SOURCES AND EFFECTS OF IONIZING RADIATION : United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR 2000 Report to the General Assembly, with Scientific Annexes

NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

OBJECTIVE. In light of the rapidly increasing frequency of pediatric CT examinations, the purpose of our study was to assess the lifetime cancer mortality risks attributable to radiation from pediatric CT.MATERIALS AND METHODS. Organ doses as a function of age-at-diagnosis were estimated for common CT examinations, and estimated attributable lifetime cancer mortality risks (per unit dose) for different organ sites were applied. Standard models that assume a linear extrapolation of risks from intermediate to low doses were applied. On the basis of current standard practice, the same exposures (milliampere-seconds) were assumed, independent of age.RESULTS. The larger doses and increased lifetime radiation risks in children produce a sharp increase, relative to adults, in estimated risk from CT. Estimated lifetime cancer mortality risks attributable to the radiation exposure from a CT in a 1-year-old are 0.18% (abdominal) and 0.07% (head)—an order of magnitude higher than for adults—although those figures st...

https://www.ajronline.org/doi/pdf/10.2214/ajr.176.2.1760289

Estimated Risks of Radiation-Induced Fatal Cancer from Pediatric CT

Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki atomic bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose respon...

https://bioone.org/journals/Radiation-Research/volume-168/issue-1/RR0763.1/Solid-Cancer-Incidence-in-Atomic-Bomb-Survivors-19581998/10.1667/RR0763.1.pdf

Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998

Papillary and follicular thyroid carcinomas are among the most curable of all cancers. However, some patients are at high risk of recurrence or even death from their cancer. Most of these patients can be identified at the time of diagnosis using well-established prognostic indicators. The extent of initial treatment and follow-up should therefore be individualized. The early discovery of persistent and recurrent disease is based on the combined use of serum thyroglobulin determination and of total body scanning with 131I. The recent availability of recombinant human thyroid stimulating hormone has greatly improved the quality of the patient's life during follow-up. Treatment of recurrences is based mainly on surgery and 131I treatment.

Papillary and follicular thyroid carcinoma.

The incidence of malignant tumors and leukemia was analyzed in 829 patients with chronic lymphocytic thyroiditis and in 829 individually age-matched and sex-matched patients with colloid goiter. Diagnoses were based on cytologic studies of specimens obtained by fine-needle aspiration biopsy. The patients were examined between 1959 and 1978 and were followed in the Swedish Cancer Register between 1959 and 1981. There was no increased risk for the total number of tumors in the thyroiditis group (53 observed vs. 52.7 expected) or in the colloid-goiter group (40 vs. 53.2, respectively; P not significant). There were six lung cancers in the thyroiditis group (2.9 expected, P not significant), and one in the group with colloid goiter. Patients with thyroiditis had an increased risk of myeloproliferative and lymphoproliferative neoplasms (12 observed vs. 3.0 expected, P less than 0.001). The risk of malignant thyroid lymphoma was greatly increased, with an estimated relative risk of 67 (4 observed vs. 0.06 expected, P less than 0.000001). There was no increased risk for any type of tumor among patients with colloid goiter.

Cancer Risks in Patients with Chronic Lymphocytic Thyroiditis

In this report, the Commission recommends approaches to national authorities for their definition of the scope of radiological protection control measures through regulations, by using its principles of justification and optimisation. The report provides advice for deciding the radiation exposure situations that should be covered by the relevant regulations because their regulatory control can be justified, and, conversely, those that may be considered for exclusion from the regulations because their regulatory control is deemed to be unamenable and unjustified. It also provides advice on the situations resulting from regulated circumstances but which may be considered by regulators for exemption from complying with specific requirements because the application of these requirements is unwarranted and exemption is the optimum option. Thus, the report describes exclusion criteria for defining the scope of radiological protection regulations, exemption criteria for planned exposure situations, and the application of these concepts in emergency exposure situations and in existing exposure situations. The report also addresses specific exposure situations such as exposure to low-energy or low-intensity adventitious radiation, cosmic radiation, naturally occurring radioactive materials, radon, commodities, and low-level radioactive waste. The quantitative criteria in the report are intended only as generic suggestions to regulators for defining the regulatory scope, in the understanding that the definitive boundaries for establishing the situations that can be or need to be regulated will depend on national approaches.

Scope of radiological protection control measures.

Cancer incidence was studied in 10,552 patients (mean age, 57 years) who received 131I therapy (mean dose, 506 MBq) for hyperthyroidism between 1950 and 1975. Follow-up on these patients was continued for an average of 15 years. Record linkage with the Swedish Cancer Register for the period 1958-1985 identified 1543 cancers occurring 1 year or more after 131I treatment, and the standardized incidence ratio (SIR) was 1.06 (95% confidence interval = 1.01-1.11). Significantly increased SIRs were observed for cancers of the lung (SIR = 1.32; n = 105) and kidney (SIR = 1.39; n = 66). Among 10-year survivors, significantly elevated risks were seen for cancers of the stomach (SIR = 1.33; n = 58), kidney (SIR = 1.51; n = 37), and brain (SIR = 1.63; n = 30). Only the risk for stomach cancer, however, increased over time (P less than .05) and with increasing activity administered (P = not significant). The risk for malignant lymphoma was significantly below expectation (SIR = 0.53; n = 11). Overall cancer risk did not increase with administered 131I dose or with time since exposure. The absence of any increase in leukemia adds further support to the view that a radiation dose delivered gradually over time is less carcinogenic than the same total dose received over a short time. Only for stomach cancer was a possible radiogenic excess suggested.

Cancer risk after iodine-131 therapy for hyperthyroidism

The risk of intracranial tumors after exposure to ionizing radiation during infancy has been studied in a pooled analysis of two Swedish hemangioma cohorts (n = 28,008). The mean absorbed intracranial dose was low (7 cGy, range 0-11.5 Gy). The cohorts were followed up in the Swedish Cancer Register for incident intracranial tumors during the period 1958-1993. Eighty-eight tumors were found in 86 individuals compared to 60.72 expected [standardized incidence ratio (SIR) 1.42, 95% confidence interval (CI) 1.13-1.75]. The SIR increased significantly in ascending dose categories (P = 0.02). Dose-response analyses were performed with Poisson regression methods. There was a significant effect of dose, and the dose-effect relationship was negatively modified by age at first treatment. This indicates a higher risk for those exposed earlier in life. A linear dose-response model modified by age at first treatment resulted in the best fit. The excess relative risk (ERR) was 2.7/Gy (95% CI 1.0-5.6). The ERR/Gy was 4.5 if the treatment was given before 5 months of age, 1.5 if it was given at 5-7 months and 0.4 if it was given later. The study thus strongly indicates that there exists a dose-response relationship between absorbed dose in the brain and the subsequent risk of developing an intracranial tumor and that the risk is higher among infants exposed at younger ages.

Intracranial Tumors after Exposure to Ionizing Radiation during Infancy: A Pooled Analysis of Two Swedish Cohorts of 28,008 Infants with Skin Hemangioma

The relation between breast cancer risk and serum levels of cholesterol and beta-lipoprotein (BLP), height, weight, Quetelet’s index and blood pressure was studied in a cohort of 46570 Swedish women less than 75 years of age. The cohort was examined between 1963 and 1965 and followed up in the Swedish Cancer Registry until 1983. During this period 1182 cases of breast cancer were reported. Of those, 196 were reported among women <50 years of age. Statistically significant positive associations were observed between height, weight, and systolic blood pressure and breast cancer risk. No clear trend in cancer risk related to serum cholesterol or BLP was seen in the total material. In a stepwise Cox multiple regression analysis only the associations with height and blood pressure remained significant. Among women, having their cancer diagnosed before the age of 50, higher Quetelet’s index was associated with a lower cancer risk, whereas a positive correlation was seen among women 350 years. In the group of younger women a high BLP level was associated with an increased risk of breast cancer. This relation became even stronger when studied in a multivariate analysis, which also showed a negative correlation between serum cholesterol and cancer risk.

https://www.tandfonline.com/doi/pdf/10.3109/02841868809090315

Lars-Erik Holm

Papers

Cancer Risks in Patients with Chronic Lymphocytic Thyroiditis

Scope of radiological protection control measures.

Cancer risk after iodine-131 therapy for hyperthyroidism

Intracranial Tumors after Exposure to Ionizing Radiation during Infancy: A Pooled Analysis of Two Swedish Cohorts of 28,008 Infants with Skin Hemangioma

Breast Cancer Risk in Relation to Serum Cholesterol, Serum Beta-Lipoprotein, Height, Weight, and Blood Pressure