Effective Dose Estimation in Fast-kV Switch Dual Energy Computed Tomography

Purpose

The objective of our study was to test a new approach to approximating organ dose by using the effective energy of the combined 80kV/140kV beam used in fast kV switch dual-energy (DE) computed tomography (CT). The two primary focuses of the study were to first validate experimentally the dose equivalency between MOSFET and ion chamber (as a gold standard) in a fast kV switch DE environment, and secondly to estimate effective dose (ED) of DECT scans using MOSFET detectors and an anthropomorphic phantom.

Materials and Methods

A GE Discovery 750 CT scanner was employed using a fast-kV switch abdomen/pelvis protocol alternating between 80 kV and 140 kV. The specific aims of our study were to (1) Characterize the effective energy of the dual energy environment; (2) Estimate the f-factor for soft tissue; (3) Calibrate the MOSFET detectors using a beam with effective energy equal to the combined DE environment; (4) Validate our calibration by using MOSFET detectors and ion chamber to measure dose at the center of a CTDI body phantom; (5) Measure ED for an abdomen/pelvis scan using an anthropomorphic phantom and applying ICRP 103 tissue weighting factors; and (6) Estimate ED using AAPM Dose Length Product (DLP) method. The effective energy of the combined beam was calculated by measuring dose with an ion chamber under varying thicknesses of aluminum to determine half-value layer (HVL).

Results

The effective energy of the combined dual-energy beams was found to be 42.8 kV. After calibration, tissue dose in the center of the CTDI body phantom was measured at 1.71 ± 0.01 cGy using an ion chamber, and 1.73±0.04 and 1.69±0.09 using two separate MOSFET detectors. This result showed a -0.93% and 1.40 % difference, respectively, between ion chamber and MOSFET. ED from the dual-energy scan was calculated as 16.49 ± 0.04 mSv by the MOSFET method and 14.62 mSv by the DLP method.

Understanding Antenatal Genetics Services in Sri Lanka: Current Landscape of Screening and Diagnostic Services and Contextual Factors Influencing Their Availability and Uptake

Background: Too little information is available on Sri Lanka’s current capacity to provide community genetic services—antenatal genetic services in particular—to understand whether building that capacity could further improve and reduce disparity in maternal and child health. This qualitative research project seeks to gather information on congenital disorders, routine antenatal care, and the current state of antenatal screening testing services within that routine antenatal to assess the feasibility of and the need for scaling up antenatal genetics services in Sri Lanka. Methods: Nineteen key informant (KI) interviews were conducted with stakeholders in antenatal care and genetic services. Seven focus group discussions were held with a total of 56 Public Health Midwives (PHMs), the health workers responsible for antenatal care at the field level. Transcripts for all interviews and FGDs were analyzed for key themes, and themes were categorized to address the specific aims of the project. Results: Antenatal genetic services play a minor role in antenatal care, with screening and diagnostic procedures available in the private sector and paid for out-of-pocket. KIs and PHMs expect that demand for antenatal genetic services will increase as patients’ purchasing power and knowledge grow but note that prohibitive abortion laws limit the ability of patients to act on test results. Genetic services compete for limited financial and human resources in the free public health system, and inadequate information on the prevalence of congenital disorders limits the ability to understand whether funding for services related to those disorders should be increased. A number of alternatives to scaling up antenatal genetic services within the free health system might be better suited to the Sri Lankan structural and social context. Conclusions: Scaling up antenatal genetic services within the public health system is not feasible in the current financial, legal, and human resource context. Yet current availability and utilization patterns contribute to regional and economic disparities, suggesting that stasis will not bring continued improvements in maternal and child health. More information on the burden of congenital disorders is necessary to fully understand if and how antenatal genetic service availability should be increased in Sri Lanka, but even before that information is gathered, examination of policies for patient referral, termination of pregnancy, and government support for individuals with genetic disease are steps that might bring extend improvements and reduce disparity in maternal and child health.

Developing and Validating a Perinatal Depression Screening Tool in Bungoma County, Kenya

Background: Depression-screening tools exist and are widely used in Western settings. There have been few studies done to explore whether or not existing tools are valid and effective to use in sub-Saharan Africa. Our study aimed to develop and validate a perinatal depression-screening tool in rural Kenya.

Methods: We utilized conducted free listing and card sorting exercises with a purposive sample of 12 women and 38 CHVs living in a rural community to explore the manifestations of perinatal depression in that setting. We used the information obtained to produce a locally relevant depression-screening tool that comprised of existing Western psychiatric concepts and locally derived items. Subsequently, we administered the novel depression-screening tool and two existing screening tools (the Edinburgh Postnatal Depression Scale and the Patient Health Questionnaire-9) to 193 women and compared the results of the screening tool with that of a gold standard structured clinical interview to determine validity.

Results: The free listing and card sorting exercise produced a set of 60 screening items. Of the items in this set, we identified the 10 items that most accurately classified cases and non-cases. This 10-item scale had a sensitivity of 100.0 and specificity of 81.2. This compared to 90.0, 31.5 and 90.0, 49.7 for the EPDS and the PHQ-9, respectively. Overall, we found a prevalence of depression of 5.2 percent.

Conclusions: The new scale does very well in terms of diagnostic validity, having the highest scores in this domain compared to the EPDS, EPDS-R and PHQ-9. The adapted scale does very well with regards to convergent validity-illustrating clear distinction between mean scores across the different categories. It does well with regards to discriminant validity, internal consistency reliability, and test-retest reliability- not securing top scores in those domains but still yielding satisfactory results.

In two minds about screening: an investigation of cervical cancer prevention among Irish women

Cervical cancer is the second most common female cancer worldwide. Cervical screening programmes can reduce the incidence of cervical cancer by up to 80 percent if the invited women participate. Previous Irish research has associated screening attendance with subjective norms, anticipated regret, higher socio-economic status and education. Greater perceived screening barriers and lacking knowledge were associated with avoidance. These findings support a variety of expectancy-value theories of behaviour. They also suggest that expectancy-value theories could benefit from the inclusion of affective predictors of behaviour, like anticipated regret. In 2008 the Republic of Ireland introduced the National Cervical Screening Programme (NCSP). This research seeks to identify the predictors of participation in the NCSP. A systematic review of reviews showed that predictors of screening participation clustered into environmental and psychological influences. There is a gap in the evidence synthesis of associations with personal characteristics and health beliefs. Thematic analysis of focus group interviews confirmed the validity of many screening predictors identified by the systematic review and expectancy-value theories. A survey of these predictors suggested that reduced screening barriers might encourage first-time participation, while regular attendance requires greater endorsement of screening benefits and stronger subjective norm and intention. Positive attitude, rather than knowledge, appeared to be crucial for strong intention, so the final study piloted an experiment comparing the utility of positive attitude in strengthening intention to the utility of information provision. Despite lacking significant differences between conditions, content analysis of participant comments suggested that a full trial would be worthwhile, given purposive sampling and improved sample retention. These findings agree with previous Irish research on the importance of screening intention, although its association with attitude appeared to be stronger in the present research. The findings further indicate that future screening promotion should consider interventions based on patients’ experiences of screening.

School and Community Screening Shows Malawi, Africa, to Have a High Prevalence of Latent Rheumatic Heart Disease

Rheumatic heart disease (RHD) is the largest cardiac cause of morbidity and mortality in the world's youth. Early detection of RHD through echocardiographic screening in asymptomatic children may identify an early stage of disease, when secondary prophylaxis has the greatest chance of stopping disease progression. Latent RHD signifies echocardiographic evidence of RHD with no known history of acute rheumatic fever and no clinical symptoms.

OBJECTIVE: Determine the prevalence of latent RHD among children ages 5-16 in Lilongwe, Malawi.

DESIGN: This is a cross-sectional study in which children ages 5 through 16 were screened for RHD using echocardiography.

SETTING: Screening was conducted in 3 schools and surrounding communities in the Lilongwe district of Malawi between February and April 2014.

OUTCOME MEASURES: Children were diagnosed as having no, borderline, or definite RHD as defined by World Heart Federation criteria. The primary reader completed offline reads of all studies. A second reader reviewed all of the studies diagnosed as RHD, plus a selection of normal studies. A third reader served as tiebreaker for discordant diagnoses. The distribution of results was compared between gender, location, and age categories using Fisher's exact test.

RESULTS: The prevalence of latent RHD was 3.4% (95% CI = 2.45, 4.31), with 0.7% definite RHD and 2.7% borderline RHD. There was no significant differences in prevalence between gender (P = .44), site (P = .6), urban vs. peri-urban (P = .75), or age (P = .79). Of those with definite RHD, all were diagnosed because of pathologic mitral regurgitation (MR) and 2 morphologic features of the mitral valve. Of those with borderline RHD, most met the criteria by having pathological MR (92.3%).

CONCLUSION: Malawi has a high rate of latent RHD, which is consistent with other results from sub-Saharan Africa. This study strongly supports the need for a RHD prevention and control program in Malawi.

A Validation Study for the Use of ROS1 Immunohistochemical Staining in Screening for ROS1 Translocations in Lung Cancer

INTRODUCTION: The presence of ROS proto-oncogene 1, receptor tyrosine kinase gene (ROS1) rearrangements in lung cancers confers sensitivity to ROS kinase inhibitors, including crizotinib. However, they are rare abnormalities (in ∼1% of non-small cell lung carcinomas) that are typically identified by fluorescence in situ hybridization (FISH), and so screening using immunohistochemical (IHC) staining would be both cost- and time-efficient.

METHODS: A cohort of lung tumors negative for other common mutations related to targeted therapies were screened to assess the sensitivity and specificity of IHC staining in detecting ROS1 gene rearrangements, enriched by four other cases first identified by FISH. A review of published data was also undertaken.

RESULTS: IHC staining was 100% sensitive (95% confidence interval: 48-100) and 83% specific (95% confidence interval: 86-100) overall when an h-score higher than 100 was used. Patients with ROS1 gene rearrangements were younger and typically never-smokers, with the tumors all being adenocarcinomas with higher-grade architectural features and focal signet ring morphologic features (two of five). Four patients treated with crizotinib showed a partial response, with three also showing a partial response to pemetrexed. Three of four patients remain alive at 13, 27, and 31 months, respectively.

CONCLUSION: IHC staining can be used to screen for ROS1 gene rearrangements, with patients herein showing a response to crizotinib. Patients with tumors that test positive according to IHC staining but negative according to FISH were also identified, which may have implications for treatment selection.

The reliability and factorial validity of the Adolescent Alcohol Involvement Scale in a large sample in the United Kingdom

The assessment of adolescent drinking behavior is a complex task, complicated by variability in drinking patterns, the transitory and developmental nature of the behavior and the reliance (for large scale studies) on self-report questionnaires. The Adolescent Alcohol Involvement Scale (Mayer & Filstead, 1979) is a 14-item screening tool designed to help to identify alcohol misusers or more problematic drinkers. The present study utilized a large sample (n = 4066) adolescents from Northern Ireland. Results of Confirmatory Factor Analyses and reliability estimates revealed that the 14-items share sufficient common variance that scores can be considered to be reliable and that the 14 items can be scored to provide a composite alcohol use score.

Fast and sensitive aflatoxin B1 and total aflatoxins ELISAs for analysis of peanuts, maize and feed ingredients

Aflatoxins are a group of carcinogenic compounds produced by Aspergillus fungi that can grow on different agricultural crops. Both acute and chronic exposure to these mycotoxins can cause serious illness. Due to the high occurrence of aflatoxins in crops worldwide fast and cost-effective analytical methods are required for the identification of contaminated agricultural commodities before they are processed into final products and placed on the market. In order to provide new tools for aflatoxin screening two prototype fast ELISA methods: one for the detection of aflatoxin B₁ and the other for total aflatoxins were developed. Seven monoclonal antibodies with unique high sensitivity and at the same time good cross-reactivity profiles were produced. The monoclonal antibodies were characterized and two antibodies showing IC₅₀ of 0.037 ng/mL and 0.031 ng/mL for aflatoxin B₁ were applied in simple and fast direct competitive ELISA tests. The methods were validated for peanut matrix as this crop is one of the most affected by aflatoxin contamination. The detection capabilities of aflatoxin B₁ and total aflatoxins ELISAs were 0.4 μg/kg and 0.3 μg/kg for aflatoxin B₁, respectively, which are one of the lowest reported values. Total aflatoxins ELISA was also validated for the detection of aflatoxins B₂, G₁ and G₂. The application of the developed tests was demonstrated by screening 32 peanut samples collected from the UK retailers. Total aflatoxins ELISA was further applied to analyse naturally contaminated maize porridge and distiller's dried grain with solubles samples and the results were correlated with these obtained by UHPLC-MS/MS method.

Fast classification in incrementally growing spaces

[EN]The classification speed of state-of-the-art classifiers such as SVM is an important aspect to be considered for emerging applications and domains such as data mining and human-computer interaction. Usually, a test-time speed increase in SVMs is achieved by somehow reducing the number of support vectors, which allows a faster evaluation of the decision function. In this paper a novel approach is described for fast classification in a PCA+SVM scenario. In the proposed approach, classification of an unseen sample is performed incrementally in increasingly larger feature spaces. As soon as the classification confidence is above a threshold the process stops and the class label is retrieved...

Modelling and Verification of a Correction Factor to Evaluate the Efficiency of Solar Thermal Collectors with the Rapid Test Method

A new method for the evaluation of the efficiency of parabolic trough collectors, called Rapid Test Method, is investigated at the Solar Institut Jülich. The basic concept is to carry out measurements under stagnation conditions. This allows a fast and inexpensive process due to the fact that no working fluid is required. With this approach, the temperature reached by the inner wall of the receiver is assumed to be the stagnation temperature and hence the average temperature inside the collector. This leads to a systematic error which can be rectified through the introduction of a correction factor. A model of the collector is simulated with COMSOL Multipyisics to study the size of the correction factor depending on collector geometry and working conditions. The resulting values are compared with experimental data obtained at a test rig at the Solar Institut Jülich. These results do not match with the simulated ones. Consequentially, it was not pos-sible to verify the model. The reliability of both the model with COMSOL Multiphysics and of the measurements are analysed. The influence of the correction factor on the rapid test method is also studied, as well as the possibility of neglecting it by measuring the receiver’s inner wall temperature where it receives the least amount of solar rays. The last two chapters analyse the specific heat capacity as a function of pressure and tem-perature and present some considerations about the uncertainties on the efficiency curve obtained with the Rapid Test Method.

Alcohol consumption and the sense of coherence in young people in educational training

The rate of consumption of alcoholic beverages has undergone changes as well as the factors that influence it. In order to understand the significance of drinking patterns, this study was conducted with a sample of young adults (N = 260) ages 20 to 30, in Lisbon. The instruments used were The Alcohol Use Disorders Identification Test and the Sense of Coherence Questionnaire. The results show that 10.8% had problems with alcohol. Those who had a lower sense of coherence, especially in the dimension of investment capacity, presented with more harmful and risky consumption patterns. We conclude that health promotion behaviors should include measures to strengthen a sense of coherence

PREVALENCE AND FACTORS ASSOCIATED WITH THE PERFORMANCE OF MAMMOGRAPHY AND PAP SMEAR TEST

Objective: To estimate the prevalence and factors associated with the performance of mammography and pap smear test in women from the city of Maringá, Paraná. Methods: Population-based cross-sectional study conducted with 345 women aged over 20 years in the period from March 2011 to April 2012. An interview was carried out using a questionnaire proposed by the Ministry of Health, which addressed sociodemographic characteristics, risk factors for chronic noncommunicable diseases and issues related to mammographic and pap screening. Data were analyzed using bivariate analysis, crude analysis with odds ratio (OR) and chi-squared test using Epi Info 3.5.1 program; multivariate analysis using logistic regression was performed using the software Statistica 7.1, with a significance level of 5% and a confidence interval of 95%. Results: The mean age of the women was 52.19 (±5.27) years. The majority (56.5%) had from 0 to 8 years of education. Additionally, 84.6% (n=266) of the women underwent pap smear and 74.3% (n=169) underwent mammography. The lower performance of pap smear test was associated with women with 9-11 years of education (p=0.01), and the lower performance of mammography was associated with women without private health insurance (p<0.01). Conclusion: The coverage of mammography and pap smear test was satisfactory among the women from Maringá, Paraná. Low education level and women who depended on the public health system presented lower performance of mammography.

Exploring coordination-driven self-assembly with autonomous chemical robots

The work presented herein focused on the automation of coordination-driven self assembly, exploring methods that allow syntheses to be followed more closely while forming new ligands, as part of the fundamental study of the digitization of chemical synthesis and discovery. Whilst the control and understanding of the principle of pre-organization and self-sorting under non-equilibrium conditions remains a key goal, a clear gap has been identified in the absence of approaches that can permit fast screening and real-time observation of the reaction process under different conditions. A firm emphasis was thus placed on the realization of an autonomous chemical robot, which can not only monitor and manipulate coordination chemistry in real-time, but can also allow the exploration of a large chemical parameter space defined by the ligand building blocks and the metal to coordinate. The self-assembly of imine ligands with copper and nickel cations has been studied in a multi-step approach using a self-built flow system capable of automatically controlling the liquid-handling and collecting data in real-time using a benchtop MS and NMR spectrometer. This study led to the identification of a transient Cu(I) species in situ which allows for the formation of dimeric and trimeric carbonato bridged Cu(II) assemblies. Furthermore, new Ni(II) complexes and more remarkably also a new binuclear Cu(I) complex, which usually requires long and laborious inert conditions, could be isolated. The study was then expanded to the autonomous optimization of the ligand synthesis by enabling feedback control on the chemical system via benchtop NMR. The synthesis of new polydentate ligands has emerged as a result of the study aiming to enhance the complexity of the chemical system to accelerate the discovery of new complexes. This type of ligand consists of 1-pyridinyl-4-imino-1,2,3-triazole units, which can coordinate with different metal salts. The studies to test for the CuAAC synthesis via microwave lead to the discovery of four new Cu complexes, one of them being a coordination polymer obtained from a solvent dependent crystallization technique. With the goal of easier integration into an automated system, copper tubing has been exploited as the chemical reactor for the synthesis of this ligand, as it efficiently enhances the rate of the triazole formation and consequently promotes the formation of the full ligand in high yields within two hours. Lastly, the digitization of coordination-driven self-assembly has been realized for the first time using an in-house autonomous chemical robot, herein named the ‘Finder’. The chemical parameter space to explore was defined by the selection of six variables, which consist of the ligand precursors necessary to form complex ligands (aldehydes, alkineamines and azides), of the metal salt solutions and of other reaction parameters – duration, temperature and reagent volumes. The platform was assembled using rounded bottom flasks, flow syringe pumps, copper tubing, as an active reactor, and in-line analytics – a pH meter probe, a UV-vis flow cell and a benchtop MS. The control over the system was then obtained with an algorithm capable of autonomously focusing the experiments on the most reactive region (by avoiding areas of low interest) of the chemical parameter space to explore. This study led to interesting observations, such as metal exchange phenomena, and also to the autonomous discovery of self assembled structures in solution and solid state – such as 1-pyridinyl-4-imino-1,2,3-triazole based Fe complexes and two helicates based on the same ligand coordination motif.

Home-based urinary HPV DNA testing in women who do not attend cervical cancer screening clinics

International audience

Sensibilidad ética y su relación con el consumo de alcohol en personal de enfermería

Propósito y Método de Estudio: El propósito fue identificar la relación que existe de la Sensibilidad Ética y el consumo de alcohol en el personal de enfermería de un hospital de salud pública del área metropolitana de Monterrey, Nuevo León. El diseño del estudio fue descriptivo correlacional. La población estuvo conformada por 325 enfermeros de ambos sexos de una institución de salud pública en el área metropolitana de Monterrey, Nuevo León. Se utilizó un muestreo aleatorio simple y el tamaño de la muestra se determinó a través del paquete estadístico n’Query Advisor Versión 4.0 ® (Elashoff, Dixon, Crede y Fothenringham, 1997). Se estimó la muestra para una proporción con un intervalo de confianza (IC) de 95%, usando un enfoque conservador (p=q=½) con un límite de error de estimación de .05 (±5%). Se determinó, una muestra final de 219 enfermeros. Se utilizó una Cédula de Datos Personales y Laborales y de Prevalencia de Consumo de Alcohol y los instrumentos: Cuestionario de Sensibilidad Ética [MSQ] que obtuvo un Coeficiente de Confiabilidad de .73 y el Test de Identificación de Trastornos Asociados al Consumo del Alcohol [AUDIT] que presentó una consistencia interna de .80. Se aplicó la prueba de Kolmogorov-Smirnov con corrección de Lilliefors y se utilizó estadística no paramétrica: U de Mann-Whitney, H de Kruskal-Wallis y Coeficiente de Correlación de Spearman. Contribución y Conclusiones: La edad promedio del consumo de alcohol fue de 18 años con un consumo de 3 bebidas alcohólicas en un día típico. La prevalencia global del consumo de alcohol fue de 84.5% con un IC 95% [79-89], la prevalencia lápsica del 70.3% con un IC 95% [64-76], la prevalencia actual fue del 50.2% con un IC 95% [43-56] y la prevalencia instantánea fue del 22.7% con un IC 95% [17-28]. El consumo de alcohol mostró diferencias significativas por sexo (X2=28.6, p=.001) el sexo femenino presentó mayor consumo sensato (64.9%) y el consumo dependiente y dañino fue mayor para el sexo masculino (42.1%, 35.1%). Así mismo se encontraron diferencias significativas de consumo de alcohol por edad (X2=12.47, p=.014), donde le personal de 35 años o más presentó mayor consumo sensato (58.8%) y dañino (18.8%) y el consumo dependiente fue mayor para el grupo de 25 a 34 años (40.4%).