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

Getting found: Indexing and the Independent Open Access Journal

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Spinal palpation: The challenges of information retrieval using available databases

PURPOSE: This study addressed 2 questions: first, what is the yield of PubMed MEDLINE for complementary and alternative medicine (CAM) studies compared to other databases; second, what is an effective search strategy to answer a sample research question on spinal palpation? METHODS: We formulated the following research question: "What is the reliability of spinal palpation procedures?" We identified specific Medical Subject Headings (MeSH) and key terms as used in osteopathic medicine, allopathic medicine, chiropractic, and physical therapy. Using PubMed, we formulated an initial search template and applied it to 12 additional selected databases. Subsequently, we applied the inclusion criteria and evaluated the yield in terms of precision and sensitivity in identifying relevant studies. RESULTS: The online search result of the 13 databases identified 1189 citations potentially addressing the research question. After excluding overlapping and nonpertinent citations and those not meeting the inclusion criteria, 49 citations remained. PubMed yielded 19, while MANTIS (Manual Alternative and Natural Therapy Index System), a manual therapy database, yielded 35 citations. Twenty-six of the 49 online citations were repeatedly indexed in 3 or more databases. Content experts and selective manual searches identified 11 additional studies. In all, we identified 60 studies that addressed the research question. The cost of the databases used for conducting this search ranged from free-of-charge to $43,000 per year for a single network subscription. CONCLUSIONS: Commonly used databases often do not provide accurate indexing or coverage of CAM publications. Subject-specific specialized databases are recommended. Access, cost, and ease of using specialized databases are limiting factors

Accuracy and precision of non-invasive cardiac output monitoring devices in perioperative medicine: A systematic review and meta-analysis

Cardiac output (CO) measurement is crucial for the guidance of therapeutic decisions in critically ill and high-risk surgical patients. Newly developed completely non-invasive CO technologies are commercially available; however, their accuracy and precision have not recently been evaluated in a meta-analysis. We conducted a systematic search using PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science to review published data comparing CO measured by bolus thermodilution with commercially available non-invasive technologies including pulse wave transit time, non-invasive pulse contour analysis, thoracic electrical bioimpedance/bioreactance, and CO2 rebreathing. The non-invasive CO technology was considered acceptable if the pooled estimate of percentage error was <30%, as previously recommended. Using a random-effects model, SD, pooled mean bias, and mean percentage error were calculated. An I2 statistic was also used to evaluate the inter-study heterogeneity. A total of 37 studies (1543 patients) were included. Mean CO of both methods was 4.78 litres min1. Bias was presented as the reference method minus the tested methods in 15 studies. Only six studies assessed the random error (repeatability) of the tested device. The overall random-effects pooled bias (limits of agreement) and the percentage error were 0,13 [2.38 ,2.12] litres min1 and 47%, respectively. Inter-study sensitivity heterogeneity was high (I283%, P<0.001). With a wide percentage error, completely non-invasive CO devices are not interchangeable with bolus thermodilution. Additional studies are warranted to demonstrate their role in improving the quality of care.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Accuracy and precision of minimally-invasive cardiac output monitoring in children: a systematic review and meta-analysis

Several minimally-invasive technologies are available for cardiac output (CO) measurement in children, but the accuracy and precision of these devices have not yet been evaluated in a systematic review and meta-analysis. We conducted a comprehensive search of the medical literature in PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science from its inception to June 2014 assessing the accuracy and precision of all minimally-invasive CO monitoring systems used in children when compared with CO monitoring reference methods. Pooled mean bias, standard deviation, and mean percentage error of included studies were calculated using a random-effects model. The inter-study heterogeneity was also assessed using an I2 statistic. A total of 20 studies (624 patients) were included. The overall random-effects pooled bias, and mean percentage error were 0.13 ± 0.44 l min−1 and 29.1 %, respectively. Significant inter-study heterogeneity was detected (P < 0.0001, I2 = 98.3 %). In the sub-analysis regarding the device, electrical cardiometry showed the smallest bias (−0.03 l min−1) and lowest percentage error (23.6 %). Significant residual heterogeneity remained after conducting sensitivity and subgroup analyses based on the various study characteristics. By meta-regression analysis, we found no independent effects of study characteristics on weighted mean difference between reference and tested methods. Although the pooled bias was small, the mean pooled percentage error was in the gray zone of clinical applicability. In the sub-group analysis, electrical cardiometry was the device that provided the most accurate measurement. However, a high heterogeneity between studies was found, likely due to a wide range of study characteristics.SCOPUS: ar.jinfo:eu-repo/semantics/publishe