Thyroid dose reconstruction for the population of Belarus after the Chernobyl accident

An ¹³¹I environmental transfer model – adapted for Belorussian conditions – was applied to estimate thyroid doses for different population groups. For this purpose the available data were analysed and the important radioecological parameters assessed, i.e. (a) the elimination rate of ¹³¹I from grass due to weathering and growth dilution, (b) the initial interception of ¹³¹I by vegetation, (c) the transfer coefficient for ¹³¹I from grass to cow's milk, (d) the yield of pasture grass and (e) the milk consumption rate. Additionally, the influence of applied countermeasures has been taken into account, such as the interruption of locally produced milk consumption, and the appropriate correction factors have been estimated. As a result, the average age-dependent thyroid doses were assessed for the Belorussian population. The highest average doses in children (> 1 Gy) have been estimated for the Bragin, Khoiniki, Narovlia and Vetka raions of the Gomel oblast. The thyroid exposure tends to decrease from the southeastern (closest to the Chernobyl nuclear power plant areas) to the northwestern part of the republic. When comparing the assessed thyroid doses with dose estimates derived from direct ¹³¹I activity measurements in thyroids (for the locations with more than 15 direct measurements), the results agree fairly well. The model calculation may perhaps overestimate thyroid doses of the population residing in the settlements of the central and northern parts of Belarus, distant from the areas with direct measurements of ¹³¹I activities in soil, grass and milk. These thyroid dose estimates may serve as a basis for further epidemiological studies and risk analyses.     

Post-Chornobyl thyroid cancers in Ukraine. Report 1: estimation of thyroid doses

About 1.8 EBq of 131I was released into the atmosphere during the Chornobyl accident that occurred in Ukraine on April 26, 1986. More than 10% of this activity was deposited on the territory of Ukraine. Beginning 4-5 years after the accident, an increase in the incidence of thyroid cancer among children, believed to be caused in part by exposure to 131I, has been observed in different regions of Ukraine. A three-level system of thyroid dose estimation was developed for the reconstruction of thyroid doses from 131I for the entire population of Ukrainian children aged 1 to 18 at the time of accident: (1) At the first level, individual doses were estimated for the approximately 99,000 children and adolescents with direct measurements of radioactivity in the thyroid (so-called direct thyroid measurements) performed in May-June of 1986; (2) at the second level, group doses by year of age and by gender were estimated for the population of 748 localities (with 208,400 children aged 1-18 in 1986) where direct thyroid measurements of good quality were performed on some of the residents; and (3) at the third level, group doses by age and by gender were estimated for the population of the localities where no thyroid measurements were made in 1986. The third-level doses were then aggregated over the population of each oblast. Data, models and procedures required for each level of thyroid dose estimation are described in the paper. At the first level, individual doses were found to range up to 27,000 mGy, with geometric and arithmetic means of 100 and 300 mGy, respectively. At the second level, group doses were found to be highest for the younger children (aged 1 to 4 years); doses for the older children (aged 16 to 18 years) were 3.5 times smaller. At the third level, average population-weighted doses were found to exceed 35 mGy in the five northern oblasts closer to the Chornobyl reactor site; to be in the 14- to 34-mGy range in seven other oblasts, Kyiv city and Crimea; and to be less than 13 mGy in all other oblasts.     

Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report II: dose estimates for the Ukrainian population

This paper describes the revision of the thyroid dosimetry system in Ukraine using new, recently available data on (i) revised ¹³¹I thyroid activities derived from direct thyroid measurements done in May and June 1986 in 146,425 individuals; (ii) revised estimates of ¹³¹I ground deposition density in each Ukrainian settlement; and (iii) estimates of age- and gender-specific thyroid masses for the Ukrainian population. The revised dosimetry system estimates the thyroid doses for the residents of the settlements divided into three levels depending on the availability of measurements of ¹³¹I thyroid activity among their residents. Thyroid doses due to ¹³¹I intake were estimated in this study for different age and gender groups of residents of 30,353 settlements in 24 oblasts of Ukraine, Autonomous Republic Krym, and cities of Kyiv and Sevastopol. Among them, dose estimates for 835 settlements were based on ¹³¹I thyroid activities measured in more than ten residents (the first level), for 690 settlements based on such measurements done in neighboring settlements (the second level), and for 28,828 settlements based on a purely empirical relationship between the thyroid doses due to ¹³¹I intake and the cumulative ¹³¹I ground deposition densities in settlements (the third level). The arithmetic mean of the thyroid doses due to ¹³¹I intake among 146,425 measured individuals was 0.23 Gy (median of 0.094 Gy); about 99.8% of them received doses less than 5 Gy. The highest oblast-average population-weighted thyroid doses were estimated for residents of Chernihiv (0.15 Gy for arithmetic mean and 0.060 Gy for geometric mean), Kyiv (0.13 and 0.051 Gy) and Zhytomyr (0.12 and 0.049 Gy) Oblasts followed by Rivne (0.10 and 0.039 Gy) and Cherkasy (0.088 and 0.032 Gy) Oblasts, and Kyiv City (0.076 and 0.031 Gy). The geometric mean of thyroid doses estimated in this study for the entire Ukraine essentially did not change in comparison with a previous estimate, 0.020 vs. 0.021 Gy, respectively. The ratio of geometric mean of oblast-specific thyroid doses estimated in the present study to previously calculated doses varied from 0.51 to 3.9. The highest increase in thyroid doses was found in areas remote from the Chornobyl nuclear power plant with a low level of radioactive contamination: by 3.9 times for Zakarpatska Oblast, 3.5 times for Luhansk Oblasts and 2.9 times for Ivano-Frankivsk Oblast. The developed thyroid dosimetry system is being used to revise the thyroid doses due to ¹³¹I intake for the individuals of post-Chornobyl radiation epidemiological studies: the Ukrainian-American cohort of individuals exposed during childhood and adolescence, the Ukrainian in utero cohort, and the Chornobyl Tissue Bank.

     

Measurement of <Superscript>131</Superscript>I activity in air indoor Polish nuclear medical hospital as a tool for an internal dose assessment

This paper presents results of ¹³¹I air activity measurements performed within nuclear medical hospitals as a tool for internal dose assessment. The study was conducted at a place of preparation and administration of ¹³¹I (“hot room”) and at a nurse station. ¹³¹I activity measurements were performed for 5 and 4 consecutive working days, at the “hot room” and nurse station, respectively. Iodine from the air was collected by a mobile HVS-30 aerosol sampler combined with a gas sampler. Both the gaseous and aerosol fractions were measurement. The activities in the gaseous fraction ranged from (28?±?1 Bq m^?3) to (492?±?4) Bq m^?3. At both sampling sites, the activity of the gaseous iodine fraction trapped on activated charcoal was significantly higher than that of the aerosol fraction captured on Petrianov filter cloth. Based on these results, an attempt has been made to estimate annual inhalation effective doses, which were found to range from 0.47 mSv (nurse female) to 1.3 mSv (technician male). The highest annual inhalation equivalent doses have been found for thyroid as 32, 27, 13, and 11 mSv, respectively, for technician male, technical female, nurse male, and nurse female. The method presented here allows to fill the gaps in internal doses measurements. Moreover, because method has been successful used for many years in radioactive contamination monitoring of air in cases of serious nuclear accidents, it should also be used in nuclear medicine.     

A radioecological model for thyroid dose reconstruction of the Belarus population following the Chernobyl accident

A radioecological model was developed to estimate thyroid exposures of the Belarus population following the Chernobyl accident. The input of the model includes an extensive data set of the ¹³⁷Cs activity per unit area deposited during the Chernobyl accident, the rainfall data for different regions of Belarus, the ¹³¹I/¹³⁷Cs ratio in the deposit and the start of the grazing period in Belarus in April/May 1986. The output of the model is the age-dependent thyroid exposure due to the intake of ¹³¹I with fresh milk. Age-dependent average thyroid doses were assessed for selected regions of Belarus. The maximum thyroid doses were estimated for the inhabitants of Gomel oblast where the highest deposition was observed among the regions considered here. The lowest doses were estimated for Vitebsk oblast with the lowest level of depositions. The mean exposures for the oblasts of Grodno, Minsk, Mogilev and Brest were very similar. The results were compared with estimations of thyroid exposure that were based on ¹³¹I measurements in human thyroids, and they are in good agreement. The model may be used for the assessment of thyroid doses in Belarus for areas where no ¹³¹I measurements are available.     

Thyroid dose and thyroid cancer incidence after the Chernobyl accident: assessments for the Zhytomyr region (Ukraine)

In the Zhytomyr region, about 52 000 measurements of the ¹³¹I activity in thyroids were performed. On the basis of these measurements, individual doses have been assessed for the people monitored and age-dependent average doses have been estimated for those settlements with more than 11 direct measurements. In order to estimate the pattern of thyroid exposure in the Zhytomyr region, these doses have been interpolated or extrapolated to population groups who were not monitored during May–June 1986. For this purpose, a model has been developed based on a correlation between thyroid dose estimates with the ¹³⁷Cs deposition and the co-ordinates of the settlements relative to Chernobyl. Collective doses of people who were born in the years 1968 to 1986 were calculated. The radiation-induced thyroid cancer incidence in the period 1991 to 1995 was assessed by subtracting the spontaneous incidence from the observed incidence. The result is considerably lower than that observed in longer periods after external exposures. Possible reasons for this difference are discussed. Received: 17 January 1997 / Accepted in revised form: 2 October 1997     

Measurement of <Superscript>131</Superscript>I activity in thyroid of nuclear medical staff and internal dose assessment in a Polish nuclear medical hospital

This paper presents results of ¹³¹I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined ¹³¹I activity was found to be above the detection limit (DL = 5 Bq of ¹³¹I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.     

<Superscript>131</Superscript>I age-dependent inhalation dose in Southern Poland from Fukushima accident

A general method for calculating doses absorbed from isotopes released in nuclear accidents is presented. As an example, this method was used to calculate doses for inhabitants of Southern Poland due to inhalation of ¹³¹I released due to the Fukushima nuclear plant accident. ¹³¹I activity measurements in the air of that region provided the basis for the study. The proposed model is based on a complex biokinetic model for iodine merging the Leggett model developed in 2010 with the human respiratory tract and gastrointestinal tract models recommended by the International Commission on Radiological Protection (ICRP). This model is described here, and it is demonstrated that resulting dose estimates are consistent with those obtained using the ICRP methodology. Using the developed model, total doses were calculated for six age groups of both genders, for gaseous and aerosol fractions alike. The committed effective dose, H ₅₀, for an adult man reached 16 nSv, which is lower than 0.001% of the background dose. The dose for the thyroid of an adult reached 0.33 μSv, which corresponds to circa 0.0007% of the dose to the population of Southern Poland after the Chernobyl nuclear plant accident.     

Estimation of 131I thyroid doses for the evacuees from Pripjat

  The thyroid doses of 49 360 inhabitants of Pripjat evacuated after the accident at Chernobyl were reconstructed. During their evacuation most of the evacuees passed through highly contaminated territories. The evaluation of a large-scale public survey showed that only about 50% of the evacuees had left the contaminated areas within 5 days and that 30% of them stayed there for more than 30 days. As a first step, the model of dose estimations was improved, and thyroid doses were assessed for the group of evacuees for whom the ¹³¹I activity in the thyroids was measured. The ¹³¹I incorporation during the first 5 days after the accident was described by a single-intake model (inhalation); later incorporations were assumed to be proportional to the radioiodine activity in milk. As a second step, the correlation between the calculated doses and individual parameters (place of residence in Pripjat, intake of stable iodine, and age at the time of the accident) was described by an empirical equation. This equation was applied to all evacuees who completed the questionnaires of the public survey. Previous dose assessments were found to overestimate the thyroid doses especially for the younger evacuees. On the basis of these estimations, collective doses and the resulting radiation risks for thyroid cancer were assessed for different age groups. Received: 28 November 1995 / Accepted in revised form: 6 March 1996     

Bone mineral density in residents of radioactive territories of Chelyabinsk Region

Operation of the Mayak plutonium production association resulted in radioactive contamination of a part of Chelyabinsk Region in the 1950–1960s. Significant gas-aerosol emission of ¹³¹I occurred since 1948; in 1957, a radiation accident resulted in ⁹⁰Sr contamination of large territories. This paper presents comparison of the bone mineral density of persons who lived on territories with different levels of ⁹⁰Sr-soil contamination with that of a control group. It was found that in 1970–1975, the bone mineral density, estimated from the mineral content in bone samples, in residents of contaminated areas born in 1936–1952 was significantly lower compared to the control group. For persons born in 1880–1935, such differences were not found. It was shown that the decrease in the bone mineral density was not related to ⁹⁰Sr exposure of osteogenic cells in the dose range from 0.1 to 1300 mGy: the coefficient of correlation between individual ⁹⁰Sr doses and bone mineral contents is not significant. The decrease in bone mineral density of persons born in 1936–1952 may be associated with exposure of the thyroid and parathyroid glands (systemic regulators of calcium metabolism) to ¹³¹I from gas-aerosol emissions from Mayak. The highest levels of gas-aerosol emissions occurred in 1948–1954 and coincided with the growth and development of the thyroid gland, characterized by intensive accumulation of ¹³¹I, and with the growth and maturation of the skeleton of persons born in the given calendar years.     

Influence of the external and internal radioactive contamination of the body and the clothes on the results of the thyroidal 131I measurements conducted in Belarus after the Chernobyl accident—Part 2: Monte Carlo simulation of response of detectors near the thyroid

This paper describes the calculation of the response of the most common types of radiation detectors that were used within the first few weeks after the Chernobyl accident to determine the activity of ¹³¹I in the thyroids of Belarusian subjects of an epidemiologic study of thyroid cancer. The radiation detectors, which were placed against the necks of the subjects, measured the exposure rates due to the emission of gamma rays resulting from the radioactive decay of ¹³¹I in their thyroids. Because of the external and internal radioactive contamination of the monitored subjects, gamma radiation from many radionuclides in various locations contributed to the exposure rates recorded by the detectors. To estimate accurately the contribution from gamma rays emitted from various internal and external parts of the body, the calibration factors of the radiation detectors, expressed in kBq per µR h^− 1, were calculated, by means of Monte Carlo simulation, for external irradiation from unit activities of 17 radionuclides located on 19 parts of the body, as well as for internal irradiation from the same 17 radionuclides in the lungs, from caesium radionuclides distributed uniformly in the whole body, and from ¹³¹I in the thyroid. The calculations were performed for six body sizes, representative of the age range of the subjects. In a companion paper, the levels of external and internal contamination of the body were estimated for a variety of exposure conditions. The results presented in the two papers were combined to calculate the ¹³¹I activities in the thyroids of all 11,732 Belarusian study subjects of an epidemiologic study of thyroid cancer and, in turn, their thyroid doses.

     

Physical and radiobiological bases of the use of125I in the management of thyrotoxicosis

Increasing interest is recently shown in the use of¹²⁵I as an alternative isotope to¹³¹I for the management of thyrotoxicosis based on the postulate that there is a relative sparing of the reproductive integrity of the thyroid follicular cell and a consequent possibility of smaller incidence of hypothyroidism after therapy. A review of the dosimetric, radiobiological and clinical aspects of the use of¹²⁵I are presented here.For the same activity though¹²⁵I gives smaller mean glanddose than¹³¹I, the dose computations at microscopic level have revealed that there is a preferential irradiation of the apical membrane compared to the nucleus of the follicular cell. The ratio of the dose to the apical membrane and that to the nucleus increases with the decrease of the percentage colloid mass of the gland. Radiobiological significance of this non-uniform dose distribution across a follicular cell, with¹²⁵I, is brought out using rat thyroid as the biological system. For the same mean gland dose the follicular cell survival is larger with¹²⁵I than with¹³¹I. 24 h radioiodine uptake is reduced in case of¹²⁵I treatment whereas it is not affected with¹²⁵I. Pilot clinical trials using¹²⁵I for the management of thyrotoxicosis are underway in some centres. Preliminary results from centres using doses 3–4 times that of the conventional¹³¹I dose are not very different from those with conventional¹³¹I therapy. Centres that used doses same as or less than the conventional¹³¹I doses, reported smaller incidence of hypothyroidism.Alexander von Humboldt Fellow in Klinikum Steglitz, Berlin     

Thyroid dose assessment for the Chernigov region (Ukraine): Estimation based on131I thyroid measurements and extrapolation of the results to districts without monitoring

Based on the results of¹³¹I thyroid activity measurements in three districts of the Chernigov region (Ukraine), individual doses were calculated and an approach of the age dependence of the average thyroid exposure was derived. Using the relationships between the thyroid doses and the¹³⁷Cs deposition as well as the location relative to the Chernobyl Nuclear Power Plant (NPP), age-dependent average thyroid doses were extrapolated also for those settlements of this region where no monitoring measurements have been carried out. The highest doses were found in the west of the region with the lowest distance to the Chernobyl NPP. In this part, the highest mean of the thyroid dose in a settlement was 3.3 Gy for infants and 0.5 Gy for adults. The collective thyroid dose was 31000 and 27 000 person-Gy for children and adults, respectively. Based on this assessment, 140 and 21 excess thyroid cancer cases are predicted for children and adults, respectively. In the years 1989 to 1991, in the whole contaminated territory of the Ukraine 0.4–1.2 cases per 100000 children were observed. Although the absolute numbers are very small, this indicates the possibility of an increase in thyroid cancer morbidity among children. The same trend also seems to be indicated in the Chernigov region. A careful epidemiological study in the future is necessary to enable a final evaluation of radioinduced cancers in this region.     

Estimation of I131 doses absorbed by the thyroid in the period from May to June 1986

In a randomly selected group of subjects the uptake of iodine radioisotopes was measured over the thyroid in the period May 6-23, 1986. From the obtained results the doses were estimated which were absorbed from April 28, 1986 until the time of complete disappearance of I131 from the thyroid. The highest dose of radiation absorbed from I131 by the thyroid was found in the youngest group (children aged 5 to 12 years) and it was 227.8 mGy (about 23 rads).     

Mutagenicity of diagnostic and therapeutical doses of radiopharmaceutical iodine-131 in Wistar rats

Iodine-131 (¹³¹I) is a radioisotope used for the diagnosis and treatment of thyroidal disorders such as hyperthyroidism and cancer. During its decay, ¹³¹I emits beta particles and gamma rays; its physical half-life is 8 days, and it is accumulated preferentially in the thyroid tissue. This study aimed to evaluate the cytotoxicity and mutagenicity of diagnostic and therapeutic doses of ¹³¹I using bone marrow cells of rats treated in vivo in a test system with a single dose by gavage. Concentrations of 5, 25, 50 and 250 μCi in 1 ml of water were used, and after 24 h, the animals were killed. Also, a concentration of 25 μCi/ml of water was used, and the animals were killed after 5 days. The results showed that no concentration of ¹³¹I was cytotoxic and that all concentrations were mutagenic. As a result, there was no statistically significant difference detected by the χ² test in the induction of chromosomal aberrations between the different doses. Thus, the present study demonstrated a significant increase in chromosomal aberration in bone marrow cells exposed to ¹³¹I regardless of the dose or the treatment time.     

Changes in the proliferative activity in the brain of offspring rats induced by the influence of131I on the maternal organism

We tested the effects of injections of small doses of¹³¹I (150 μCi) into female rats on brain development in their offspring. The brains of rats whose embryogenesis was influenced by incorporated¹³¹I were studied with the use of an immunohistochemical technique (monoclonal antibodies to nuclear antigen of cell proliferation). Single injections of¹³¹I in the above dose were shown to noticeably suppress the cell proliferative activity in a few structures of the brain of newborn rats. The most significant drop in the proliferative index in the external layers of the cerebellum was observed after¹³¹I injections performed on the 16th day of embryogenesis (when the embryonal thyroid gland begins its functioning).     

Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?

One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (¹³¹I) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the ¹³¹I-related risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiation-related risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer.     

NLR、PLR与分化型甲状腺癌术后131I清甲效果的关系及其预测价值分析

摘要 目的：探讨中性粒细胞/淋巴细胞比值（NLR）、血小板/淋巴细胞比值（PLR）与分化型甲状腺癌（DTC）术后碘131（¹³¹I）清甲治疗效果的关系及对DTC术后¹³¹I清甲效果的预测价值。方法：选择2019年3月至2021年12月在江苏大学附属徐州医院行甲状腺切除术且术后进行¹³¹I清甲治疗的DTC患者150例为研究对象,根据¹³¹I清甲治疗效果分为清甲成功组（107例）和清甲未成功组（43例）,通过检查血常规获得中性粒细胞计数、血小板计数、淋巴细胞计数并计算NLR、PLR,比较两组NLR、PLR;采用单因素及多因素logistics回归模型分析¹³¹I清甲疗效的影响因素,采用受试者工作特征曲线（ROC）分析NLR、PLR对¹³¹I清甲治疗效果的预测价值。结果：清甲成功组NLR、PLR低于清甲未成功组（P＜0.05）,单因素分析显示清甲成功组促甲状腺激素（TSH）高于清甲未成功组,甲状腺球蛋白（Tg）水平低于清甲未成功组,清甲成功组病灶最大径小于清甲未成功组（P＜0.05）;多因素logistics回归分析显示,高NLR、PLR、Tg是¹³¹I清甲治疗失败的独立危险因素（P＜0.05）;NLR、PLR及联合检测预测¹³¹I清甲治疗效果的ROC曲线下面积（AUC）分别为0.760、0.732、0.829,NLR与PLR联合检测的AUC高于二者单独检测。结论：高NLR、PLR是DTC术后¹³¹I清甲未成功的独立危险因素,早期检测NLR、PLR对DTC术后¹³¹I清甲治疗效果具有较好的预测价值。     

不同剂量131I对分化型甲状腺癌患者摄碘率、甲状腺激素水平及生活质量的影响

摘要 目的：探讨不同剂量¹³¹I对分化型甲状腺癌（DTC）患者摄碘率、甲状腺激素水平及生活质量的影响。方法：选取2018年6月～2020年6月我院收治的DTC患者100例,均接受¹³¹I清甲治疗,根据放射剂量的不同分为小剂量组（100mci）和大剂量组（150mci）,例数均为50例。比较两组患者摄碘率、甲状腺激素水平、肝肾功能、生活质量和不良反应发生率。结果：小剂量组2 h、6 h、24 h的摄碘率高于大剂量组（P<0.05）。小剂量组的清甲率高于大剂量组（P<0.05）。两组治疗1个月后促甲状腺激素（TSH）、游离三碘甲状腺原氨酸（FT3）、甲状腺球蛋白（TG）水平下降（P<0.05）;小剂量组治疗1个月后TSH、FT3、TG水平低于大剂量组（P<0.05）。两组治疗前、治疗1个月后的组间、组内门冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、碱性磷酸酶（ALP）、血清尿素（Urea）、肌酐（Cr）、尿酸（UA）水平对比,差异均无统计学意义（P>0.05）。小剂量组的生活质量优良率高于大剂量组（P<0.05）。小剂量组的不良反应发生率低于大剂量组（P<0.05）。结论：不同剂量¹³¹I清甲治疗对DTC患者肝肾功能无明显影响,但选用100mci剂量可提高DTC患者摄碘率,减轻对甲状腺功能的损害,同时还可提高患者的生活质量,减少不良反应发生率。     

Evaluation of equivalent body burden in the thyroid for the people of Poland on results of 131I absorption after the disaster in Czernobyl. Determination of thyroid blockade with potassium iodide]

An assessment of effectiveness of the administering of single dose of stable iodine in Poland on the reduction of 131I doses in thyroid has been performed. 5-compartment model of metabolism of iodine developed by Johnson has been used to evaluate predicted levels of stable iodine and 131I content in thyroid and commitment dose equivalent H50 for different doses of stable iodine and various age and sex group population. The measured values of 131I concentration in air and in milk and standard values for milk and food consumption and inhalation rate as well as metabolic parameters were used. Theoretical calculations showed that administering of stable iodine on 1986-04-28, 1986-04-29, 1986-04-30 and 1986-05-01 could have reduced committed dose equivalent H50 form ingestion with inhalation pathway by about 44%, 40%, 26%, 12% respectively. On the basis of measured 131I activity in the thyroid for inhabitants from different districts in Poland (1400 measurement) committed dose equivalents were determined and analysis of radiation hazard from 131I were performed. In the most contaminated regions of Poland average H50 doses for children 1-5 and 5-10 years old are close to 50 mSv (permissible level for population) and maximal doses exceed this limit four times. These maximal doses occurred for about from 5% inhabitants from these area. In the moderate and low contaminated regions of Poland the average doses are fivefold and tenfold less respectively.