Studies Of Atomic Bomb Survivors Research Articles

The proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionizing radiation

The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionizing radiation, such as those experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily on studies of the Japanese atomic bomb survivors imply that low-level exposure to ionizing radiation, including ubiquitous natural background radiation, also raises the risk of childhood leukaemia. Using two sets of recently published leukaemia risk models and estimates of natural background radiation red-bone-marrow doses received by children, about 20% of the cases of childhood leukaemia in Great Britain are predicted to be attributable to this source. However, for one of these sets of risk models this attributable fraction is materially dependent on how the radiation-induced risk is assumed to be transferred between the Japanese atomic bomb survivors and Western children. Over a range of annual doses representing the range (0.5-2.5 mSv/year) experienced by most populations, the attributable proportion for the preferred risk-transfer model varies between 8 and 30%, with small deviations from a linear relationship that are largely due to the saturation of the model, although again this range of attributable fractions depends on the assumed transfer of risk between populations.

Health outcomes of low-dose ionizing radiation exposure among medical workers: a cohort study of the Canadian national dose registry of radiation workers

Medical workers can be exposed to low-dose ionizing radiation from various sources. The potential cancer risks associated with ionizing radiation exposure have been derived from cohort studies of Japanese atomic bomb survivors who had experienced acute, high-level exposure. Since such extrapolations are subject to uncertainty, direct information is needed on the risk associated with chronic low-dose occupational exposure to ionizing radiation. To determine the occupational doses of ionizing radiation and examine possible associations with mortality rates and cancer incidence in a cohort of medical workers deriving from the National Dose Registry of Canada (NDR) over the period of 1951-1987. Standardized mortality and incidence ratios (SMR and SIR, respectively) were ascertained by linking NDR data for a cohort of 67 562 medical workers (23 580 males and 43 982 females) with the data maintained by the Canadian Mortality, and Cancer Incidence databases. Dosimetry information was obtained from the National Dosimetry Services. During the follow-up period, 1309 incident cases of cancer (509 in males, 800 in females) and 1325 deaths (823 in males, 502 in females) were observed. Mortality from cancer and non-cancer causes was generally below expected as compared to the general Canadian population. Thyroid cancer incidence was significantly elevated both among males and females, with a combined SIR of 1.74 and 90% CI: 1.40-2.10. The findings confirm previous reports on an increased risk of the thyroid cancer among medical workers occupationally exposed to ionizing radiation. Over the last 50 years, radiation protection measures have been effective in reducing radiation exposures of medical workers to the current very low levels.

Atomic Bomb Health Benefits

Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment.

Radiation-induced Cancer Risk from Annual Computed Tomography for Patients with Cystic Fibrosis

Computed tomography (CT) is being considered as a tool for routine monitoring of lung damage in people with cystic fibrosis. Concern has been raised, however, about the associated risk of radiation-induced cancer. To estimate the risk of radiation-induced cancer from lung CT for patients with cystic fibrosis, assuming annual monitoring starting at age 2 years. Radiation risk models (derived primarily from the study of Japanese atomic bomb survivors) were used to estimate the excess risk of radiation-induced cancer for the organs that receive measurable doses from lung CT. Two scenarios were considered: median survival to age 36 years (approximate current median survival) and median survival to age 50 years (projected median survival by 2030). The estimated risk of radiation-induced cancer from annual lung CT was 0.02% for males and 0.07% for females assuming median survival to age 36 years. The estimated risks increased to 0.08% for males and 0.46% for females assuming median survival increases to age 50 years. The risks are higher for females because of the risk of radiation-induced breast cancer (50% of total risk) and higher risk of thyroid cancer. The cumulative risk of radiation-induced cancer from repeated lung CT scans for patients with cystic fibrosis is relatively small (less than 0.5%). However, routine monitoring should not be recommended until there is a demonstrated benefit that will outweigh these risks.

Measurement of 63Ni produced in Cu samples by the Hiroshima atomic bomb

The 63Ni in copper samples exposed by the Hiroshima atomic bomb was clearly measured for the first time by liquid scientillation method For the measurement, the chemical separation scheme previously developed was improved The obtained result was agreed with that estimated by the new dosimetry system for atomic bomb survivor studies, DS02.

The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: Design, Epidemiological Methods and Descriptive Results

Radiation protection standards are based mainly on risk estimates from studies of atomic bomb survivors in Japan. The validity of extrapolations from the relatively high-dose acute exposures in this population to the low-dose, protracted or fractionated environmental and occupational exposures of primary public health concern has long been the subject of controversy. A collaborative retrospective cohort study was conducted to provide direct estimates of cancer risk after low-dose protracted exposures. The study included nearly 600,000 workers employed in 154 facilities in 15 countries. This paper describes the design, methods and results of descriptive analyses of the study. The main analyses included 407,391 nuclear industry workers employed for at least 1 year in a participating facility who were monitored individually for external radiation exposure and whose doses resulted predominantly from exposure to higher-energy photon radiation. The total duration of follow-up was 5,192,710 person-years. There were 24,158 deaths from all causes, including 6,734 deaths from cancer. The total collective dose was 7,892 Sv. The overall average cumulative recorded dose was 19.4 mSv. A strong healthy worker effect was observed in most countries. This study provides the largest body of direct evidence to date on the effects of low-dose protracted exposures to external photon radiation.

Long-term health consequences of atomic bomb radiation: RERF Life Span Study

Abstract. To determine the possible late health effects of atomic-bomb radiation, Radiation Effects Research Foundation (RERF) has been conducting mortality follow-up on a fixed cohort of 120,000 members (Life Span Study cohort or LSS cohort) since 1950. Through record linkage with local cancer registries in Hiroshima and Nagasaki, RERF has also been conducting cancer incidence studies of atomic bomb survivors since 1958. The central finding of the study is an increase in cancer risk. Besides the increase in leukemia risk, increase in risks of solid cancers such as cancers of the breast, lung and colon have also been demonstrated. Radiation-induced leukemia occurred 2 to 3 years after exposure, reached its peak within 6 to 8 years after the bombing, and has since declined steadily. However, radiation-related solid cancer began to appear at later years and the risk still remains to be present, even today. An increase of solid cancer risk appears to be larger for those exposed as children than those exposed as adults. However, since a majority of those exposed as children are still alive and risk estimates for them are uncertain at this stage, it is essential to continue their follow-up. Recently, the LSS also demonstrates an excess risk of death from non-cancer diseases, largely from cardiovascular, digestive and respiratory diseases. Further investigation is of absolute necessity in order to determine whether or not the excess was caused by atomic bomb radiation.

Radiation-induced cardiovascular diseases: Is the epidemiologic evidence compatible with the radiobiologic data?

The Life Span Study of Japanese atomic bomb survivors demonstrates that radiation exposure significantly increased the risk of developing ischemic heart disease, in particular myocardial infarction. Similarly, epidemiologic investigations in very large populations of patients who had received postoperative radiotherapy for breast cancer or for peptic ulcer demonstrate that radiation exposure of the heart with an average equivalent single dose of approximately 2 Gy significantly increased the risk of developing ischemic heart disease more than 10 years after irradiation. These epidemiologic findings are compatible with radiobiologic data on the pathogenesis of radiation-induced heart disease in experimental animals. The critical target structure appears to be the endothelial lining of blood vessels, in particular arteries, leading to early functional alterations such as pro-inflammatory responses and other changes, which are slowly progressive. Research should concentrate on the interaction of these radiation-induced endothelial changes with the early stages of age-related atherosclerosis to develop criteria for optimizing treatment plans in radiotherapy and also potential interventional strategies.

UNDERSTANDING ESTIMATION OF TIME AND AGE EFFECT-MODIFICATION OF RADIATION-INDUCED CANCER RISKS AMONG ATOMIC-BOMB SURVIVORS

In radiation risk assessment based on follow-up data, estimation of the excess relative cancer rate involves evaluation of effect-modification by time-related factors such as age at exposure, time since exposure, and attained age. Because these variables are collinear, the regression coefficients purportedly measuring effect-modification of the radiation-related excess relative rate by time and age factors generally differ from the individual effects of these factors. For example, depending on whether it is an age-at-exposure/attained-age effect-modification model or an age-at-exposure/time-since-exposure model which is used, the regression coefficient for the effect of changes in age at exposure on the excess relative rate per Gray measures the combined effects of changes in both age at exposure and time since exposure, or of age at exposure and attained age, respectively, rather than the individual effect of changes in age at exposure, which is of interest for scientific purposes. Such insights should be integrated when reporting and interpreting estimates for time-related risk modification in cohort studies of radiation-exposed populations. Cancer incidence data for the Life Span Study of atomic-bomb survivors are used for illustration in parallel to theory. In summary, model coefficients for time-since-exposure, age-at-exposure, and attained-age effects on radiation-induced cancer risks among atomic-bomb survivors and in other cohort studies estimate combined effects (estimable combined effects are explicated). An appropriate unequivocal display of results for effect-modification is suggested. Goodness of fit appears unreliable for sorting out the most significant effect-modifiers. For example, a model including only one of the effect-modifiers may provide a fit similar to a model including the other two effect-modifiers, even when only the latter are actually related to effect-modification. Also, due to collinearity between these effect-modifier variables, all three models with two of the effect-modifiers necessarily show equivalent fits.

Survivors of the Atomic Bombings of Hiroshima and Nagasaki: Key Findings and Future Perspectives

TS2-08 Abstract: Studies of Japanese atomic bomb survivors have provided considerable information on the long-term health effects of radiation exposure in a population of all ages and both genders who were exposed to a wide range of doses. Of particular note have been the dose–response analyses conducted for various cancer types that have considered the modifying effects of factors such as age and time. Although more than 60 years have passed since the bombings, continued follow up of the survivors will be important to learn more about the lifetime risks from exposure at young ages and what might be the risks of noncancer diseases at relatively low doses. This presentation summarizes key findings and open questions associated with these studies.

Dose Estimation for Atomic Bomb Survivor Studies: Its Evolution and Present Status

In the decade after the bombings of Hiroshima and Nagasaki, several large cohorts of survivors were organized for studies of radiation health effects. The U.S. Atomic Bomb Casualty Commission (ABCC) and its U.S./Japan successor, the Radiation Effects Research Foundation (RERF), have performed continuous studies since then, with extensive efforts to collect data on survivor locations and shielding and to create systems to estimate individual doses from the bombs' neutrons and gamma rays. Several successive systems have been developed by extramural working groups and collaboratively implemented by ABCC and RERF investigators. We describe the cohorts and the history and evolution of dose estimation from early efforts through the newest system, DS02, emphasizing the technical development and use of DS02. We describe procedures and data developed at RERF to implement successive systems, including revised rosters of survivors, development of methods to calculate doses for some classes of persons not fitting criteria of the basic systems, and methods to correct for bias arising from errors in calculated doses. We summarize calculated doses and illustrate their change and elaboration through the various systems for a hypothetical example case in each city. We conclude with a description of current efforts and plans for further improvements.

Breast cancer incidence in U.S. radiologic technologists

Studies of atomic bomb survivors and medically exposed populations have demonstrated an increased risk of breast cancer associated with acute or protracted, intermediate-dose or high-dose, ionizing radiation; however, the risks associated with low-dose and low-dose-rate (protracted) exposures are less certain. The authors evaluated incident breast cancer risks from 1983 to 1998 according to employment characteristics and a 4-level proxy index for cumulative radiation exposure based on 2 mail surveys among 56,436 U.S. female radiologic technologists who were certified from 1925 to 1980, adjusting for established breast cancer risk factors. During follow-up, 1050 new breast cancer diagnoses were ascertained. Compared with radiologic technologists who began working in 1970 or later, adjusted breast cancer risks for those who first worked in the 1960s, 1950s, 1940s, from 1935 to 1939, and before 1935 were 1.0 (95% confidence interval [CI], 0.8-1.2), 1.2 (95% CI, 0.9-1.6), 1.0 (95% CI, 0.7-1.5), 1.8 (95% CI, 1.0-3.2), and 2.9 (95% CI, 1.3-6.2), respectively. The risk rose with the number of years worked before 1940 (P value for trend = .002) and was elevated significantly among those who began working before age 17 years (relative risk, 2.6; 95% CI, 1.3-5.1; 10 women) but was not related to the total years worked in the 1940s or later. Compared with technologists who had a Level 1 (minimal) proxy index for cumulative radiation exposure, breast cancer risks were 1.0 (95% CI, 0.9-1.2), 1.0 (95% CI, 0.7-1.3), and 1.5 (95% CI, 1.0-2.2), respectively, for technologists who had Level 2, Level 3, and Level 4 (highest) exposure. Breast cancer risk was elevated significantly in female radiologic technologists who experienced daily low-dose radiation exposures over several years that potentially resulted in appreciable cumulative exposure. The increased risk for total years worked before 1940, but not later, was consistent with decreasing occupational radiation exposures, improvements in radiation technology, and more stringent radiation protection standards over time.

Solid tumor risks after high doses of ionizing radiation

There is increasing concern regarding radiation-related second-cancer risks in long-term radiotherapy survivors and a corresponding need to be able to predict cancer risks at high radiation doses. Although cancer risks at moderately low radiation doses are reasonably understood from atomic bomb survivor studies, there is much more uncertainty at the high doses used in radiotherapy. It has generally been assumed that cancer induction decreases rapidly at high doses due to cell killing. However, recent studies of radiation-induced second cancers in the lung and breast, covering a very wide range of doses, contradict this assumption. A likely resolution of this disagreement comes from considering cellular repopulation during and after radiation exposure. Such repopulation tends to counteract cell killing and accounts for the large discrepancies between the current standard model for cancer induction at high doses and recent second-cancer data. We describe and apply a biologically based minimally parameterized model of dose-dependent cancer risks, incorporating carcinogenic effects, cell killing, and, additionally, proliferation/repopulation effects. Including stem-cell repopulation leads to risk estimates consistent with high-dose second-cancer data. A simplified version of the model provides a practical and parameter-free approach to predicting high-dose cancer risks, based only on data for atomic bomb survivors (who were exposed to lower total doses) and the demographic variables of the population of interest. Incorporating repopulation effects provides both a mechanistic understanding of cancer risks at high doses and a practical methodology for predicting cancer risks in organs exposed to high radiation doses, such as during radiotherapy.

The Protective Role of Fruits and Vegetables against Radiation-Induced Cancer

The role of fruits and vegetables in protecting against radiation-induced cancer and the positive evidence from epidemiology and ancillary investigations are discussed in this review. The recently reported Hiroshima and Nagasaki atomic bomb survivor studies provide strong evidence for the protective role of fruits and vegetables against radiation-induced cancer. The anticarcinogenic substances contained in, and the anticarcinogenic mechanisms proposed for, fruits and vegetables are reviewed. The anticarcinogenic effectiveness of fruits and vegetables are compared with that of dietary supplements. The reasons for the observed superiority of fruits and vegetables are advanced.

放射線防護に関する生物学・疫学分野の研究

In this paper, an outline of the biological and epidemiological evidence for radiation protection is presented together with the strengths and limitations of these studies in radiation risk evaluation. Various types of research can provide useful information to complement the risk estimates based on atomic-bomb survivor studies, particularly the effects of low-dose and lowdose rate radiation. Some basic issues in synthesizing scientific information for radiation risk evaluation are also discussed.

LEUKEMIA AMONG URANIUM MINERS — LATE EFFECTS OF EXPOSURE TO URANIUM DUST?

Introduction The evidence of the risk of leukaemia from ionizing radiation is mainly based on studies of atomic bomb survivors and populations exposed to x rays for diagnostic or therapeutic purposes. There are also an increasing number of occupational studies. The evidence of leukaemia risk from radon among uranium miners is limited. The presentation reports on recent observations among Czech uranium miners by 1999.

Prevalence of hepatitis B virus infection among atomic bomb survivors.

The aim of this study was to determine whether the prevalence of hepatitis B virus (HBV) carriers increased with atomic bomb radiation dose, and whether radiation decreased the ability to clear HBV among the atomic bomb survivors. The study subjects were 6,121 participants in the Adult Health Study of atomic bomb survivors in Hiroshima and Nagasaki. After adjustment for age, sex, city and potential confounders, the rates of seropositivity for hepatitis B surface antigen (HBsAg), indicating current HBV infections, and anti-hepatitis B core antibody, indicating either cured or current infections, increased with radiation dose. However, no relationship was observed between radiation and anti-hepatitis B surface antibody (indicating cured infection). The proportion of persons who were unable to clear the virus, as the proportion of HBsAg-positive persons among those ever infected by HBV (positive for HBsAg or surface or core hepatitis B antibody), increased significantly with radiation dose among those receiving blood transfusions. This proportion was not related to dose among those who reported no such transfusions. The findings may suggest a lower likelihood of clearance after HBV infection among those who were more likely to have been infected with HBV as adults after atomic bomb irradiation rather than as infants or adults prior to irradiation.

Breast cancer risk among the survivors of atomic bomb and patients exposed to therapeutic ionising radiation

Radiation induced breast cancer is a highly complex phenomenon, which most likely involves the accumulation of several genetic and epigenetic events. Studies of atomic bomb survivors, patients who underwent multiple fluoroscopic examinations during treatment for pulmonary tuberculosis, those who received therapeutic radiation for benign breast disease, such as acute post-partum mastitis, or those with an enlarged thymus or skin haemangioma and patients with Hodgkin's disease treated by mantle radiotherapy established that the risk of breast cancer increases with exposure to ionising radiation. The carcinogenic effect of therapeutic or accidental radiation is highest when exposure occurs during childhood and exposure after age 40 imparts low or minimal risk. The risk of bilateral breast cancer is not significantly increased in the survivors of atomic bomb and therapeutic radiations. Fractionated exposures for therapeutic radiation are similar to a single exposure of the same total dose in their ability to induce breast cancer; this risk remains high for many years after exposure. Younger age at first full term pregnancy confers a protective effect against the risk of breast cancer in the survivors of atomic bomb but long-term data on this beneficial effect after therapeutic radiation is not available.

Tumorigenesis in high-dose total body irradiated rhesus monkeys--a life span study.

In the early sixties, studies have been performed at the TNO-Institutes for Health Research on acute effects of high dose total body irradiation (TBI) with X-rays and fission neutrons in Rhesus monkeys and the protective effect of autologous bone marrow transplantation (BMT). The surviving animals of this study were kept to investigate late radiation effects, ie, tumorigenesis. TBI in combination with chemotherapy, followed by rescue with BMT is increasingly used for the treatment of hematological malignancies and refractory autoimmune disease. The risk of radiation carcinogenesis after this treatment is of growing concern in man. Studies on tumor induction in nonhuman primates are of relevance in this context since the response of this species to radiation does not differ much from that in man. The group of long-term surviving monkeys comprised nine neutron irradiated animals (average total body dose 3A Gy, range 2.3-4.4 Gy) and 20 X-irradiated monkeys (average total body dose 7.1 Gy, range 2.8-8.6 Gy). A number of 21 age-matched nonirradiated Rhesus monkeys served as a control-group. All animals wereregularly screened for the occurrence of tumors. Complete necropsies were performed after natural death or euthanasia. At postirradiation intervals of 4-21 years an appreciable number of malignant tumors was observed. In the neutron irradiated group eight out of nine animals died with 1 or more malignant tumors. In the X-irradiated group this fraction was 10 out of 20. The tumors in the control group, in seven out of 21 animals, appeared at much older age compared with those in the irradiated cohorts. The histogenesis of the malignant tumors was diverse, as was the case for benign tumors. The observed shortening of latency periods and life span, as well as, the increase of mean number of tumors per tumor bearing animal for benign neoplasms parallels the trend observed for malignant tumors. The results of this study were compared to other radiation late effects after TBI followed by different BMT treatment modalities in Rhesus monkeys. The observation that the carcinogenic risk of TBI in the Rhesus monkeys is similar to that derived from the studies of the Japanese atomic bomb survivors and the increase of the risk by a factor of 8 emphasizes the need for regular screening for secondary radiation-induced tumors in long-term surviving patients after TBI followed by BMT.

Think Twice Before Ordering That CT

Radiology| October 01 2002 Think Twice Before Ordering That CT AAP Grand Rounds (2002) 8 (4): 41–42. https://doi.org/10.1542/gr.8-4-41 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Think Twice Before Ordering That CT. AAP Grand Rounds October 2002; 8 (4): 41–42. https://doi.org/10.1542/gr.8-4-41 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: cancer, computed tomography, diagnostic radiologic examination, radiation exposure, radiologists, radiotherapy dosage, cancer risk, spiral computed tomography Source: Society of Pediatric Radiology. The ALARA (As Low As Reasonably Achievable) concept in pediatric CT intelligent dose reduction. Multidisciplinary conference organized by the Society of Pediatric Radiology. August 18–19, 2001. Pediatr Radiol. 2002;32:217–313. On January 22, 2001, USA Today published a front page article entitled “Radiation from CT scans in children linked to cancer.”1 This controversial and somewhat distorted report sensationalized the results of 3 articles and an editorial published in the February 2001 issue of the American Journal of Roentgenology. Roentgenology 2–,4 The 3 articles included an estimation of cancer risk from pediatric computed tomography (CT), a critical evaluation of why the helical CT technical settings used throughout the general radiology community were not adjusted for children, and strategies on how to minimize radiation dose during pediatric body CT using a single detector helical scanner. A flood of public outcry hit the medical community, focused primarily on pediatricians. Concerned, fearful, and angry parents worried about their child’s CT examination, and in some cases blamed CT radiation for their child’s cancer. In response, the Society for Pediatric Radiology organized a conference in August 2001 to address the scientific aspects of this controversy and expand on the “ALARA” (As Low As Reasonably Achievable) concept that is generally applied by radiologists to any medically necessary radiation exposure. The following summarizes excerpts from those presentations. The use of pediatric CT exams has risen from 4% of all CT scans performed in 1989 to around 10% today. An estimated 2.7 million children receive CT exams every year in the United States. CT scans account for only 10% of x-ray exams but contribute a disproportionate 67% of the overall collective radiation dose. Multiple exams are often performed in the same patient with approximately 30% of patients having at least 3 CT exams; 11% have more. Children are more sensitive to radiation than adults by a factor of 10; girls are at more risk than boys by a factor of 2; and exposure at a younger age (especially below 15 years) carries a significantly higher risk of cancer. Since radiation-induced cancers appear at about the same age as spontaneous cancers of a similar type, it takes many years to test the current “estimation” of increased cancer risk in patients exposed to CT, a technology which has not been around long enough to permit such study in children. The reported risks are “estimates” calculated from a multitude of factors that are dependent upon radiation dose per organ as a function of gender, age, weight, type of CT, and dose calculation based on electronic models and data from studies of atomic bomb survivors. Nonetheless, it is certain that radiation from CT scans is a contributing factor to the rate of cancer in the general public, although to what extent is difficult to accurately determine. The ALARA conference organizers call for a more judicious selection of patients for CT examination and note the need for further investigation of appropriate parameters... You do not currently have access to this content.