 17 solid tumors per 100 such individuals exposed. Administration of multiple ablation treatments, as often occurs with metastases, could result in doses ranging from 0.7 to 1 Gy, with corresponding increases in the lifetime cancer risk. CONCLUSION: These estimates suggest the need for additional research and a possible need for surveillance of young Chernobyl thyroid cancer patients who received 131I ablation treatment.
The level of radiation exposure in children in Belarus caused by the Chernobyl accident was investigated on the basis of whole body 137Cs count. The subjects were 10,062 children (4,762 boys and 5,300 girls) in Mogilev and Gomel, Belarus, who received Chernobyl Sasakawa Health and Medical Cooperation Project health examinations from May 1991 to December 1992 and who were 5-16 y old at the time of examination. The median whole body 137Cs count per body weight varied from 21-48 Bq kg-1 and from 28-126 Bq kg-1 in Mogilev oblast and Gomel oblast, respectively. (The "oblast" is the largest administrative district constituting the country. Belarus consists of 6 oblasts). Corresponding annual effective dose equivalents were all less than the public dose limit of 1 mSv y-1, but the observed levels in the children were considerably higher than the average level of 2.3 Bq kg-1 reported in the past for the former Soviet Union.
Comment In: Health Phys. 1995 May;68(5):733-57730075
Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated (89,90)Sr, the EPR and FISH assays were supported by measurements of (90)Sr-body burdens and estimates of (90)Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from (137)Cs incorporated in donors' soft tissues. It is shown here that the TRDS-based absorbed doses in tooth enamel and muscle are in agreement with EPR- and FISH-based estimates within uncertainty bounds. Basically, this agreement between the estimates has confirmed the validity of external doses calculated with the TRDS.
This study was carried out to assess the annual per capita effective dose from medical diagnostic procedures using computed tomography (CT) in Canada. Relevant data concerning the nature and the frequency of various diagnostic CT examinations were obtained from the reports on Medical Imaging in Canada and Diagnostic Services in Ontario. Doses associated with examinations of different types were based primarily on typical effective doses used in the National Council on Radiation Protection and Measurements Report 160 with considerations of limited dose information surveyed in Canada. The results show that the per capita annual effective dose from diagnostic CT exams was 0.74 mSv in 2006, up from 0.19 mSv in 1991. This significant increase in population radiation dose from CT scans is due mainly to a more than doubling in the examination rate and to a higher radiation dose per procedure from the newer generation of multi-detector CTs.
The Chernobyl fallout is an enduring challenge to reindeer husbandry in Norway, and South Sámi reindeer herders in central and southern Norway are as contaminated by (137)Cs as inhabitants close to Chernobyl. Therefore, Norwegian authorities continuously recommend to these reindeer herders the use of countermeasures to reduce their intake of (137)Cs. In this study, the authors have applied data on contamination levels in reindeer, results of dietary surveys, and whole body monitoring data in low and high contaminated areas to estimate the effectiveness of countermeasures and resulting averted doses to the reindeer herders. In the most contaminated area, the various countermeasures applied reduced radiocesium ingestion doses during 1986-2009 by about 73%, to an integrated dose of about 17 mSv. However, to comply with the recommended (137)Cs ingestion dose limit of 1 mSv y(-1), the study indicates that reindeer herders in the most contaminated areas will need to carry on with their countermeasures for another 10-15 y. Furthermore, the study indicates that whole body monitoring is an important tool to assess individual doses and countermeasure effectiveness in long-term management of a contamination situation and that such monitoring may be required to reach long-term reference levels.
A variety of anthropometric measurements was made in a randomized population sample of middle-aged women in five age strata in whom body composition was estimated from total body potassium and total body water determined by whole body counting and isotope dilution technique, respectively. No significant differences with age were found for total body potassium or total body water. A significant age difference was found for body fat mass. Simple linear correlations between anthropometric variables and body fat mass estimates were found to be 0.90, 0.86, 0.77 for body weight, buttock circumference, and sum of triceps and subscapular skinfold thicknesses, respectively. Multiple regression analysis showed that these three variables accounted for 80 to 91% of the variation in body fat in the different age strata studied. Multiple regression equations for prediction of body fat from anthropometric variables are given. In about two-thirds of the subjects, the difference between predicted body fat mass and estimated body fat mass was found to be less than +/- 2.5 kg.
Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11-90; measurements were performed in 2006-2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20-50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20-30 years- 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60-80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy.