The Risk of Cancer from CT Scans and Other Sources of Low-Dose Radiation: A Critical Appraisal of Methodologic Quality

AbstractIntroduction: Concern exists that radiation exposure from computerized tomography (CT) will cause thousands of malignancies. Other experts share the same perspective regarding the risk from additional sources of low-dose ionizing radiation, such as the releases from Three Mile Island (1979; Pennsylvania USA) and Fukushima (2011; Okuma, Fukushima Prefecture, Japan) nuclear power plant disasters. If this premise is false, the fear of cancer leading patients and physicians to avoid CT scans and disaster responders to initiate forcedevacuations is unfounded.Study Objective: This investigation provides a quantitative evaluation of the methodologic quality of studies to determine the evidentiary strength supporting or refuting a causal relationshipbetween low-dose radiation and cancer. It will assess the number of higher qualitystudies that support or question the role of low-dose radiation in oncogenesis.Methods: This investigation is a systematic, methodologic review of articles published from 1975–2017 examining cancer risk from external low-dose x-ray and gamma radiation, defined as less than 200 millisievert (mSv). Following the PRISMA guidelines, the authors performed a search of the PubMed, Cochrane, Scopus, and Web of Science databases. Methodologies of selected articles were scored using the Newcastle Ottawa Scale (NOS) and a tool identifying 11 lower quality indicators. Manuscript methodologies were rankedas higher quality if they scored no lower than seven out of nine on the NOS and contained no more than two lower quality indicators. Investigators then characterized articles as supporting or not supporting a causal relationship between low-dose radiation and cancer.Results: Investigators identified 4,382 articles for initial review. A total of 62 articles met all inclusion/exclusion criteria and were evaluated in this study. Quantitative evaluation of the manuscripts’ methodologic strengths found 25 studies met higher quality criteria while 37 studies met lower quality criteria. Of the 25 studies with higher quality methods, 21 out of 25did not support cancer induction by low-dose radiation (P = .0003).Conclusions: A clear preponderance of articles with higher quality methods found no increased risk of cancer from low-dose radiation. The evidence suggests that exposure to multiple CT scans and other sources of low-dose radiation with a cumulative dose up to 100 mSv (approximately 10 scans), and possibly as high as 200 mSv (approximately 20 scans), does not increase cancer risk

Incidence of thyroid cancer in Golestan province of Iran: Some initial observations

Objectives: The incidence of thyroid cancer is increasing in several countries. The main aim of this study was to find and describe province-specific estimates of incidence in males and females by age groups for thyroid cancer. Methodology: The data used in this study were collected from a cancer registry that was established by Health Deputy of Golestan province for a period of one year (2004), in different age groups. Thyroid cancer data was identified and collected through the eighteen Pathology Laboratory centers (where males and female populations is referred) in Golestan province. Results: A total of 348 females and 409 males cases with cancer representing all sites were identified during the study period. It included seventeen females and five male thyroid cancer patients. In female's thyroid cancer, there were twelve papillary carcinoma (70.6%), two medullary carcinoma, one carcinoma anaplastic and one carcinoma (5.9%). In male's, there were two papillary carcinoma (40%) and one follicular carcinoma. The incidence of thyroid cancer in 70-79 age groups for females and males was the highest and lowest in age group 10-19 years' in females and 30-39 years in males. Conclusion: The incidence of thyroid cancer is higher in females when compared with males as per this one year study. However since this is just one year data, it needs to be studied further to confirm these findings

Secure Method Invocation in JASON

We describe the Secure Method Invocation (SMI) framework implemented for Jason, our Javacard As Secure Objects Networks platform. Jason realises the secure object store paradigm, that reconciles the card-as-storage-element and card-as-processing-element views. In this paradigm, smart cards are viewed as secure containers for objects, whose methods can be called straightforwardly and securely using SMI. Jason is currently being developed as a middleware layer that securely interconnects an arbitrary number of smart cards, terminals and back-office systems over the Internet

Java Card:An analysis of the most successful smart card operating system

To explain why the Java Card operating system has become the most successful smart card operating system to date, we analyze the realized features of the current Java Card version, we argue it could be enhanced by adding a number of intended features and we discuss a set of complementary features that have been suggested. No technology can be successful without the right people and the right circumstances, so we provide some insights in the personal and historical historic aspects of the success of Java Card

An evaluation of theories concerning the health effects of low-dose radiation exposures

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2012."June 2012." Cataloged from PDF version of thesis.Includes bibliographical references (p. 50-55).The danger of high, acute doses of radiation is well documented, but the effects of low-dose radiation below 100 mSv is still heavily debated. Four theories concerning the effects of lowdose radiation are presented here: supra-linearity, linear-no-threshold (LNT), threshold, and hormesis. The available evidence for and against these theories, which falls into the categories of either epidemiological studies, in vitro cell experiments, or in vivo animal experiments, includes studies which support each of the four theories. Currently, all radiation risk estimates are based on an LNT interpretation of the life span study (LSS) of atomic bomb survivors in Japan. However, while this pattern is undisputed at high doses, this linear extrapolation of risk to low doses is challenged by many recent experiments involving cell mechanisms and animal models, and there is also high uncertainty involved in estimating risk using only epidemiological studies.. Variations have also been observed depending on dose-rate, the organ at risk, and other factors for which the current data cannot adequately account. While the evidence is still inconclusive, the existence of a threshold in human responses to low-dose radiation would drastically alter current guidelines, such as those currently restricting many people from returning to their hometowna in Fukushima, Japan. Thus, it is important to further investigate these low*dose responses in order to more fully describe the risks and to create more accurate radiation guidelines.by Elizabeth J. Wei.S.B

INTEROCC : Occupational exposure assessment for electromagnetic fields and risk of brain tumours. Development of a new source-based approach

Introducción: Con el fin de mejorar los métodos de evaluación de la exposición a campos electromagnéticos, desarrollamos un nuevo método basado en fuentes de exposición en lugar de códigos de ocupación. Mediciones obtenidas de la bibliografía fueron recopiladas, evaluadas y compiladas en una base de datos para ser posteriormente combinadas en forma de una matriz fuente-exposición. Esta matriz, junto a otros determinantes de la exposición, fue usada para calcular índices de exposición acumulada. El riesgo de mayor incidencia de tumores cerebrales, glioma y meningioma, se analizó usando estas estimaciones acumuladas. Los resultados del análisis mostraron un ligero incremento del riesgo de glioma en los grupos de trabajadores más expuestos a campos electromagnéticos de alta frecuencia en las ventanas de exposición más cercanas a la fecha de diagnóstico/referencia y en todas las ventanas para meningioma. En campos de frecuencia intermedia, se encontraron ligeros aumentos de riesgo solo en glioma en las ventanas de exposición más recientes. Estos resultados pueden reflejar que los campos electromagnéticos de alta frecuencia pueden tener un papel en las etapas más tardías de la carcinogénesis (promoción y progresión)Introduction: To improve exposure assessment methods for electromagnetic fields, we developed a methodology based on sources of exposure rather than job titles. Methods: Measurements collected from the literature were assessed and summarized into a source-exposure matrix (SEM). The SEM and personal determinants of exposure were combined to obtain individual indices cumulative exposure, which were used to assess risk of brain tumours, glioma an meningioma Results: Over 3,000 records were obtained and judged useful, creating a SEM with exposure estimates for 312 EMF sources. Overall the analysis yielded no association between glioma or meningioma risk and cumulative exposure to RF or IF EMF. However, some positive associations were identified for RF and IF EMF in the highest exposed groups in the 1- to 4-year exposure window for glioma, and in all windows for meningioma and RF only. These results might reflect a possible role of high frequency EMF in the later stages of carcinogenesis (promotion and progression)