Lifetime Risk Of Cancer Mortality Research Articles

Quantitative assessment of provability of radiation-related cancers considering unavoidable existence of unadjusted risk factors

The attribution of stochastic effects to exposure to ionizing radiation has been qualitatively discussed by introducing two distinct concepts of provability and probability. This study aims to develop a method of quantitatively assessing the provability of radiation-related cancers. To this end, the ‘minimum provable dose’ (MPD) was developed and applied to actual cancer mortality in Japan. The background lifetime risk of cancer mortality was calculated for the esophagus, stomach, colon, liver, lungs, skin, breasts, ovaries, bladder, and bone marrow as well as the age-specific risk coefficients reproducing those given in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP). Comparing the relative ratio of MPDs, which was defined herein as the ‘provability index’ (PI), we quantitatively ranked radiation-related cancers for different tissues and organs predicated on provability for ages of 10, 30, 50, and 0–85+ years at exposure. We discuss the radiological protection of male emergency workers focusing on cancers highly prioritized according to the ranking (i.e. colon, bone marrow, and bladder). The present study proposed the system to quantitatively evaluate the level of radiological protection taking into account the variations of the background cancer risk on the provability of radiation-related cancers.

Radiation Safety Knowledge and Perceptions among Residents: A Potential Improvement Opportunity for Graduate Medical Education in the United States

<h3>Rationale and Objectives</h3> To investigate residents' knowledge of adverse effects of ionizing radiation, frequency of their education on radiation safety, and their use of radioprotective equipment. <h3>Materials and Methods</h3> Residents from 15/16 residency programs at Emory University were asked to complete a resident radiation safety survey through SurveyMonkey^®. The associations between the residents' knowledge and use of radioprotective equipment with residents' specialty and year of training were investigated. <h3>Results</h3> Response rate was 32.5% (173/532 residents). Thirty-nine percent residents reported radiation safety is discussed in their residency curriculum at least every 6 months. Ninety-five percent believed in a link between radiation exposure and development of cancer. Overall and Radiology residents' knowledge about specific estimated dose effects (correct responses) was limited: radiation dose associated with fetus brain malformation in pregnancy (10% vs. 26%), risk of developing cataract in interventional personnel (27% vs. 47%), lifetime risk of cancer mortality from a single abdominal computed tomography (CT) in children (22% vs. 29%), greater radiosensitivity of children compared to adults (35% vs. 50%), and relative radiation dose from an abdominal CT compared to a chest x-ray (51% vs. 48%). Radiology residents had modestly higher knowledge. There was no significant difference in residents' knowledge across their postgraduate training years. Use of lead thyroid shields was reported by 86% (97% radiology vs. 80% nonradiology; <i>P</i> = .03) and radiation-monitoring badges in 39% (68% radiology vs. 15% nonradiology; <i>P</i> < .001) of the residents. <h3>Conclusions</h3> Although radiology residents scored higher, knowledge of radiation safety for patients and healthcare workers is limited among residents regardless of medical specialty. These findings emphasize the need for educational initiatives.

Calculation of Background Lifetime Risk of Cancer Mortality in Japan

Calculation of Background Lifetime Risk of Cancer Mortality in Japan

Calculation of Background Lifetime Risk of Cancer Mortality in Japan

Calculation of Background Lifetime Risk of Cancer Mortality in Japan

Unjustified CT examinations in young patients

The doses of radiation from computed tomography (CT) are relatively high, yet CT is being increasingly utilized. Furthermore, the radiation-induced lifetime risk of cancer mortality is higher at younger age. The purpose of this study was to find out whether previous CT examinations done on patients aged under 35 years were justified, and if not, whether there would have been other, more justifiable imaging modalities available. Fifty CT examinations of the head and 30 CT examinations each of the lumbar spine, cervical spine, abdomen, nasal sinuses and trauma were evaluated consecutively since the beginning of the year 2005 by using electronic patient files, the referral guidelines for imaging recommended by the European Commission and certain principles of classification. Seventy-seven per cent of the CT examinations of the lumbar spine, 36% of the head, 37% of the abdomen, 20% of the nasal sinuses and 3% of the cervical spine were unjustified. Most of these unjustified examinations could have been replaced by magnetic resonance imaging. In order to reduce utilization of ionizing radiation, both the referring practitioner and the radiologist responsible for the examination should carefully consider the justification for CT examinations and the possibility of using other imaging modalities.

Meta-analysis of dioxin cancer dose response for three occupational cohorts.

This article presents a meta analysis of data from three cohorts occupationally exposed to TCDD and related compounds. A statistically significant (p = 0.02) trend was found in total cancer mortality with increasing dioxin exposure. The trend tests show an increase in total cancer at cumulative TEQ (unit of measurement for TCDD-like compounds that is defined as the amount of TCDD that would produce the same toxicity as a mixture of TCDD-like compounds) serum levels that would result from lifetime intake of 7 pg TEQ/kg body weight/day, with no increase at 6 pg/kg/day. A linear dose response provided a good fit to the combined data and predicted an ED(01) (dioxin exposure resulting in a 0.01 increase in lifetime risk of cancer mortality) of 45 pg/kg/day (95% confidence interval, 21-324). The U.S. Environmental Protection Agency estimates that current lifetime human exposures to dioxin average approximately 1 pg/kg/day (99% percentile: 3 pg/kg/day). Although it appears unlikely that current exposures through foods would reach either 7 pg/kg/day or the ED(01), our analysis argues for careful consideration of the upper ranges of long-term average exposures for dioxins.

Pilot study risk assessment for selected problems at three U.S. Department of Energy facilities

Objective and realistic human health risk assessments were performed for environmental problems at the Savannah River Site (SRS), the Fernald Environmental Management Project (FEMP), and the Nevada Test Site (NTS). At the SRS, cancer mortality risks were analyzed for projected public exposures to 3H and 137Cs released into the Savannah River. For annual human exposures to SRS tritium in Savannah River water, calculated incremental individual lifetime risks in two human receptor populations were small (8×10 −7; upper 95 percentile point of the distribution). The 95th percentile point of the distribution for incremental individual lifetime risks from one year's exposure to 137Cs is less than 10 −8. No deaths are expected in either population as a result of exposures to tritium or cesium released to the Savannah River from the SRS. Routine releases of radon and radon progeny from the K-65 silos at FEMP resulted in individual lifetime risks greater than 1×10 −4 only for onsite workers and fenceline residents. Population risks were less than 1.0 for all identified receptor populations. Assessment of risks from exposure to uranium in ground water released by the FEMP predicted no toxic effects for human receptors. All estimated cancer risks were small. The largest predicted individual lifetime risk was for a well close to the facility (1.3×10 −5). For the various above-ground shot sites at the NTS, the highest predicted lifetime cancer risks are for a resident farmer, assuming a loss of institutional control, and exceed 1×10 −4 at the 95th cumulative percentile level. At 50 000 and 100 000 y in the future, the predicted cancer risks are all below 10 −6. In the assessment of exposure to radionuclides in ground water at the NTS, for an individual onsite near the site boundary, the geometric mean of the maximum potential excess lifetime risk of cancer mortality for an individual is 7×10 −3. For an individual using water offsite, the geometric mean of the maximum potential excess lifetime risk of cancer mortality is 7×10 −7.