This section describes the spectrum and the scale of the nonmalignant diseases that have been found among exposed populations. Adverse effects as a result of Chernobyl irradiation have been found in every group that has been studied. Brain damage has been found in individuals directly exposed--liquidators and those living in the contaminated territories, as well as in their offspring. Premature cataracts; tooth and mouth abnormalities; and blood, lymphatic, heart, lung, gastrointestinal, urologic, bone, and skin diseases afflict and impair people, young and old alike. Endocrine dysfunction, particularly thyroid disease, is far more common than might be expected, with some 1,000 cases of thyroid dysfunction for every case of thyroid cancer, a marked increase after the catastrophe. There are genetic damage and birth defects especially in children of liquidators and in children born in areas with high levels of radioisotope contamination. Immunological abnormalities and increases in viral, bacterial, and parasitic diseases are rife among individuals in the heavily contaminated areas. For more than 20 years, overall morbidity has remained high in those exposed to the irradiation released by Chernobyl. One cannot give credence to the explanation that these numbers are due solely to socioeconomic factors. The negative health consequences of the catastrophe are amply documented in this chapter and concern millions of people.
Health effects as a result of the accident at the Chernobyl nuclear power plant occurred in 1986 are considered in the paper. Wrong prognosis of the health effects with respect to mortality and morbidity among the population exposed to low radiation doses is shown. Proven increase in thyroid cancer cases among people who were children aged from 0 to 18 at the time of the accident is shown. Linear relationship between thyroid cancer cases and dose to thyroid ranged from 0.2 to 4.0 Gy is considered. An additional absolute risk of thyroid cancer in children varies in the range 1.9-2.6 cases per 10(4) person-year Gy. During the fifteen years following the accident no cases of acute and chronic radiation sickness have been revealed because the population living in contaminated areas received low radiation doses. Also, exposures to low radiation doses did not result in excess of malignant tumors among population. In some cases the outcomes of acute radiation sickness were as follows: radiation damages to the skin, cancer cataracts, development of oncopathology.
In the context of oncologic therapy for children, radiation therapy is frequently indicated. This study identified the frequency of and reasons for the development of high-grade acute toxicity and possible sequelae.
Irradiated children have been prospectively documented since 2001 in the Registry for the Evaluation of Side Effects After Radiation in Childhood and Adolescence (RiSK) database in Germany and since 2008 in the registry for radiation therapy toxicity (RADTOX) in Sweden. Data were collected using standardized, published forms. Toxicity classification was based on Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria.
As of June 2013, 1500 children have been recruited into the RiSK database and 485 into the RADTOX registry leading to an analysis population of 1359 patients (age range 0-18). A total of 18.9% (n=257) of all investigated patients developed high-grade acute toxicity (grades 3/4). High-grade toxicity of the bone marrow was documented for 63.8% (n=201) of those patients, oral mucositis for 7.6% (n=24), and dermatitis for 7.6% (n=24). Patients with high-grade acute toxicity received concomitant chemotherapy more frequently (56%) than patients with no or lower acute toxicity (31.5%). In multivariate analyses, concomitant chemotherapy, diagnosis of Ewing sarcoma, and total radiation dose showed a statistically noticeable effect (P=.05) on acute toxicity, whereas age, concomitant chemotherapy, Hodgkin lymphoma, Ewing sarcoma, total radiation dose, and acute toxicity influenced the time until maximal late toxicity.
Generally, high-grade acute toxicity after irradiation in children and adolescence occurs in a moderate proportion of patients (18.9%). As anticipated, the probability of acute toxicity appeared to depend on the prescribed dose as well as concomitant chemotherapy. The occurrence of chronic toxicity correlates with the prior acute toxicity grade. Age seems to influence the time until maximal late toxicity but not the development of acute toxicity.
BACKGROUND: The number of CT examinations performed in Denmark increased from 14,500 examinations in 1979 to 301,617 in 2005. This implies increased radiation dose to the population. On this background, an analysis of the practice for CT examinations including potential limitations of radiation exposure and the associated risk is needed. PURPOSES: To analyse 1) the current use of CT in a university department compared to 1996, 2) the radiation dose and risk associated with the examinations and 3) the use of CT in Denmark since 1979. MATERIAL AND METHODS: The administrative data of CT examinations performed in the Department of Radiology, Aarhus Sygehus, during 2005 and 1996, respectively, were obtained. Additionally national CT data were obtained from the database at the National Board of Health. RESULTS: In 1996 1,840 patients obtained 5,538 CT examinations at Aarhus Sygehus. Their mean age was 46.7 years (0-88). The most frequent referring speciality was oncology followed by abdominal surgery and orthopaedic surgery. In 2005 3,769 patients obtained 11,216 CT examinations. They were generally older with a mean age of 56.9 years (0-97). The most frequent referring speciality was oncology followed by chest medicine and abdominal surgery. In 2005 the total effective dose was 71,043 mSv (mean 18.9 mSv/per patient). According to the BEIR VII model this radiation level corresponded to a risk for inducing a cancer in 7 patients, being fatal in half of them. The national data showed a gradual increase of the number of CT examinations from 1979 to 2005, most pronounced after year 2000 coinciding with the introduction of multi-slice CT (MSCT). CONCLUSION: The number of CT examinations at Aarhus Sygehus doubled during a 9 year period. The increase occured especially in middle and high age groups.
[Analysis of the epidemiological data concerning radiation carcinogenic effects and approaches to the low doses' upper limits determination in the aspect of a threshold of the unhealthy influences of ionizing radiation]
The analysis of the epidemiological data regarding cancer mortality in cohorts of Japanese A-bomb survivors and Chermobyl liquidators exposed to different doses suggests that there are good reasons for recognizing the threshold of the radiocarcinogenic effect in the region of about 200 Gy (mSv). The analysis of solid cancer mortality in Japanese cohort, which exceeded the expected one in a dose diapason of 5-200 mSv, revealed a (quasi) plateau in a dose-effect curve and led to the conclusion that the nature of the overshoot is non-radiogenic. The analysis of supposedly dose dependent leucosis incidence in the limited low dose diapason in the Chernobyl cohort showed that the real coefficient of the excess absolute or relative radiation risk could not be received in the case because the larger part curve was placed under the control level. In supporting the principle of single hit in a cell nucleus as a base of microdosimetric determination of low radiation doses, the approach to objective delimitation between low, intermediate and high doses regions has been proposed. The low doses upper limit of sparse ionizing radiation for cell nucleus of 8 microns in diameter has been evaluated as 0.65 mGy. It can serve for evaluation of the dose rate threshold regarding the safe chronic radiation levels in the environment.
Death records were used to analyze cancer mortality in the rural areas of the Kamensky District, Sverdlovsk Region, within the East-Urals radioactive track area. A study group showed a significant increase in cancer mortality as compared with a control group (65 of the 691 examinees; 90% confidence interval (CI) 18-144; the mean colonic radiation dose was 80 and 3 mGy in the study and control groups, respectively). The additional relative risk per colonic dose was 1.3 Gy(-1) (90% CI 0.36-2.9 Gy(-1)). The association of the additional relative risk with the age-related and time factors was studied and revealed.
According to reports by the former USSR government, IAEA and WHO, no case of acute radiation effects was recognized among inhabitants who were evacuated from the 30-km zone around the Chernobyl site soon after the accident on April 26, 1986. Along with the collapse of the USSR, however, several documents appeared that report the occurrence of acute radiation effects among inhabitants. In order to check the possibility of acute radiation effects among evacuees, we evaluated the external dose of evacuees until their evacuation based on the data about the radiation situation soon after the accident. Our estimates indicate that a substantial number of inhabitants in some villages could have received more than 0.5 Sv that is recognized by ICRP and UNSCEAR as a threshold dose for a clinically significant depression of the blood-forming function of bone marrow. Some of them could have received more than 1 Sv.