Comparison of bispectral index and entropy monitoring in patients undergoing internalisation of deep brain stimulators

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Suparna Bharadwaj

2016-01-01

Full Text Available Introduction: Depth of anaesthesia (DOA monitors are shown to reduce the intra-operative dose of anaesthetic agents, provide haemodynamic stability and shorten emergence times. Electroencephalography (EEG based DOA monitors such as bispectral index (BIS and entropy have been calibrated and validated in healthy subjects. Hence the clinical effectiveness of these monitors may be affected when monitoring patients with neurological disorders (e.g., epilepsy, dystonia, dementia and Parkinson's disease. The aim of this study was to determine whether BIS and entropy correlate with each other and with clinical indices of DOA in patients with movement disorders under general anaesthesia (GA. Materials and Methods: We conducted a prospective, observational study in patients with movement disorders undergoing internalization of deep brain stimulators. All patients received standard GA with age-adjusted mean alveolar concentration (aaMAC of an inhalational agent between 0.7 and 1.1. BIS and entropy sensors were applied on the patient's left forehead. Data collected included clinical parameters and EEG-based DOA indices. Correlation analysis was performed between entropy, BIS and the clinical indices of DOA. Bland Altman analysis was performed to determine the agreement between BIS and entropy. Results: Thirty patients were studied (mean age was 58.4 ± 11 years, male: female 18:12 and weight 79.2 ± 17 kg. Indications for deep brain stimulation were Parkinson's disease (n = 25, essential tremors (n = 2 and dystonia (n = 3. There was a very strong positive correlation between BIS and response entropy (RE (r = 0.932 and BIS and state entropy (SE (r = 0.950 and a strong negative correlation among aaMAC and BIS, RE and SE with r values of −0.686, −0.788 and −0.732, respectively. However, there was no correlation between BIS, RE, SE and haemodynamic values. Conclusion: Our study showed that BIS and entropy perform well in patients with movement disorders

Valorization procedure of x-ray equipment in the mammography equipment

International Nuclear Information System (INIS)

Ruiz, M. A.; Ordonez, J.; Antolin, E.; Andres, J. C. de; Gonzalez, I.; Arranz, L.; Sastre, J. M.; Ferrer, N.

2006-01-01

The Ramon y Cajal Hospital mammography service has three X-rays units, two of them with high resolution computed radiography (CR) system and one with flat-panel (FP)-based full-field digital mammography system. Periodic control dose tests in patients have shown lower glandular dose levels (DGM) than references provided by European Protocol for de Quality Control of de Physical and Technical Aspects of Mammography Screening. In this work, we have tried to establish an easy method for DGM calculation which is representative of the three equipment results. For this aim, we have defined an index which is measured along the time like a reference point. This index is defined as the relation between the blind test punctuations of a standard phantom image given by at least three radiologists in the Unit, and the average DGM values obtained in 20 patients in each Unit (using random thickness and random mama composition). (Author)

Research on Sustainable Development Level Evaluation of Resource-based Cities Based on Shapely Entropy and Chouqet Integral

Science.gov (United States)

Zhao, Hui; Qu, Weilu; Qiu, Weiting

2018-03-01

In order to evaluate sustainable development level of resource-based cities, an evaluation method with Shapely entropy and Choquet integral is proposed. First of all, a systematic index system is constructed, the importance of each attribute is calculated based on the maximum Shapely entropy principle, and then the Choquet integral is introduced to calculate the comprehensive evaluation value of each city from the bottom up, finally apply this method to 10 typical resource-based cities in China. The empirical results show that the evaluation method is scientific and reasonable, which provides theoretical support for the sustainable development path and reform direction of resource-based cities.

Differences between state entropy and bispectral index during analysis of identical electroencephalogram signals: a comparison with two randomised anaesthetic techniques.

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Pilge, Stefanie; Kreuzer, Matthias; Karatchiviev, Veliko; Kochs, Eberhard F; Malcharek, Michael; Schneider, Gerhard

2015-05-01

It is claimed that bispectral index (BIS) and state entropy reflect an identical clinical spectrum, the hypnotic component of anaesthesia. So far, it is not known to what extent different devices display similar index values while processing identical electroencephalogram (EEG) signals. To compare BIS and state entropy during analysis of identical EEG data. Inspection of raw EEG input to detect potential causes of erroneous index calculation. Offline re-analysis of EEG data from a randomised, single-centre controlled trial using the Entropy Module and an Aspect A-2000 monitor. Klinikum rechts der Isar, Technische Universität München, Munich. Forty adult patients undergoing elective surgery under general anaesthesia. Blocked randomisation of 20 patients per anaesthetic group (sevoflurane/remifentanil or propofol/remifentanil). Isolated forearm technique for differentiation between consciousness and unconsciousness. Prediction probability (PK) of state entropy to discriminate consciousness from unconsciousness. Correlation and agreement between state entropy and BIS from deep to light hypnosis. Analysis of raw EEG compared with index values that are in conflict with clinical examination, with frequency measures (frequency bands/Spectral Edge Frequency 95) and visual inspection for physiological EEG patterns (e.g. beta or delta arousal), pathophysiological features such as high-frequency signals (electromyogram/high-frequency EEG or eye fluttering/saccades), different types of electro-oculogram or epileptiform EEG and technical artefacts. PK of state entropy was 0.80 and of BIS 0.84; correlation coefficient of state entropy with BIS 0.78. Nine percent BIS and 14% state entropy values disagreed with clinical examination. Highest incidence of disagreement occurred after state transitions, in particular for state entropy after loss of consciousness during sevoflurane anaesthesia. EEG sequences which led to false 'conscious' index values often showed high

Evaluation of Intensive Construction Land Use in the Emerging City Based on PSR-Entropy model

Science.gov (United States)

Jia, Yuanyuan; Lei, Guangyu

2018-01-01

A comprehensive understanding of emerging city land utilization and the evaluation of intensive land use in the Emerging City will provide the comprehensive and reliable technical basis for the planning and management. It is an important node. According to the Han cheng from 2008 to 2016 years of land use, based on PSR-Entropy model of land use evaluation system, using entropy method to determine the index weight, the introduction of comprehensive index method to evaluate the degree of land use. The results show that the intensive land use comprehensive evaluation index of Han cheng increased from 2008 to 2015, but the land intensive use can not achieve the standards. The potential of further enhancing space is relatively large.

Entropy maximization under the constraints on the generalized Gini index and its application in modeling income distributions

Science.gov (United States)

Khosravi Tanak, A.; Mohtashami Borzadaran, G. R.; Ahmadi, J.

2015-11-01

In economics and social sciences, the inequality measures such as Gini index, Pietra index etc., are commonly used to measure the statistical dispersion. There is a generalization of Gini index which includes it as special case. In this paper, we use principle of maximum entropy to approximate the model of income distribution with a given mean and generalized Gini index. Many distributions have been used as descriptive models for the distribution of income. The most widely known of these models are the generalized beta of second kind and its subclass distributions. The obtained maximum entropy distributions are fitted to the US family total money income in 2009, 2011 and 2013 and their relative performances with respect to generalized beta of second kind family are compared.

Prediction Model of Collapse Risk Based on Information Entropy and Distance Discriminant Analysis Method

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Hujun He

2017-01-01

Full Text Available The prediction and risk classification of collapse is an important issue in the process of highway construction in mountainous regions. Based on the principles of information entropy and Mahalanobis distance discriminant analysis, we have produced a collapse hazard prediction model. We used the entropy measure method to reduce the influence indexes of the collapse activity and extracted the nine main indexes affecting collapse activity as the discriminant factors of the distance discriminant analysis model (i.e., slope shape, aspect, gradient, and height, along with exposure of the structural face, stratum lithology, relationship between weakness face and free face, vegetation cover rate, and degree of rock weathering. We employ postearthquake collapse data in relation to construction of the Yingxiu-Wolong highway, Hanchuan County, China, as training samples for analysis. The results were analyzed using the back substitution estimation method, showing high accuracy and no errors, and were the same as the prediction result of uncertainty measure. Results show that the classification model based on information entropy and distance discriminant analysis achieves the purpose of index optimization and has excellent performance, high prediction accuracy, and a zero false-positive rate. The model can be used as a tool for future evaluation of collapse risk.

Task-based strategy for optimized contrast enhanced breast imaging: analysis of six imaging techniques for mammography and tomosynthesis

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Ikejimba, Lynda; Kiarashi, Nooshin; Lin, Yuan; Chen, Baiyu; Ghate, Sujata V.; Zerhouni, Moustafa; Samei, Ehsan; Lo, Joseph Y.

2012-03-01

Digital breast tomosynthesis (DBT) is a novel x-ray imaging technique that provides 3D structural information of the breast. In contrast to 2D mammography, DBT minimizes tissue overlap potentially improving cancer detection and reducing number of unnecessary recalls. The addition of a contrast agent to DBT and mammography for lesion enhancement has the benefit of providing functional information of a lesion, as lesion contrast uptake and washout patterns may help differentiate between benign and malignant tumors. This study used a task-based method to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: contrast enhanced mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Imaging performance was characterized using a detectability index d', derived from the system task transfer function (TTF), an imaging task, iodine contrast, and the noise power spectrum (NPS). The task modeled a 5 mm lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d' was generated as a function of dose and iodine concentration. In general, higher dose gave higher d', but for the lowest iodine concentration and lowest dose, dual energy subtraction tomosynthesis and temporal subtraction tomosynthesis demonstrated the highest performance.

Does gender discrimination impact regular mammography screening? Findings from the race differences in screening mammography study.

Science.gov (United States)

Dailey, Amy B; Kasl, Stanislav V; Jones, Beth A

2008-03-01

ABSTRACT Objective: To determine if gender discrimination, conceptualized as a negative life stressor, is a deterrent to adherence to mammography screening guidelines. African American and white women (1451) aged 40-79 years who obtained an index screening mammogram at one of five urban hospitals in Connecticut between October 1996 and January 1998 were enrolled in this study. This logistic regression analysis includes the 1229 women who completed telephone interviews at baseline and follow-up (average 29.4 months later) and for whom the study outcome, nonadherence to age-specific mammography screening guidelines, was determined. Gender discrimination was measured as lifetime experience in seven possible situations. Gender discrimination, reported by nearly 38% of the study population, was significantly associated with nonadherence to mammography guidelines in women with annual family incomes of > or =$50,000 (OR 1.99, 95% CI 1.33, 2.98) and did not differ across racial/ethnic group. Our findings suggest that gender discrimination can adversely influence regular mammography screening in some women. With nearly half of women nonadherent to screening mammography guidelines in this study and with decreasing mammography rates nationwide, it is important to address the complexity of nonadherence across subgroups of women. Life stressors, such as experiences of gender discrimination, may have considerable consequences, potentially influencing health prevention prioritization in women.

Determinants of mammography screening behavior in Iranian women: A population-based study

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Mitra Moodi

2012-01-01

Full Text Available Background: Breast cancer remains a substantial health concern in Iran due to delay and late stage at diagnosis and treatment. Despite the potential benefits of mammography screening for early detection of breast cancer, the performance of this screening among Iranian women is low. For planning appropriate intervention, this study was carried out to identify mammography rates and explore determinants of mammography screening behavior in females of Isfahan, Iran. Materials and Methods: In this population-based study, 384 women of 40 years and older were interviewed by telephone. The Farsi version of Champion′s Health Belief Model scale (CHBMS was used to examine factors associated with mammography screening. The obtained data were analyzed by SPSS (version 16.0 using statistical Chi-square, Fisher Exact test, t-test and multiple logistic regression model to identify the importance rate of socio-demographic and Health Belief Model (HBM variables to predict mammography screening behavior. In all of tests, the level of significant was considered a = 0.05. Results: Mean age ΁ SD of women was 52.24 ΁ 8.2 years. Of the 384 participants, 44.3% reported at least one mammogram in their lifetime. Logistic regression analysis indicated that women were more likely to have mammography if they heard/read about breast cancer (OR = 4.17, 95% CI 2.09, 8.34, menopause in lower age (OR = 0.2, 95% CI 0.87, 0.99 and history of breast problem (OR = 0.9, 95% CI 0.12, 0.32. Also, women who perceived more benefits of mammography (OR = 1.84, 95% CI 1.63, 2.09, fewer barriers of mammography (OR = 0.91, 95% CI 0.86, 0.96 and had more motivation for health (OR = 0.94, 95% CI 0.89, 1 were more likely to have mammography. Conclusion: The findings indicated that the rate of mammography screening among women in Isfahan province is low and highlights the need for developing a comprehensive national breast cancer control program, which should be considered as the first

Body weight and sensitivity of screening mammography

DEFF Research Database (Denmark)

Njor, Sisse H.; von Euler-Chelpin, My; Tjønneland, Anne

2016-01-01

benefit more from screening than other women. Methods: We combined data from the Danish Diet, Cancer and Health study and the organised population-based screening mammography programme in Copenhagen, Denmark. Women were categorised according to body mass index (BMI) (...Aim: Obese women tend to participate less in breast cancer screening than normal weight women. However, obese women have fattier breast than normal weight women, and screening mammography works better in fatty than in dense breasts. One might, therefore, hypothesise that obese women would actually......, and 35+). We measured recall rate, sensitivity and specificity for subsequent screens with a 2-year follow-up period. Results: The study included 6787 women. The recall rate varied from 1.4% for women with BMI women with BMI 35+, test for trend p = 0.86. Sensitivity varied from 42% (95...

Breast mass detection in mammography and tomosynthesis via fully convolutional network-based heatmap regression

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Zhang, Jun; Cain, Elizabeth Hope; Saha, Ashirbani; Zhu, Zhe; Mazurowski, Maciej A.

2018-02-01

Breast mass detection in mammography and digital breast tomosynthesis (DBT) is an essential step in computerized breast cancer analysis. Deep learning-based methods incorporate feature extraction and model learning into a unified framework and have achieved impressive performance in various medical applications (e.g., disease diagnosis, tumor detection, and landmark detection). However, these methods require large-scale accurately annotated data. Unfortunately, it is challenging to get precise annotations of breast masses. To address this issue, we propose a fully convolutional network (FCN) based heatmap regression method for breast mass detection, using only weakly annotated mass regions in mammography images. Specifically, we first generate heat maps of masses based on human-annotated rough regions for breast masses. We then develop an FCN model for end-to-end heatmap regression with an F-score loss function, where the mammography images are regarded as the input and heatmaps for breast masses are used as the output. Finally, the probability map of mass locations can be estimated with the trained model. Experimental results on a mammography dataset with 439 subjects demonstrate the effectiveness of our method. Furthermore, we evaluate whether we can use mammography data to improve detection models for DBT, since mammography shares similar structure with tomosynthesis. We propose a transfer learning strategy by fine-tuning the learned FCN model from mammography images. We test this approach on a small tomosynthesis dataset with only 40 subjects, and we show an improvement in the detection performance as compared to training the model from scratch.

Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

Science.gov (United States)

Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

2014-01-01

Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d′, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d′ was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d′, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d′ values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of inplane structures and

EEG entropy measures in anesthesia

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Zhenhu eLiang

2015-02-01

Full Text Available Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs’ effect is lacking. In this study, we compare the capability of twelve entropy indices for monitoring depth of anesthesia (DoA and detecting the burst suppression pattern (BSP, in anesthesia induced by GA-BAergic agents.Methods: Twelve indices were investigated, namely Response Entropy (RE and State entropy (SE, three wavelet entropy (WE measures (Shannon WE (SWE, Tsallis WE (TWE and Renyi WE (RWE, Hilbert-Huang spectral entropy (HHSE, approximate entropy (ApEn, sample entropy (SampEn, Fuzzy entropy, and three permutation entropy (PE measures (Shannon PE (SPE, Tsallis PE (TPE and Renyi PE (RPE. Two EEG data sets from sevoflurane-induced and isoflu-rane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, phar-macokinetic / pharmacodynamic (PK/PD modeling and prediction probability analysis were applied. The multifractal detrended fluctuation analysis (MDFA as a non-entropy measure was compared.Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline vari-ability, higher coefficient of determination and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an ad-vantage in computation efficiency compared with MDFA.Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure.Significance: Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA.

EEG entropy measures in anesthesia

Science.gov (United States)

Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

2015-01-01

Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation

Reproducibility of Mammography Units, Film Processing and Quality Imaging

International Nuclear Information System (INIS)

Gaona, Enrique

2003-01-01

The purpose of this study was to carry out an exploratory survey of the problems of quality control in mammography and processors units as a diagnosis of the current situation of mammography facilities. Measurements of reproducibility, optical density, optical difference and gamma index are included. Breast cancer is the most frequently diagnosed cancer and is the second leading cause of cancer death among women in the Mexican Republic. Mammography is a radiographic examination specially designed for detecting breast pathology. We found that the problems of reproducibility of AEC are smaller than the problems of processors units because almost all processors fall outside of the acceptable variation limits and they can affect the mammography quality image and the dose to breast. Only four mammography units agree with the minimum score established by ACR and FDA for the phantom image

Use of Iodine-based contrast media in digital full-field mammography - initial experience

International Nuclear Information System (INIS)

Diekmann, F.; Diekmann, S.; Taupitz, M.; Bick, U.; Winzer, K.-J.; Huettner, C.; Muller, S.; Jeunehomme, F.; Hamm, B.

2003-01-01

Aim: To investigate the use of iodine-based contrast media in digital full-field mammography. Methods: After performing initial phantom studies, seven patients underwent digital mammography (Senographe 2000D, GE Medical Systems, Milwaukee, USA) using a specially filtered beam before as well as 60, 120, and 180 seconds after injection of 80 ml of iodine contrast medium (Ultravist 370, Schering AG, Germany). The precontrast mammograms were then subtracted from the postcontrast mammograms and the resulting images compared with a contrast-enhanced dynamic MRI study, performed on all women. Results: Contrast medium accumulation within the tumors was visualized with a good quality in all cases. The conditions under which successful contrast-enhanced digital mammography can be performed were determined in phantom studies. Conclusions: Contrast-enhanced digital mammography has a potential for improving the visualization of breast tumors in mammography using special beam filtering, adjusted X-ray parameters, proper timing, and suitable subtraction software. (orig.) [de

Study and Application of Grey Entropy Weight Decision Making in Risk Management

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DeYu Kong

2009-03-01

Full Text Available In traditional risk evaluation, the weight of a risk index is given in advance, so it lacks objectivity. Using weights and properties generated by entropy concepts, including the idea of information entropy, the comprehensive weight, which can be combined with entropy weight, is calculated. A grey evaluation model of a project risk evaluation index based on comprehensive entropy weight is built. Further, we present empirical research on a real project, which indicates that this approach calculates easily, gives weight scientifically, and provides evaluation accurately.

Screen-film mammography versus full-field digital mammography in a population-based screening program: The Sogn and Fjordane study

International Nuclear Information System (INIS)

Juel, Inger-Marie; Johannessen, Gunnar; Skaane, Per; Roth Hoff, Solveig; Hofvind, Solveig

2010-01-01

Background: Studies comparing analog and digital mammography in breast cancer screening have shown conflicting results. Little is known about the use of digital photon-counting detectors. Purpose: To retrospectively compare performance indicators in screen-film (SFM) and full-field digital mammography (FFDM) using a photon-counting detector in a population-based screening program. Material and Methods: The Norwegian Social Science Data Services approved the study, which was part of the Norwegian Breast Cancer Screening Program. The program invites women aged 50-69 years to two-view mammography biannually. The study period was January 2005 to June 2006 for SFM and August 2006 to December 2007 for FFDM. Independent double reading was performed using a five-point rating scale for probability of cancer. Recalls due to abnormal mammography were retrospectively reviewed by an expert panel. Performance indicators for the two techniques were compared. Attendance rate was 83.6% (7442/8901) for SFM and 82.0% (6932/8451) for FFDM. Results: The recall rate due to abnormal mammography, cancer detection rate and positive predictive value did not differ significantly between SFM and FFDM: recall 2.3% (174/7442) versus 2.4% (168/6932), cancer detection 0.39% (29/7442) versus 0.48% (33/6932), positive predictive value 16.7% (29/174) versus 19.6% (33/168), respectively (P>0.05 for all). The recall rate due to technically inadequate mammograms was 0.3% (19/7442) for SFM and 0.01% (1/6932) for FFDM. In the retrospective review, a significantly higher proportion of calcifications and asymmetric density were categorized as normal or definitively benign in FFDM compared with SFM. The average glandular dose was 2.17 mGy for SFM and 1.25 mGy for FFDM. Conclusion: Performance indicators show that FFDM using photon-counting detector is suitable for breast cancer screening. The lower radiation dose and lower recalls due to technically inadequate mammograms are of importance in mammography

Quality Imaging - Comparison of CR Mammography with Screen-Film Mammography

International Nuclear Information System (INIS)

Gaona, E.; Azorin Nieto, J.; Iran Diaz Gongora, J. A.; Arreola, M.; Casian Castellanos, G.; Perdigon Castaneda, G. M.; Franco Enriquez, J. G.

2006-01-01

The aim of this work is a quality imaging comparison of CR mammography images printed to film by a laser printer with screen-film mammography. A Giotto and Elscintec dedicated mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in screen-film mammography. Four CR mammography units from two different manufacturers and three dedicated x-ray mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in CR mammography. The tests quality image included an assessment of system resolution, scoring phantom images, Artifacts, mean optical density and density difference (contrast). In this study, screen-film mammography with a quality control program offers a significantly greater level of quality image relative to CR mammography images printed on film

Crane Safety Assessment Method Based on Entropy and Cumulative Prospect Theory

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Aihua Li

2017-01-01

Full Text Available Assessing the safety status of cranes is an important problem. To overcome the inaccuracies and misjudgments in such assessments, this work describes a safety assessment method for cranes that combines entropy and cumulative prospect theory. Firstly, the proposed method transforms the set of evaluation indices into an evaluation vector. Secondly, a decision matrix is then constructed from the evaluation vectors and evaluation standards, and an entropy-based technique is applied to calculate the index weights. Thirdly, positive and negative prospect value matrices are established from reference points based on the positive and negative ideal solutions. Thus, this enables the crane safety grade to be determined according to the ranked comprehensive prospect values. Finally, the safety status of four general overhead traveling crane samples is evaluated to verify the rationality and feasibility of the proposed method. The results demonstrate that the method described in this paper can precisely and reasonably reflect the safety status of a crane.

Information Entropy Measures for Stand Structural Diversity:Joint Entropy

Institute of Scientific and Technical Information of China (English)

Lei Xiangdong; Lu Yuanchang

2004-01-01

Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) has been the most widely used measure of species diversity. It is generally thought that tree size diversity could serve as a good proxy for height diversity. However, tree size diversity and height diversity for stand structure is not completely consistent. Stand diameter cannot reflect height information completely. Either tree size diversity or height diversity is one-dimensional information entropy measure. This paper discussed the method of multiple-dimensional information entropy measure with the concept of joint entropy. It is suggested that joint entropy is a good measure for describing overall stand structural diversity.

Contrast-enhanced spectral mammography based on a photon-counting detector: quantitative accuracy and radiation dose

Science.gov (United States)

Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

2017-03-01

Contrast-enhanced mammography has been used to demonstrate functional information about a breast tumor by injecting contrast agents. However, a conventional technique with a single exposure degrades the efficiency of tumor detection due to structure overlapping. Dual-energy techniques with energy-integrating detectors (EIDs) also cause an increase of radiation dose and an inaccuracy of material decomposition due to the limitations of EIDs. On the other hands, spectral mammography with photon-counting detectors (PCDs) is able to resolve the issues induced by the conventional technique and EIDs using their energy-discrimination capabilities. In this study, the contrast-enhanced spectral mammography based on a PCD was implemented by using a polychromatic dual-energy model, and the proposed technique was compared with the dual-energy technique with an EID in terms of quantitative accuracy and radiation dose. The results showed that the proposed technique improved the quantitative accuracy as well as reduced radiation dose comparing to the dual-energy technique with an EID. The quantitative accuracy of the contrast-enhanced spectral mammography based on a PCD was slightly improved as a function of radiation dose. Therefore, the contrast-enhanced spectral mammography based on a PCD is able to provide useful information for detecting breast tumors and improving diagnostic accuracy.

Assessment of automatic exposure control performance in digital mammography using a no-reference anisotropic quality index

Science.gov (United States)

Barufaldi, Bruno; Borges, Lucas R.; Bakic, Predrag R.; Vieira, Marcelo A. C.; Schiabel, Homero; Maidment, Andrew D. A.

2017-03-01

Automatic exposure control (AEC) is used in mammography to obtain acceptable radiation dose and adequate image quality regardless of breast thickness and composition. Although there are physics methods for assessing the AEC, it is not clear whether mammography systems operate with optimal dose and image quality in clinical practice. In this work, we propose the use of a normalized anisotropic quality index (NAQI), validated in previous studies, to evaluate the quality of mammograms acquired using AEC. The authors used a clinical dataset that consists of 561 patients and 1,046 mammograms (craniocaudal breast views). The results show that image quality is often maintained, even at various radiation levels (mean NAQI = 0.14 +/- 0.02). However, a more careful analysis of NAQI reveals that the average image quality decreases as breast thickness increases. The NAQI is reduced by 32% on average, when the breast thickness increases from 31 to 71 mm. NAQI also decreases with lower breast density. The variation in breast parenchyma alone cannot fully account for the decrease of NAQI with thickness. Examination of images shows that images of large, fatty breasts are often inadequately processed. This work shows that NAQI can be applied in clinical mammograms to assess mammographic image quality, and highlights the limitations of the automatic exposure control for some images.

Multidimensional scaling analysis of financial time series based on modified cross-sample entropy methods

Science.gov (United States)

He, Jiayi; Shang, Pengjian; Xiong, Hui

2018-06-01

Stocks, as the concrete manifestation of financial time series with plenty of potential information, are often used in the study of financial time series. In this paper, we utilize the stock data to recognize their patterns through out the dissimilarity matrix based on modified cross-sample entropy, then three-dimensional perceptual maps of the results are provided through multidimensional scaling method. Two modified multidimensional scaling methods are proposed in this paper, that is, multidimensional scaling based on Kronecker-delta cross-sample entropy (MDS-KCSE) and multidimensional scaling based on permutation cross-sample entropy (MDS-PCSE). These two methods use Kronecker-delta based cross-sample entropy and permutation based cross-sample entropy to replace the distance or dissimilarity measurement in classical multidimensional scaling (MDS). Multidimensional scaling based on Chebyshev distance (MDSC) is employed to provide a reference for comparisons. Our analysis reveals a clear clustering both in synthetic data and 18 indices from diverse stock markets. It implies that time series generated by the same model are easier to have similar irregularity than others, and the difference in the stock index, which is caused by the country or region and the different financial policies, can reflect the irregularity in the data. In the synthetic data experiments, not only the time series generated by different models can be distinguished, the one generated under different parameters of the same model can also be detected. In the financial data experiment, the stock indices are clearly divided into five groups. Through analysis, we find that they correspond to five regions, respectively, that is, Europe, North America, South America, Asian-Pacific (with the exception of mainland China), mainland China and Russia. The results also demonstrate that MDS-KCSE and MDS-PCSE provide more effective divisions in experiments than MDSC.

Digital mammography

International Nuclear Information System (INIS)

Bick, Ulrich; Diekmann, Felix

2010-01-01

This state-of-the-art reference book provides in-depth coverage of all aspects of digital mammography, including detector technology, image processing, computer-aided diagnosis, soft-copy reading, digital workflow, and PACS. Specific advantages and disadvantages of digital mammography in comparison to screen-film mammography are thoroughly discussed. By including authors from both North America and Europe, the book is able to outline variations in the use, acceptance, and quality assurance of digital mammography between the different countries and screening programs. Advanced imaging techniques and future developments such as contrast mammography and digital breast tomosynthesis are also covered in detail. All of the chapters are written by internationally recognized experts and contain numerous high-quality illustrations. This book will be of great interest both to clinicians who already use or are transitioning to digital mammography and to basic scientists working in the field. (orig.)

Autonomous entropy-based intelligent experimental design

Science.gov (United States)

Malakar, Nabin Kumar

2011-07-01

The aim of this thesis is to explore the application of probability and information theory in experimental design, and to do so in a way that combines what we know about inference and inquiry in a comprehensive and consistent manner. Present day scientific frontiers involve data collection at an ever-increasing rate. This requires that we find a way to collect the most relevant data in an automated fashion. By following the logic of the scientific method, we couple an inference engine with an inquiry engine to automate the iterative process of scientific learning. The inference engine involves Bayesian machine learning techniques to estimate model parameters based upon both prior information and previously collected data, while the inquiry engine implements data-driven exploration. By choosing an experiment whose distribution of expected results has the maximum entropy, the inquiry engine selects the experiment that maximizes the expected information gain. The coupled inference and inquiry engines constitute an autonomous learning method for scientific exploration. We apply it to a robotic arm to demonstrate the efficacy of the method. Optimizing inquiry involves searching for an experiment that promises, on average, to be maximally informative. If the set of potential experiments is described by many parameters, the search involves a high-dimensional entropy space. In such cases, a brute force search method will be slow and computationally expensive. We develop an entropy-based search algorithm, called nested entropy sampling, to select the most informative experiment. This helps to reduce the number of computations necessary to find the optimal experiment. We also extended the method of maximizing entropy, and developed a method of maximizing joint entropy so that it could be used as a principle of collaboration between two robots. This is a major achievement of this thesis, as it allows the information-based collaboration between two robotic units towards a same

Entropy inequalities from reflection positivity

International Nuclear Information System (INIS)

Casini, H

2010-01-01

We investigate the question of whether the entropy and the Renyi entropies of the vacuum state reduced to a region of space can be represented in terms of correlators in quantum field theory. In this case, the positivity relations for the correlators are mapped into inequalities for the entropies. We write them using a real-time version of reflection positivity, which can be generalized to general quantum systems. Using this generalization we can prove an infinite sequence of inequalities which are obeyed by the Renyi entropies of integer index. There is one independent inequality involving any number of different subsystems. In quantum field theory the inequalities acquire a simple geometrical form and are consistent with the integer index Renyi entropies being given by vacuum expectation values of twisting operators in the Euclidean formulation. Several possible generalizations and specific examples are analyzed

Topology, entropy, and Witten index of dilaton black holes

International Nuclear Information System (INIS)

Gibbons, G.W.; Kallosh, R.E.

1995-01-01

We have found that for extreme dilaton black holes an inner boundary must be introduced in addition to the outer boundary to give an integer value to the Euler number. The resulting manifolds have (if one identifies imaginary time) a topology S 1 xRxS 2 and Euler number χ=0 in contrast with the nonextreme case with χ=2. The entropy of extreme U(1) dilaton black holes is already known to be zero. We include a review of some recent ideas due to Hawking on the Reissner-Nordstroem case. By regarding all extreme black holes as having an inner boundary, we conclude that the entropy of all extreme black holes, including [U(1)] 2 black holes, vanishes. We discuss the relevance of this to the vanishing of quantum corrections and the idea that the functional integral for extreme holes gives a Witten index. We have studied also the topology of ''moduli space'' of multi-black-holes. The quantum mechanics on black hole moduli spaces is expected to be supersymmetric despite the fact that they are not hyper-Kaehler since the corresponding geometry has a torsion unlike the BPS monopole case. Finally, we describe the possibility of extreme black hole fission for states with an energy gap. The energy released, as a proportion of the initial rest mass, during the decay of an electromagnetic black hole is 300 times greater than that released by the fission of a 235 U nucleus

Mammography Facilities

Data.gov (United States)

U.S. Department of Health & Human Services — The Mammography Facility Database is updated periodically based on information received from the four FDA-approved accreditation bodies: the American College of...

A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

International Nuclear Information System (INIS)

Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung

2014-01-01

Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

Energy Technology Data Exchange (ETDEWEB)

Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung [Yonsei University, Wonju (Korea, Republic of)

2014-06-15

Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

Entropy Evaluation Based on Value Validity

Directory of Open Access Journals (Sweden)

Tarald O. Kvålseth

2014-09-01

Full Text Available Besides its importance in statistical physics and information theory, the Boltzmann-Shannon entropy S has become one of the most widely used and misused summary measures of various attributes (characteristics in diverse fields of study. It has also been the subject of extensive and perhaps excessive generalizations. This paper introduces the concept and criteria for value validity as a means of determining if an entropy takes on values that reasonably reflect the attribute being measured and that permit different types of comparisons to be made for different probability distributions. While neither S nor its relative entropy equivalent S* meet the value-validity conditions, certain power functions of S and S* do to a considerable extent. No parametric generalization offers any advantage over S in this regard. A measure based on Euclidean distances between probability distributions is introduced as a potential entropy that does comply fully with the value-validity requirements and its statistical inference procedure is discussed.

Multiscale sample entropy and cross-sample entropy based on symbolic representation and similarity of stock markets

Science.gov (United States)

Wu, Yue; Shang, Pengjian; Li, Yilong

2018-03-01

A modified multiscale sample entropy measure based on symbolic representation and similarity (MSEBSS) is proposed in this paper to research the complexity of stock markets. The modified algorithm reduces the probability of inducing undefined entropies and is confirmed to be robust to strong noise. Considering the validity and accuracy, MSEBSS is more reliable than Multiscale entropy (MSE) for time series mingled with much noise like financial time series. We apply MSEBSS to financial markets and results show American stock markets have the lowest complexity compared with European and Asian markets. There are exceptions to the regularity that stock markets show a decreasing complexity over the time scale, indicating a periodicity at certain scales. Based on MSEBSS, we introduce the modified multiscale cross-sample entropy measure based on symbolic representation and similarity (MCSEBSS) to consider the degree of the asynchrony between distinct time series. Stock markets from the same area have higher synchrony than those from different areas. And for stock markets having relative high synchrony, the entropy values will decrease with the increasing scale factor. While for stock markets having high asynchrony, the entropy values will not decrease with the increasing scale factor sometimes they tend to increase. So both MSEBSS and MCSEBSS are able to distinguish stock markets of different areas, and they are more helpful if used together for studying other features of financial time series.

Interval breast cancers in the 'screening with tomosynthesis or standard mammography' (STORM) population-based trial.

Science.gov (United States)

Houssami, Nehmat; Bernardi, Daniela; Caumo, Francesca; Brunelli, Silvia; Fantò, Carmine; Valentini, Marvi; Romanucci, Giovanna; Gentilini, Maria A; Zorzi, Manuel; Macaskill, Petra

2018-04-01

The prospective 'screening with tomosynthesis or standard mammography' (STORM) trial recruited women participating in biennial breast screening in Italy (2011-2012), and compared sequential screen-readings based on 2D-mammography alone or based on tomosynthesis (integrated 2D/3D-mammography). The STORM trial showed that tomosynthesis screen-reading significantly increased breast cancer detection compared to 2D-mammography alone. The present study completes reporting of the trial by examining interval breast cancers ascertained at two year follow-up. 9 interval breast cancers were identified; the estimated interval cancer rate was 1.23/1000 screens [9/7292] (95%CI 0.56 to 2.34) or 1.24/1000 negative screens [9/7235] (95%CI 0.57 to 2.36). In concurrently screened women who attended the same screening services and received 2D-mammography, interval cancer rate was 1.60/1000 screens [40/25,058] (95% CI 1.14 to 2.17) or 1.61/1000 negative screens [40/24,922] (95% CI 1.15 to 2.18). Estimated screening sensitivity for the STORM trial was 85.5% [59/69] (95%CI 75.0%-92.8%), and that for 2D-mammography screening was 77.3% [136/176] (95%CI 70.4%-83.2%). Interval breast cancer rate amongst screening participants in the STORM trial was marginally lower (and screening sensitivity higher) than estimates amongst 2D-screened women; these findings should be interpreted with caution given the small number of interval cases and the sample size of the trial. Much larger screening studies, or pooled analyses, are required to examine interval cancer rates arising after breast tomosynthesis screening versus digital mammography screening. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimating the relative utility of screening mammography.

Science.gov (United States)

Abbey, Craig K; Eckstein, Miguel P; Boone, John M

2013-05-01

The concept of diagnostic utility is a fundamental component of signal detection theory, going back to some of its earliest works. Attaching utility values to the various possible outcomes of a diagnostic test should, in principle, lead to meaningful approaches to evaluating and comparing such systems. However, in many areas of medical imaging, utility is not used because it is presumed to be unknown. In this work, we estimate relative utility (the utility benefit of a detection relative to that of a correct rejection) for screening mammography using its known relation to the slope of a receiver operating characteristic (ROC) curve at the optimal operating point. The approach assumes that the clinical operating point is optimal for the goal of maximizing expected utility and therefore the slope at this point implies a value of relative utility for the diagnostic task, for known disease prevalence. We examine utility estimation in the context of screening mammography using the Digital Mammographic Imaging Screening Trials (DMIST) data. We show how various conditions can influence the estimated relative utility, including characteristics of the rating scale, verification time, probability model, and scope of the ROC curve fit. Relative utility estimates range from 66 to 227. We argue for one particular set of conditions that results in a relative utility estimate of 162 (±14%). This is broadly consistent with values in screening mammography determined previously by other means. At the disease prevalence found in the DMIST study (0.59% at 365-day verification), optimal ROC slopes are near unity, suggesting that utility-based assessments of screening mammography will be similar to those found using Youden's index.

A comparison of the accuracy of film-screen mammography, full-field digital mammography, and digital breast tomosynthesis

International Nuclear Information System (INIS)

Michell, M.J.; Iqbal, A.; Wasan, R.K.; Evans, D.R.; Peacock, C.; Lawinski, C.P.; Douiri, A.; Wilson, R.; Whelehan, P.

2012-01-01

Aim: To measure the change in diagnostic accuracy of conventional film-screen mammography and full-field digital mammography (FFDM) with the addition of digital breast tomosynthesis (DBT) in women recalled for assessment following routine screening. Materials and methods: Ethics approval for the study was granted. Women recalled for assessment following routine screening with screen-film mammography were invited to participate. Participants underwent bilateral, two-view FFDM and two-view DBT. Readers scored each lesion separately for probability of malignancy on screen-film mammography, FFDM, and then DBT. The scores were compared with the presence or absence of malignancy based on the final histopathology outcome. Results: Seven hundred and thirty-eight women participated (93.2% recruitment rate). Following assessment 204 (26.8%) were diagnosed as malignant (147 invasive and 57 in-situ tumours), 286 (37.68%) as benign, and 269 (35.4%) as normal. The diagnostic accuracy was evaluated by using receiving operating characteristic (ROC) and measurement of area under the curve (AUC). The AUC values demonstrated a significant (p = 0.0001) improvement in the diagnostic accuracy with the addition of DBT combined with FFDM and film-screen mammography (AUC = 0.9671) when compared to FFDM plus film-screen mammography (AUC = 0.8949) and film-screen mammography alone (AUC = 0.7882). The effect was significantly greater for soft-tissue lesions [AUC was 0.9905 with the addition of DBT and AUC was 0.9201 for FFDM with film-screen mammography combined (p = 0.0001)] compared to microcalcification [with the addition of DBT (AUC = 0.7920) and for FFDM with film-screen mammography combined (AUC = 0.7843; p = 0.3182)]. Conclusion: The addition of DBT increases the accuracy of mammography compared to FFDM and film-screen mammography combined and film-screen mammography alone in the assessment of screen-detected soft-tissue mammographic abnormalities.

Algebraic entropy for algebraic maps

International Nuclear Information System (INIS)

Hone, A N W; Ragnisco, Orlando; Zullo, Federico

2016-01-01

We propose an extension of the concept of algebraic entropy, as introduced by Bellon and Viallet for rational maps, to algebraic maps (or correspondences) of a certain kind. The corresponding entropy is an index of the complexity of the map. The definition inherits the basic properties from the definition of entropy for rational maps. We give an example with positive entropy, as well as two examples taken from the theory of Bäcklund transformations. (letter)

Cost-effectiveness of increasing access to mammography through mobile mammography for older women.

Science.gov (United States)

Naeim, Arash; Keeler, Emmett; Bassett, Lawrence W; Parikh, Jay; Bastani, Roshan; Reuben, David B

2009-02-01

To compare the costs of mobile and stationary mammography and examine the incremental cost-effectiveness of using mobile mammography to increase screening rates. A cost-effectiveness analysis was performed using effectiveness data from a randomized clinical trial and modeling of costs associated with the mobile mammography intervention. The trial involved 60 community-based meal sites, senior centers, and clubs. Four hundred ninety-nine individuals were enrolled in the study, of whom 463 had outcome data available for analysis. Costs were calculated for stationary and mobile mammography, as well as costs due to differences in technology and film versus digital. Incremental cost-effectiveness (cost per additional screen) was modeled, and sensitivity analysis was performed by altering efficiency (throughput) and effectiveness based on subgroup data from the randomized trial. The estimated annual costs were $435,162 for a stationary unit, $539,052 for a mobile film unit, and $456, 392 for a mobile digital unit. Assuming mobile units are less efficient (50% annual volume), the cost per screen was $41 for a stationary unit, $86 for a mobile film unit, and $102 for a mobile digital unit. The incremental cost per additional screen were $207 for a mobile film unit and $264 for a mobile digital unit over a stationary unit. Although mobile mammography is a more effective way to screen older women, the absolute cost per screen of mobile units is higher, whereas the reimbursement is no different. Financial barriers may impede the widespread use of this approach.

Entropy-based financial asset pricing.

Directory of Open Access Journals (Sweden)

Mihály Ormos

Full Text Available We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return-entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy.

Entropy-based financial asset pricing.

Science.gov (United States)

Ormos, Mihály; Zibriczky, Dávid

2014-01-01

We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return-entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy.

The U.S. Online News Coverage of Mammography Based on a Google News Search.

Science.gov (United States)

Young Lin, Leng Leng; Rosenkrantz, Andrew B

2017-12-01

To characterize online news coverage relating to mammography, including articles' stance toward screening mammography. Google News was used to search U.S. news sites over a 9-year period (2006-2015) based on the search terms "mammography" and "mammogram." The top 100 search results were recorded. Identified articles were manually reviewed. The top 100 news articles were from the following sources: local news outlet (50%), national news outlet (24%), nonimaging medical source (13%), entertainment or culture news outlet (6%), business news outlet (4%), peer-reviewed journal (1%), and radiology news outlet (1%). Most common major themes were the screening mammography controversy (29%), description of a new breast imaging technology (23%), dense breasts (11%), and promotion of a public screening initiative (11%). For the most recent year, article stance toward screening mammography was 59%, favorable; 16%, unfavorable; and 25%, neutral. After 2010, there was an abrupt shift in articles' stances from neutral to both favorable and unfavorable. A wide range of online news sources addressed a range of issues related to mammography. National, rather than local, news sites were more likely to focus on the screening controversy and more likely to take an unfavorable view. The controversial United States Preventive Services Task Force guidelines may have influenced articles to take a stance on screening mammography. As such online news may impact public perception of the topic and thus potentially impact guideline adherence, radiologists are encouraged to maintain awareness of this online coverage and to support the online dissemination of reliable and accurate information. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Ultrasonic mammography

International Nuclear Information System (INIS)

Hueneke, B.

1982-01-01

608 women are examined by means of ultrasonic mammography during the period of 1 year. 432 patients were examined with the compound method with the U.I. Octoson, a water tank scanner, and 176 patients with the real time method with a directly connected linear-array-scanner. The following results were obtained at the end of the examination period: In the ultrasonic and also in the X-ray mammogram tumour diameters can be determined with an error rate of +- 30%. In the diagnosing of carcinomas, a significant dependence of the exactness on the sice of the tumour is found for the combination of the five methods tested (clinical examination, X-ray mammography, ultrasonic mammography, thermography, cytology). Classifying the individual methods with regard to their exactness, X-ray mammography ranks in front of ultrasonic mammography. Mastopathic changes in the breast can be screened by means of ultrasonic mammography. The structure of the changes can be determined more exactly than with an X-ray picture which is due to the possibility of differentiating solid and cystic structures. In diagnosing fibro-adenomas and establishing diagnoses on young women with dense gland bodies, ultrasonic mammography is superior to radiology both in the ability of screening a finding of a fibro-adenoma (US=88%, X-ray=75%) and in the possibility of classifying it as ''more benign than malignant''. (orig./MG) [de

Entropy-Based Algorithm for Supply-Chain Complexity Assessment

Directory of Open Access Journals (Sweden)

Boris Kriheli

2018-03-01

Full Text Available This paper considers a graph model of hierarchical supply chains. The goal is to measure the complexity of links between different components of the chain, for instance, between the principal equipment manufacturer (a root node and its suppliers (preceding supply nodes. The information entropy is used to serve as a measure of knowledge about the complexity of shortages and pitfalls in relationship between the supply chain components under uncertainty. The concept of conditional (relative entropy is introduced which is a generalization of the conventional (non-relative entropy. An entropy-based algorithm providing efficient assessment of the supply chain complexity as a function of the SC size is developed.

Readability assessment of internet-based patient education materials related to mammography for breast cancer screening.

Science.gov (United States)

AlKhalili, Rend; Shukla, Pratik A; Patel, Ronak H; Sanghvi, Saurin; Hubbi, Basil

2015-03-01

The US Department of Health and Human Services (USDHHS) recommends that Internet-based patient education materials (IPEMs) be written below the sixth-grade reading level to target the average American adult. This study was designed to determine the readability of IPEMs regarding mammography for breast cancer screening. Three-hundred mammography-related Web sites were reviewed for IPEMs. Forty-two IPEMs that met the Health on the Net Foundation Code of Conduct were assessed for readability level with four readability indices that use existing algorithms based on word and sentence length to quantitatively analyze Internet sources for language intricacy including the following: Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease Score (FRES), Simple Measure of Gobbledygook (SMOG), and Gunning Frequency of Gobbledygook (Gunning FOG; GFOG). Results were compared to national recommendations, and intergroup analysis was performed. No IPEMs (0%) regarding mammography were written at or below the sixth-grade reading level, based on FKGL. The mean readability scores were as follows: FRES, 49.04 ± 10.62; FKGL, 10.71 ± 2.01; SMOG, 13.33 ± 1.67; and Gunning FOG, 14.32 ± 2.18. These scores indicate that the readability of mammography IPEMs is written at a "difficult" level, significantly above the recommended sixth-grade reading level (P < .05) determined by the USDHHS. IPEMs related to mammography are written well above the recommended sixth-grade level and likely reflect other IPEMs in diagnostic radiology. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

Upper entropy axioms and lower entropy axioms

International Nuclear Information System (INIS)

Guo, Jin-Li; Suo, Qi

2015-01-01

The paper suggests the concepts of an upper entropy and a lower entropy. We propose a new axiomatic definition, namely, upper entropy axioms, inspired by axioms of metric spaces, and also formulate lower entropy axioms. We also develop weak upper entropy axioms and weak lower entropy axioms. Their conditions are weaker than those of Shannon–Khinchin axioms and Tsallis axioms, while these conditions are stronger than those of the axiomatics based on the first three Shannon–Khinchin axioms. The subadditivity and strong subadditivity of entropy are obtained in the new axiomatics. Tsallis statistics is a special case of satisfying our axioms. Moreover, different forms of information measures, such as Shannon entropy, Daroczy entropy, Tsallis entropy and other entropies, can be unified under the same axiomatics

Entropy generation method to quantify thermal comfort

Science.gov (United States)

Boregowda, S. C.; Tiwari, S. N.; Chaturvedi, S. K.

2001-01-01

The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a function of entropy generation. In order to verify the entropy-based thermal comfort model, human thermal physiological responses due to changes in ambient conditions are simulated using a well established and validated human thermal model developed at the Institute of Environmental Research of Kansas State University (KSU). The finite element based KSU human thermal computer model is being utilized as a "Computational Environmental Chamber" to conduct series of simulations to examine the human thermal responses to different environmental conditions. The output from the simulation, which include human thermal responses and input data consisting of environmental conditions are fed into the thermal comfort model. Continuous monitoring of thermal comfort in comfortable and extreme environmental conditions is demonstrated. The Objective Thermal Comfort values obtained from the entropy-based model are validated against regression based Predicted Mean Vote (PMV) values. Using the corresponding air temperatures and vapor pressures that were used in the computer simulation in the regression equation generates the PMV values. The preliminary results indicate that the OTCI and PMV values correlate well under ideal conditions. However, an experimental study

Coherence and entanglement measures based on Rényi relative entropies

International Nuclear Information System (INIS)

Zhu, Huangjun; Hayashi, Masahito; Chen, Lin

2017-01-01

We study systematically resource measures of coherence and entanglement based on Rényi relative entropies, which include the logarithmic robustness of coherence, geometric coherence, and conventional relative entropy of coherence together with their entanglement analogues. First, we show that each Rényi relative entropy of coherence is equal to the corresponding Rényi relative entropy of entanglement for any maximally correlated state. By virtue of this observation, we establish a simple operational connection between entanglement measures and coherence measures based on Rényi relative entropies. We then prove that all these coherence measures, including the logarithmic robustness of coherence, are additive. Accordingly, all these entanglement measures are additive for maximally correlated states. In addition, we derive analytical formulas for Rényi relative entropies of entanglement of maximally correlated states and bipartite pure states, which reproduce a number of classic results on the relative entropy of entanglement and logarithmic robustness of entanglement in a unified framework. Several nontrivial bounds for Rényi relative entropies of coherence (entanglement) are further derived, which improve over results known previously. Moreover, we determine all states whose relative entropy of coherence is equal to the logarithmic robustness of coherence. As an application, we provide an upper bound for the exact coherence distillation rate, which is saturated for pure states. (paper)

Multiscale Shannon entropy and its application in the stock market

Science.gov (United States)

Gu, Rongbao

2017-10-01

In this paper, we perform a multiscale entropy analysis on the Dow Jones Industrial Average Index using the Shannon entropy. The stock index shows the characteristic of multi-scale entropy that caused by noise in the market. The entropy is demonstrated to have significant predictive ability for the stock index in both long-term and short-term, and empirical results verify that noise does exist in the market and can affect stock price. It has important implications on market participants such as noise traders.

Entropy-Based Clutter Rejection for Intrawall Diagnostics

Directory of Open Access Journals (Sweden)

Raffaele Solimene

2012-01-01

Full Text Available The intrawall diagnostic problem of detecting localized inhomogeneities possibly present within the wall is addressed. As well known, clutter arising from masonry structure can impair detection of embedded scatterers due to high amplitude reflections that wall front face introduces. Moreover, internal multiple reflections also can make it difficult ground penetrating radar images (radargramms interpretation. To counteract these drawbacks, a clutter rejection method, properly tailored on the wall features, is mandatory. To this end, here we employ a windowing strategy based on entropy measures of temporal traces “similarity.” Accordingly, instants of time for which radargramms exhibit entropy values greater than a prescribed threshold are “silenced.” Numerical results are presented in order to show the effectiveness of the entropy-based clutter rejection algorithm. Moreover, a comparison with the standard average trace subtraction is also included.

Entropy of the Mixture of Sources and Entropy Dimension

OpenAIRE

Smieja, Marek; Tabor, Jacek

2011-01-01

We investigate the problem of the entropy of the mixture of sources. There is given an estimation of the entropy and entropy dimension of convex combination of measures. The proof is based on our alternative definition of the entropy based on measures instead of partitions.

Screen-film mammography

International Nuclear Information System (INIS)

Logan, W.W.; Janus, J.A.

1987-01-01

The development of screen-film mammography has resulted in the re-emergence of confidence, rather than fear, in mammography. When screen-film mammography is performed with state-of-the-art dedicated equipment utilizing vigorous breast compression and a ''soft'' x-ray beam for improved contrast, screen-film images are equivalent or superior to those of reduced-dose xeromammography and superior to those of nonscreen film mammography. Technological aids for conversion from xeromammographic or nonscreen film mammographic techniques to screen-film techniques have been described. Screen-film mammography should not be attempted until dedicated equipment has been obtained and the importance of vigorous compression has been understood

Development of Malaysian women fertility index: Evidence from Shannon's entropy

Science.gov (United States)

Jalil, Wan Aznie Fatihah Wan Abd; Sharif, Shamshuritawati

2017-11-01

A fertility rate is a measure of the average number of children a woman will have during her childbearing years. Malaysia is now facing a population crisis and the fertility rate continues to decline. This situation will have implications for the age structure of the population where percentages of senior citizens are higher than percentages of people aged below 5 years old. Malaysia is expected to reach aging population status by the year 2035. As the aging population has a very long average life expectancy, the government needs to spend a lot on medical costs for senior citizens and need to increase budgets for pensions. The government may be required to increase tax revenues to support the growing older population. The falling fertility rate requires proper control by relevant authorities, especially through planning and implementation of strategic and effective measures. Hence, this paper aims to develop a fertility index using Shannon's entropy method. The results show that Selangor, Johor, and Sarawak are among the states with the highest values of the fertility index. On the other end of the spectrum, Terengganu, W.P. Labuan, and Perlis are ranked in the last positions according to the fertility index. The information generated from the results in this study can be used as a primary source for the government to design appropriate policies to mitigate dwindling fertility rates among Malaysian women.

Combined Forecasting of Rainfall Based on Fuzzy Clustering and Cross Entropy

Directory of Open Access Journals (Sweden)

Baohui Men

2017-12-01

Full Text Available Rainfall is an essential index to measure drought, and it is dependent upon various parameters including geographical environment, air temperature and pressure. The nonlinear nature of climatic variables leads to problems such as poor accuracy and instability in traditional forecasting methods. In this paper, the combined forecasting method based on data mining technology and cross entropy is proposed to forecast the rainfall with full consideration of the time-effectiveness of historical data. In view of the flaws of the fuzzy clustering method which is easy to fall into local optimal solution and low speed of operation, the ant colony algorithm is adopted to overcome these shortcomings and, as a result, refine the model. The method for determining weights is also improved by using the cross entropy. Besides, the forecast is conducted by analyzing the weighted average rainfall based on Thiessen polygon in the Beijing–Tianjin–Hebei region. Since the predictive errors are calculated, the results show that improved ant colony fuzzy clustering can effectively select historical data and enhance the accuracy of prediction so that the damage caused by extreme weather events like droughts and floods can be greatly lessened and even kept at bay.

Dual-energy contrast-enhanced mammography.

Science.gov (United States)

Travieso Aja, M M; Rodríguez Rodríguez, M; Alayón Hernández, S; Vega Benítez, V; Luzardo, O P

2014-01-01

The degree of vascularization in breast lesions is related to their malignancy. For this reason, functional diagnostic imaging techniques have become important in recent years. Dual-energy contrast-enhanced mammography is a new, apparently promising technique in breast cancer that provides information about the degree of vascularization of the lesion in addition to the morphological information provided by conventional mammography. This article describes the state of the art for dual-energy contrast-enhanced mammography. Based on 15 months' clinical experience, we illustrate this review with clinical cases that allow us to discuss the advantages and limitations of this technique. Copyright © 2014 SERAM. Published by Elsevier Espana. All rights reserved.

the use of entropy index for gender inequality analysis

African Journals Online (AJOL)

DJFLEX

years old; the share of females in wage employment in the non-agricultural ... have greater access to education than females and the gap in access ... (1) is referred to as Shannon entropy (see Ciuperca and Girardin, 2005). Shannon entropy has the property of symmetry i.e. the measure is unchanged if the outcomes i.

Entropy-Based Model for Interpreting Life Systems in Traditional Chinese Medicine

Directory of Open Access Journals (Sweden)

Guo-lian Kang

2008-01-01

Full Text Available Traditional Chinese medicine (TCM treats qi as the core of the human life systems. Starting with a hypothetical correlation between TCM qi and the entropy theory, we address in this article a holistic model for evaluating and unveiling the rule of TCM life systems. Several new concepts such as acquired life entropy (ALE, acquired life entropy flow (ALEF and acquired life entropy production (ALEP are propounded to interpret TCM life systems. Using the entropy theory, mathematical models are established for ALE, ALEF and ALEP, which reflect the evolution of life systems. Some criteria are given on physiological activities and pathological changes of the body in different stages of life. Moreover, a real data-based simulation shows life entropies of the human body with different ages, Cold and Hot constitutions and in different seasons in North China are coincided with the manifestations of qi as well as the life evolution in TCM descriptions. Especially, based on the comparative and quantitative analysis, the entropy-based model can nicely describe the evolution of life entropies in Cold and Hot individuals thereby fitting the Yin–Yang theory in TCM. Thus, this work establishes a novel approach to interpret the fundamental principles in TCM, and provides an alternative understanding for the complex life systems.

An Entropy-Based Measure for Assessing Fuzziness in Logistic Regression

Science.gov (United States)

Weiss, Brandi A.; Dardick, William

2016-01-01

This article introduces an entropy-based measure of data-model fit that can be used to assess the quality of logistic regression models. Entropy has previously been used in mixture-modeling to quantify how well individuals are classified into latent classes. The current study proposes the use of entropy for logistic regression models to quantify…

Tomosynthesis and contrast-enhanced digital mammography: recent advances in digital mammography

International Nuclear Information System (INIS)

Diekmann, Felix; Bick, Ulrich

2007-01-01

Digital mammography is more and more replacing conventional mammography. Initial concerns about an inferior image quality of digital mammography have been largely overcome and recent studies even show digital mammography to be superior in women with dense breasts, while at the same time reducing radiation exposure. Nevertheless, an important limitation of digital mammography remains: namely, the fact that summation may obscure lesions in dense breast tissue. However, digital mammography offers the option of so-called advanced applications, and two of these, contrast-enhanced mammography and tomosynthesis, are promising candidates for improving the detection of breast lesions otherwise obscured by the summation of dense tissue. Two techniques of contrast-enhanced mammography are available: temporal subtraction of images acquired before and after contrast administration and the so-called dual-energy technique, which means that pairs of low/high-energy images acquired after contrast administration are subtracted. Tomosynthesis on the other hand provides three-dimensional information on the breast. The images are acquired with different angulations of the X-ray tube while the object or detector is static. Various reconstruction algorithms can then be applied to the set of typically nine to 28 source images to reconstruct 1-mm slices with a reduced risk of obscuring pathology. Combinations of both advanced applications have only been investigated in individual experimental studies; more advanced software algorithms and CAD systems are still in their infancy and have only undergone preliminary clinical evaluation. (orig.)

IN-cross Entropy Based MAGDM Strategy under Interval Neutrosophic Set Environment

Directory of Open Access Journals (Sweden)

Shyamal Dalapati

2017-12-01

Full Text Available Cross entropy measure is one of the best way to calculate the divergence of any variable from the priori one variable. We define a new cross entropy measure under interval neutrosophic set (INS environment, which we call IN-cross entropy measure and prove its basic properties. We also develop weighted IN-cross entropy measure and investigats its basic properties. Based on the weighted IN-cross entropy measure, we develop a novel strategy for multi attribute group decision making (MAGDM strategy under interval neutrosophic environment. The proposed multi attribute group decision making strategy is compared with the existing cross entropy measure based strategy in the literature under interval neutrosophic set environment. Finally, an illustrative example of multi attribute group decision making problem is solved to show the feasibility, validity and efficiency of the proposed MAGDM strategy.

Design of a sensitive grating-based phase contrast mammography prototype (Conference Presentation)

Science.gov (United States)

Arboleda Clavijo, Carolina; Wang, Zhentian; Köhler, Thomas; van Stevendaal, Udo; Martens, Gerhard; Bartels, Matthias; Villanueva-Perez, Pablo; Roessl, Ewald; Stampanoni, Marco

2017-03-01

Grating-based phase contrast mammography can help facilitate breast cancer diagnosis, as several research works have demonstrated. To translate this technique to the clinics, it has to be adapted to cover a large field of view within a limited exposure time and with a clinically acceptable radiation dose. This indicates that a straightforward approach would be to install a grating interferometer (GI) into a commercial mammography device. We developed a wave propagation based optimization method to select the most convenient GI designs in terms of phase and dark-field sensitivities for the Philips Microdose Mammography (PMM) setup. The phase sensitivity was defined as the minimum detectable breast tissue electron density gradient, whereas the dark-field sensitivity was defined as its corresponding signal-to-noise Ratio (SNR). To be able to derive sample-dependent sensitivity metrics, a visibility reduction model for breast tissue was formulated, based on previous research works on the dark-field signal and utilizing available Ultra-Small-Angle X-ray Scattering (USAXS) data and the outcomes of measurements on formalin-fixed breast tissue specimens carried out in tube-based grating interferometers. The results of this optimization indicate the optimal scenarios for each metric are different and fundamentally depend on the noise behavior of the signals and the visibility reduction trend with respect to the system autocorrelation length. In addition, since the inter-grating distance is constrained by the space available between the breast support and the detector, the best way we have to improve sensitivity is to count on a small G2 pitch.

Inequity of healthcare utilization on mammography examination and Pap smear screening in Thailand: Analysis of a population-based household survey.

Directory of Open Access Journals (Sweden)

Sukanya Chongthawonsatid

Full Text Available Healthcare in Thailand is not equally distributed, and not all people can equally access healthcare resources even if they are covered by health insurance. To examine factors associated with the utilization of mammography examination for breast cancer and Pap smear screening for cervical cancer, data from the national reproductive health survey conducted by the National Statistical Office of Thailand in 2009 was examined. The survey was carried out on 15,074,126 women aged 30-59 years. The results showed that the wealthier respondents had more mammograms than did the lower-income groups. The concentration index was 0.144. The data on Pap smears for cervical cancer also showed that the wealthier respondents were more likely to have had a Pap smear than their lower-income counterparts. The concentration index was 0.054. Determinants of mammography examination were education, followed by health welfare and wealth index, whereas the determinants of Pap smear screening were wealth index, followed by health welfare and education. The government should support greater education for women because education was associated with socioeconomic status and wealth. There should be an increase in the number of screening campaigns, mobile clinics, and low-cost mammograms and continued support for accessibility to mammograms, especially in rural areas and low-income communities.

Computer-aided diagnostics of screening mammography using content-based image retrieval

Science.gov (United States)

Deserno, Thomas M.; Soiron, Michael; de Oliveira, Júlia E. E.; de A. Araújo, Arnaldo

2012-03-01

Breast cancer is one of the main causes of death among women in occidental countries. In the last years, screening mammography has been established worldwide for early detection of breast cancer, and computer-aided diagnostics (CAD) is being developed to assist physicians reading mammograms. A promising method for CAD is content-based image retrieval (CBIR). Recently, we have developed a classification scheme of suspicious tissue pattern based on the support vector machine (SVM). In this paper, we continue moving towards automatic CAD of screening mammography. The experiments are based on in total 10,509 radiographs that have been collected from different sources. From this, 3,375 images are provided with one and 430 radiographs with more than one chain code annotation of cancerous regions. In different experiments, this data is divided into 12 and 20 classes, distinguishing between four categories of tissue density, three categories of pathology and in the 20 class problem two categories of different types of lesions. Balancing the number of images in each class yields 233 and 45 images remaining in each of the 12 and 20 classes, respectively. Using a two-dimensional principal component analysis, features are extracted from small patches of 128 x 128 pixels and classified by means of a SVM. Overall, the accuracy of the raw classification was 61.6 % and 52.1 % for the 12 and the 20 class problem, respectively. The confusion matrices are assessed for detailed analysis. Furthermore, an implementation of a SVM-based CBIR system for CADx in screening mammography is presented. In conclusion, with a smarter patch extraction, the CBIR approach might reach precision rates that are helpful for the physicians. This, however, needs more comprehensive evaluation on clinical data.

A comparison between index of entropy and catastrophe theory methods for mapping groundwater potential in an arid region.

Science.gov (United States)

Al-Abadi, Alaa M; Shahid, Shamsuddin

2015-09-01

In this study, index of entropy and catastrophe theory methods were used for demarcating groundwater potential in an arid region using weighted linear combination techniques in geographical information system (GIS) environment. A case study from Badra area in the eastern part of central of Iraq was analyzed and discussed. Six factors believed to have influence on groundwater occurrence namely elevation, slope, aquifer transmissivity and storativity, soil, and distance to fault were prepared as raster thematic layers to facility integration into GIS environment. The factors were chosen based on the availability of data and local conditions of the study area. Both techniques were used for computing weights and assigning ranks vital for applying weighted linear combination approach. The results of application of both modes indicated that the most influential groundwater occurrence factors were slope and elevation. The other factors have relatively smaller values of weights implying that these factors have a minor role in groundwater occurrence conditions. The groundwater potential index (GPI) values for both models were classified using natural break classification scheme into five categories: very low, low, moderate, high, and very high. For validation of generated GPI, the relative operating characteristic (ROC) curves were used. According to the obtained area under the curve, the catastrophe model with 78 % prediction accuracy was found to perform better than entropy model with 77 % prediction accuracy. The overall results indicated that both models have good capability for predicting groundwater potential zones.

Fractal Image Compression Based on High Entropy Values Technique

Directory of Open Access Journals (Sweden)

Douaa Younis Abbaas

2018-04-01

Full Text Available There are many attempts tried to improve the encoding stage of FIC because it consumed time. These attempts worked by reducing size of the search pool for pair range-domain matching but most of them led to get a bad quality, or a lower compression ratio of reconstructed image. This paper aims to present a method to improve performance of the full search algorithm by combining FIC (lossy compression and another lossless technique (in this case entropy coding is used. The entropy technique will reduce size of the domain pool (i. e., number of domain blocks based on the entropy value of each range block and domain block and then comparing the results of full search algorithm and proposed algorithm based on entropy technique to see each of which give best results (such as reduced the encoding time with acceptable values in both compression quali-ty parameters which are C. R (Compression Ratio and PSNR (Image Quality. The experimental results of the proposed algorithm proven that using the proposed entropy technique reduces the encoding time while keeping compression rates and reconstruction image quality good as soon as possible.

Entropy Error Model of Planar Geometry Features in GIS

Institute of Scientific and Technical Information of China (English)

LI Dajun; GUAN Yunlan; GONG Jianya; DU Daosheng

2003-01-01

Positional error of line segments is usually described by using "g-band", however, its band width is in relation to the confidence level choice. In fact, given different confidence levels, a series of concentric bands can be obtained. To overcome the effect of confidence level on the error indicator, by introducing the union entropy theory, we propose an entropy error ellipse index of point, then extend it to line segment and polygon,and establish an entropy error band of line segment and an entropy error donut of polygon. The research shows that the entropy error index can be determined uniquely and is not influenced by confidence level, and that they are suitable for positional uncertainty of planar geometry features.

Arithmetic of quantum entropy function

International Nuclear Information System (INIS)

Sen, Ashoke

2009-01-01

Quantum entropy function is a proposal for computing the entropy associated with the horizon of a black hole in the extremal limit, and is related via AdS/CFT correspondence to the dimension of the Hilbert space in a dual quantum mechanics. We show that in N = 4 supersymmetric string theories, quantum entropy function formalism naturally explains the origin of the subtle differences between the microscopic degeneracies of quarter BPS dyons carrying different torsion, i.e. different arithmetical properties. These arise from additional saddle points in the path integral - whose existence depends on the arithmetical properties of the black hole charges - constructed as freely acting orbifolds of the original AdS 2 x S 2 near horizon geometry. During this analysis we demonstrate that the quantum entropy function is insensitive to the details of the infrared cutoff used in the computation, and the details of the boundary terms added to the action. We also discuss the role of the asymptotic symmetries of AdS 2 in carrying out the path integral in the definition of quantum entropy function. Finally we show that even though quantum entropy function is expected to compute the absolute degeneracy in a given charge and angular momentum sector, it can also be used to compute the index. This can then be compared with the microscopic computation of the index.

Discovering mammography-based machine learning classifiers for breast cancer diagnosis.

Science.gov (United States)

Ramos-Pollán, Raúl; Guevara-López, Miguel Angel; Suárez-Ortega, Cesar; Díaz-Herrero, Guillermo; Franco-Valiente, Jose Miguel; Rubio-Del-Solar, Manuel; González-de-Posada, Naimy; Vaz, Mario Augusto Pires; Loureiro, Joana; Ramos, Isabel

2012-08-01

This work explores the design of mammography-based machine learning classifiers (MLC) and proposes a new method to build MLC for breast cancer diagnosis. We massively evaluated MLC configurations to classify features vectors extracted from segmented regions (pathological lesion or normal tissue) on craniocaudal (CC) and/or mediolateral oblique (MLO) mammography image views, providing BI-RADS diagnosis. Previously, appropriate combinations of image processing and normalization techniques were applied to reduce image artifacts and increase mammograms details. The method can be used under different data acquisition circumstances and exploits computer clusters to select well performing MLC configurations. We evaluated 286 cases extracted from the repository owned by HSJ-FMUP, where specialized radiologists segmented regions on CC and/or MLO images (biopsies provided the golden standard). Around 20,000 MLC configurations were evaluated, obtaining classifiers achieving an area under the ROC curve of 0.996 when combining features vectors extracted from CC and MLO views of the same case.

Entropy model of dissipative structure on corporate social responsibility

Science.gov (United States)

Li, Zuozhi; Jiang, Jie

2017-06-01

Enterprise is prompted to fulfill the social responsibility requirement by the internal and external environment. In this complex system, some studies suggest that firms have an orderly or chaotic entropy exchange behavior. Based on the theory of dissipative structure, this paper constructs the entropy index system of corporate social responsibility(CSR) and explores the dissipative structure of CSR through Brusselator model criterion. Picking up listed companies of the equipment manufacturing, the research shows that CSR has positive incentive to negative entropy and promotes the stability of dissipative structure. In short, the dissipative structure of CSR has a positive impact on the interests of stakeholders and corporate social images.

Using Link Disconnection Entropy Disorder to Detect Fast Moving Nodes in MANETs.

Science.gov (United States)

Alvarez, Carlos F; Palafox, Luis E; Aguilar, Leocundo; Sanchez, Mauricio A; Martinez, Luis G

2016-01-01

Mobile ad-hoc networks (MANETs) are dynamic by nature; this dynamism comes from node mobility, traffic congestion, and other transmission conditions. Metrics to evaluate the effects of those conditions shine a light on node's behavior in an ad-hoc network, helping to identify the node or nodes with better conditions of connection. In this paper, we propose a relative index to evaluate a single node reliability, based on the link disconnection entropy disorder using neighboring nodes as reference. Link disconnection entropy disorder is best used to identify fast moving nodes or nodes with unstable communications, this without the need of specialized sensors such as GPS. Several scenarios were studied to verify the index, measuring the effects of Speed and traffic density on the link disconnection entropy disorder. Packet delivery ratio is associated to the metric detecting a strong relationship, enabling the use of the link disconnection entropy disorder to evaluate the stability of a node to communicate with other nodes. To expand the utilization of the link entropy disorder, we identified nodes with higher speeds in network simulations just by using the link entropy disorder.

Mammography and radiation risk; Mammographie und Strahlenrisiko

Energy Technology Data Exchange (ETDEWEB)

Jung, H. [Hamburg Univ. (Germany). Inst. fuer Biophysik und Strahlenbiologie

1998-10-01

Breast cancer is the most frequent malignant neoplasia among women in Germany. The use of mammography as the most relevant diagnostic procedure has increased rapidly over the last decade. Radiation risks associated with mammography may be estimated from the results of numerous epidemiological studies providing risk coefficients for breast cancer in relation to age at exposure. Various calculations can be performed using the risk coefficients. For instance, a single mammography examination (bilateral, two views of each breast) of a women aged 45 may enhance the risk of developing breast cancer during her lifetime numerically from about 12% of 12.0036%. This increase in risk is lower by a factor of 3,300 as compared to the risk of developing breast cancer in the absence of radiation exposure. At the age of 40 or more, the benefit of mammography exceeds the radiation risk by a factor of about 100. At higher ages this factor increases further. Finally, the dualism of individual risk and collective risk is considered. It is shown that the individual risk of a patient, even after multiple mammography examinations, is vanishingly small. Nevertheless, the basic principle of minimising radiation exposure must be followed to keep the collective risk in the total population as low as reasonably achievable. (orig.) [Deutsch] Das Mammakarzinom ist in Deutschland die haeufigste Krebserkrankung der Frau, und entsprechend oft wird die Mammographie als das derzeit wichtigste Diagnoseverfahren eingesetzt. Zur Beurteilung des mit einer mammographischen Untersuchung verbundenen Strahlenrisikos liegen die Resultate einer groesseren Anzahl strahlenepidemiologischer Studien vor. Diese liefern den Risikokoeffizienten fuer Brustkrebs in Abhaengigkeit vom Lebensalter bei Strahlenexposition und ermoeglichen somit die Berechnung des altersabhaengigen Strahlenrisikos. Beispielsweise wird durch eine einmalige Mammographie-Untersuchung (bilateral, je zwei Aufnahmen in zwei Ebenen) bei einer 45

Study on patient exposure from mammography, 3

International Nuclear Information System (INIS)

Sato, Miyao

1983-01-01

Risks and benefits of the patient from mammography performed in Japan were estimated, and the indication of mammography were discussed. 1) Breast cancers induced by mammography were estimated based on the average breast dose, the average life span, risks of radiation-induced breast cancer and the breast cancer significant factor. 2) The breast cancer significant factor was calculated, similar to those of leukemia significant factor by Hashizume, from latent periods of radiation-induced breast cancer and the excess breast cancer induction rate in female A-bomb survivors. 3) Numbers of the deaths and Lost-years were calculated from risks of radiation-induced breast cancer, incidence of breast cancer by mammography, cure rate of breast cancer, average life span and latent period of radiation-induced breast cancer. 4) Numbers of the increased life and years saved were calculated from the improved rate of the ability of diagnosis, frequency of mammography, the average life span and cure rate of breast cancer. 5) Induction of leukemia, lung cancer and thyroid cancer by mammography also were investigated. Its contribution was not significant, compared to the induction of breast cancer. 6) Comparing risk and benefit, the latter was much higher than the former by factors of 71-76. This was suggested the efficacy of mammography. 7) From a pointview of risk and benefit, routine mammography is contraindicative for 10-19 years old women because of large risk, the indication must be scrutinized for 20-29 years old ones, and the benefit increases with age for over 30 years old ones so that mammography was positively admitted for the symptomatic women. (author)

Multi-Level Wavelet Shannon Entropy-Based Method for Single-Sensor Fault Location

Directory of Open Access Journals (Sweden)

Qiaoning Yang

2015-10-01

Full Text Available In actual application, sensors are prone to failure because of harsh environments, battery drain, and sensor aging. Sensor fault location is an important step for follow-up sensor fault detection. In this paper, two new multi-level wavelet Shannon entropies (multi-level wavelet time Shannon entropy and multi-level wavelet time-energy Shannon entropy are defined. They take full advantage of sensor fault frequency distribution and energy distribution across multi-subband in wavelet domain. Based on the multi-level wavelet Shannon entropy, a method is proposed for single sensor fault location. The method firstly uses a criterion of maximum energy-to-Shannon entropy ratio to select the appropriate wavelet base for signal analysis. Then multi-level wavelet time Shannon entropy and multi-level wavelet time-energy Shannon entropy are used to locate the fault. The method is validated using practical chemical gas concentration data from a gas sensor array. Compared with wavelet time Shannon entropy and wavelet energy Shannon entropy, the experimental results demonstrate that the proposed method can achieve accurate location of a single sensor fault and has good anti-noise ability. The proposed method is feasible and effective for single-sensor fault location.

Entropies, Partitionings and Heart Rate Variability

Czech Academy of Sciences Publication Activity Database

Paluš, Milan; Zebrowski, J.

2009-01-01

Roč. 51, č. 2 (2009), s. 65-72 ISSN 0001-7604 Institutional research plan: CEZ:AV0Z10300504 Keywords : coarse-grained entropy rate * HR variability * entropy Subject RIV: BB - Applied Statistics, Operational Research http://www.activitas.org/index.php/nervosa/article/view/25

Teaching atlas of mammography

International Nuclear Information System (INIS)

Tabar, L.; Dean, P.B.

1985-01-01

The illustrated case reports in this teaching atlas cover practically the entire range of possible pathological changes and are based on in-patient case material and 80,000 screening documents. The two basic approaches, - detection and analysis of changes -, are taught comprehensively and in great detail. A systematic procedure for analysing the mammographies, in order to detect even the very least changes, and its practical application is explained using mammographies showing unclear findings at first sight. A system of coordinates is presented which allows precise localisation of the changes. Exercises for practising the technique of identifying the pathological changes round up the methodolical chapters. Additional imaging technical enhancements and detail enlargements are of great help in interpreting the findings. The specific approach adopted for this teaching atlas is a 'reverse procedure', which leaves the beaten track and starts with analysing the mammographies and evaluating the radiographic findings, in order to finally derive the diagnosis. (orig./CB) [de

TU-EF-207-02: Spectral Mammography Based on Photon Counting Detectors

Energy Technology Data Exchange (ETDEWEB)

Molloi, S. [University of California (United States)

2015-06-15

Breast imaging technology is advancing on several fronts. In digital mammography, the major technological trend has been on optimization of approaches for performing combined mammography and tomosynthesis using the same system. In parallel, photon-counting slot-scan mammography is now in clinical use and more efforts are directed towards further development of this approach for spectral imaging. Spectral imaging refers to simultaneous acquisition of two or more energy-windowed images. Depending on the detector and associated electronics, there are a number of ways this can be accomplished. Spectral mammography using photon-counting detectors can suppress electronic noise and importantly, it enables decomposition of the image into various material compositions of interest facilitating quantitative imaging. Spectral imaging can be particularly important in intravenously injected contrast mammography and eventually tomosynthesis. The various approaches and applications of spectral mammography are discussed. Digital breast tomosynthesis relies on the mechanical movement of the x-ray tube to acquire a number of projections in a predefined arc, typically from 9 to 25 projections over a scan angle of +/−7.5 to 25 degrees depending on the particular system. The mechanical x-ray tube motion requires relatively long acquisition time, typically between 3.7 to 25 seconds depending on the system. Moreover, mechanical scanning may have an effect on the spatial resolution due to internal x-ray filament or external mechanical vibrations. New x-ray source arrays have been developed and they are aimed at replacing the scanned x-ray tube for improved acquisition time and potentially for higher spatial resolution. The potential advantages and challenges of this approach are described. Combination of digital mammography and tomosynthesis in a single system places increased demands on certain functional aspects of the detector and overall performance, particularly in the tomosynthesis

TU-EF-207-02: Spectral Mammography Based on Photon Counting Detectors

International Nuclear Information System (INIS)

Molloi, S.

2015-01-01

Breast imaging technology is advancing on several fronts. In digital mammography, the major technological trend has been on optimization of approaches for performing combined mammography and tomosynthesis using the same system. In parallel, photon-counting slot-scan mammography is now in clinical use and more efforts are directed towards further development of this approach for spectral imaging. Spectral imaging refers to simultaneous acquisition of two or more energy-windowed images. Depending on the detector and associated electronics, there are a number of ways this can be accomplished. Spectral mammography using photon-counting detectors can suppress electronic noise and importantly, it enables decomposition of the image into various material compositions of interest facilitating quantitative imaging. Spectral imaging can be particularly important in intravenously injected contrast mammography and eventually tomosynthesis. The various approaches and applications of spectral mammography are discussed. Digital breast tomosynthesis relies on the mechanical movement of the x-ray tube to acquire a number of projections in a predefined arc, typically from 9 to 25 projections over a scan angle of +/−7.5 to 25 degrees depending on the particular system. The mechanical x-ray tube motion requires relatively long acquisition time, typically between 3.7 to 25 seconds depending on the system. Moreover, mechanical scanning may have an effect on the spatial resolution due to internal x-ray filament or external mechanical vibrations. New x-ray source arrays have been developed and they are aimed at replacing the scanned x-ray tube for improved acquisition time and potentially for higher spatial resolution. The potential advantages and challenges of this approach are described. Combination of digital mammography and tomosynthesis in a single system places increased demands on certain functional aspects of the detector and overall performance, particularly in the tomosynthesis

Does health status influence intention regarding screening mammography?

International Nuclear Information System (INIS)

Park, Keeho; Park, Jong-Hyock; Park, Jae-Hyun; Kim, Hui-Jeong; Park, Bo-Yoon

2010-01-01

We analyzed information surveyed from a community-based sample of Korean women older than 40 years of age to understand the relationships between health status and screening behavior. In a cross-sectional population-based study, a two-stage, geographically stratified household-based sampling design was used for assembly of a probability sample of women aged 40-69 years living in Gunpo in Korea, resulting in a total sample size of 503 women. The primary outcome variable for this analysis was the respondent's intention to obtain a mammogram. Predictor variables included health status and other factors known to influence the use of cancer screening, such as age, education, income, marital status and the presence of co-morbid illnesses. Health status was assessed by using the EuroQol (EQ-5D). The median EQ visual analogue scale score was 75.0, ranging from 20 to 100. In bivariate analyses, the percentage of women reporting to have intention toward mammography use decreased with worsening health status. Women who had problems with mobility or anxiety/depression showed lower intention to undergo future screening mammography. Multivariate logistic regression confirmed that health status was significantly associated with intention toward mammography use. Anxiety or depression was an independent predictor of future screening mammography use. Health status is significantly associated with intention regarding screening mammography use. Physicians or other health professionals should be aware that health status is an important component for health promotion, and should pay more attention to clients' possible vulnerability in screening mammography use due to their poor health status. (author)

Experience with digital mammography

Directory of Open Access Journals (Sweden)

G. P. Korzhenkova

2011-01-01

Full Text Available The use of digital techniques in mammography has become a last step for completing the process of digitization in diagnostic imaging. It is assumed that such a spatial decision will be required for digital mammography, as well as for high-resolution intensifying screen-film systems used in conventional mammography and that the digital techniques will be limited by the digitizer pixel size on detecting minor structures, such as microcalcifications. The introduction of digital technologies in mammography involves a tight control over an image and assures its high quality.

Entropy-based automated classification of independent components separated from fMCG

International Nuclear Information System (INIS)

Comani, S; Srinivasan, V; Alleva, G; Romani, G L

2007-01-01

Fetal magnetocardiography (fMCG) is a noninvasive technique suitable for the prenatal diagnosis of the fetal heart function. Reliable fetal cardiac signals can be reconstructed from multi-channel fMCG recordings by means of independent component analysis (ICA). However, the identification of the separated components is usually accomplished by visual inspection. This paper discusses a novel automated system based on entropy estimators, namely approximate entropy (ApEn) and sample entropy (SampEn), for the classification of independent components (ICs). The system was validated on 40 fMCG datasets of normal fetuses with the gestational age ranging from 22 to 37 weeks. Both ApEn and SampEn were able to measure the stability and predictability of the physiological signals separated with ICA, and the entropy values of the three categories were significantly different at p <0.01. The system performances were compared with those of a method based on the analysis of the time and frequency content of the components. The outcomes of this study showed a superior performance of the entropy-based system, in particular for early gestation, with an overall ICs detection rate of 98.75% and 97.92% for ApEn and SampEn respectively, as against a value of 94.50% obtained with the time-frequency-based system. (note)

Characterization of microcalcification: can digital monitor zooming replace magnification mammography in full-field digital mammography?

International Nuclear Information System (INIS)

Kim, Min Jung; Kim, Eun-Kyung; Kwak, Jin Young; Son, Eun Ju; Youk, Ji Hyun; Choi, Seon Hyeong; Oh, Ki Keun; Han, Mooyoung

2009-01-01

The aim of this study was to compare the diagnostic accuracy and image quality of microcalcifications in zoomed digital contact mammography with digital magnification mammography. Three radiologists with different levels of experience in mammography reviewed 120 microcalcification clusters in 111 patients with a full-field digital mammography system relying on digital magnification mammogram (MAG) images and zoomed images from contact mammography (ZOOM) using commercially available zooming systems on monitors. Each radiologist estimated the probability of malignancy and rated the image quality and confidence rate. Performance was evaluated by sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic (ROC) analysis. All three radiologists rated MAG images higher than ZOOM images for sensitivity with statistical significance (average value, 92% vs. 87%, P<0.05) and performance by ROC analysis improved with MAG imaging. The confidence rate for diagnosis decision and the assessment of lesion characteristics were also better in MAG images than in ZOOM images with statistical significance (P<0.0001). Digital magnification mammography can enhance diagnostic performance when characterizing microcalcifications. Images zoomed from digital contact mammography cannot serve as an alternative to direct magnification digital mammography. (orig.)

Implementation of Synthesized Two-dimensional Mammography in a Population-based Digital Breast Tomosynthesis Screening Program

Science.gov (United States)

Zuckerman, Samantha P.; Keller, Brad M.; Maidment, Andrew D. A.; Barufaldi, Bruno; Weinstein, Susan P.; Synnestvedt, Marie; McDonald, Elizabeth S.

2016-01-01

Purpose To evaluate the early implementation of synthesized two-dimensional (s2D) mammography in a population screened entirely with s2D and digital breast tomosynthesis (DBT) (referred to as s2D/DBT) and compare recall rates and cancer detection rates to historic outcomes of digital mammography combined with DBT (referred to as digital mammography/DBT) screening. Materials and Methods This was an institutional review board–approved and HIPAA-compliant retrospective interpretation of prospectively acquired data with waiver of informed consent. Compared were recall rates, biopsy rates, cancer detection rates, and radiation dose for 15 571 women screened with digital mammography/DBT from October 1, 2011, to February 28, 2013, and 5366 women screened with s2D/DBT from January 7, 2015, to June 30, 2015. Two-sample z tests of equal proportions were used to determine statistical significance. Results Recall rate for s2D/DBT versus digital mammography/DBT was 7.1% versus 8.8%, respectively (P < .001). Biopsy rate for s2D/DBT versus digital mammography/DBT decreased (1.3% vs 2.0%, respectively; P = .001). There was no significant difference in cancer detection rate for s2D/DBT versus digital mammography/DBT (5.03 of 1000 vs 5.45 of 1000, respectively; P = .72). The average glandular dose was 39% lower in s2D/DBT versus digital mammography/DBT (4.88 mGy vs 7.97 mGy, respectively; P < .001). Conclusion Screening with s2D/DBT in a large urban practice resulted in similar outcomes compared with digital mammography/DBT imaging. Screening with s2D/DBT allowed for the benefits of DBT with a decrease in radiation dose compared with digital mammography/DBT. © RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on August 11, 2016. PMID:27467468

Practical digital mammography

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Beverly E. [Washington Univ., Seattle, WA (United States)]|[Virginia Mason Medical Center, VA (United States)

2008-07-01

This book is meant for the radiologist who is facing the challenge of organizing a digital mammographic imaging center. This text is meant to be a practical book that provides information about digital mammographic physics and equipment which will allow one to intelligently compare technologies and systems. Some of the major challenges include: large expense; rapidly changing technology, and inconsistent connectivity; and finally, need for strong information technology support. The initial conversion cost to digital mammographic imaging is relatively expensive due to the cost of digital mammography hardware, software, and storage. Virtually all other imaging modalities are being converted to purely digital storage and transfer, and the digital trend in mammography is inevitable. Technical advantages of digital mammography are described. However, the improved flexibility in image display and transfer are some of its strongest features. In conclusion, although there are increasing imaging modalities that may be used to evaluate breast disease, mammography will continue to play a key role in detecting breast cancer. To be an effective imager, the radiologist should become familiar with digital mammography and understand its role within the increasing complex structure of breast imaging techniques.

Practical digital mammography

International Nuclear Information System (INIS)

Hashimoto, Beverly E.

2008-01-01

This book is meant for the radiologist who is facing the challenge of organizing a digital mammographic imaging center. This text is meant to be a practical book that provides information about digital mammographic physics and equipment which will allow one to intelligently compare technologies and systems. Some of the major challenges include: large expense; rapidly changing technology, and inconsistent connectivity; and finally, need for strong information technology support. The initial conversion cost to digital mammographic imaging is relatively expensive due to the cost of digital mammography hardware, software, and storage. Virtually all other imaging modalities are being converted to purely digital storage and transfer, and the digital trend in mammography is inevitable. Technical advantages of digital mammography are described. However, the improved flexibility in image display and transfer are some of its strongest features. In conclusion, although there are increasing imaging modalities that may be used to evaluate breast disease, mammography will continue to play a key role in detecting breast cancer. To be an effective imager, the radiologist should become familiar with digital mammography and understand its role within the increasing complex structure of breast imaging techniques

The improvement of Clausius entropy and its application in entropy analysis

Institute of Scientific and Technical Information of China (English)

WU Jing; GUO ZengYuan

2008-01-01

The defects of Cleusius entropy which Include s premise of reversible process and a process quantlty of heat in Its definition are discussed in this paper. Moreover, the heat temperature quotient under reversible conditions, i.e. (δQ/T)rev, is essentially a process quantity although it is numerically equal to the entropy change. The sum of internal energy temperature quotient and work temperature quotient is defined as the improved form of Clausius entropy and it can be further proved to be a state funcllon. Unlike Clausius entropy, the improved deflnltion consists of system properties wlthout premise just like other state functions, for example, pressure p and enthalpy h, etc. it is unnecessary to invent reversible paths when calculating entropy change for irreversible processes based on the improved form of entropy since it is independent of process. Furthermore, entropy balance equations for internally and externally irreversible processes are deduced respectively based on the concepts of thermal reservoir entropy transfer and system entropy transfer. Finally, some examples are presented to show that the improved deflnitlon of Clausius entropy provides a clear concept as well as a convenient method for en-tropy change calculation.

Epoch-based Entropy for Early Screening of Alzheimer's Disease.

Science.gov (United States)

Houmani, N; Dreyfus, G; Vialatte, F B

2015-12-01

In this paper, we introduce a novel entropy measure, termed epoch-based entropy. This measure quantifies disorder of EEG signals both at the time level and spatial level, using local density estimation by a Hidden Markov Model on inter-channel stationary epochs. The investigation is led on a multi-centric EEG database recorded from patients at an early stage of Alzheimer's disease (AD) and age-matched healthy subjects. We investigate the classification performances of this method, its robustness to noise, and its sensitivity to sampling frequency and to variations of hyperparameters. The measure is compared to two alternative complexity measures, Shannon's entropy and correlation dimension. The classification accuracies for the discrimination of AD patients from healthy subjects were estimated using a linear classifier designed on a development dataset, and subsequently tested on an independent test set. Epoch-based entropy reached a classification accuracy of 83% on the test dataset (specificity = 83.3%, sensitivity = 82.3%), outperforming the two other complexity measures. Furthermore, it was shown to be more stable to hyperparameter variations, and less sensitive to noise and sampling frequency disturbances than the other two complexity measures.

Financial time series analysis based on effective phase transfer entropy

Science.gov (United States)

Yang, Pengbo; Shang, Pengjian; Lin, Aijing

2017-02-01

Transfer entropy is a powerful technique which is able to quantify the impact of one dynamic system on another system. In this paper, we propose the effective phase transfer entropy method based on the transfer entropy method. We use simulated data to test the performance of this method, and the experimental results confirm that the proposed approach is capable of detecting the information transfer between the systems. We also explore the relationship between effective phase transfer entropy and some variables, such as data size, coupling strength and noise. The effective phase transfer entropy is positively correlated with the data size and the coupling strength. Even in the presence of a large amount of noise, it can detect the information transfer between systems, and it is very robust to noise. Moreover, this measure is indeed able to accurately estimate the information flow between systems compared with phase transfer entropy. In order to reflect the application of this method in practice, we apply this method to financial time series and gain new insight into the interactions between systems. It is demonstrated that the effective phase transfer entropy can be used to detect some economic fluctuations in the financial market. To summarize, the effective phase transfer entropy method is a very efficient tool to estimate the information flow between systems.

Baseline Screening Mammography: Performance of Full-Field Digital Mammography Versus Digital Breast Tomosynthesis.

Science.gov (United States)

McDonald, Elizabeth S; McCarthy, Anne Marie; Akhtar, Amana L; Synnestvedt, Marie B; Schnall, Mitchell; Conant, Emily F

2015-11-01

Baseline mammography studies have significantly higher recall rates than mammography studies with available comparison examinations. Digital breast tomosynthesis reduces recalls when compared with digital mammographic screening alone, but many sites operate in a hybrid environment. To maximize the effect of screening digital breast tomosynthesis with limited resources, choosing which patient populations will benefit most is critical. This study evaluates digital breast tomosynthesis in the baseline screening population. Outcomes were compared for 10,728 women who underwent digital mammography screening, including 1204 (11.2%) baseline studies, and 15,571 women who underwent digital breast tomosynthesis screening, including 1859 (11.9%) baseline studies. Recall rates, cancer detection rates, and positive predictive values were calculated. Logistic regression estimated the odds ratios of recall for digital mammography versus digital breast tomosynthesis for patients undergoing baseline screening and previously screened patients, adjusted for age, race, and breast density. In the baseline subgroup, recall rates for digital mammography and digital breast tomosynthesis screening were 20.5% and 16.0%, respectively (p = 0.002); digital breast tomosynthesis screening in the baseline subgroup resulted in a 22% reduction in recall compared with digital mammography, or 45 fewer patients recalled per 1000 patients screened. Digital breast tomosynthesis screening in the previously screened patients resulted in recall reduction of 14.3% (p tomosynthesis than from digital mammography alone.

Driver Fatigue Detection System Using Electroencephalography Signals Based on Combined Entropy Features

Directory of Open Access Journals (Sweden)

Zhendong Mu

2017-02-01

Full Text Available Driver fatigue has become one of the major causes of traffic accidents, and is a complicated physiological process. However, there is no effective method to detect driving fatigue. Electroencephalography (EEG signals are complex, unstable, and non-linear; non-linear analysis methods, such as entropy, maybe more appropriate. This study evaluates a combined entropy-based processing method of EEG data to detect driver fatigue. In this paper, 12 subjects were selected to take part in an experiment, obeying driving training in a virtual environment under the instruction of the operator. Four types of enthrones (spectrum entropy, approximate entropy, sample entropy and fuzzy entropy were used to extract features for the purpose of driver fatigue detection. Electrode selection process and a support vector machine (SVM classification algorithm were also proposed. The average recognition accuracy was 98.75%. Retrospective analysis of the EEG showed that the extracted features from electrodes T5, TP7, TP8 and FP1 may yield better performance. SVM classification algorithm using radial basis function as kernel function obtained better results. A combined entropy-based method demonstrates good classification performance for studying driver fatigue detection.

Comparison of tomosynthesis plus digital mammography and digital mammography alone for breast cancer screening.

Science.gov (United States)

Haas, Brian M; Kalra, Vivek; Geisel, Jaime; Raghu, Madhavi; Durand, Melissa; Philpotts, Liane E

2013-12-01

To compare screening recall rates and cancer detection rates of tomosynthesis plus conventional digital mammography to those of conventional digital mammography alone. All patients presenting for screening mammography between October 1, 2011, and September 30, 2012, at four clinical sites were reviewed in this HIPAA-compliant retrospective study, for which the institutional review board granted approval and waived the requirement for informed consent. Patients at sites with digital tomosynthesis were offered screening with digital mammography plus tomosynthesis. Patients at sites without tomosynthesis underwent conventional digital mammography. Recall rates were calculated and stratified according to breast density and patient age. Cancer detection rates were calculated and stratified according to the presence of a risk factor for breast cancer. The Fisher exact test was used to compare the two groups. Multivariate logistic regression was used to assess the effect of screening method, breast density, patient age, and cancer risk on the odds of recall from screening. A total of 13 158 patients presented for screening mammography; 6100 received tomosynthesis. The overall recall rate was 8.4% for patients in the tomosynthesis group and 12.0% for those in the conventional mammography group (P tomosynthesis reduced recall rates for all breast density and patient age groups, with significant differences (P tomosynthesis versus 5.2 per 1000 in patients receiving conventional mammography alone (P = .70). Patients undergoing tomosynthesis plus digital mammography had significantly lower screening recall rates. The greatest reductions were for those younger than 50 years and those with dense breasts. A nonsignificant 9.5% increase in cancer detection was observed in the tomosynthesis group. © RSNA, 2013.

Improved Ordinary Measure and Image Entropy Theory based intelligent Copy Detection Method

Directory of Open Access Journals (Sweden)

Dengpan Ye

2011-10-01

Full Text Available Nowadays, more and more multimedia websites appear in social network. It brings some security problems, such as privacy, piracy, disclosure of sensitive contents and so on. Aiming at copyright protection, the copy detection technology of multimedia contents becomes a hot topic. In our previous work, a new computer-based copyright control system used to detect the media has been proposed. Based on this system, this paper proposes an improved media feature matching measure and an entropy based copy detection method. The Levenshtein Distance was used to enhance the matching degree when using for feature matching measure in copy detection. For entropy based copy detection, we make a fusion of the two features of entropy matrix of the entropy feature we extracted. Firstly,we extract the entropy matrix of the image and normalize it. Then, we make a fusion of the eigenvalue feature and the transfer matrix feature of the entropy matrix. The fused features will be used for image copy detection. The experiments show that compared to use these two kinds of features for image detection singly, using feature fusion matching method is apparent robustness and effectiveness. The fused feature has a high detection for copy images which have been received some attacks such as noise, compression, zoom, rotation and so on. Comparing with referred methods, the method proposed is more intelligent and can be achieved good performance.

Logarithmic black hole entropy corrections and holographic Renyi entropy

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, Subhash [The Institute of Mathematical Sciences, Chennai (India); KU Leuven - KULAK, Department of Physics, Kortrijk (Belgium)

2018-01-15

The entanglement and Renyi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Renyi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order G{sub D}{sup 0}. The entropic c-function and the inequalities of the Renyi entropy are also satisfied even with the correction terms. (orig.)

Logarithmic black hole entropy corrections and holographic Renyi entropy

International Nuclear Information System (INIS)

Mahapatra, Subhash

2018-01-01

The entanglement and Renyi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Renyi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order G D 0 . The entropic c-function and the inequalities of the Renyi entropy are also satisfied even with the correction terms. (orig.)

The Grading Entropy-based Criteria for Structural Stability of Granular Materials and Filters

Directory of Open Access Journals (Sweden)

Janos Lőrincz

2015-05-01

Full Text Available This paper deals with three grading entropy-based rules that describe different soil structure stability phenomena: an internal stability rule, a filtering rule and a segregation rule. These rules are elaborated on the basis of a large amount of laboratory testing and from existing knowledge in the field. Use is made of the theory of grading entropy to derive parameters which incorporate all of the information of the grading curve into a pair of entropy-based parameters that allow soils with common behaviours to be grouped into domains on an entropy diagram. Applications of the derived entropy-based rules are presented by examining the reason of a dam failure, by testing against the existing filter rules from the literature, and by giving some examples for the design of non-segregating grading curves (discrete particle size distributions by dry weight. A physical basis for the internal stability rule is established, wherein the higher values of base entropy required for granular stability are shown to reflect the closeness between the mean and maximum grain diameters, which explains how there are sufficient coarser grains to achieve a stable grain skeleton.

The improvement of Clausius entropy and its application in entropy analysis

Institute of Scientific and Technical Information of China (English)

2008-01-01

The defects of Clausius entropy which include a premise of reversible process and a process quantity of heat in its definition are discussed in this paper. Moreover, the heat temperature quotient under reversible conditions, i.e. (δQ/T)rev, is essentially a process quantity although it is numerically equal to the entropy change. The sum of internal energy temperature quotient and work temperature quotient is defined as the improved form of Clausius entropy and it can be further proved to be a state function. Unlike Clausius entropy, the improved definition consists of system properties without premise just like other state functions, for example, pressure p and enthalpy h, etc. It is unnecessary to invent reversible paths when calculating entropy change for irreversible processes based on the improved form of entropy since it is independent of process. Furthermore, entropy balance equations for internally and externally irreversible processes are deduced respectively based on the concepts of thermal reservoir entropy transfer and system entropy transfer. Finally, some examples are presented to show that the improved definition of Clausius entropy provides a clear concept as well as a convenient method for en- tropy change calculation.

An Entropy-Based Network Anomaly Detection Method

Directory of Open Access Journals (Sweden)

Przemysław Bereziński

2015-04-01

Full Text Available Data mining is an interdisciplinary subfield of computer science involving methods at the intersection of artificial intelligence, machine learning and statistics. One of the data mining tasks is anomaly detection which is the analysis of large quantities of data to identify items, events or observations which do not conform to an expected pattern. Anomaly detection is applicable in a variety of domains, e.g., fraud detection, fault detection, system health monitoring but this article focuses on application of anomaly detection in the field of network intrusion detection.The main goal of the article is to prove that an entropy-based approach is suitable to detect modern botnet-like malware based on anomalous patterns in network. This aim is achieved by realization of the following points: (i preparation of a concept of original entropy-based network anomaly detection method, (ii implementation of the method, (iii preparation of original dataset, (iv evaluation of the method.

Access Selection Algorithm of Heterogeneous Wireless Networks for Smart Distribution Grid Based on Entropy-Weight and Rough Set

Science.gov (United States)

Xiang, Min; Qu, Qinqin; Chen, Cheng; Tian, Li; Zeng, Lingkang

2017-11-01

To improve the reliability of communication service in smart distribution grid (SDG), an access selection algorithm based on dynamic network status and different service types for heterogeneous wireless networks was proposed. The network performance index values were obtained in real time by multimode terminal and the variation trend of index values was analyzed by the growth matrix. The index weights were calculated by entropy-weight and then modified by rough set to get the final weights. Combining the grey relational analysis to sort the candidate networks, and the optimum communication network is selected. Simulation results show that the proposed algorithm can implement dynamically access selection in heterogeneous wireless networks of SDG effectively and reduce the network blocking probability.

Safety assessment of dangerous goods transport enterprise based on the relative entropy aggregation in group decision making model.

Science.gov (United States)

Wu, Jun; Li, Chengbing; Huo, Yueying

2014-01-01

Safety of dangerous goods transport is directly related to the operation safety of dangerous goods transport enterprise. Aiming at the problem of the high accident rate and large harm in dangerous goods logistics transportation, this paper took the group decision making problem based on integration and coordination thought into a multiagent multiobjective group decision making problem; a secondary decision model was established and applied to the safety assessment of dangerous goods transport enterprise. First of all, we used dynamic multivalue background and entropy theory building the first level multiobjective decision model. Secondly, experts were to empower according to the principle of clustering analysis, and combining with the relative entropy theory to establish a secondary rally optimization model based on relative entropy in group decision making, and discuss the solution of the model. Then, after investigation and analysis, we establish the dangerous goods transport enterprise safety evaluation index system. Finally, case analysis to five dangerous goods transport enterprises in the Inner Mongolia Autonomous Region validates the feasibility and effectiveness of this model for dangerous goods transport enterprise recognition, which provides vital decision making basis for recognizing the dangerous goods transport enterprises.

Image quality in conventional film screen system, digital phosphor storage plate mammography in magnification technique and digital mammography in CCD-technique

International Nuclear Information System (INIS)

Schulz-Wendtland, R.; Aichinger, U.; Boehner, C.; Dobritz, M.; Bautz, W.; Saebel, M.

2000-01-01

Purpose: Comparison of image quality between conventional film screen system, digital phosphor storage plate mammography in magnification technique and digital mammography in CCD-technique. Materials and Methods: Radiograms of a RMI-mammography phantom were acquired using a conventional film screen system, two digital storage plate systems and two digital systems in CCD-technique. Additionally, the radiograms of one digital phosphor storage plate system were post-processed emphasizing contrast and included in the comparison. Results: The detectability of details was the best with the digital mammography in CCD-technique in comparison with the conventional film screen technique resp. digital phosphor storage plate in magnification technique. Conclusions: Based on these results there is the possibility to replace the conventional film screen system by further studies - this has to be confirmed. (orig.) [de

CMOS cassette for digital upgrade of film-based mammography systems

Science.gov (United States)

Baysal, Mehmet A.; Toker, Emre

2006-03-01

While full-field digital mammography (FFDM) technology is gaining clinical acceptance, the overwhelming majority (96%) of the installed base of mammography systems are conventional film-screen (FSM) systems. A high performance, and economical digital cassette based product to conveniently upgrade FSM systems to FFDM would accelerate the adoption of FFDM, and make the clinical and technical advantages of FFDM available to a larger population of women. The planned FFDM cassette is based on our commercial Digital Radiography (DR) cassette for 10 cm x 10 cm field-of-view spot imaging and specimen radiography, utilizing a 150 micron columnar CsI(Tl) scintillator and 48 micron active-pixel CMOS sensor modules. Unlike a Computer Radiography (CR) cassette, which requires an external digitizer, our DR cassette transfers acquired images to a display workstation within approximately 5 seconds of exposure, greatly enhancing patient flow. We will present the physical performance of our prototype system against other FFDM systems in clinical use today, using established objective criteria such as the Modulation Transfer Function (MTF), Detective Quantum Efficiency (DQE), and subjective criteria, such as a contrast-detail (CD-MAM) observer performance study. Driven by the strong demand from the computer industry, CMOS technology is one of the lowest cost, and the most readily accessible technologies available for FFDM today. Recent popular use of CMOS imagers in high-end consumer cameras have also resulted in significant advances in the imaging performance of CMOS sensors against rivaling CCD sensors. This study promises to take advantage of these unique features to develop the first CMOS based FFDM upgrade cassette.

Entropy-Based Privacy against Profiling of User Mobility

Directory of Open Access Journals (Sweden)

Alicia Rodriguez-Carrion

2015-06-01

Full Text Available Location-based services (LBSs flood mobile phones nowadays, but their use poses an evident privacy risk. The locations accompanying the LBS queries can be exploited by the LBS provider to build the user profile of visited locations, which might disclose sensitive data, such as work or home locations. The classic concept of entropy is widely used to evaluate privacy in these scenarios, where the information is represented as a sequence of independent samples of categorized data. However, since the LBS queries might be sent very frequently, location profiles can be improved by adding temporal dependencies, thus becoming mobility profiles, where location samples are not independent anymore and might disclose the user’s mobility patterns. Since the time dimension is factored in, the classic entropy concept falls short of evaluating the real privacy level, which depends also on the time component. Therefore, we propose to extend the entropy-based privacy metric to the use of the entropy rate to evaluate mobility profiles. Then, two perturbative mechanisms are considered to preserve locations and mobility profiles under gradual utility constraints. We further use the proposed privacy metric and compare it to classic ones to evaluate both synthetic and real mobility profiles when the perturbative methods proposed are applied. The results prove the usefulness of the proposed metric for mobility profiles and the need for tailoring the perturbative methods to the features of mobility profiles in order to improve privacy without completely loosing utility.

Exploring the effects of climatic variables on monthly precipitation variation using a continuous wavelet-based multiscale entropy approach.

Science.gov (United States)

Roushangar, Kiyoumars; Alizadeh, Farhad; Adamowski, Jan

2018-08-01

Understanding precipitation on a regional basis is an important component of water resources planning and management. The present study outlines a methodology based on continuous wavelet transform (CWT) and multiscale entropy (CWME), combined with self-organizing map (SOM) and k-means clustering techniques, to measure and analyze the complexity of precipitation. Historical monthly precipitation data from 1960 to 2010 at 31 rain gauges across Iran were preprocessed by CWT. The multi-resolution CWT approach segregated the major features of the original precipitation series by unfolding the structure of the time series which was often ambiguous. The entropy concept was then applied to components obtained from CWT to measure dispersion, uncertainty, disorder, and diversification of subcomponents. Based on different validity indices, k-means clustering captured homogenous areas more accurately, and additional analysis was performed based on the outcome of this approach. The 31 rain gauges in this study were clustered into 6 groups, each one having a unique CWME pattern across different time scales. The results of clustering showed that hydrologic similarity (multiscale variation of precipitation) was not based on geographic contiguity. According to the pattern of entropy across the scales, each cluster was assigned an entropy signature that provided an estimation of the entropy pattern of precipitation data in each cluster. Based on the pattern of mean CWME for each cluster, a characteristic signature was assigned, which provided an estimation of the CWME of a cluster across scales of 1-2, 3-8, and 9-13 months relative to other stations. The validity of the homogeneous clusters demonstrated the usefulness of the proposed approach to regionalize precipitation. Further analysis based on wavelet coherence (WTC) was performed by selecting central rain gauges in each cluster and analyzing against temperature, wind, Multivariate ENSO index (MEI), and East Atlantic (EA) and

Average glandular dose in routine mammography screening using a Sectra Microdose Mammography unit

International Nuclear Information System (INIS)

Hemdal, B.; Herrnsdorf, L.; Andersson, I.; Bengtsson, G.; Heddson, B.; Olsson, M.

2005-01-01

The Sectra MicroDose Mammography system is based on direct photon counting (with a solid-state detector), and a substantially lower dose to the breast than when using conventional system can be expected. In this work absorbed dose measurements have been performed for the first unit used in routine mammography screening (at the Hospitals of Helsingborg (Sweden)). Two European protocols on dosimetry in mammography have been followed. Measurement of half value layer (HVL) cannot be performed as prescribed, but this study has demonstrated than non-invasive measurements of HVL can be performed accurately with a sensitive and well collimated solid-state detector with simultaneous correction for the energy dependence. The average glandular dose for a 50 mm standard breast with 50% glandularity, simulated by 45 mm polymethylmethacrylate, was found to be 0.21 and 0.28 mGy in March and December 2004, respectively. These values are much lower than for any other mammography system on the market today. It has to be stressed that the measurement were made using the current clinical settings and that no systematic optimisation of the relationship between absorbed dose and diagnostic image quality has been performed within the present study. In order to further increase the accuracy of absorbed dose measurements for this unit, the existing dose protocols should be revised to account also for the tungsten/aluminium anode/filter combination, the multi-slit pre-collimator device and the occurrence of a dose profile in the scanning direction. (authors)

Assessment of sustainable urban transport development based on entropy and unascertained measure.

Science.gov (United States)

Li, Yancang; Yang, Jing; Shi, Huawang; Li, Yijie

2017-01-01

To find a more effective method for the assessment of sustainable urban transport development, the comprehensive assessment model of sustainable urban transport development was established based on the unascertained measure. On the basis of considering the factors influencing urban transport development, the comprehensive assessment indexes were selected, including urban economical development, transport demand, environment quality and energy consumption, and the assessment system of sustainable urban transport development was proposed. In view of different influencing factors of urban transport development, the index weight was calculated through the entropy weight coefficient method. Qualitative and quantitative analyses were conducted according to the actual condition. Then, the grade was obtained by using the credible degree recognition criterion from which the urban transport development level can be determined. Finally, a comprehensive assessment method for urban transport development was introduced. The application practice showed that the method can be used reasonably and effectively for the comprehensive assessment of urban transport development.

Influence of age and menstrual cycle on mammography and MR imaging of the breast; Einfluss von Alter und Menstruationszyklus auf Mammographie und MR-Mammographie

Energy Technology Data Exchange (ETDEWEB)

Mueller-Schimpfle, M.; Ohmenhaeuser, K.; Claussen, C.D. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik

1997-09-01

Age and menstrual cycle have an important influence on the breast. This well-known fact is experienced in the daily routine of gynecologists and radiologists. The number of publications addressing the effect of these influences on imaging, however, is surprisingly low. The aim of this work is to describe the influences of age and menstrual cycle on the breast and to address their clinical relevance for mammography and MR mammography. Therefore, own data are presented concerning the age and menstrual cycle influences on breast parenchyma in dynamic MR mammography. Literature data are used to correlate mammography and MR imaging findings with these influences. The changes of the breast due to age and menstrual cycle have important direct implications on performing and reading conventional mammography and MR mammography. The knowledge of these changes is also helpful in the interpretation of findings when comparing different methods. Finally, the data gained by using imaging methods enable important basic insights into physiology and physiopathology of the breast in vivo. (orig.) [Deutsch] Alter und Menstruationszyklus stellen wichtige Einflussfaktoren auf die Mamma dar. Diese Tatsache ist klinisch lange bekannt und im Alltag des Gynaekologen wie Radiologen staendig praesent. Dagegen ist die Anzahl der Publikationen zu den Auswirkungen dieser Einfluesse auf die Bildgebung erstaunlich niedrig. Ziel dieser Arbeit ist es, die alters- und zyklusabhaengigen Veraenderungen der Mamma und deren klinische Relevanz fuer die Mammographie und MR-Mammographie darzustellen. Zu diesem Zweck werden aus einer eigenen Studie Daten der dynamischen MR-Tomographie zum Alters- und Zykluseinfluss auf das Mammaparenchym praesentiert. Darueber hinaus werden diese Einflussfaktoren mit mammographischen und MR-tomographischen Daten aus der Literatur korreliert. Dabei zeigt sich, dass sich aus den alters- und menstruationszyklusbedingten Veraenderungen der Brust wichtige unmittelbare

Novel Application of a Multiscale Entropy Index as a Sensitive Tool for Detecting Subtle Vascular Abnormalities in the Aged and Diabetic

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Hsien-Tsai Wu

2013-01-01

Full Text Available Although previous studies have shown the successful use of pressure-induced reactive hyperemia as a tool for the assessment of endothelial function, its sensitivity remains questionable. This study aims to investigate the feasibility and sensitivity of a novel multiscale entropy index (MEI in detecting subtle vascular abnormalities in healthy and diabetic subjects. Basic anthropometric and hemodynamic parameters, serum lipid profiles, and glycosylated hemoglobin levels were recorded. Arterial pulse wave signals were acquired from the wrist with an air pressure sensing system (APSS, followed by MEI and dilatation index (DI analyses. MEI succeeded in detecting significant differences among the four groups of subjects: healthy young individuals, healthy middle-aged or elderly individuals, well-controlled diabetic individuals, and poorly controlled diabetic individuals. A reduction in multiscale entropy reflected age- and diabetes-related vascular changes and may serve as a more sensitive indicator of subtle vascular abnormalities compared with DI in the setting of diabetes.

Response costs of mammography adherence: Iranian women's perceptions.

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Khodayarian, Mahsa; Mazloomi-Mahmoodabad, Seyed Saied; Lamyian, Minoor; Morowatisharifabad, Mohammad Ali; Tavangar, Hossein

2016-01-01

Mammography as the most common secondary prevention method has known to be helpful in detecting breast cancer at the early stages. Low level of participation among women toward mammography uptake due to cultural beliefs is a great concern. This study aimed at exploring the perceptions of women about response costs of mammography adherence (MA) in Yazd, Iran. A qualitative study using semi-structured interviews was performed. Fourteen women,one oncology nurse, and a breast cancer survivor were purposefully interviewed. Interviews were transcribed verbatim and analyzed by directed content analysis method based on protection motivation theory (PMT). One main theme was emerged from the analysis namely called "response costs".Two main categories were also emerged from the data; (1) psychological barriers with six subcategories including "embarrassment," "worry about being diagnosed with cancer," "preoccupation with underlying disease," "misconception about mammography," "need for an accompanying person," and "internalizing the experiences of the others," and (2) maladaptive coping modes which encompassed three subcategories: "religious faith," "fatalism," and"avoidance and denial." Useful information was provided about the response costs of mammography utilization based on the perceptions of women. Cognitive barriers may be decreased by conducting modifications in women's awareness and attitude toward MA as well as changing the national health system infrastructures. Incorporating religious and cultural belief systems into MA educational programs through motivational messages is recommended.

Entropy Viscosity and L1-based Approximations of PDEs: Exploiting Sparsity

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2015-10-23

AFRL-AFOSR-VA-TR-2015-0337 Entropy Viscosity and L1-based Approximations of PDEs: Exploiting Sparsity Jean-Luc Guermond TEXAS A & M UNIVERSITY 750...REPORT DATE (DD-MM-YYYY) 09-05-2015 2. REPORT TYPE Final report 3. DATES COVERED (From - To) 01-07-2012 - 30-06-2015 4. TITLE AND SUBTITLE Entropy ...conservation equations can be stabilized by using the so-called entropy viscosity method and we proposed to to investigate this new technique. We

On the Entropy Based Associative Memory Model with Higher-Order Correlations

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Masahiro Nakagawa

2010-01-01

Full Text Available In this paper, an entropy based associative memory model will be proposed and applied to memory retrievals with an orthogonal learning model so as to compare with the conventional model based on the quadratic Lyapunov functional to be minimized during the retrieval process. In the present approach, the updating dynamics will be constructed on the basis of the entropy minimization strategy which may be reduced asymptotically to the above-mentioned conventional dynamics as a special case ignoring the higher-order correlations. According to the introduction of the entropy functional, one may involve higer-order correlation effects between neurons in a self-contained manner without any heuristic coupling coefficients as in the conventional manner. In fact we shall show such higher order coupling tensors are to be uniquely determined in the framework of the entropy based approach. From numerical results, it will be found that the presently proposed novel approach realizes much larger memory capacity than that of the quadratic Lyapunov functional approach, e.g., associatron.

Application of a partitioning procedure based on Rao quadratic entropy index to characterize the temporal evolution of in situ varietal and genetic diversity of bread wheat in France over the period 1981-2006.

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Perronne, Rémi; Goldringer, Isabelle

2018-04-01

We present and highlight a partitioning procedure based on the Rao quadratic entropy index to assess temporal in situ inter-annual varietal and genetic changes of crop diversity. For decades, Western-European agroecosystems have undergone profound changes, among which a reduction of crop genetic diversity. These changes have been highlighted in numerous studies, but no unified partitioning procedure has been proposed to compute the inter-annual variability in both varietal and genetic diversity. To fill this gap, we tested, adjusted and applied a partitioning procedure based on the Rao quadratic entropy index that made possible to describe the different components of crop diversity as well as to account for the relative acreages of varieties. To emphasize the relevance of this procedure, we relied on a case study focusing on the temporal evolution of bread wheat diversity in France over the period 1981-2006 at both national and district scales. At the national scale, we highlighted a decrease of the weighted genetic replacement indicating that varieties sown in the most recent years were more genetically similar than older ones. At the district scale, we highlighted sudden changes in weighted genetic replacement in some agricultural regions that could be due to fast shifts of successive leading varieties over time. Other regions presented a relatively continuous increase of genetic similarity over time, potentially due to the coexistence of a larger number of co-leading varieties that got closer genetically. Based on the partitioning procedure, we argue that a tendency of in situ genetic homogenization could be compared to some of its potential causes, such as a decrease in the speed of replacement or an increase in between-variety genetic similarity over time.

Implementation of Quality Control Protocol in Mammography: A Serbian Experience

International Nuclear Information System (INIS)

Ciraj Bjelac, O.; Kosutic, D.; Arandjic, D.; Kovacevic, M.

2008-01-01

Mammography is method of choice for early detection of breast cancer. In Serbia, mammography is performed only clinically, although there is a long term plan to introduce mammography as screening method. Currently there are 60 mammography units in practice in Serbia, resulting with 70 000 mammographies annually. The purpose of this paper is preliminary evaluation of the mammography practice in Serbia, having in mind the annual number of examinations and fact that part of examination is performed on women without any clinical signs. For pilot implementation of Quality Control (QC) protocol in mammography, five hospitals with highest workload have been selected, representing the typical mammography practice in Serbia. Developed QC protocol, based on European guidelines for quality assurance in breast cancer screening and diagnosis, actual practice and resources, includes equipment testing and maintenance, staff training and QC management and allocation of responsibilities. Subsequently, it should be applied on the national scale. The survey demonstrated considerable variations in technical parameters that affect image quality and patients doses. Mean glandular doses ranged from 0.12 to 2.8 mGy, while reference optical density ranged from 1.2 to 2.8. Main problems were associated with film processing, viewing conditions and optical density control. The preliminary survey of mammography practice highlighted the need for optimization of radiation protection and training of operating staff, although the survey itself was very valuable learning process for all participants. Furthermore, systematic implementation of QC protocol should provide reliable performance of mammography units and maintain satisfactory image quality and keep patient doses as low as reasonably practical.(author)

Entropy equilibrium equation and dynamic entropy production in environment liquid

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

The entropy equilibrium equation is the basis of the nonequilibrium state thermodynamics. But the internal energy implies the kinetic energy of the fluid micelle relative to mass center in the classical entropy equilibrium equation at present. This internal energy is not the mean kinetic energy of molecular movement in thermodynamics. Here a modified entropy equilibrium equation is deduced, based on the concept that the internal energy is just the mean kinetic energy of the molecular movement. A dynamic entropy production is introduced into the entropy equilibrium equation to describe the dynamic process distinctly. This modified entropy equilibrium equation can describe not only the entropy variation of the irreversible processes but also the reversible processes in a thermodynamic system. It is more reasonable and suitable for wider applications.

A Method of Rotating Machinery Fault Diagnosis Based on the Close Degree of Information Entropy

Institute of Scientific and Technical Information of China (English)

GENG Jun-bao; HUANG Shu-hong; JIN Jia-shan; CHEN Fei; LIU Wei

2006-01-01

This paper presents a method of rotating machinery fault diagnosis based on the close degree of information entropy. In the view of the information entropy, we introduce four information entropy features of the rotating machinery, which describe the vibration condition of the machinery. The four features are, respectively, denominated as singular spectrum entropy, power spectrum entropy, wavelet space state feature entropy and wavelet power spectrum entropy. The value scopes of the four information entropy features of the rotating machinery in some typical fault conditions are gained by experiments, which can be acted as the standard features of fault diagnosis. According to the principle of the shorter distance between the more similar models, the decision-making method based on the close degree of information entropy is put forward to deal with the recognition of fault patterns. We demonstrate the effectiveness of this approach in an instance involving the fault pattern recognition of some rotating machinery.

Curvature Entropy for Curved Profile Generation

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Koichiro Sato

2012-03-01

Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.

Multiattribute Decision Making Based on Entropy under Interval-Valued Intuitionistic Fuzzy Environment

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Yingjun Zhang

2013-01-01

Full Text Available Multiattribute decision making (MADM is one of the central problems in artificial intelligence, specifically in management fields. In most cases, this problem arises from uncertainty both in the data derived from the decision maker and the actions performed in the environment. Fuzzy set and high-order fuzzy sets were proven to be effective approaches in solving decision-making problems with uncertainty. Therefore, in this paper, we investigate the MADM problem with completely unknown attribute weights in the framework of interval-valued intuitionistic fuzzy (IVIF set (IVIFS. We first propose a new definition of IVIF entropy and some calculation methods for IVIF entropy. Furthermore, we propose an entropy-based decision-making method to solve IVIF MADM problems with completely unknown attribute weights. Particular emphasis is put on assessing the attribute weights based on IVIF entropy. Instead of the traditional methods, which use divergence among attributes or the probabilistic discrimination of attributes to obtain attribute weights, we utilize the IVIF entropy to assess the attribute weights based on the credibility of the decision-making matrix for solving the problem. Finally, a supplier selection example is given to demonstrate the feasibility and validity of the proposed MADM method.

Mammography in Norway: Image quality and total performance

International Nuclear Information System (INIS)

Olsen, J.B.; Skretting, A.; Widmark, A.

1997-04-01

This report describes a method for assessing the total performance in mammography based on Receiver Operating Characteristic (ROC) analysis. In the time period from December 1993 to March 1994 the method was applied to assess the total performance of all the 45 Norwegian mammography laboratories operative at that time. Image quality characteristics in each laboratory was established by use of well-known phantoms

Logarithmic black hole entropy corrections and holographic Rényi entropy

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Mahapatra, Subhash

2018-01-01

The entanglement and Rényi entropies for spherical entangling surfaces in CFTs with gravity duals can be explicitly calculated by mapping these entropies first to the thermal entropy on hyperbolic space and then, using the AdS/CFT correspondence, to the Wald entropy of topological black holes. Here we extend this idea by taking into account corrections to the Wald entropy. Using the method based on horizon symmetries and the asymptotic Cardy formula, we calculate corrections to the Wald entropy and find that these corrections are proportional to the logarithm of the area of the horizon. With the corrected expression for the entropy of the black hole, we then find corrections to the Rényi entropies. We calculate these corrections for both Einstein and Gauss-Bonnet gravity duals. Corrections with logarithmic dependence on the area of the entangling surface naturally occur at the order GD^0. The entropic c-function and the inequalities of the Rényi entropy are also satisfied even with the correction terms.

A multiparametric automatic method to monitor long-term reproducibility in digital mammography: results from a regional screening programme.

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Gennaro, G; Ballaminut, A; Contento, G

2017-09-01

This study aims to illustrate a multiparametric automatic method for monitoring long-term reproducibility of digital mammography systems, and its application on a large scale. Twenty-five digital mammography systems employed within a regional screening programme were controlled weekly using the same type of phantom, whose images were analysed by an automatic software tool. To assess system reproducibility levels, 15 image quality indices (IQIs) were extracted and compared with the corresponding indices previously determined by a baseline procedure. The coefficients of variation (COVs) of the IQIs were used to assess the overall variability. A total of 2553 phantom images were collected from the 25 digital mammography systems from March 2013 to December 2014. Most of the systems showed excellent image quality reproducibility over the surveillance interval, with mean variability below 5%. Variability of each IQI was 5%, with the exception of one index associated with the smallest phantom objects (0.25 mm), which was below 10%. The method applied for reproducibility tests-multi-detail phantoms, cloud automatic software tool to measure multiple image quality indices and statistical process control-was proven to be effective and applicable on a large scale and to any type of digital mammography system. • Reproducibility of mammography image quality should be monitored by appropriate quality controls. • Use of automatic software tools allows image quality evaluation by multiple indices. • System reproducibility can be assessed comparing current index value with baseline data. • Overall system reproducibility of modern digital mammography systems is excellent. • The method proposed and applied is cost-effective and easily scalable.

The self-referred mammography patient

International Nuclear Information System (INIS)

Reynolds, H.E.; Jackson, V.P.

1990-01-01

This paper compares the demographics, knowledge, and attitudes of women who refer themselves for screening mammography with those who undergo mammography on the advice of their physicians. Four hundred eighty-five consecutive mammography patients (437 doctor preferred [DR], 48 self-referred [SR]) completed a survey during their mammography appointment. The sample population contained a wide range of socioeconomic groups. While similar in age, race, and employment status to DR patients, SR patients were significantly more likely to have a family income of more than 30,000 per year, be college graduates, and report that they were in good or excellent health

Evaluation of the performance characteristic for mammography by using edge device

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Won [Dept. of Radiology, Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Choi, Jwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, The Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [Dept. of Medical Science, The Soonchunhyang University, Asan (Korea, Republic of); Lee, Eul Kyu [Dept. of Radiology, Inje Paik University Hospital Jeo-dong, Seoul (Korea, Republic of); Son, Soon Yong [Dept. of Radiological Technology, The Wonkwang Health Science University, Iksan (Korea, Republic of); Son, Jin Hyun; Min, Jung Whan [Dept. of Radiological Technology, The Shingu University, Sungnam (Korea, Republic of)

2016-09-15

The purpose of this study was to evaluation of the performance characteristic for mammography by using edge device that mammography equipment improves essential in the correct diagnosis for the maintenance. We measured the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using the 61267 RQA-M2 based on commission standard international electro-technical commission (IEC). As a results, spatial resolution of dimensions tomo and lorad selenia mammography were maintained at 10 mm-1 and NPS and DQE including the low nyquist frequency indicated to 6.0 mm-1. Therefore, regularly QA of mammography system should be necessary. This study can be contribute to evaluate QA for performance characteristic of mammography of DDR system.

Towards an entropy-based detached-eddy simulation

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Zhao, Rui; Yan, Chao; Li, XinLiang; Kong, WeiXuan

2013-10-01

A concept of entropy increment ratio ( s¯) is introduced for compressible turbulence simulation through a series of direct numerical simulations (DNS). s¯ represents the dissipation rate per unit mechanical energy with the benefit of independence of freestream Mach numbers. Based on this feature, we construct the shielding function f s to describe the boundary layer region and propose an entropy-based detached-eddy simulation method (SDES). This approach follows the spirit of delayed detached-eddy simulation (DDES) proposed by Spalart et al. in 2005, but it exhibits much better behavior after their performances are compared in the following flows, namely, pure attached flow with thick boundary layer (a supersonic flat-plate flow with high Reynolds number), fully separated flow (the supersonic base flow), and separated-reattached flow (the supersonic cavity-ramp flow). The Reynolds-averaged Navier-Stokes (RANS) resolved region is reliably preserved and the modeled stress depletion (MSD) phenomenon which is inherent in DES and DDES is partly alleviated. Moreover, this new hybrid strategy is simple and general, making it applicable to other models related to the boundary layer predictions.

MRI and mammography surveillance of women at increased risk for breast cancer: recommendations using an evidence-based approach.

Science.gov (United States)

Granader, Elon J; Dwamena, Ben; Carlos, Ruth C

2008-12-01

To evaluate breast cancer screening with mammography and magnetic resonance imaging (MRI) in high-risk populations, including women with the BRCA mutation, using an evidence-based approach. The MEDLINE, PubMed, EBM Reviews, ACP Journal Club, Cochrane Database MEDSEARCH, and SCOPUS databases were accessed and searched for articles up to August 2007. Articles were collected using the following terms and medical subject headings (MeSH) that applied to the focused clinical question: "BRCA1" and "BRCA2" with "mammography," "MRI," "prevention," "screening," and "surveillance." References from retrieved articles were also used to identify relevant papers. Abstracts were screened and relevant papers retrieved. Retrieved papers were graded for quality. Summary performance measures were obtained by random effects modeling of study-specific performance estimates and standard errors derived from the multiple 2 x 2 tables. Additionally, studies meeting the Centre for Evidence-Based Medicine level 2b quality were reviewed. In women with an increased risk without the BRCA gene, cancer detection rates by MRI were 0.011 (95% confidence interval [CI] 0.003-0.019), by mammography 0.005 (95% CI 0.002-0.008), and by a combination of both, 0.012 (95% CI 0.004-0.020). False-positive rates by MRI, mammography, or a combination of both were 0.10 (95% CI 0.03-0.18), 0.05 (95% CI 0.03-0.06), and 0.14 (95% CI 0.04-0.24). In BRCA positive women, cancer detection rates by MRI were 0.027 (95% CI 0.015-0.040), by mammography 0.010 (95% CI 0.005-0.016), and by a combination of both 0.031 (95% CI 0.018-0.045). False-positive rates by MRI, mammography, or a combination of both were 0.10 (95% CI 0.01-0.19), 0.05 (95% CI 0.03-0.07), and 0.14 (95% CI 0.04-0.24), respectively. The data support an essential role for screening MRI in women with an increased risk for breast cancer.

European radiographers' challenges from mammography education and clinical practice - an integrative review.

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Metsälä, Eija; Richli Meystre, Nicole; Pires Jorge, José; Henner, Anja; Kukkes, Tiina; Sá Dos Reis, Cláudia

2017-06-01

This study aims to identify European radiographers' challenges in clinical performance in mammography and the main areas of mammography that require more and better training. An extensive search was performed to identify relevant studies focused on clinical practice, education and training in mammography published between January 2010 and December 2015 in the English language. The data were analysed by using deductive thematic analysis. A total of 27 full text articles were read, evaluating their quality. Sixteen articles out of 27 were finally selected for this integrative review. The main challenges of radiographers' mammography education/training can be divided into three groups: training needs, challenges related to radiographers, and challenges related to the organization of education. The most common challenges of clinical performance in mammography among European radiographers involved technical performance, the quality of practices, and patient-centeredness. The introduction of harmonized mammography guidelines across Europe may serve as an evidence-based tool to be implemented in practice and education. However, the variability in human and material resources as well as the different cultural contexts should be considered during this process. • Radiographers' awareness of their professional identity and enhancing multiprofessional cooperation in mammography. • Radiographers' responsibilities regarding image quality (IQ) and optimal breast imaging performance. • Patient-centred mammography services focusing on the psychosocial needs of the patient. • Challenges: positioning, QC-testing, IQ-assessment, optimization of breast compression, communication, teamwork, and patient-centred care. • Introduction of evidence-based guidelines in Europe to harmonize mammography practice and education.

Characterization of complexity in the electroencephalograph activity of Alzheimer's disease based on fuzzy entropy.

Science.gov (United States)

Cao, Yuzhen; Cai, Lihui; Wang, Jiang; Wang, Ruofan; Yu, Haitao; Cao, Yibin; Liu, Jing

2015-08-01

In this paper, experimental neurophysiologic recording and statistical analysis are combined to investigate the nonlinear characteristic and the cognitive function of the brain. Fuzzy approximate entropy and fuzzy sample entropy are applied to characterize the model-based simulated series and electroencephalograph (EEG) series of Alzheimer's disease (AD). The effectiveness and advantages of these two kinds of fuzzy entropy are first verified through the simulated EEG series generated by the alpha rhythm model, including stronger relative consistency and robustness. Furthermore, in order to detect the abnormality of irregularity and chaotic behavior in the AD brain, the complexity features based on these two fuzzy entropies are extracted in the delta, theta, alpha, and beta bands. It is demonstrated that, due to the introduction of fuzzy set theory, the fuzzy entropies could better distinguish EEG signals of AD from that of the normal than the approximate entropy and sample entropy. Moreover, the entropy values of AD are significantly decreased in the alpha band, particularly in the temporal brain region, such as electrode T3 and T4. In addition, fuzzy sample entropy could achieve higher group differences in different brain regions and higher average classification accuracy of 88.1% by support vector machine classifier. The obtained results prove that fuzzy sample entropy may be a powerful tool to characterize the complexity abnormalities of AD, which could be helpful in further understanding of the disease.

Image quality of digital mammography images produced using wet and dry laser imaging systems

International Nuclear Information System (INIS)

Al Khalifah, K.; Brindhaban, A.; AlArfaj, R.; Jassim, O.

2006-01-01

Introduction: A study was carried out to compare the quality of digital mammographic images printed or processed by a wet laser imaging system and a dedicated mammographic dry laser imaging system. Material and methods: Digital images of a tissue equivalent breast phantom were obtained using a GE Senographe 2000D digital mammography system and different target/filter combinations of the X-ray tube. These images were printed on films using the Fuji FL-IM D wet laser imaging system and the Kodak DryView 8600 dry laser imaging system. The quality of images was assessed in terms of detectability of microcalcifications and simulated tumour masses by five radiologists. In addition, the contrast index and speed index of the two systems were measured using the step wedge in the phantom. The unpaired, unequal variance t-test was used to test any statistically significant differences. Results: There were no significant (p < 0.05) differences between the images printed using the two systems in terms of microcalcification and tumour mass detectability. The wet system resulted in slightly higher contrast index while the dry system showed significantly higher speed index. Conclusion: Both wet and dry laser imaging systems can produce mammography images of good quality on which 0.2 mm microcalcifications and 2 mm tumour masses can be detected. Dry systems are preferable due to the absence of wet chemical processing and solid or liquid chemical waste. The wet laser imaging systems, however, still represent a useful alternative to dry laser imaging systems for mammography studies

Using the modified sample entropy to detect determinism

Energy Technology Data Exchange (ETDEWEB)

Xie Hongbo, E-mail: xiehb@sjtu.or [Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Department of Biomedical Engineering, Jiangsu University, Zhenjiang (China); Guo Jingyi [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Zheng Yongping, E-mail: ypzheng@ieee.or [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Reseach Institute of Innovative Products and Technologies, Hong Kong Polytechnic University (Hong Kong)

2010-08-23

A modified sample entropy (mSampEn), based on the nonlinear continuous and convex function, has been proposed and proven to be superior to the standard sample entropy (SampEn) in several aspects. In this Letter, we empirically investigate the ability of the mSampEn statistic combined with surrogate data method to detect determinism. The effects of the datasets length and noise on the proposed method to differentiate between deterministic and stochastic dynamics are tested on several benchmark time series. The noise performance of the mSampEn statistic is also compared with the singular value decomposition (SVD) and symplectic geometry spectrum (SGS) based methods. The results indicate that the mSampEn statistic is a robust index for detecting determinism in short and noisy time series.

Sample Entropy-Based Approach to Evaluate the Stability of Double-Wire Pulsed MIG Welding

Directory of Open Access Journals (Sweden)

Ping Yao

2014-01-01

Full Text Available According to the sample entropy, this paper deals with a quantitative method to evaluate the current stability in double-wire pulsed MIG welding. Firstly, the sample entropy of current signals with different stability but the same parameters is calculated. The results show that the more stable the current, the smaller the value and the standard deviation of sample entropy. Secondly, four parameters, which are pulse width, peak current, base current, and frequency, are selected for four-level three-factor orthogonal experiment. The calculation and analysis of desired signals indicate that sample entropy values are affected by welding current parameters. Then, a quantitative method based on sample entropy is proposed. The experiment results show that the method can preferably quantify the welding current stability.

2D Tsallis Entropy for Image Segmentation Based on Modified Chaotic Bat Algorithm

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Zhiwei Ye

2018-03-01

Full Text Available Image segmentation is a significant step in image analysis and computer vision. Many entropy based approaches have been presented in this topic; among them, Tsallis entropy is one of the best performing methods. However, 1D Tsallis entropy does not consider make use of the spatial correlation information within the neighborhood results might be ruined by noise. Therefore, 2D Tsallis entropy is proposed to solve the problem, and results are compared with 1D Fisher, 1D maximum entropy, 1D cross entropy, 1D Tsallis entropy, fuzzy entropy, 2D Fisher, 2D maximum entropy and 2D cross entropy. On the other hand, due to the existence of huge computational costs, meta-heuristics algorithms like genetic algorithm (GA, particle swarm optimization (PSO, ant colony optimization algorithm (ACO and differential evolution algorithm (DE are used to accelerate the 2D Tsallis entropy thresholding method. In this paper, considering 2D Tsallis entropy as a constrained optimization problem, the optimal thresholds are acquired by maximizing the objective function using a modified chaotic Bat algorithm (MCBA. The proposed algorithm has been tested on some actual and infrared images. The results are compared with that of PSO, GA, ACO and DE and demonstrate that the proposed method outperforms other approaches involved in the paper, which is a feasible and effective option for image segmentation.

Logarithmic terms in entanglement entropies of 2D quantum critical points and Shannon entropies of spin chains.

Science.gov (United States)

Zaletel, Michael P; Bardarson, Jens H; Moore, Joel E

2011-07-08

Universal logarithmic terms in the entanglement entropy appear at quantum critical points (QCPs) in one dimension (1D) and have been predicted in 2D at QCPs described by 2D conformal field theories. The entanglement entropy in a strip geometry at such QCPs can be obtained via the "Shannon entropy" of a 1D spin chain with open boundary conditions. The Shannon entropy of the XXZ chain is found to have a logarithmic term that implies, for the QCP of the square-lattice quantum dimer model, a logarithm with universal coefficient ±0.25. However, the logarithm in the Shannon entropy of the transverse-field Ising model, which corresponds to entanglement in the 2D Ising conformal QCP, is found to have a singular dependence on the replica or Rényi index resulting from flows to different boundary conditions at the entanglement cut.

Bubble Entropy: An Entropy Almost Free of Parameters.

Science.gov (United States)

Manis, George; Aktaruzzaman, Md; Sassi, Roberto

2017-11-01

Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors. Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation

Studies Comparing Screen-Film Mammography and Full-Field Digital Mammography in Breast Cancer Screening: Updated Review

International Nuclear Information System (INIS)

Skaane, P.

2009-01-01

Full-field digital mammography (FFDM) has several potential benefits as compared with screen-film mammography (SFM) in mammography screening. Digital technology also opens for implementation of advanced applications, including computer-aided detection (CAD) and tomosynthesis. Phantom studies and experimental clinical studies have shown that FFDM is equal or slightly superior to SFM for detection and characterization of mammographic abnormalities. Despite obvious advantages, the conversion to digital mammography has been slower than anticipated, and not only due to higher costs. Until very recently, some countries did not even permit the use of digital mammography in breast cancer screening. The reason for this reluctant attitude was concern about lower spatial resolution and about using soft-copy reading. Furthermore, there was a lack of data supporting improved diagnostic accuracy using FFDM in a screening setting, since two pioneer trials both showed nonsignificantly lower cancer detection rate at FFDM. The 10 studies comparing FFDM and SFM in mammography screening published so far have shown divergent and rather conflicting results. Nevertheless, there is a rapid conversion to digital mammography in breast cancer screening in many western countries. The aim of this article is to give an updated review of these studies, discuss the conflicting findings, and draw some conclusions from the results

A Novel Entropy-Based Decoding Algorithm for a Generalized High-Order Discrete Hidden Markov Model

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Jason Chin-Tiong Chan

2018-01-01

Full Text Available The optimal state sequence of a generalized High-Order Hidden Markov Model (HHMM is tracked from a given observational sequence using the classical Viterbi algorithm. This classical algorithm is based on maximum likelihood criterion. We introduce an entropy-based Viterbi algorithm for tracking the optimal state sequence of a HHMM. The entropy of a state sequence is a useful quantity, providing a measure of the uncertainty of a HHMM. There will be no uncertainty if there is only one possible optimal state sequence for HHMM. This entropy-based decoding algorithm can be formulated in an extended or a reduction approach. We extend the entropy-based algorithm for computing the optimal state sequence that was developed from a first-order to a generalized HHMM with a single observational sequence. This extended algorithm performs the computation exponentially with respect to the order of HMM. The computational complexity of this extended algorithm is due to the growth of the model parameters. We introduce an efficient entropy-based decoding algorithm that used reduction approach, namely, entropy-based order-transformation forward algorithm (EOTFA to compute the optimal state sequence of any generalized HHMM. This EOTFA algorithm involves a transformation of a generalized high-order HMM into an equivalent first-order HMM and an entropy-based decoding algorithm is developed based on the equivalent first-order HMM. This algorithm performs the computation based on the observational sequence and it requires OTN~2 calculations, where N~ is the number of states in an equivalent first-order model and T is the length of observational sequence.

Low-Pass Filtering Approach via Empirical Mode Decomposition Improves Short-Scale Entropy-Based Complexity Estimation of QT Interval Variability in Long QT Syndrome Type 1 Patients

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Vlasta Bari

2014-09-01

Full Text Available Entropy-based complexity of cardiovascular variability at short time scales is largely dependent on the noise and/or action of neural circuits operating at high frequencies. This study proposes a technique for canceling fast variations from cardiovascular variability, thus limiting the effect of these overwhelming influences on entropy-based complexity. The low-pass filtering approach is based on the computation of the fastest intrinsic mode function via empirical mode decomposition (EMD and its subtraction from the original variability. Sample entropy was exploited to estimate complexity. The procedure was applied to heart period (HP and QT (interval from Q-wave onset to T-wave end variability derived from 24-hour Holter recordings in 14 non-mutation carriers (NMCs and 34 mutation carriers (MCs subdivided into 11 asymptomatic MCs (AMCs and 23 symptomatic MCs (SMCs. All individuals belonged to the same family developing long QT syndrome type 1 (LQT1 via KCNQ1-A341V mutation. We found that complexity indexes computed over EMD-filtered QT variability differentiated AMCs from NMCs and detected the effect of beta-blocker therapy, while complexity indexes calculated over EMD-filtered HP variability separated AMCs from SMCs. The EMD-based filtering method enhanced features of the cardiovascular control that otherwise would have remained hidden by the dominant presence of noise and/or fast physiological variations, thus improving classification in LQT1.

The mammography screening employee inreach program.

Science.gov (United States)

Robinson, Joanne; Seltzer, Vicki; Lawrence, Loretta; Autz, George; Kostroff, Karen; Weiselberg, Lora; Colagiacomo, Maria

2007-02-01

To determine whether our health care employees were undergoing mammography screening according to American Cancer Society guidelines and to determine whether aggressive outreach, education and streamlining of mammography scheduling could improve compliance. All female employees at North Shore University Hospital (NSUH) and several other health system facilities (SF) were sent mailings to their homes that included breast health education and mammography screening guidelines, a questionnaire regarding their own mammography screening history and the opportunity to have their mammography screening scheduled by the Mammography Screening Employee Inreach Program (MSEIP) coordinator. Of the approximately 2,700 female employees aged 40 and over at NSUH and SF, 2,235 (82.7%) responded to the questionnaire, and 1,455 had a mammogram done via the MSEIP. Of the 1,455, 43% either were overdue for a mammogram or had never had one. During a second year of the MSEIP at NSUH and SF, an additional 1,706 mammograms were done. People employed in health care jobs do not necessarily avail themselves of appropriate health care screening. An aggressive program that utilized education, outreach and assistance with scheduling was effective in increasing compliance with mammography screening.

Relation Entropy and Transferable Entropy Think of Aggregation on Group Decision Making

Institute of Scientific and Technical Information of China (English)

CHENG Qi-yue; QIU Wan-hua; LIU Xiao-feng

2002-01-01

In this paper, aggregation question based on group decision making and a single decision making is studied. The theory of entropy is applied to the sets pair analysis. The system of relation entropy and the transferable entropy notion are put. The character is studied. An potential by the relation entropy and transferable entropy are defined. It is the consistency measure on the group between a single decision making. We gained a new aggregation effective definition on the group misjudge.

Fuzzy 2-partition entropy threshold selection based on Big Bang–Big Crunch Optimization algorithm

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Baljit Singh Khehra

2015-03-01

Full Text Available The fuzzy 2-partition entropy approach has been widely used to select threshold value for image segmenting. This approach used two parameterized fuzzy membership functions to form a fuzzy 2-partition of the image. The optimal threshold is selected by searching an optimal combination of parameters of the membership functions such that the entropy of fuzzy 2-partition is maximized. In this paper, a new fuzzy 2-partition entropy thresholding approach based on the technology of the Big Bang–Big Crunch Optimization (BBBCO is proposed. The new proposed thresholding approach is called the BBBCO-based fuzzy 2-partition entropy thresholding algorithm. BBBCO is used to search an optimal combination of parameters of the membership functions for maximizing the entropy of fuzzy 2-partition. BBBCO is inspired by the theory of the evolution of the universe; namely the Big Bang and Big Crunch Theory. The proposed algorithm is tested on a number of standard test images. For comparison, three different algorithms included Genetic Algorithm (GA-based, Biogeography-based Optimization (BBO-based and recursive approaches are also implemented. From experimental results, it is observed that the performance of the proposed algorithm is more effective than GA-based, BBO-based and recursion-based approaches.

A new entropy based method for computing software structural complexity

CERN Document Server

Roca, J L

2002-01-01

In this paper a new methodology for the evaluation of software structural complexity is described. It is based on the entropy evaluation of the random uniform response function associated with the so called software characteristic function SCF. The behavior of the SCF with the different software structures and their relationship with the number of inherent errors is investigated. It is also investigated how the entropy concept can be used to evaluate the complexity of a software structure considering the SCF as a canonical representation of the graph associated with the control flow diagram. The functions, parameters and algorithms that allow to carry out this evaluation are also introduced. After this analytic phase follows the experimental phase, verifying the consistency of the proposed metric and their boundary conditions. The conclusion is that the degree of software structural complexity can be measured as the entropy of the random uniform response function of the SCF. That entropy is in direct relation...

A two-phase copula entropy-based multiobjective optimization approach to hydrometeorological gauge network design

Science.gov (United States)

Xu, Pengcheng; Wang, Dong; Singh, Vijay P.; Wang, Yuankun; Wu, Jichun; Wang, Lachun; Zou, Xinqing; Chen, Yuanfang; Chen, Xi; Liu, Jiufu; Zou, Ying; He, Ruimin

2017-12-01

Hydrometeorological data are needed for obtaining point and areal mean, quantifying the spatial variability of hydrometeorological variables, and calibration and verification of hydrometeorological models. Hydrometeorological networks are utilized to collect such data. Since data collection is expensive, it is essential to design an optimal network based on the minimal number of hydrometeorological stations in order to reduce costs. This study proposes a two-phase copula entropy- based multiobjective optimization approach that includes: (1) copula entropy-based directional information transfer (CDIT) for clustering the potential hydrometeorological gauges into several groups, and (2) multiobjective method for selecting the optimal combination of gauges for regionalized groups. Although entropy theory has been employed for network design before, the joint histogram method used for mutual information estimation has several limitations. The copula entropy-based mutual information (MI) estimation method is shown to be more effective for quantifying the uncertainty of redundant information than the joint histogram (JH) method. The effectiveness of this approach is verified by applying to one type of hydrometeorological gauge network, with the use of three model evaluation measures, including Nash-Sutcliffe Coefficient (NSC), arithmetic mean of the negative copula entropy (MNCE), and MNCE/NSC. Results indicate that the two-phase copula entropy-based multiobjective technique is capable of evaluating the performance of regional hydrometeorological networks and can enable decision makers to develop strategies for water resources management.

Breast cancer imaging: Mammography among women of up to 45 years

International Nuclear Information System (INIS)

Schnejder-Wilk, A.

2010-01-01

Background: Among women under the age of 40, screening mammography examinations are not performed routinely. An ultrasonography scan is considered to be a basic breast imaging examination among younger women. The purpose of this study was to analyze mammography images, as well as to evaluate the usefulness and role of mammography in breast cancer diagnostic processes in women of up to 45 years, based on own experience. Material/Methods: A retrospective analysis of mammography images, including 144 cases of breast cancer diagnosed in the group of 140 women of 45 years of age. All the patients underwent pre-treatment mammography and surgery procedure. The images were evaluated in accordance to BIRADS criteria. Lesions detectable in mammography were grouped as follows: spiculated mass; nonmicrocalcified oval/round mass; microcalcified mass (regardless of shape); microcalcifications; architectural distortion; breast tissue asymmetry. Results: The most common mammographic symptom was solid tumor (41%), followed by microcalcified tumors (20.8%). Clusters of microcalcifications constituted 17.4% of mammography findings. In 4.9% of mammography scans, examination did not reveal any pathological lesions. Conclusions: Breast cancer mammograms of women aged up to 45 years do not differ from diagnostic pictures of breast cancer in older women. The diagnostic appearance of breast cancer in 1/3 of the patients involved microcalcifications detectable only on mammograms. All the women with suspicion of breast cancer should have their mammography examinations performed, irrespective of ultrasonography scans. (author)

A computerized expert system for mammography

International Nuclear Information System (INIS)

Jackson, V.P.; Dines, K.A.; Bassett, L.W.

1988-01-01

The authors have developed a computer-based expert system to aid in the interpretation of mammograms, breast sonograms, and clinical findings. The radiologist enters clinical and image data into the artificial intelligence system and receives a prediction of the etiology of lesions seen on breast imaging studies. This prototype interactive system has undergone preliminary clinical testing and evaluation. Ultimately, a more refined and complex system will be of value in mammography education, for general radiologists without ready access to mammography experts, for paramedical personnel, and for all mammographers in need of a breast imaging database and reporting systems

An entropy-based analysis of lane changing behavior: An interactive approach.

Science.gov (United States)

Kosun, Caglar; Ozdemir, Serhan

2017-05-19

As a novelty, this article proposes the nonadditive entropy framework for the description of driver behaviors during lane changing. The authors also state that this entropy framework governs the lane changing behavior in traffic flow in accordance with the long-range vehicular interactions and traffic safety. The nonadditive entropy framework is the new generalized theory of thermostatistical mechanics. Vehicular interactions during lane changing are considered within this framework. The interactive approach for the lane changing behavior of the drivers is presented in the traffic flow scenarios presented in the article. According to the traffic flow scenarios, 4 categories of traffic flow and driver behaviors are obtained. Through the scenarios, comparative analyses of nonadditive and additive entropy domains are also provided. Two quadrants of the categories belong to the nonadditive entropy; the rest are involved in the additive entropy domain. Driving behaviors are extracted and the scenarios depict that nonadditivity matches safe driving well, whereas additivity corresponds to unsafe driving. Furthermore, the cooperative traffic system is considered in nonadditivity where the long-range interactions are present. However, the uncooperative traffic system falls into the additivity domain. The analyses also state that there would be possible traffic flow transitions among the quadrants. This article shows that lane changing behavior could be generalized as nonadditive, with additivity as a special case, based on the given traffic conditions. The nearest and close neighbor models are well within the conventional additive entropy framework. In this article, both the long-range vehicular interactions and safe driving behavior in traffic are handled in the nonadditive entropy domain. It is also inferred that the Tsallis entropy region would correspond to mandatory lane changing behavior, whereas additive and either the extensive or nonextensive entropy region would

Entropy Based Analysis of DNS Query Traffic in the Campus Network

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Dennis Arturo Ludeña Romaña

2008-10-01

Full Text Available We carried out the entropy based study on the DNS query traffic from the campus network in a university through January 1st, 2006 to March 31st, 2007. The results are summarized, as follows: (1 The source IP addresses- and query keyword-based entropies change symmetrically in the DNS query traffic from the outside of the campus network when detecting the spam bot activity on the campus network. On the other hand (2, the source IP addresses- and query keywordbased entropies change similarly each other when detecting big DNS query traffic caused by prescanning or distributed denial of service (DDoS attack from the campus network. Therefore, we can detect the spam bot and/or DDoS attack bot by only watching DNS query access traffic.

Entropy-based Probabilistic Fatigue Damage Prognosis and Algorithmic Performance Comparison

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National Aeronautics and Space Administration — In this paper, a maximum entropy-based general framework for probabilistic fatigue damage prognosis is investigated. The proposed methodology is based on an...

Entropy-based probabilistic fatigue damage prognosis and algorithmic performance comparison

Data.gov (United States)

National Aeronautics and Space Administration — In this paper, a maximum entropy-based general framework for probabilistic fatigue damage prognosis is investigated. The proposed methodology is based on an...

Mechanistic modeling for mammography screening risks

International Nuclear Information System (INIS)

Bijwaard, Harmen

2008-01-01

Full text: Western populations show a very high incidence of breast cancer and in many countries mammography screening programs have been set up for the early detection of these cancers. Through these programs large numbers of women (in the Netherlands, 700.000 per year) are exposed to low but not insignificant X-ray doses. ICRP based risk estimates indicate that the number of breast cancer casualties due to mammography screening can be as high as 50 in the Netherlands per year. The number of lives saved is estimated to be much higher, but for an accurate calculation of the benefits of screening a better estimate of these risks is indispensable. Here it is attempted to better quantify the radiological risks of mammography screening through the application of a biologically based model for breast tumor induction by X-rays. The model is applied to data obtained from the National Institutes of Health in the U.S. These concern epidemiological data of female TB patients who received high X-ray breast doses in the period 1930-1950 through frequent fluoroscopy of their lungs. The mechanistic model that is used to describe the increased breast cancer incidence is based on an earlier study by Moolgavkar et al. (1980), in which the natural background incidence of breast cancer was modeled. The model allows for a more sophisticated extrapolation of risks to the low dose X-ray exposures that are common in mammography screening and to the higher ages that are usually involved. Furthermore, it allows for risk transfer to other (non-western) populations. The results have implications for decisions on the frequency of screening, the number of mammograms taken at each screening, minimum and maximum ages for screening and the transfer to digital equipment. (author)

Comparative study of dose estimation in the change a conventional mammography to digital mammography

International Nuclear Information System (INIS)

Vazquez Vazquez, R.; Otero Martinez, C.; Soto Bua, M.; Santamarina Vazquez, F.; Carril Iglesias, S.; Lobato Busto, R.; Luna Vega, V.; Mosquera Sueiro, J.; Sqanchez Garcia, M.; Pombar Camean, M.

2011-01-01

Mammographic studies are now one of the most demanding radiological because of its effectiveness in detecting breast cancer early. The introduction of digital mammography has been a major advance because it has overcome some of the limitations of conventional systems. Due to the nature of the radiosensitive glandular tissue becomes very important control of the dose given to patients. In the present study is to analyze the variations in dosimetry that can exist between a conventional mammography and digital mammography.

Entropy based fingerprint for local crystalline order

Science.gov (United States)

Piaggi, Pablo M.; Parrinello, Michele

2017-09-01

We introduce a new fingerprint that allows distinguishing between liquid-like and solid-like atomic environments. This fingerprint is based on an approximate expression for the entropy projected on individual atoms. When combined with local enthalpy, this fingerprint acquires an even finer resolution and it is capable of discriminating between different crystal structures.

Regional Sustainable Development Analysis Based on Information Entropy-Sichuan Province as an Example.

Science.gov (United States)

Liang, Xuedong; Si, Dongyang; Zhang, Xinli

2017-10-13

According to the implementation of a scientific development perspective, sustainable development needs to consider regional development, economic and social development, and the harmonious development of society and nature, but regional sustainable development is often difficult to quantify. Through an analysis of the structure and functions of a regional system, this paper establishes an evaluation index system, which includes an economic subsystem, an ecological environmental subsystem and a social subsystem, to study regional sustainable development capacity. A sustainable development capacity measure model for Sichuan Province was established by applying the information entropy calculation principle and the Brusselator principle. Each subsystem and entropy change in a calendar year in Sichuan Province were analyzed to evaluate Sichuan Province's sustainable development capacity. It was found that the established model could effectively show actual changes in sustainable development levels through the entropy change reaction system, at the same time this model could clearly demonstrate how those forty-six indicators from the three subsystems impact on the regional sustainable development, which could make up for the lack of sustainable development research.

Radiation exposure of contrast-enhanced spectral mammography compared with full-field digital mammography.

Science.gov (United States)

Jeukens, Cécile R L P N; Lalji, Ulrich C; Meijer, Eduard; Bakija, Betina; Theunissen, Robin; Wildberger, Joachim E; Lobbes, Marc B I

2014-10-01

Contrast-enhanced spectral mammography (CESM) shows promising initial results but comes at the cost of increased dose as compared with full-field digital mammography (FFDM). We aimed to quantitatively assess the dose increase of CESM in comparison with FFDM. Radiation exposure-related data (such as kilovoltage, compressed breast thickness, glandularity, entrance skin air kerma (ESAK), and average glandular dose (AGD) were retrieved for 47 CESM and 715 FFDM patients. All examinations were performed on 1 mammography unit. Radiation dose values reported by the unit were validated by phantom measurements. Descriptive statistics of the patient data were generated using a statistical software package. Dose values reported by the mammography unit were in good qualitative agreement with those of phantom measurements. Mean ESAK was 10.5 mGy for a CESM exposure and 7.46 mGy for an FFDM exposure. Mean AGD for a CESM exposure was 2.80 mGy and 1.55 mGy for an FFDM exposure. Compared with our institutional FFDM, the AGD of a single CESM exposure is increased by 1.25 mGy (+81%), whereas ESAK is increased by 3.07 mGy (+41%). Dose values of both techniques meet the recommendations for maximum dose in mammography.

Instability risk assessment of construction waste pile slope based on fuzzy entropy

Science.gov (United States)

Ma, Yong; Xing, Huige; Yang, Mao; Nie, Tingting

2018-05-01

Considering the nature and characteristics of construction waste piles, this paper analyzed the factors affecting the stability of the slope of construction waste piles, and established the system of the assessment indexes for the slope failure risks of construction waste piles. Based on the basic principles and methods of fuzzy mathematics, the factor set and the remark set were established. The membership grade of continuous factor indexes is determined using the "ridge row distribution" function, while that for the discrete factor indexes was determined by the Delphi Method. For the weight of factors, the subjective weight was determined by the Analytic Hierarchy Process (AHP) and objective weight by the entropy weight method. And the distance function was introduced to determine the combination coefficient. This paper established a fuzzy comprehensive assessment model of slope failure risks of construction waste piles, and assessed pile slopes in the two dimensions of hazard and vulnerability. The root mean square of the hazard assessment result and vulnerability assessment result was the final assessment result. The paper then used a certain construction waste pile slope as the example for analysis, assessed the risks of the four stages of a landfill, verified the assessment model and analyzed the slope's failure risks and preventive measures against a slide.

Analysis Using Popularity Awareness Index, Recency Index and Purchase Diversity in Group Buying

OpenAIRE

Shirai, Yasuyuki; Morita, Hiroyuki; Nakamoto, Masakazu; Oyama, Satoshi

2014-01-01

We propose new metrics for customers’ purchasing behaviors in a group buying coupon website, based on HITS algorithms and information entropy: that is, popularity awareness index, recency index, and purchase diversity. These indices are used to classify customers and predict future behaviors. This paper includes definitions of these new indices to be used in real group buying websites. In these websites, adequate characteristics for customers are strongly required and are critical for marketi...

Optimization and large scale computation of an entropy-based moment closure

Science.gov (United States)

Kristopher Garrett, C.; Hauck, Cory; Hill, Judith

2015-12-01

We present computational advances and results in the implementation of an entropy-based moment closure, MN, in the context of linear kinetic equations, with an emphasis on heterogeneous and large-scale computing platforms. Entropy-based closures are known in several cases to yield more accurate results than closures based on standard spectral approximations, such as PN, but the computational cost is generally much higher and often prohibitive. Several optimizations are introduced to improve the performance of entropy-based algorithms over previous implementations. These optimizations include the use of GPU acceleration and the exploitation of the mathematical properties of spherical harmonics, which are used as test functions in the moment formulation. To test the emerging high-performance computing paradigm of communication bound simulations, we present timing results at the largest computational scales currently available. These results show, in particular, load balancing issues in scaling the MN algorithm that do not appear for the PN algorithm. We also observe that in weak scaling tests, the ratio in time to solution of MN to PN decreases.

Digital mammography; Mamografia digital

Energy Technology Data Exchange (ETDEWEB)

Chevalier, M.; Torres, R.

2010-07-01

Mammography represents one of the most demanding radiographic applications, simultaneously requiring excellent contrast sensitivity, high spatial resolution, and wide dynamic range. Film/screen is the most widely extended image receptor in mammography due to both its high spatial resolution and contrast. The film/screen limitations are related with its narrow latitude, structural noise and that is at the same time the medium for the image acquisition, storage and presentation. Several digital detector made with different technologies can overcome these difficulties. Here, these technologies as well as their main advantages and disadvantages are analyzed. Also it is discussed its impact on the mammography examinations, mainly on the breast screening programs. (Author).

Dual-energy mammography: simulation studies

International Nuclear Information System (INIS)

Bliznakova, K; Kolitsi, Z; Pallikarakis, N

2006-01-01

This paper presents a mammography simulator and demonstrates its applicability in feasibility studies in dual-energy (DE) subtraction mammography. This mammography simulator is an evolution of a previously presented x-ray imaging simulation system, which has been extended with new functionalities that are specific for DE simulations. The new features include incident exposure and dose calculations, the implementation of a DE subtraction algorithm as well as amendments to the detector and source modelling. The system was then verified by simulating experiments and comparing their results against published data. The simulator was used to carry out a feasibility study of the applicability of DE techniques in mammography, and more precisely to examine whether this modality could result in better visualization and detection of microcalcifications. Investigations were carried out using a 3D breast software phantom of average thickness, monoenergetic and polyenergetic beam spectra and various detector configurations. Dual-shot techniques were simulated. Results showed the advantage of using monoenergetic in comparison with polyenergetic beams. Optimization studies with monochromatic sources were carried out to obtain the optimal low and high incident energies, based on the assessment of the figure of merit of the simulated microcalcifications in the subtracted images. The results of the simulation study with the optimal energies demonstrated that the use of the DE technique can improve visualization and increase detectability, allowing identification of microcalcifications of sizes as small as 200 μm. The quantitative results are also verified by means of a visual inspection of the synthetic images

Artificial Neural Networks in Mammography Interpretation and Diagnostic Decision Making

Directory of Open Access Journals (Sweden)

Turgay Ayer

2013-01-01

Full Text Available Screening mammography is the most effective means for early detection of breast cancer. Although general rules for discriminating malignant and benign lesions exist, radiologists are unable to perfectly detect and classify all lesions as malignant and benign, for many reasons which include, but are not limited to, overlap of features that distinguish malignancy, difficulty in estimating disease risk, and variability in recommended management. When predictive variables are numerous and interact, ad hoc decision making strategies based on experience and memory may lead to systematic errors and variability in practice. The integration of computer models to help radiologists increase the accuracy of mammography examinations in diagnostic decision making has gained increasing attention in the last two decades. In this study, we provide an overview of one of the most commonly used models, artificial neural networks (ANNs, in mammography interpretation and diagnostic decision making and discuss important features in mammography interpretation. We conclude by discussing several common limitations of existing research on ANN-based detection and diagnostic models and provide possible future research directions.

Global sensitivity analysis for fuzzy inputs based on the decomposition of fuzzy output entropy

Science.gov (United States)

Shi, Yan; Lu, Zhenzhou; Zhou, Yicheng

2018-06-01

To analyse the component of fuzzy output entropy, a decomposition method of fuzzy output entropy is first presented. After the decomposition of fuzzy output entropy, the total fuzzy output entropy can be expressed as the sum of the component fuzzy entropy contributed by fuzzy inputs. Based on the decomposition of fuzzy output entropy, a new global sensitivity analysis model is established for measuring the effects of uncertainties of fuzzy inputs on the output. The global sensitivity analysis model can not only tell the importance of fuzzy inputs but also simultaneously reflect the structural composition of the response function to a certain degree. Several examples illustrate the validity of the proposed global sensitivity analysis, which is a significant reference in engineering design and optimization of structural systems.

The criteria for selecting a method for unfolding neutron spectra based on the information entropy theory

International Nuclear Information System (INIS)

Zhu, Qingjun; Song, Fengquan; Ren, Jie; Chen, Xueyong; Zhou, Bin

2014-01-01

To further expand the application of an artificial neural network in the field of neutron spectrometry, the criteria for choosing between an artificial neural network and the maximum entropy method for the purpose of unfolding neutron spectra was presented. The counts of the Bonner spheres for IAEA neutron spectra were used as a database, and the artificial neural network and the maximum entropy method were used to unfold neutron spectra; the mean squares of the spectra were defined as the differences between the desired and unfolded spectra. After the information entropy of each spectrum was calculated using information entropy theory, the relationship between the mean squares of the spectra and the information entropy was acquired. Useful information from the information entropy guided the selection of unfolding methods. Due to the importance of the information entropy, the method for predicting the information entropy using the Bonner spheres' counts was established. The criteria based on the information entropy theory can be used to choose between the artificial neural network and the maximum entropy method unfolding methods. The application of an artificial neural network to unfold neutron spectra was expanded. - Highlights: • Two neutron spectra unfolding methods, ANN and MEM, were compared. • The spectrum's entropy offers useful information for selecting unfolding methods. • For the spectrum with low entropy, the ANN was generally better than MEM. • The spectrum's entropy was predicted based on the Bonner spheres' counts

Minimum Entropy-Based Cascade Control for Governing Hydroelectric Turbines

Directory of Open Access Journals (Sweden)

Mifeng Ren

2014-06-01

Full Text Available In this paper, an improved cascade control strategy is presented for hydroturbine speed governors. Different from traditional proportional-integral-derivative (PID control and model predictive control (MPC strategies, the performance index of the outer controller is constructed by integrating the entropy and mean value of the tracking error with the constraints on control energy. The inner controller is implemented by a proportional controller. Compared with the conventional PID-P and MPC-P cascade control methods, the proposed cascade control strategy can effectively decrease fluctuations of hydro-turbine speed under non-Gaussian disturbance conditions in practical hydropower plants. Simulation results show the advantages of the proposed cascade control method.

Value at risk estimation with entropy-based wavelet analysis in exchange markets

Science.gov (United States)

He, Kaijian; Wang, Lijun; Zou, Yingchao; Lai, Kin Keung

2014-08-01

In recent years, exchange markets are increasingly integrated together. Fluctuations and risks across different exchange markets exhibit co-moving and complex dynamics. In this paper we propose the entropy-based multivariate wavelet based approaches to analyze the multiscale characteristic in the multidimensional domain and improve further the Value at Risk estimation reliability. Wavelet analysis has been introduced to construct the entropy-based Multiscale Portfolio Value at Risk estimation algorithm to account for the multiscale dynamic correlation. The entropy measure has been proposed as the more effective measure with the error minimization principle to select the best basis when determining the wavelet families and the decomposition level to use. The empirical studies conducted in this paper have provided positive evidence as to the superior performance of the proposed approach, using the closely related Chinese Renminbi and European Euro exchange market.

Bi-directional x-ray phase-contrast mammography.

Directory of Open Access Journals (Sweden)

Kai Scherer

Full Text Available Phase-contrast x-ray imaging is a promising improvement of conventional absorption-based mammography for early tumor detection. This potential has been demonstrated recently, utilizing structured gratings to obtain differential phase and dark-field scattering images. However, the inherently anisotropic imaging sensitivity of the proposed mono-directional approach yields only insufficient diagnostic information, and has low diagnostic sensitivity to highly oriented structures. To overcome these limitations, we present a two-directional x-ray phase-contrast mammography approach and demonstrate its advantages by applying it to a freshly dissected, cancerous mastectomy breast specimen. We illustrate that the two-directional scanning procedure overcomes the insufficient diagnostic value of a single scan, and reliably detects tumor structures, independently from their orientation within the breast. Our results indicate the indispensable diagnostic necessity and benefit of a multi-directional approach for x-ray phase-contrast mammography.

Tackling Information Asymmetry in Networks: A New Entropy-Based Ranking Index

Science.gov (United States)

Barucca, Paolo; Caldarelli, Guido; Squartini, Tiziano

2018-06-01

Information is a valuable asset in socio-economic systems, a significant part of which is entailed into the network of connections between agents. The different interlinkages patterns that agents establish may, in fact, lead to asymmetries in the knowledge of the network structure; since this entails a different ability of quantifying relevant, systemic properties (e.g. the risk of contagion in a network of liabilities), agents capable of providing a better estimation of (otherwise) inaccessible network properties, ultimately have a competitive advantage. In this paper, we address the issue of quantifying the information asymmetry of nodes: to this aim, we define a novel index—InfoRank—intended to rank nodes according to their information content. In order to do so, each node ego-network is enforced as a constraint of an entropy-maximization problem and the subsequent uncertainty reduction is used to quantify the node-specific accessible information. We, then, test the performance of our ranking procedure in terms of reconstruction accuracy and show that it outperforms other centrality measures in identifying the "most informative" nodes. Finally, we discuss the socio-economic implications of network information asymmetry.

One more hurdle to increasing mammography screening: pubescent, adolescent, and prior mammography screening experiences.

Science.gov (United States)

Thomas, Eileen; Usher, LaToya

2009-01-01

Approximately $8.1 billion dollars is spent each year in the United States alone on the treatment of breast cancer. Survival rates are dependent on access to, and utilization of, early detection services. The primary reason for disparity in breast cancer mortality is the delay in time to diagnosis, resulting in poor prognosis. Despite ongoing research to understand barriers to mammography screening, recent studies report a decrease in mammography screening among all racial groups. A qualitative approach was used to elicit information from 36 White non- Hispanic, African-American, Hispanic, and Native American women without a history of breast cancer. Women were invited to share written or audiotape-recorded narratives about experiences pertaining to their breasts and their mammography screening experiences. Major categories identified were: teasing, family norms and values, media/societal influence, body image, and mammography screening experiences. The resulting effects of these experiences left these women with feelings of shame and "conflict" regarding their breasts. The major theme identified was breast conflict. Findings suggest that breast conflict may persist throughout the lifespan and can have a negative influence on a woman's decision to participate in mammography screening. The authors hypothesize that experiences that occur during adolescence pertaining to young girls' breasts can influence a women's body image, which in turn can later in life affect health-seeking behaviors related to mammography screening. These findings have implications for public health practice in planning for breast cancer screening, education, and interventions for women from diverse racial/ethnics groups.

Symbolic transfer entropy-based premature signal analysis

International Nuclear Information System (INIS)

Wang Jun; Yu Zheng-Feng

2012-01-01

In this paper, we use symbolic transfer entropy to study the coupling strength between premature signals. Numerical experiments show that three types of signal couplings are in the same direction. Among them, normal signal coupling is the strongest, followed by that of premature ventricular contractions, and that of atrial premature beats is the weakest. The T test shows that the entropies of the three signals are distinct. Symbolic transfer entropy requires less data, can distinguish the three types of signals and has very good computational efficiency. (interdisciplinary physics and related areas of science and technology)

Calibration procedures for mammography dosemeters in Poland

International Nuclear Information System (INIS)

Gwiazdowska, B.; Ulkowski, P.; Tolwinski, J.; Bulski, W.

2002-01-01

Breast cancer is the most frequent tumour in women and the effectiveness of the treatment depends dramatically on the early detection of the disease. That is the reason why in Poland the mammography control examinations are strongly supported by the Centre of Oncology. In Poland there are over 400 mammography units which account for about 300,000 examinations per year. An investigation performed by the Medical Physics Department of the Centre of Oncology in Warsaw at about 100 mammography facilities proved that in most cases the doses absorbed by the patients could be reduced without decrease of image quality. This is one of the reasons why the Polish Secondary Standard Dosimetry Laboratory (SSDL) dealing mainly with calibration of radiotherapy dosemeters is extending its activities and therefore new facilities and equipment adapted for calibration of mammographic dosemeters have been installed. The mammography dosimetry calibration equipment is permanently installed in the same laboratory room where the radiotherapy dosemeters are calibrated. A base of a mammography unit no longer in clinical use, together with its movable system has been adapted to handle ionization chamber holders. An X-ray tube with a 50 kV high frequency generator was also installed. The tube, a Varian type OEG-50-2, (designed for laboratory applications) with molybdenum anode of an anode angle 23,7 deg. and with a large focus, effective size approximately 5 mm 2 , has an inherent filtration of 0,25 mm beryllium. It is installed in a housing with 2mm lead shielding; a cone shaped beam is formed by a system of three collimators

Mammography: MedlinePlus Health Topic

Science.gov (United States)

... Questions (National Cancer Institute) Mammography for Women with Breast Implants (American Cancer Society) Also in Spanish Mammography: What You Need to Know (Food and Drug Administration) Nipple Aspirate Test Is ... Specifics Breast Tomosynthesis (American College of Radiology, Radiological Society of ...

Generalized sample entropy analysis for traffic signals based on similarity measure

Science.gov (United States)

Shang, Du; Xu, Mengjia; Shang, Pengjian

2017-05-01

Sample entropy is a prevailing method used to quantify the complexity of a time series. In this paper a modified method of generalized sample entropy and surrogate data analysis is proposed as a new measure to assess the complexity of a complex dynamical system such as traffic signals. The method based on similarity distance presents a different way of signals patterns match showing distinct behaviors of complexity. Simulations are conducted over synthetic data and traffic signals for providing the comparative study, which is provided to show the power of the new method. Compared with previous sample entropy and surrogate data analysis, the new method has two main advantages. The first one is that it overcomes the limitation about the relationship between the dimension parameter and the length of series. The second one is that the modified sample entropy functions can be used to quantitatively distinguish time series from different complex systems by the similar measure.

Application of phase contrast imaging to mammography

International Nuclear Information System (INIS)

Tohyama, Keiko; Yamada, Katsuhiko; Katafuchi, Tetsuro; Matsuo, Satoru; Morishita, Junji

2005-01-01

Phase contrast images were obtained experimentally by using a customized mammography unit with a nominal focal spot size of 100 μm and variable source-to-image distances of up to 1.5 m. The purpose of this study was to examine the applicability and potential usefulness of phase contrast imaging for mammography. A mammography phantom (ACR156 RMI phantom) was imaged, and its visibility was examined. The optical density of the phantom images was adjusted to approximately 1.3 for both the contact and phase contrast images. Forty-one observers (18 medical doctors and 23 radiological technologists) participated in visual evaluation of the images. Results showed that, in comparison with the images of contact mammography, the phantom images of phase contrast imaging demonstrated statistically significantly superior visibility for fibers, clustered micro-calcifications, and masses. Therefore, phase contrast imaging obtained by using the customized mammography unit would be useful for improving diagnostic accuracy in mammography. (author)

Mammography

Science.gov (United States)

... breast cancer Whether there is any harm from breast cancer screening, such as side effects from testing or overtreatment of cancer when it's discovered Mammography is performed to screen women to detect early breast cancer when it is ...

Calculating the Entropy of Solid and Liquid Metals, Based on Acoustic Data

Science.gov (United States)

Tekuchev, V. V.; Kalinkin, D. P.; Ivanova, I. V.

2018-05-01

The entropies of iron, cobalt, rhodium, and platinum are studied for the first time, based on acoustic data and using the Debye theory and rigid-sphere model, from 298 K up to the boiling point. A formula for the melting entropy of metals is validated. Good agreement between the research results and the literature data is obtained.

Analysis of utilization patterns and associated costs of the breast imaging and diagnostic procedures after screening mammography

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Vlahiotis A

2018-03-01

Full Text Available Anna Vlahiotis,1 Brian Griffin,2 A Thomas Stavros,3 Jay Margolis1 1Value Based Care, Outcomes Research, Truven Health Analytics, an IBM Company, Bethesda, MD USA; 2Value Based Care, Outcomes Research, Truven Health Analytics, an IBM Company, Newark, NJ, USA; 3Seno Medical Instruments, Inc., San Antonio, TX, USA Background: Little data exist on real-world patterns and associated costs of downstream breast diagnostic procedures following an abnormal screening mammography or clinical exam.Objectives: To analyze the utilization patterns in real-world clinical settings for breast imaging and diagnostic procedures, including the frequency and volume of patients and procedures, procedure sequencing, and associated health care expenditures.Materials and methods: Using medical claims from 2011 to 2015 MarketScan Commercial and Medicare Databases, adult females with breast imaging/diagnostic procedures (diagnostic mammography, ultrasound, molecular breast imaging, tomosynthesis, magnetic resonance imaging, or biopsy other than screening mammography were selected. Continuous health plan coverage without breast diagnostic procedures was required for ≥13 months before the first found breast diagnostic procedure (index event, with a 13-month post-index follow-up period. Key outcomes included diagnostic procedure volumes, sequences, and payments. Results reported descriptively were projected to provide US national patient and procedure volumes.Results: The final sample of 875,526 patients was nationally projected to 12,394,432 patients annually receiving 8,732,909 diagnostic mammograms (53.3% of patients, 6,987,399 breast ultrasounds (42.4% of patients, and 1,585,856 biopsies (10.3% of patients. Following initial diagnostic procedures, 49.4% had second procedures, 20.1% followed with third procedures, and 10.0% had a fourth procedure. Mean (SD costs for diagnostic mammograms of US$349 ($493, ultrasounds US$132 ($134, and biopsies US$1,938 ($2,343 contributed

Budget Impact Analysis of Switching to Digital Mammography in a Population-Based Breast Cancer Screening Program: A Discrete Event Simulation Model

Science.gov (United States)

Comas, Mercè; Arrospide, Arantzazu; Mar, Javier; Sala, Maria; Vilaprinyó, Ester; Hernández, Cristina; Cots, Francesc; Martínez, Juan; Castells, Xavier

2014-01-01

Objective To assess the budgetary impact of switching from screen-film mammography to full-field digital mammography in a population-based breast cancer screening program. Methods A discrete-event simulation model was built to reproduce the breast cancer screening process (biennial mammographic screening of women aged 50 to 69 years) combined with the natural history of breast cancer. The simulation started with 100,000 women and, during a 20-year simulation horizon, new women were dynamically entered according to the aging of the Spanish population. Data on screening were obtained from Spanish breast cancer screening programs. Data on the natural history of breast cancer were based on US data adapted to our population. A budget impact analysis comparing digital with screen-film screening mammography was performed in a sample of 2,000 simulation runs. A sensitivity analysis was performed for crucial screening-related parameters. Distinct scenarios for recall and detection rates were compared. Results Statistically significant savings were found for overall costs, treatment costs and the costs of additional tests in the long term. The overall cost saving was 1,115,857€ (95%CI from 932,147 to 1,299,567) in the 10th year and 2,866,124€ (95%CI from 2,492,610 to 3,239,638) in the 20th year, representing 4.5% and 8.1% of the overall cost associated with screen-film mammography. The sensitivity analysis showed net savings in the long term. Conclusions Switching to digital mammography in a population-based breast cancer screening program saves long-term budget expense, in addition to providing technical advantages. Our results were consistent across distinct scenarios representing the different results obtained in European breast cancer screening programs. PMID:24832200

Entropy and equilibrium via games of complexity

Science.gov (United States)

Topsøe, Flemming

2004-09-01

It is suggested that thermodynamical equilibrium equals game theoretical equilibrium. Aspects of this thesis are discussed. The philosophy is consistent with maximum entropy thinking of Jaynes, but goes one step deeper by deriving the maximum entropy principle from an underlying game theoretical principle. The games introduced are based on measures of complexity. Entropy is viewed as minimal complexity. It is demonstrated that Tsallis entropy ( q-entropy) and Kaniadakis entropy ( κ-entropy) can be obtained in this way, based on suitable complexity measures. A certain unifying effect is obtained by embedding these measures in a two-parameter family of entropy functions.

Nonsymmetric entropy and maximum nonsymmetric entropy principle

International Nuclear Information System (INIS)

Liu Chengshi

2009-01-01

Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.

Towards an information extraction and knowledge formation framework based on Shannon entropy

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Iliescu Dragoș

2017-01-01

Full Text Available Information quantity subject is approached in this paperwork, considering the specific domain of nonconforming product management as information source. This work represents a case study. Raw data were gathered from a heavy industrial works company, information extraction and knowledge formation being considered herein. Involved method for information quantity estimation is based on Shannon entropy formula. Information and entropy spectrum are decomposed and analysed for extraction of specific information and knowledge-that formation. The result of the entropy analysis point out the information needed to be acquired by the involved organisation, this being presented as a specific knowledge type.

Breast imaging and reporting data system - Mammography. ACR BI-RADS registered -Mammography

International Nuclear Information System (INIS)

Fischer, U.; Helbrich, T.

2006-01-01

ACR BI-RADS registered mammography is an established technique in all German-speaking countries and has become a standard part of all mammographic findings. The first German-language edition three years ago made a significant contribution to this. This is the second, revised and edited edition. It is based on the fourth English-language edition of the ACR which was published in 2003. (orig.)

Fault detection of the connection of lithium-ion power batteries based on entropy for electric vehicles

Science.gov (United States)

Yao, Lei; Wang, Zhenpo; Ma, Jun

2015-10-01

This paper proposes a method of fault detection of the connection of Lithium-Ion batteries based on entropy for electric vehicle. In electric vehicle operation process, some factors, such as road conditions, driving habits, vehicle performance, always affect batteries by vibration, which easily cause loosing or virtual connection between batteries. Through the simulation of the battery charging and discharging experiment under vibration environment, the data of voltage fluctuation can be obtained. Meanwhile, an optimal filtering method is adopted using discrete cosine filter method to analyze the characteristics of system noise, based on the voltage set when batteries are working under different vibration frequency. Experimental data processed by filtering is analyzed based on local Shannon entropy, ensemble Shannon entropy and sample entropy. And the best way to find a method of fault detection of the connection of lithium-ion batteries based on entropy is presented for electric vehicle. The experimental data shows that ensemble Shannon entropy can predict the accurate time and the location of battery connection failure in real time. Besides electric-vehicle industry, this method can also be used in other areas in complex vibration environment.

At what age should screening mammography be recommended for Asian women?

International Nuclear Information System (INIS)

Tsuchida, Junko; Nagahashi, Masayuki; Rashid, Omar M; Takabe, Kazuaki; Wakai, Toshifumi

2015-01-01

Although regular screening mammography has been suggested to be associated with improvements in the relative survival of breast cancer in recent years, the appropriate age to start screening mammography remains controversial. In November 2009, the United States Preventive Service Task Force published updated guidelines for breast cancer, which no longer support routine screening mammography for women aged 40–49 years, but instead, defer the choice of screening in that age group to the patient and physician. The age to begin screening differs between guidelines, including those from the Task Force, the American Cancer Society and the World Health Organization. It remains unclear how this discrepancy impacts patient survival, especially among certain subpopulations. Although the biological characteristics of breast cancer and peak age of incidence differ among different ethnic populations, there have been few reports that evaluate the starting age for screening mammography based on ethnicity. Here, we discuss the benefits and harm of screening mammography in the fifth decade, and re-evaluate the starting age for screening mammography taking ethnicity into account, focusing on the Asian population. Breast cancer incidence peaked in the fifth decade in Asian women, which has been thought to be due to a combination of biological and environmental factors. Previous reports suggest that Asian women in their 40s may receive more benefit and less harm from screening mammography than the age-matched non-Asian US population. Therefore, starting screening mammography at age 40 may be beneficial for women of Asian ethnicity in well-resourced countries, such as Japanese women who reside in Japan

A Novel Entropy-Based Centrality Approach for Identifying Vital Nodes in Weighted Networks

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Tong Qiao

2018-04-01

Full Text Available Measuring centrality has recently attracted increasing attention, with algorithms ranging from those that simply calculate the number of immediate neighbors and the shortest paths to those that are complicated iterative refinement processes and objective dynamical approaches. Indeed, vital nodes identification allows us to understand the roles that different nodes play in the structure of a network. However, quantifying centrality in complex networks with various topological structures is not an easy task. In this paper, we introduce a novel definition of entropy-based centrality, which can be applicable to weighted directed networks. By design, the total power of a node is divided into two parts, including its local power and its indirect power. The local power can be obtained by integrating the structural entropy, which reveals the communication activity and popularity of each node, and the interaction frequency entropy, which indicates its accessibility. In addition, the process of influence propagation can be captured by the two-hop subnetworks, resulting in the indirect power. In order to evaluate the performance of the entropy-based centrality, we use four weighted real-world networks with various instance sizes, degree distributions, and densities. Correspondingly, these networks are adolescent health, Bible, United States (US airports, and Hep-th, respectively. Extensive analytical results demonstrate that the entropy-based centrality outperforms degree centrality, betweenness centrality, closeness centrality, and the Eigenvector centrality.

Image quality and radiation exposure in digital storage plate mammography with magnification technique

International Nuclear Information System (INIS)

Fiedler, E.; Aichinger, U.; Boehner, C.; Schulz-Wendtland, R.; Bautz, W.; Saebel, M.

1999-01-01

Purpose: Comparison of image quality between digital phosphor storage plate mammography in magnification technique and a conventional film screen system regarding the special aspect of radiation exposure. Materials and Methods: Radiograms of a RMI-mammography phantom were acquired using a conventional film screen system and two digital storage plate systems. Additionally, the radiograms of one digital system were postprocessed emphasizing contrast and included in the comparison. Results: The detectability of details in storage plate mammographies with magnification technique is almost equal to that of film screen mammographies. Thereby, lower radiation exposures were necessary using the digital systems. Conclusions: Based on these results, storage plate mammography in magnification technique is used in clinical routine at our institution. The correct parameters in image postprocessing are of elementary importance for detail detectability. Future studies must show, whether the lower radiation exposure in digital radiograms of the breast, revealing much higher background noise, will allow the same detail detectability as film screen mammographies. (orig.) [de

Rayleigh imaging in spectral mammography

Science.gov (United States)

Berggren, Karl; Danielsson, Mats; Fredenberg, Erik

2016-03-01

Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.

Fundamental limits on quantum dynamics based on entropy change

Science.gov (United States)

Das, Siddhartha; Khatri, Sumeet; Siopsis, George; Wilde, Mark M.

2018-01-01

It is well known in the realm of quantum mechanics and information theory that the entropy is non-decreasing for the class of unital physical processes. However, in general, the entropy does not exhibit monotonic behavior. This has restricted the use of entropy change in characterizing evolution processes. Recently, a lower bound on the entropy change was provided in the work of Buscemi, Das, and Wilde [Phys. Rev. A 93(6), 062314 (2016)]. We explore the limit that this bound places on the physical evolution of a quantum system and discuss how these limits can be used as witnesses to characterize quantum dynamics. In particular, we derive a lower limit on the rate of entropy change for memoryless quantum dynamics, and we argue that it provides a witness of non-unitality. This limit on the rate of entropy change leads to definitions of several witnesses for testing memory effects in quantum dynamics. Furthermore, from the aforementioned lower bound on entropy change, we obtain a measure of non-unitarity for unital evolutions.

Si-strip photon counting detectors for contrast-enhanced spectral mammography

Science.gov (United States)

Chen, Buxin; Reiser, Ingrid; Wessel, Jan C.; Malakhov, Nail; Wawrzyniak, Gregor; Hartsough, Neal E.; Gandhi, Thulasi; Chen, Chin-Tu; Iwanczyk, Jan S.; Barber, William C.

2015-08-01

We report on the development of silicon strip detectors for energy-resolved clinical mammography. Typically, X-ray integrating detectors based on scintillating cesium iodide CsI(Tl) or amorphous selenium (a-Se) are used in most commercial systems. Recently, mammography instrumentation has been introduced based on photon counting Si strip detectors. The required performance for mammography in terms of the output count rate, spatial resolution, and dynamic range must be obtained with sufficient field of view for the application, thus requiring the tiling of pixel arrays and particular scanning techniques. Room temperature Si strip detector, operating as direct conversion x-ray sensors, can provide the required speed when connected to application specific integrated circuits (ASICs) operating at fast peaking times with multiple fixed thresholds per pixel, provided that the sensors are designed for rapid signal formation across the X-ray energy ranges of the application. We present our methods and results from the optimization of Si-strip detectors for contrast enhanced spectral mammography. We describe the method being developed for quantifying iodine contrast using the energy-resolved detector with fixed thresholds. We demonstrate the feasibility of the method by scanning an iodine phantom with clinically relevant contrast levels.

Ultra-Fast Image Reconstruction of Tomosynthesis Mammography Using GPU.

Science.gov (United States)

Arefan, D; Talebpour, A; Ahmadinejhad, N; Kamali Asl, A

2015-06-01

Digital Breast Tomosynthesis (DBT) is a technology that creates three dimensional (3D) images of breast tissue. Tomosynthesis mammography detects lesions that are not detectable with other imaging systems. If image reconstruction time is in the order of seconds, we can use Tomosynthesis systems to perform Tomosynthesis-guided Interventional procedures. This research has been designed to study ultra-fast image reconstruction technique for Tomosynthesis Mammography systems using Graphics Processing Unit (GPU). At first, projections of Tomosynthesis mammography have been simulated. In order to produce Tomosynthesis projections, it has been designed a 3D breast phantom from empirical data. It is based on MRI data in its natural form. Then, projections have been created from 3D breast phantom. The image reconstruction algorithm based on FBP was programmed with C++ language in two methods using central processing unit (CPU) card and the Graphics Processing Unit (GPU). It calculated the time of image reconstruction in two kinds of programming (using CPU and GPU).

Ultra-Fast Image Reconstruction of Tomosynthesis Mammography Using GPU

Directory of Open Access Journals (Sweden)

Arefan D

2015-06-01

Full Text Available Digital Breast Tomosynthesis (DBT is a technology that creates three dimensional (3D images of breast tissue. Tomosynthesis mammography detects lesions that are not detectable with other imaging systems. If image reconstruction time is in the order of seconds, we can use Tomosynthesis systems to perform Tomosynthesis-guided Interventional procedures. This research has been designed to study ultra-fast image reconstruction technique for Tomosynthesis Mammography systems using Graphics Processing Unit (GPU. At first, projections of Tomosynthesis mammography have been simulated. In order to produce Tomosynthesis projections, it has been designed a 3D breast phantom from empirical data. It is based on MRI data in its natural form. Then, projections have been created from 3D breast phantom. The image reconstruction algorithm based on FBP was programmed with C++ language in two methods using central processing unit (CPU card and the Graphics Processing Unit (GPU. It calculated the time of image reconstruction in two kinds of programming (using CPU and GPU.

Family/Friend Recommendations and Mammography Intentions: The Roles of Perceived Mammography Norms and Support

Science.gov (United States)

Molina, Yamile; Ornelas, India J.; Doty, Sarah L.; Bishop, Sonia; Beresford, Shirley A. A.; Coronado, Gloria D.

2015-01-01

Identifying factors that increase mammography use among Latinas is an important public health priority. Latinas are more likely to report mammography intentions and use, if a family member or friend recommends that they get a mammogram. Little is known about the mechanisms underlying the relationship between social interactions and mammography…

Contrast-enhanced spectral mammography vs. mammography and MRI - clinical performance in a multi-reader evaluation

NARCIS (Netherlands)

Fallenberg, E.M.; Schmitzberger, F.F.; Amer, H.; Ingold-Heppner, B.; Balleyguier, C.; Diekmann, F.; Engelken, F.; Mann, R.M.; Renz, D.M.; Bick, U.; Hamm, B.; Dromain, C.

2017-01-01

OBJECTIVES: To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study. METHODS: One hundred seventy-eight women (mean age 53 years) with invasive breast

Fault Diagnosis Method Based on Information Entropy and Relative Principal Component Analysis

Directory of Open Access Journals (Sweden)

Xiaoming Xu

2017-01-01

Full Text Available In traditional principle component analysis (PCA, because of the neglect of the dimensions influence between different variables in the system, the selected principal components (PCs often fail to be representative. While the relative transformation PCA is able to solve the above problem, it is not easy to calculate the weight for each characteristic variable. In order to solve it, this paper proposes a kind of fault diagnosis method based on information entropy and Relative Principle Component Analysis. Firstly, the algorithm calculates the information entropy for each characteristic variable in the original dataset based on the information gain algorithm. Secondly, it standardizes every variable’s dimension in the dataset. And, then, according to the information entropy, it allocates the weight for each standardized characteristic variable. Finally, it utilizes the relative-principal-components model established for fault diagnosis. Furthermore, the simulation experiments based on Tennessee Eastman process and Wine datasets demonstrate the feasibility and effectiveness of the new method.

Slit aperture technique for mammography

International Nuclear Information System (INIS)

Friedrich, M.

1984-01-01

Following a discussion of various principles used in the elimination of scatter, the prototype of a simple slit aperture mammography apparatus is described (modified Mammomat, Siemens). The main advantage of this technique compared with grid mammography is a halving of the radiation dose for identical image quality, using an identical film system. The technical requirements (heavy duty tube, new generator) are, however, considerable. If the film-screen systems currently in use are to remain the common systems for the future, then the development of a multi-lamellar slit diaphragm technique carries much promise for mammography. (orig.) [de

Digital mammography and their developments

International Nuclear Information System (INIS)

Wienbeck, Susanne

2015-01-01

At the present time digital mammography is a satisfactory breast diagnostic imaging in clinical as well as screening mammography in defined age groups. Nevertheless it shows beside the application of ionizing radiation in women with dense breasts limitations in the detection of non calcification breast cancers. Tomosynthesis, digital contrast-enhanced mammography and breast-CT with or without contrast media lead to better results. Especially the application of contrast media for the visualisation of the tumor angiogenesis is invariably superior to all other non-contrast imaging modalities. However, the excellent results of breast MRI will be probably accessible with none of the new procedures.

Entropy, neutro-entropy and anti-entropy for neutrosophic information

OpenAIRE

Vasile Patrascu

2017-01-01

This approach presents a multi-valued representation of the neutrosophic information. It highlights the link between the bifuzzy information and neutrosophic one. The constructed deca-valued structure shows the neutrosophic information complexity. This deca-valued structure led to construction of two new concepts for the neutrosophic information: neutro-entropy and anti-entropy. These two concepts are added to the two existing: entropy and non-entropy. Thus, we obtained the following triad: e...

Usefulness of mammography in the diagnosis and management of breast disease in postmenopausal women

Energy Technology Data Exchange (ETDEWEB)

Lamas, A.M.; Horwitz, R.I.; Peck, D.

1984-12-07

The clinical usefulness of mammography in postmenopausal women was evaluated by conducting a ''vertical'' analysis using indexes of sensitivity and specificity, and a separate ''horizontal'' analysis assessing the relationship between the mammographic test result and the occurrence of specific clinical management decisions. The patients included 105 women with breast cancer, 104 women with fibrocystic breast disease, and 103 women with clinically benign breasts. The study confirmed the generally accepted high values reported for the sensitivity and for the specificity of mammography as a test for breast cancer, while also helping to reconcile the widely varying indexes of test efficacy reported in some studies. The authors also observed that physicians' management decisions vary according to the mammographic interpretation, and include such distinctive clinical strategies as watchful expectancy (observe and follow), repeated mammograms, or breast biopsy. Future studies will need to determine reasons for specific management decisions, especially when they appear to contradict authoritative recommendations.

Usefulness of mammography in the diagnosis and management of breast disease in postmenopausal women

International Nuclear Information System (INIS)

Lamas, A.M.; Horwitz, R.I.; Peck, D.

1984-01-01

The clinical usefulness of mammography in postmenopausal women was evaluated by conducting a ''vertical'' analysis using indexes of sensitivity and specificity, and a separate ''horizontal'' analysis assessing the relationship between the mammographic test result and the occurrence of specific clinical management decisions. The patients included 105 women with breast cancer, 104 women with fibrocystic breast disease, and 103 women with clinically benign breasts. The study confirmed the generally accepted high values reported for the sensitivity and for the specificity of mammography as a test for breast cancer, while also helping to reconcile the widely varying indexes of test efficacy reported in some studies. The authors also observed that physicians' management decisions vary according to the mammographic interpretation, and include such distinctive clinical strategies as watchful expectancy (observe and follow), repeated mammograms, or breast biopsy. Future studies will need to determine reasons for specific management decisions, especially when they appear to contradict authoritative recommendations

Physical entropy, information entropy and their evolution equations

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Inspired by the evolution equation of nonequilibrium statistical physics entropy and the concise statistical formula of the entropy production rate, we develop a theory of the dynamic information entropy and build a nonlinear evolution equation of the information entropy density changing in time and state variable space. Its mathematical form and physical meaning are similar to the evolution equation of the physical entropy: The time rate of change of information entropy density originates together from drift, diffusion and production. The concise statistical formula of information entropy production rate is similar to that of physical entropy also. Furthermore, we study the similarity and difference between physical entropy and information entropy and the possible unification of the two statistical entropies, and discuss the relationship among the principle of entropy increase, the principle of equilibrium maximum entropy and the principle of maximum information entropy as well as the connection between them and the entropy evolution equation.

Explaining the entropy concept and entropy components

Directory of Open Access Journals (Sweden)

Marko Popovic

2018-04-01

Full Text Available Total entropy of a thermodynamic system consists of two components: thermal entropy due to energy, and residual entropy due to molecular orientation. In this article, a three-step method for explaining entropy is suggested. Step one is to use a classical method to introduce thermal entropy STM as a function of temperature T and heat capacity at constant pressure Cp: STM = ∫(Cp/T dT. Thermal entropy is the entropy due to uncertainty in motion of molecules and vanishes at absolute zero (zero-point energy state. It is also the measure of useless thermal energy that cannot be converted into useful work. The next step is to introduce residual entropy S0 as a function of the number of molecules N and the number of distinct orientations available to them in a crystal m: S0 = N kB ln m, where kB is the Boltzmann constant. Residual entropy quantifies the uncertainty in molecular orientation. Residual entropy, unlike thermal entropy, is independent of temperature and remains present at absolute zero. The third step is to show that thermal entropy and residual entropy add up to the total entropy of a thermodynamic system S: S = S0 + STM. This method of explanation should result in a better comprehension of residual entropy and thermal entropy, as well as of their similarities and differences. The new method was tested in teaching at Faculty of Chemistry University of Belgrade, Serbia. The results of the test show that the new method has a potential to improve the quality of teaching.

Comparative evaluation of average glandular dose and image of digital mammography and film mammography in Minas Gerais, Brazil

International Nuclear Information System (INIS)

Nogueira, M.; Leyton, F.; Rodrigue, L. L.C.; Oliveira, M.A.; Joana, G.S.; Silva, S.D.

2015-01-01

Breast cancer is the most common cancer among women, and early detection is critical to its diagnosis and treatment. Mammography is the best method for breast-cancer screening and is capable of reducing mortality rates To date, the most effective method for early detection of breast cancer has been x-ray mammography for which the screen/film (SF) technique has been the gold standard. Digital mammography has been proposed as a substitute for film mammography given the benefits inherent to digital technology. The purpose of our study was to compare the technical performance of digital mammographic and screen-film mammography. A PMMA phantom with objects to simulate breast structures. For the screen/film (SF) technique the results showed that 54% mammography units did not achieve the minimum acceptable performance as far the image quality. Besides, 67% services showed inadequate performance in their processing systems, which had significant influence on the image quality. At the mean glandular dose only 44% of digital systems evaluated were compliant in all thicknesses of PMMA. The average glandular dose AGD was 90 % higher than in screen/film systems. (authors)

Image quality in mammography

International Nuclear Information System (INIS)

Haus, A.G.; Doi, K.; Metz, C.E.; Bernstein, J.

1976-01-01

In mammography, image quality is a function of the shape, size, and x-ray absorption properties of the anatomic part to be radiographed and of the lesion to be detected; it also depends on geometric unsharpness, and the resolution, characteristic curve and noise properties of the recording system. X-ray energy spectra, modulation transfer functions, Wiener spectra, characteristic and gradient curves, and radiographs of a breast phantom and of a resected breast specimen containing microcalcifications are used in a review of some current considerations of the factors, and the complex relationship among factors, that affect image quality in mammography. Image quality and patient radiation exposure in mammography are interrelated. An approach to the problem of evaluating the trade-off between diagnostic certainty and the cost or risk of performing a breast imaging procedure is discussed

Entropy, neutro-entropy and anti-entropy for neutrosophic information

OpenAIRE

Vasile Patrascu

2017-01-01

This article shows a deca-valued representation of neutrosophic information in which are defined the following features: truth, falsity, weak truth, weak falsity, ignorance, contradiction, saturation, neutrality, ambiguity and hesitation. Using these features, there are constructed computing formulas for entropy, neutro-entropy and anti-entropy.

From facts to arguments: A study of the 2014 Swiss controversy over systematic mammography screening.

Science.gov (United States)

Perrenoud, Caroline; Stiefel, Friedrich; Bourquin, Céline

2018-06-01

The Swiss Medical Board (SMB) has recently revived the controversy over mammography screening by recommending to stop the introduction of new systematic mammography screening programs. This study aimed to examine the Swiss media coverage of the release of the SMB report. The dataset consisted of 25 newspaper and "medical magazine" articles, and TV/radio interviews. The analytic approach was based on argumentation theory. Authority and community arguments were the most frequent types of arguments. With respect to authority arguments, stakeholders for instance challenged or supported the expertise of the SMB by referring to the competence of external figures of authority. Community arguments were based on common values such as life (saved thanks to systematic mammography screening) and money (costs associated with unnecessary care induced by systematic mammography screening). The efficiency of mammography screening which was the key issue of the debate appeared to be largely eluded, and the question of what women should do endures. While interpersonal and interprofessional communication has become a major topic of interest in the medical community, it appears that media communication on mammography screening is still rather ineffective. We call in particular for a more fact-based discussion. Copyright © 2017 Elsevier B.V. All rights reserved.

At what age should screening mammography be recommended for Asian women?

Science.gov (United States)

Tsuchida, Junko; Nagahashi, Masayuki; Rashid, Omar M; Takabe, Kazuaki; Wakai, Toshifumi

2015-07-01

Although regular screening mammography has been suggested to be associated with improvements in the relative survival of breast cancer in recent years, the appropriate age to start screening mammography remains controversial. In November 2009, the United States Preventive Service Task Force published updated guidelines for breast cancer, which no longer support routine screening mammography for women aged 40-49 years, but instead, defer the choice of screening in that age group to the patient and physician. The age to begin screening differs between guidelines, including those from the Task Force, the American Cancer Society and the World Health Organization. It remains unclear how this discrepancy impacts patient survival, especially among certain subpopulations. Although the biological characteristics of breast cancer and peak age of incidence differ among different ethnic populations, there have been few reports that evaluate the starting age for screening mammography based on ethnicity. Here, we discuss the benefits and harm of screening mammography in the fifth decade, and re-evaluate the starting age for screening mammography taking ethnicity into account, focusing on the Asian population. Breast cancer incidence peaked in the fifth decade in Asian women, which has been thought to be due to a combination of biological and environmental factors. Previous reports suggest that Asian women in their 40s may receive more benefit and less harm from screening mammography than the age-matched non-Asian US population. Therefore, starting screening mammography at age 40 may be beneficial for women of Asian ethnicity in well-resourced countries, such as Japanese women who reside in Japan. © 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Multiscale Permutation Entropy Based Rolling Bearing Fault Diagnosis

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Jinde Zheng

2014-01-01

Full Text Available A new rolling bearing fault diagnosis approach based on multiscale permutation entropy (MPE, Laplacian score (LS, and support vector machines (SVMs is proposed in this paper. Permutation entropy (PE was recently proposed and defined to measure the randomicity and detect dynamical changes of time series. However, for the complexity of mechanical systems, the randomicity and dynamic changes of the vibration signal will exist in different scales. Thus, the definition of MPE is introduced and employed to extract the nonlinear fault characteristics from the bearing vibration signal in different scales. Besides, the SVM is utilized to accomplish the fault feature classification to fulfill diagnostic procedure automatically. Meanwhile, in order to avoid a high dimension of features, the Laplacian score (LS is used to refine the feature vector by ranking the features according to their importance and correlations with the main fault information. Finally, the rolling bearing fault diagnosis method based on MPE, LS, and SVM is proposed and applied to the experimental data. The experimental data analysis results indicate that the proposed method could identify the fault categories effectively.

Evidence on Synthesized Two-dimensional Mammography Versus Digital Mammography When Using Tomosynthesis (Three-dimensional Mammography) for Population Breast Cancer Screening.

Science.gov (United States)

Houssami, Nehmat

2017-09-28

One limitation of using digital breast tomosynthesis (3-dimensional [3D] mammography) technology with conventional (2-dimensional [2D]) mammography for breast cancer (BC) screening is the increased radiation dose from dual acquisitions. To resolve this problem, synthesized 2D (s2D) reconstruction images similar to 2D mammography were developed using tomosynthesis acquisitions. The present review summarizes the evidence for s2D versus digital mammography (2D) when using tomosynthesis (3D) for BC screening to address whether using s2D instead of 2D (alongside 3D) will yield similar detection measures. Comparative population screening studies have provided consistent evidence that cancer detection rates do not differ between integrated 2D/3D (range, 5.45-8.5/1000 screens) and s2D/3D (range, 5.03-8.8/1000 screens). Also, although the recall measures were relatively heterogeneous across included studies, little difference was found between the 2 modalities. The mean glandular dose for s2D/3D was 55% to 58% of that for 2D/3D. In the context of BC screening, s2D/3D involves substantially less radiation than 2D/3D and provides similar detection measures. Thus, consideration of transitioning to tomosynthesis screening should aim to use s2D/3D to minimize harm. Copyright © 2017 Elsevier Inc. All rights reserved.

Thermoluminescence dosimetry in quality imaging in CR mammography systems

Energy Technology Data Exchange (ETDEWEB)

Gaona, E.; Franco E, J.G. [UAM-Xochimilco, 04960 Mexico D.F. (Mexico); Azorin N, J. [UAM-Iztapalapa, 09340 Mexico D.F. (Mexico); Diaz G, J.A.I. [CICATA, Unidad Legaria, Av. Legaria 694, 11599 mexico D.F. (Mexico); Arreola, M. [Department of Radiology, Shands Hospital at UF, PO Box 100374, Gainesville, FL 32610-0374 (United States)

2006-07-01

The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and ACR use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, Full Field Digital Mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one CR mammography system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium fluoro halide. We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated x-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement. (Author)

Thermoluminescence dosimetry in quality imaging in CR mammography systems

International Nuclear Information System (INIS)

Gaona, E.; Franco E, J.G.; Azorin N, J.; Diaz G, J.A.I.; Arreola, M.

2006-01-01

The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and ACR use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, Full Field Digital Mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one CR mammography system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium fluoro halide. We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated x-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement. (Author)

Quality control of mammography departments in Slovakia

International Nuclear Information System (INIS)

Horvathova, M.; Nikodemova, D.

2007-01-01

Complete test of publication follows. Considering the fact that mammary gland is the most sensitive organ to ionizing radiation, the Commission of the Ministry of Health of SR for QA in radiology organized a pilot two-run country wide audit conducted in 42 mammography departments that have met the beforehand criteria. During the audit the methods for establishing the individual parameters in technical and clinical part of quality assurance in mammography were elaborated and implemented. Technical and clinical parameters of the imaging process that mostly affect the quality of diagnostic information were followed up. These parameters included: the object thickness compensation, optical density deviation, evaluation of the film quality by means of special phantom, etc. Important measurement of ESDs at participating departments enabled to compare the radiation load of mammography patients in Slovakia with reference values in European guidelines. The uniform standard method for QA at mammography departments was elaborated and published as the regulation of the Ministry of Health for performance of preventive mammography examinations in SR. The presented results show the improved quality of mammography examinations due to regular check-ups of technical and clinical parameters and fulfilment of the required values in all parameters. The audit results are the basis for continuous quality assessment of mammography departments as a main prerequisite for conducting preventive examinations and for health insurance purposes.

A novel evaluation method for building construction project based on integrated information entropy with reliability theory.

Science.gov (United States)

Bai, Xiao-ping; Zhang, Xi-wei

2013-01-01

Selecting construction schemes of the building engineering project is a complex multiobjective optimization decision process, in which many indexes need to be selected to find the optimum scheme. Aiming at this problem, this paper selects cost, progress, quality, and safety as the four first-order evaluation indexes, uses the quantitative method for the cost index, uses integrated qualitative and quantitative methodologies for progress, quality, and safety indexes, and integrates engineering economics, reliability theories, and information entropy theory to present a new evaluation method for building construction project. Combined with a practical case, this paper also presents detailed computing processes and steps, including selecting all order indexes, establishing the index matrix, computing score values of all order indexes, computing the synthesis score, sorting all selected schemes, and making analysis and decision. Presented method can offer valuable references for risk computing of building construction projects.

Screening mammography beliefs and recommendations: a web-based survey of primary care physicians

Directory of Open Access Journals (Sweden)

Yasmeen Shagufta

2012-02-01

Full Text Available Abstract Background The appropriateness and cost-effectiveness of screening mammography (SM for women younger than 50 and older than 74 years is debated in the clinical research community, among health care providers, and by the American public. This study explored primary care physicians' (PCPs perceptions of the influence of clinical practice guidelines for SM; the recommendations for SM in response to hypothetical case scenarios; and the factors associated with perceived SM effectiveness and recommendations in the US from June to December 2009 before the United States Preventive Services Task Force (USPSTF recently revised guidelines. Methods A nationally representative sample of 11,922 PCPs was surveyed using a web-based questionnaire. The response rate was 5.7% (684; (41% 271 family physicians (FP, (36% 232 general internal medicine physicians (IM, (23% 150 obstetrician-gynaecologists (OBG, and (0.2% 31 others. Cross-sectional analysis examined PCPs perceived effectiveness of SM, and recommendation for SM in response to hypothetical case scenarios. PCPs responses were measured using 4-5 point adjectival scales. Differences in perceived effectiveness and recommendations for SM were examined after adjusting for PCPs specialty, race/ethnicity, and the US region. Results Compared to IM and FP, OBG considered SM more effective in reducing breast cancer mortality among women aged 40-49 years (p = 0.003. Physicians consistently recommended mammography to women aged 50-69 years with no differences by specialty (p = 0.11. However, 94% of OBG "always recommended" SM to younger and 86% of older women compared to 81% and 67% for IM and 84% and 59% for FP respectively (p = p = Conclusions A majority of physicians, especially OBG, favour aggressive breast cancer screening for women from 40 through 79 years of age, including women with short life expectancy. Policy interventions should focus on educating providers to provide tailored recommendations for

Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size.

Science.gov (United States)

Fallenberg, E M; Dromain, C; Diekmann, F; Engelken, F; Krohn, M; Singh, J M; Ingold-Heppner, B; Winzer, K J; Bick, U; Renz, D M

2014-01-01

To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography (CESM) is slowly being introduced into clinical practice. • Access to breast MRI is limited by availability and lack of reimbursement. • Initial results show a better sensitivity of CESM and MRI than conventional mammography. • CESM showed a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography offers promise, seemingly providing information comparable to MRI.

Risk Contagion in Chinese Banking Industry: A Transfer Entropy-Based Analysis

Directory of Open Access Journals (Sweden)

Jianping Li

2013-12-01

Full Text Available What is the impact of a bank failure on the whole banking industry? To resolve this issue, the paper develops a transfer entropy-based method to determine the interbank exposure matrix between banks. This method constructs the interbank market structure by calculating the transfer entropy matrix using bank stock price sequences. This paper also evaluates the stability of Chinese banking system by simulating the risk contagion process. This paper contributes to the literature on interbank contagion mainly in two ways: it establishes a convincing connection between interbank market and transfer entropy, and exploits the market information (stock price rather than presumptions to determine the interbank exposure matrix. Second, the empirical analysis provides an in depth understanding of the stability of the current Chinese banking system.

Music viewed by its entropy content: A novel window for comparative analysis.

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Gerardo Febres

Full Text Available Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the '2nd Order Entropy'. Applying these methods to a variety of musical pieces showed how the space of 'symbolic specific diversity-entropy' and that of '2nd order entropy' captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning.

Music viewed by its entropy content: A novel window for comparative analysis.

Science.gov (United States)

Febres, Gerardo; Jaffe, Klaus

2017-01-01

Polyphonic music files were analyzed using the set of symbols that produced the Minimal Entropy Description, which we call the Fundamental Scale. This allowed us to create a novel space to represent music pieces by developing: (a) a method to adjust a textual description from its original scale of observation to an arbitrarily selected scale, (b) a method to model the structure of any textual description based on the shape of the symbol frequency profiles, and (c) the concept of higher order entropy as the entropy associated with the deviations of a frequency-ranked symbol profile from a perfect Zipfian profile. We call this diversity index the '2nd Order Entropy'. Applying these methods to a variety of musical pieces showed how the space of 'symbolic specific diversity-entropy' and that of '2nd order entropy' captures characteristics that are unique to each music type, style, composer and genre. Some clustering of these properties around each musical category is shown. These methods allow us to visualize a historic trajectory of academic music across this space, from medieval to contemporary academic music. We show that the description of musical structures using entropy, symbol frequency profiles and specific symbolic diversity allows us to characterize traditional and popular expressions of music. These classification techniques promise to be useful in other disciplines for pattern recognition and machine learning.

Data on the cost-benefit analysis of mammography

International Nuclear Information System (INIS)

Zarand, P.; Pentek, Z.

1982-01-01

The radiation exposure and the cost per examination are compared in the case of three methods: non-screen film mammography, 10-dose mammography and xeromammography. 10-dose mammography results in the lowest radiation exposure whereas xeromammography has the lowest cost. (L.E.)

Advanced Breast Cancer as Indicator of Quality Mammography

International Nuclear Information System (INIS)

Gaona, Enrique

2003-01-01

Breast cancer is the most frequently diagnosed cancer and is the second leading cause of cancer death among women in the Mexican Republic. Mammography is the more important screening tool for detecting early breast cancer. Screening mammography involves taking x-rays from two views from each breast, typically from above (cranial-caudal view, CC) and from an oblique or angled view (mediolateral-oblique, MLO). The purpose of this study was to carry out an exploratory survey of the issue of patients with advanced breast cancer who have had a screening mammography. A general result of the survey is that 22.5% of all patients (102) with advanced breast cancer that participated in the study had previous screening mammography. But we should consider that 10% of breast cancers are not detected by mammography. Only 70% of the family doctors prescribed a diagnostic mammography when the first symptoms were diagnosed

Entropy of Iterated Function Systems and Their Relations with Black Holes and Bohr-Like Black Holes Entropies

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Christian Corda

2018-01-01

Full Text Available In this paper we consider the metric entropies of the maps of an iterated function system deduced from a black hole which are known the Bekenstein–Hawking entropies and its subleading corrections. More precisely, we consider the recent model of a Bohr-like black hole that has been recently analysed in some papers in the literature, obtaining the intriguing result that the metric entropies of a black hole are created by the metric entropies of the functions, created by the black hole principal quantum numbers, i.e., by the black hole quantum levels. We present a new type of topological entropy for general iterated function systems based on a new kind of the inverse of covers. Then the notion of metric entropy for an Iterated Function System ( I F S is considered, and we prove that these definitions for topological entropy of IFS’s are equivalent. It is shown that this kind of topological entropy keeps some properties which are hold by the classic definition of topological entropy for a continuous map. We also consider average entropy as another type of topological entropy for an I F S which is based on the topological entropies of its elements and it is also an invariant object under topological conjugacy. The relation between Axiom A and the average entropy is investigated.

Biological Aging and Life Span Based on Entropy Stress via Organ and Mitochondrial Metabolic Loading

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Kalyan Annamalai

2017-10-01

Full Text Available The energy for sustaining life is released through the oxidation of glucose, fats, and proteins. A part of the energy released within each cell is stored as chemical energy of Adenosine Tri-Phosphate molecules, which is essential for performing life-sustaining functions, while the remainder is released as heat in order to maintain isothermal state of the body. Earlier literature introduced the availability concepts from thermodynamics, related the specific irreversibility and entropy generation rates to metabolic efficiency and energy release rate of organ k, computed whole body specific entropy generation rate of whole body at any given age as a sum of entropy generation within four vital organs Brain, Heart, Kidney, Liver (BHKL with 5th organ being the rest of organs (R5 and estimated the life span using an upper limit on lifetime entropy generated per unit mass of body, σM,life. The organ entropy stress expressed in terms of lifetime specific entropy generated per unit mass of body organs (kJ/(K kg of organ k was used to rank organs and heart ranked highest while liver ranked lowest. The present work includes the effects of (1 two additional organs: adipose tissue (AT and skeletal muscles (SM which are of importance to athletes; (2 proportions of nutrients oxidized which affects blood temperature and metabolic efficiencies; (3 conversion of the entropy stress from organ/cellular level to mitochondrial level; and (4 use these parameters as metabolism-based biomarkers for quantifying the biological aging process in reaching the limit of σM,life. Based on the 7-organ model and Elia constants for organ metabolic rates for a male of 84 kg steady mass and using basic and derived allometric constants of organs, the lifetime energy expenditure is estimated to be 2725 MJ/kg body mass while lifetime entropy generated is 6050 kJ/(K kg body mass with contributions of 190; 1835.0; 610; 290; 700; 1470 and 95 kJ/K contributed by AT-BHKL-SM-R7 to 1 kg body

Film-Screen Mammography versus digital storage plate mammography: Hard copy and monitor display of microcalcifications and focal findings - A retrospective clinical and histologic analysis

International Nuclear Information System (INIS)

Schulz-Wendtland, R.; Wenkel, E.; Aichinger, U.; Tartsch, M.; Kuchar, I.; Bautz, W.

2003-01-01

Purpose: A retrospective clinical-histological study to determine the diagnostic accuracy of mammography using conventional screen-film cassettes (hard copy), high-resolution digital phosphor storage plates (hard copy) and monitor display (soft copy) for microcalcifications and focal lesions (BI-RADS TM category 4 or 5). Materials and methods: From April to November 2001, 76 patients underwent conventional film-screen mammography and, after diagnosis and preoperative wire localization, digital mammography with the same exposure parameters. Five investigators retrospectively determined the diagnosis after the operation from randomly distributed mediolateral views (hard-copy reading) and from the monitor display (soft-copy reading). These results were correlated with the final histology. Results: The accuracy of conventional screen-film mammography, digital mammography and monitor-displayed mammography was 67%, 65% and 68% for all findings, (n = 76), 59%, 59% and 68% for microcalcifications (n = 44) and 75%, 72% and 63% for focal lesions (n = 32). The overall results showed no difference. Conclusions: Our findings indicate equivalence of conventional screen-film mammography, high-resolution digital phosphor storage plate mammography and monitor-displayed mammography. (orig.) [de

[Stochastic characteristics of daily precipitation and its spatiotemporal difference over China based on information entropy].

Science.gov (United States)

Li, Xin Xin; Sang, Yan Fang; Xie, Ping; Liu, Chang Ming

2018-04-01

Daily precipitation process in China showed obvious randomness and spatiotemporal variation. It is important to accurately understand the influence of precipitation changes on control of flood and waterlogging disaster. Using the daily precipitation data measured at 520 stations in China during 1961-2013, we quantified the stochastic characteristics of daily precipitation over China based on the index of information entropy. Results showed that the randomness of daily precipitation in the southeast region were larger than that in the northwest region. Moreover, the spatial distribution of stochastic characteristics of precipitation was different at various grades. Stochastic characteri-stics of P 0 (precipitation at 0.1-10 mm) was large, but the spatial variation was not obvious. The stochastic characteristics of P 10 (precipitation at 10-25 mm) and P 25 (precipitation at 25-50 mm) were the largest and their spatial difference was obvious. P 50 (precipitation ≥50 mm) had the smallest stochastic characteristics and the most obviously spatial difference. Generally, the entropy values of precipitation obviously increased over the last five decades, indicating more significantly stochastic characteristics of precipitation (especially the obvious increase of heavy precipitation events) in most region over China under the scenarios of global climate change. Given that the spatial distribution and long-term trend of entropy values of daily precipitation could reflect thespatial distribution of stochastic characteristics of precipitation, our results could provide scientific basis for the control of flood and waterlogging disaster, the layout of agricultural planning, and the planning of ecological environment.

Image coding based on maximum entropy partitioning for identifying ...

Indian Academy of Sciences (India)

A new coding scheme based on maximum entropy partitioning is proposed in our work, particularly to identify the improbable intensities related to different emotions. The improbable intensities when used as a mask decode the facial expression correctly, providing an effectiveplatform for future emotion categorization ...

Evaluation index system of steel industry sustainable development based on entropy method and topsis method

Science.gov (United States)

Ronglian, Yuan; Mingye, Ai; Qiaona, Jia; Yuxuan, Liu

2018-03-01

Sustainable development is the only way for the development of human society. As an important part of the national economy, the steel industry is an energy-intensive industry and needs to go further for sustainable development. In this paper, we use entropy method and Topsis method to evaluate the development of China’s steel industry during the “12th Five-Year Plan” from four aspects: resource utilization efficiency, main energy and material consumption, pollution status and resource reuse rate. And we also put forward some suggestions for the development of China’s steel industry.

Computer assisted visualization of digital mammography images

International Nuclear Information System (INIS)

Funke, M.; Breiter, N.; Grabbe, E.; Netsch, T.; Biehl, M.; Peitgen, H.O.

1999-01-01

Purpose: In a clinical study, the feasibility of using a mammography workstation for the display and interpretation of digital mammography images was evaluated and the results were compared with the corresponding laser film hard copies. Materials and Methods: Digital phosphorous plate radiographs of the entire breast were obtained in 30 patients using a direct magnification mammography system. The images were displayed for interpretation on the computer monitor of a dedicated mammography workstation and also presented as laser film hard copies on a film view box for comparison. The images were evaluted with respect to the image handling, the image quality and the visualization of relevant structures by 3 readers. Results: Handling and contrast of the monitor displayed images were found to be superior compared with the film hard copies. Image noise was found in some cases but did not compromise the interpretation of the monitor images. The visualization of relevant structures was equal with both modalities. Altogether, image interpretation with the mammography workstation was considered to be easy, quick and confident. Conclusions: Computer-assisted visualization and interpretation of digital mammography images using a dedicated workstation can be performed with sufficiently high diagnostic accuracy. (orig.) [de

Investigation of actual conditions of mammography in Kagoshima prefecture

International Nuclear Information System (INIS)

Baba, Natsuki; Tanimoto, Eriko; Kobayashi, Yasuhiro; Kuma, Kouji

2009-01-01

We surveyed the actual conditions of mammography with regard to image quality and radiation dose at 44 facilities in Kagoshima prefecture in 1999. In April 2004, guidelines for mammography newly included the standard of digital mammography. From September to October 2005, the survey was conducted at 48 facilities, and the results of the survey were compared with that in 1999. We visited 44 of the 48 facilities, and visually evaluated the image quality of mammograms for RMI156 and clinical mammograms. In addition, we measured average mammary gland dose at each facility. The number of the mammography device that satisfied the specified guideline criterion was larger than that in 1999. Image quality for the RMI156 mammograms improved. However, the results of the present survey revealed several problems. First, the number of facilities that had quality control instruments for mammography are few. Second, radiological technologists, medical doctors, and nurses did not share knowledge or information regarding mammography. Finally, there were differences in devices and image quality for mammography among the facilities. We achieved an understanding of the actual conditions of mammography in Kagoshima prefecture by visiting many facilities, evaluating image quality, and communicating with many staff members. Our results may be useful for the development of mammography examinations. (author)

A comparison of digital mammography detectors and emerging technology

International Nuclear Information System (INIS)

Diffey, J.L.

2015-01-01

The overall diagnostic accuracy of digital mammography in the context of screening has been shown to be similar or slightly better than screen-film mammography. However, digital mammography encompasses both Computed Radiography (CR) and integrated Digital Radiography (DR) and there is increasing evidence to suggest that differences in detector technology are associated with variations in cancer detection rate, dose and image quality. These differences are examined in detail. Although digital mammography offers many advantages compared to screen-film, there are still some limitations with its use as a screening tool and reduced cancer detection in dense breasts remains an issue. Digital mammography detectors have paved the way for emerging technologies which may offer improvements. Taking the definition of mammography to only include X-ray imaging of the breast, this article focuses on tomosynthesis, contrast-enhanced digital mammography, stereoscopic mammography and dedicated breast computed tomography. Advanced software applications such as Computed Aided Detection (CAD) and quantitative breast density assessment are also presented. The benefits and limitations of each technique are discussed. - Highlights: • Digital detector technology affects cancer detection rate, dose and image quality. • Digital detectors have facilitated new technologies such as tomosynthesis. • 3-D techniques reduce superimposition and increase cancer detection in dense breasts. • Contrast-enhanced mammography demonstrates improved sensitivity and specificity.

Deep learning in mammography and breast histology, an overview and future trends.

Science.gov (United States)

Hamidinekoo, Azam; Denton, Erika; Rampun, Andrik; Honnor, Kate; Zwiggelaar, Reyer

2018-07-01

Recent improvements in biomedical image analysis using deep learning based neural networks could be exploited to enhance the performance of Computer Aided Diagnosis (CAD) systems. Considering the importance of breast cancer worldwide and the promising results reported by deep learning based methods in breast imaging, an overview of the recent state-of-the-art deep learning based CAD systems developed for mammography and breast histopathology images is presented. In this study, the relationship between mammography and histopathology phenotypes is described, which takes biological aspects into account. We propose a computer based breast cancer modelling approach: the Mammography-Histology-Phenotype-Linking-Model, which develops a mapping of features/phenotypes between mammographic abnormalities and their histopathological representation. Challenges are discussed along with the potential contribution of such a system to clinical decision making and treatment management. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Using entropy measures to characterize human locomotion.

Science.gov (United States)

Leverick, Graham; Szturm, Tony; Wu, Christine Q

2014-12-01

Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

Update on new technologies in digital mammography

Directory of Open Access Journals (Sweden)

Patterson SK

2014-08-01

Full Text Available Stephanie K Patterson, Marilyn A Roubidoux Division of Breast Imaging, Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA Abstract: Despite controversy regarding mammography's efficacy, it continues to be the most commonly used breast cancer-screening modality. With the development of digital mammography, some improved benefit has been shown in women with dense breast tissue. However, the density of breast tissue continues to limit the sensitivity of conventional mammography. We discuss the development of some derivative digital technologies, primarily digital breast tomosynthesis, and their strengths, weaknesses, and potential patient impact. Keywords: screening mammography, breast cancer, contrast media, digital breast tomosynthesis

A Connection Entropy Approach to Water Resources Vulnerability Analysis in a Changing Environment

Directory of Open Access Journals (Sweden)

Zhengwei Pan

2017-11-01

Full Text Available This paper establishes a water resources vulnerability framework based on sensitivity, natural resilience and artificial adaptation, through the analyses of the four states of the water system and its accompanying transformation processes. Furthermore, it proposes an analysis method for water resources vulnerability based on connection entropy, which extends the concept of contact entropy. An example is given of the water resources vulnerability in Anhui Province of China, which analysis illustrates that, overall, vulnerability levels fluctuated and showed apparent improvement trends from 2001 to 2015. Some suggestions are also provided for the improvement of the level of water resources vulnerability in Anhui Province, considering the viewpoint of the vulnerability index.

Towards an entropy-based analysis of log variability

DEFF Research Database (Denmark)

Back, Christoffer Olling; Debois, Søren; Slaats, Tijs

2017-01-01

the development of hybrid miners: given a (sub-)log, can we determine a priori whether the log is best suited for imperative or declarative mining? We propose using the concept of entropy, commonly used in information theory. We consider different measures for entropy that could be applied and show through...... experimentation on both synthetic and real-life logs that these entropy measures do indeed give insights into the complexity of the log and can act as an indicator of which mining paradigm should be used....

Towards an Entropy-based Analysis of Log Variability

DEFF Research Database (Denmark)

Back, Christoffer Olling; Debois, Søren; Slaats, Tijs

2018-01-01

the development of hybrid miners: given a log, can we determine a priori whether the log is best suited for imperative or declarative mining? We propose using the concept of entropy, commonly used in information theory. We consider different measures for entropy that could be applied and show through...... experimentation on both synthetic and real-life logs that these entropy measures do indeed give insights into the complexity of the log and can act as an indicator of which mining paradigm should be used....

Comprehensive evaluation of global energy interconnection development index

Science.gov (United States)

Liu, Lin; Zhang, Yi

2018-04-01

Under the background of building global energy interconnection and realizing green and low-carbon development, this article constructed the global energy interconnection development index system which based on the current situation of global energy interconnection development. Through using the entropy method for the weight analysis of global energy interconnection development index, and then using gray correlation method to analyze the selected countries, this article got the global energy interconnection development index ranking and level classification.

Giant irreversible positive to large reversible negative magnetic entropy change evolution in Tb-based bulk metallic glass

International Nuclear Information System (INIS)

Luo Qiang; Schwarz, Bjoern; Mattern, Norbert; Eckert, Juergen

2010-01-01

We study the effects of amorphous structure and random anisotropy on the magnetic entropy change in a series of Tb-based amorphous alloys. The amorphous structure broadens the peak of magnetic entropy change and facilitates the adjustment of properties. The peak magnetic entropy change above the spin freezing temperature first depends on the average magnetic moment approximately linearly and second on the exchange interaction and random anisotropy. Large and broad reversible negative magnetic entropy changes are observed above the spin freezing temperature and giant positive irreversible magnetic entropy changes which associate with the internal entropy production are obtained well below.

Radiographic techniques for digital mammography

International Nuclear Information System (INIS)

Horita, Katsuhei

2007-01-01

Since the differences in X-ray absorption between various breast tissues are small, a dedicated X-ray system for examination of the breast and a high-contrast, high-resolution screen/film system (SFM) (light-receiving system) are employed for X-ray diagnosis. Currently, however, there is a strong trend toward digital imaging in the field of general radiography, and this trend is also reflected in the field of mammographic examination. In fact, approximately 70% of facilities purchasing new mammography systems are now selecting a digital mammography system (DRM). Given this situation, this report reviews the differences between SFM and DRM and discusses the radiographic techniques and quality assurance procedures for digital mammography. (author)

Entropy-based implied volatility and its information content

NARCIS (Netherlands)

X. Xiao (Xiao); C. Zhou (Chen)

2016-01-01

markdownabstractThis paper investigates the maximum entropy approach on estimating implied volatility. The entropy approach also allows to measure option implied skewness and kurtosis nonparametrically, and to construct confidence intervals. Simulations show that the en- tropy approach outperforms

Comparative performance of modern digital mammography systems in a large breast screening program

Energy Technology Data Exchange (ETDEWEB)

Yaffe, Martin J., E-mail: martin.yaffe@sri.utoronto.ca; Bloomquist, Aili K.; Hunter, David M.; Mawdsley, Gordon E. [Physical Sciences Division, Sunnybrook Research Institute, Departments of Medical Biophysics and Medical Imaging, University of Toronto, Ontario M4N 3M5 (Canada); Chiarelli, Anna M. [Prevention and Cancer Control, Cancer Care Ontario, Dalla Lana School of Public Health, University of Toronto, Ontario M4N 3M5, Canada and Ontario Breast Screening Program, Cancer Care Ontario, Toronto, Ontario M5G 1X3 (Canada); Muradali, Derek [Ontario Breast Screening Program, Cancer Care Ontario, Toronto, Ontario M5G 1X3 (Canada); Mainprize, James G. [Physical Sciences Division, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5 (Canada)

2013-12-15

Purpose: To compare physical measures pertaining to image quality among digital mammography systems utilized in a large breast screening program. To examine qualitatively differences in these measures and differences in clinical cancer detection rates between CR and DR among sites within that program. Methods: As part of the routine quality assurance program for screening, field measurements are made of several variables considered to correlate with the diagnostic quality of medical images including: modulation transfer function, noise equivalent quanta, d′ (an index of lesion detectability) and air kerma to allow estimation of mean glandular dose. In addition, images of the mammography accreditation phantom are evaluated. Results: It was found that overall there were marked differences between the performance measures of DR and CR mammography systems. In particular, the modulation transfer functions obtained with the DR systems were found to be higher, even for larger detector element sizes. Similarly, the noise equivalent quanta, d′, and the phantom scores were higher, while the failure rates associated with low signal-to-noise ratio and high dose were lower with DR. These results were consistent with previous findings in the authors’ program that the breast cancer detection rates at sites employing CR technology were, on average, 30.6% lower than those that used DR mammography. Conclusions: While the clinical study was not large enough to allow a statistically powered system-by-system assessment of cancer detection accuracy, the physical measures expressing spatial resolution, and signal-to-noise ratio are consistent with the published finding that sites employing CR systems had lower cancer detection rates than those using DR systems for screening mammography.

Trimodel Mammography with Perfect Coregistration

Science.gov (United States)

2017-02-01

background, the major confounding factor in reading mammography; the imaging characteristics suggest that this contrast mechanism would be preferable...image with enhanced edges and reduced anatomical background, the major confounding factor in reading mammography; the imaging characteristics suggest...subjects, vertebrate animals , biohazards, and/or select agents Describe significant deviations, unexpected outcomes, or changes in approved protocols

Digital mammography: Mixed feature neural network with spectral entropy decision for detection of microcalcifications

Energy Technology Data Exchange (ETDEWEB)

Zheng, B. [Univ. of South Florida, Tampa, FL (United States)]|[Nanjing Univ. of Posts and Telecommunications (China). Dept. of Telecommunication Engineering; Qian, W.; Clarke, L.P. [Univ. of South Florida, Tampa, FL (United States)

1996-10-01

A computationally efficient mixed feature based neural network (MFNN) is proposed for the detection of microcalcification clusters (MCC`s) in digitized mammograms. The MFNN employs features computed in both the spatial and spectral domain and uses spectral entropy as a decision parameter. Backpropagation with Kalman Filtering (KF) is employed to allow more efficient network training as required for evaluation of different features, input images, and related error analysis. A previously reported, wavelet-based image-enhancement method is also employed to enhance microcalcification clusters for improved detection. The relative performance of the MFNN for both the raw and enhanced images is evaluated using a common image database of 30 digitized mammograms, with 20 images containing 21 biopsy proven MCC`s and ten normal cases. The computed sensitivity (true positive (TP) detection rate) was 90.1% with an average low false positive (FP) detection of 0.71 MCCs/image for the enhanced images using a modified k-fold validation error estimation technique. The corresponding computed sensitivity for the raw images was reduced to 81.4% and with 0.59 FP`s MCCs/image. A relative comparison to an earlier neural network (NN) design, using only spatially related features, suggests the importance of the addition of spectral domain features when the raw image data are analyzed.

Digital mammography: Mixed feature neural network with spectral entropy decision for detection of microcalcifications

International Nuclear Information System (INIS)

Zheng, B.

1996-01-01

A computationally efficient mixed feature based neural network (MFNN) is proposed for the detection of microcalcification clusters (MCC's) in digitized mammograms. The MFNN employs features computed in both the spatial and spectral domain and uses spectral entropy as a decision parameter. Backpropagation with Kalman Filtering (KF) is employed to allow more efficient network training as required for evaluation of different features, input images, and related error analysis. A previously reported, wavelet-based image-enhancement method is also employed to enhance microcalcification clusters for improved detection. The relative performance of the MFNN for both the raw and enhanced images is evaluated using a common image database of 30 digitized mammograms, with 20 images containing 21 biopsy proven MCC's and ten normal cases. The computed sensitivity (true positive (TP) detection rate) was 90.1% with an average low false positive (FP) detection of 0.71 MCCs/image for the enhanced images using a modified k-fold validation error estimation technique. The corresponding computed sensitivity for the raw images was reduced to 81.4% and with 0.59 FP's MCCs/image. A relative comparison to an earlier neural network (NN) design, using only spatially related features, suggests the importance of the addition of spectral domain features when the raw image data are analyzed

An SVM Based Approach for the Analysis Of Mammography Images

Science.gov (United States)

Gan, X.; Kapsokalivas, L.; Skaliotis, A.; Steinhöfel, K.; Tangaro, S.

2007-09-01

Mammography is among the most popular imaging techniques used in the diagnosis of breast cancer. Nevertheless distinguishing between healthy and ill images is hard even for an experienced radiologist, because a single image usually includes several regions of interest (ROIs). The hardness of this classification problem along with the substantial amount of data, gathered from patients' medical history, motivates the use of a machine learning approach as part of a CAD (Computer Aided Detection) tool, aiming to assist radiologists in the characterization of mammography images. Specifically, our approach involves: i) the ROI extraction, ii) the Feature Vector extraction, iii) the Support Vector Machine (SVM) classification of ROIs and iv) the characterization of the whole image. We evaluate the performance of our approach in terms of the SVM's training and testing error and in terms of ROI specificity—sensitivity. The results show a relation between the number of features used and the SVM's performance.

An SVM Based Approach for the Analysis Of Mammography Images

International Nuclear Information System (INIS)

Gan, X.; Kapsokalivas, L.; Skaliotis, A.; Steinhoefel, K.; Tangaro, S.

2007-01-01

Mammography is among the most popular imaging techniques used in the diagnosis of breast cancer. Nevertheless distinguishing between healthy and ill images is hard even for an experienced radiologist, because a single image usually includes several regions of interest (ROIs). The hardness of this classification problem along with the substantial amount of data, gathered from patients' medical history, motivates the use of a machine learning approach as part of a CAD (Computer Aided Detection) tool, aiming to assist radiologists in the characterization of mammography images. Specifically, our approach involves: i) the ROI extraction, ii) the Feature Vector extraction, iii) the Support Vector Machine (SVM) classification of ROIs and iv) the characterization of the whole image. We evaluate the performance of our approach in terms of the SVM's training and testing error and in terms of ROI specificity - sensitivity. The results show a relation between the number of features used and the SVM's performance

Optimizing an estuarine water quality monitoring program through an entropy-based hierarchical spatiotemporal Bayesian framework

Science.gov (United States)

Alameddine, Ibrahim; Karmakar, Subhankar; Qian, Song S.; Paerl, Hans W.; Reckhow, Kenneth H.

2013-10-01

The total maximum daily load program aims to monitor more than 40,000 standard violations in around 20,000 impaired water bodies across the United States. Given resource limitations, future monitoring efforts have to be hedged against the uncertainties in the monitored system, while taking into account existing knowledge. In that respect, we have developed a hierarchical spatiotemporal Bayesian model that can be used to optimize an existing monitoring network by retaining stations that provide the maximum amount of information, while identifying locations that would benefit from the addition of new stations. The model assumes the water quality parameters are adequately described by a joint matrix normal distribution. The adopted approach allows for a reduction in redundancies, while emphasizing information richness rather than data richness. The developed approach incorporates the concept of entropy to account for the associated uncertainties. Three different entropy-based criteria are adopted: total system entropy, chlorophyll-a standard violation entropy, and dissolved oxygen standard violation entropy. A multiple attribute decision making framework is adopted to integrate the competing design criteria and to generate a single optimal design. The approach is implemented on the water quality monitoring system of the Neuse River Estuary in North Carolina, USA. The model results indicate that the high priority monitoring areas identified by the total system entropy and the dissolved oxygen violation entropy criteria are largely coincident. The monitoring design based on the chlorophyll-a standard violation entropy proved to be less informative, given the low probabilities of violating the water quality standard in the estuary.

Image Quality and Patient Dose Optimisation in Mammography in Slovakia

International Nuclear Information System (INIS)

Horvathova, M.; Nikodemova, D.; Prikazska, M.

2003-01-01

Breast cancer represents also in Slovakia the greatest cancer risk for women, with great incidence and mortality. Conventional film-screen mammography is still the primary breast imaging modality with increasing number of mammography units and mammography examinations. From the radiation protection point of view achievement of good practice in mammography department by implementation of quality assurance play an important role for reduction of patients doses. Introduction of QA needs trained and experienced staff and requires close collaboration between radiologists, medical physicist and radiographers. At the beginning of nineties at the Institute of Preventive and Clinical Medicine we started with a survey of mean glandular doses at 15 existing mammography units in the country. On the basis of a questionnaire in the year 1991 were performed 10 488 mammography examinations, where due to out of date mammography units the mean glandular dose reached more as 3 mGy. In the following years the claim to the modern mammography units kept growing and in the year 1999 the total number of 63 mammography units were operating in Slovakia providing about 101 471 mammography examinations. According to the alarming increase of the number of mammography examinations it is absolutely necessary to work out criteria and principles for Quality Control at mammography workplaces in our country and make it obligatory for the staff of all mammography units. Summarising the CRP results it can be stated that they: 1) Initiated the suggestion of unified QA/QC criteria in mammography and the urgent need to implement them into the national program of radiology image quality improvement; 2) Remitted on unhomogenity not only in the equipment outfit but also in the procedure of evaluation of the measured parameters and imaging quality; 3) Revealed the shortcomings in the everyday practice of mammography units which can be removed only by comprehensive by training of personal in imaging radiology

Mammography screening: A major issue in medicine.

Science.gov (United States)

Autier, Philippe; Boniol, Mathieu

2018-02-01

Breast cancer mortality is declining in most high-income countries. The role of mammography screening in these declines is much debated. Screening impacts cancer mortality through decreasing the incidence of number of advanced cancers with poor prognosis, while therapies and patient management impact cancer mortality through decreasing the fatality of cancers. The effectiveness of cancer screening is the ability of a screening method to curb the incidence of advanced cancers in populations. Methods for evaluating cancer screening effectiveness are based on the monitoring of age-adjusted incidence rates of advanced cancers that should decrease after the introduction of screening. Likewise, cancer-specific mortality rates should decline more rapidly in areas with screening than in areas without or with lower levels of screening but where patient management is similar. These two criteria have provided evidence that screening for colorectal and cervical cancer contributes to decreasing the mortality associated with these two cancers. In contrast, screening for neuroblastoma in children was discontinued in the early 2000s because these two criteria were not met. In addition, overdiagnosis - i.e. the detection of non-progressing occult neuroblastoma that would not have been life-threatening during the subject's lifetime - is a major undesirable consequence of screening. Accumulating epidemiological data show that in populations where mammography screening has been widespread for a long time, there has been no or only a modest decline in the incidence of advanced cancers, including that of de novo metastatic (stage IV) cancers at diagnosis. Moreover, breast cancer mortality reductions are similar in areas with early introduction and high penetration of screening and in areas with late introduction and low penetration of screening. Overdiagnosis is commonplace, representing 20% or more of all breast cancers among women invited to screening and 30-50% of screen

Mammography - recent technical developments and their clinical potential

Energy Technology Data Exchange (ETDEWEB)

Hemdal, Bengt; Mattsson, Soeren [Malmoe Univ. Hospital (Sweden). Dept. of Radiation Physics; Andersson, Ingvar [Malmoe Univ. Hospital (Sweden). Dept. of Diagnostic Radiology; Thilander Klang, Anne [Sahlgrenska Univ. Hospital, Goeteborg (Sweden). Dept. of Medical Physics and Biomedical Engineering; Bengtsson, Gert; Jarlman, O. [Lund Univ. Hospital (Sweden). Dept. of Diagnostic Radiology; Leitz, Wolfram [Swedish Radiation Protection Authority, Stockholm (Sweden); Bjurstam, Nils [Univ. of North Norway, Troms (Norway). Dept. of Radiology

2002-05-01

The recent technical developments in digital as well as screen-film X-ray mammography have been reviewed in order to evaluate their clinical potential and to analyse possible lines for future development. Material and methods: The scientific literature has been reviewed, conferences covered and contacts with colleagues developed. Companies in the field have been inquired and invited for presentations. Own experience has been gathered from different screen-film and digital mammography systems. Results and conclusions: Although there are important complementary techniques such as ultrasound and magnetic resonance imaging (MRI), X-ray mammography is still the golden standard for breast imaging. It is relatively simple and cost-effective, and it is presently the only realistic technique for screening in a large scale. It is still largely the only technique that can detect breast cancer in a pre invasive stage. Equipment for digital mammography is commercially available both with small area and full field technique (FFDM). The development of FFDM systems is now intense, as well as the development of dedicated workstations and computer-aided detection (CAD). In spite of this, the introduction of digital mammography has been very slow compared to most other X-ray examinations due to high costs and technical challenges to meet the high demands on image quality and dose in mammography as well as the demands on specialised workflow support for screening mammography and suitable display techniques. Film reading of digital mammograms has been the most common display mode so far, but to take full advantage of the digital concept, diagnostic as well as logistic, monitor reading must be applied. There is a potential of FFDM systems for significantly higher image quality or significantly lower dose than screen-film mammography (SFM), or both. Further research is necessary to fully use this potential. The investment costs are much higher for digital than screen-film mammography

Mammography - recent technical developments and their clinical potential

International Nuclear Information System (INIS)

Hemdal, Bengt; Mattsson, Soeren; Bjurstam, Nils

2002-05-01

The recent technical developments in digital as well as screen-film X-ray mammography have been reviewed in order to evaluate their clinical potential and to analyse possible lines for future development. Material and methods: The scientific literature has been reviewed, conferences covered and contacts with colleagues developed. Companies in the field have been inquired and invited for presentations. Own experience has been gathered from different screen-film and digital mammography systems. Results and conclusions: Although there are important complementary techniques such as ultrasound and magnetic resonance imaging (MRI), X-ray mammography is still the golden standard for breast imaging. It is relatively simple and cost-effective, and it is presently the only realistic technique for screening in a large scale. It is still largely the only technique that can detect breast cancer in a pre invasive stage. Equipment for digital mammography is commercially available both with small area and full field technique (FFDM). The development of FFDM systems is now intense, as well as the development of dedicated workstations and computer-aided detection (CAD). In spite of this, the introduction of digital mammography has been very slow compared to most other X-ray examinations due to high costs and technical challenges to meet the high demands on image quality and dose in mammography as well as the demands on specialised workflow support for screening mammography and suitable display techniques. Film reading of digital mammograms has been the most common display mode so far, but to take full advantage of the digital concept, diagnostic as well as logistic, monitor reading must be applied. There is a potential of FFDM systems for significantly higher image quality or significantly lower dose than screen-film mammography (SFM), or both. Further research is necessary to fully use this potential. The investment costs are much higher for digital than screen-film mammography

Mammographic image restoration using maximum entropy deconvolution

International Nuclear Information System (INIS)

Jannetta, A; Jackson, J C; Kotre, C J; Birch, I P; Robson, K J; Padgett, R

2004-01-01

An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization

A Novel Evaluation Method for Building Construction Project Based on Integrated Information Entropy with Reliability Theory

Directory of Open Access Journals (Sweden)

Xiao-ping Bai

2013-01-01

Full Text Available Selecting construction schemes of the building engineering project is a complex multiobjective optimization decision process, in which many indexes need to be selected to find the optimum scheme. Aiming at this problem, this paper selects cost, progress, quality, and safety as the four first-order evaluation indexes, uses the quantitative method for the cost index, uses integrated qualitative and quantitative methodologies for progress, quality, and safety indexes, and integrates engineering economics, reliability theories, and information entropy theory to present a new evaluation method for building construction project. Combined with a practical case, this paper also presents detailed computing processes and steps, including selecting all order indexes, establishing the index matrix, computing score values of all order indexes, computing the synthesis score, sorting all selected schemes, and making analysis and decision. Presented method can offer valuable references for risk computing of building construction projects.

Digital mammography: current state and future aspects

Energy Technology Data Exchange (ETDEWEB)

Fischer, U.; Baum, F. [Womens Health Care Center Goettingen, Diagnostisches Brustzentrum Goettingen, Goettingen (Germany); Hermann, K.P. [Georg-August-Universitaet Goettingen, Abteilung Diagnostische Radiologie, Goettingen (Germany)

2006-01-01

The introduction of digital technique in mammography has been the last step in completing the process of digitalization in diagnostic imaging. Meanwhile, some different digital techniques as well as a couple of different digital mammography systems were developed and have already been available for some years. In this review article, the relevant data of key studies are reported, the current status is defined, and perspectives of digital mammography are described. (orig.)

Mammography and breast sonography in transsexual women

International Nuclear Information System (INIS)

Weyers, S.; Villeirs, G.; Vanherreweghe, E.; Verstraelen, H.; Monstrey, S.; Van den Broecke, R.; Gerris, J.

2010-01-01

Data on the necessity of performing screening mammographies in transsexual women are lacking. The main objective of this study was to assess the possibility to perform mammography and breast sonography in transsexual women. Fifty Dutch-speaking transsexual women were interviewed about the following: attitude towards mammography and breast sonography, importance attributed to and satisfaction with breast appearance, opinion about the necessity of breast check-up, expectations regarding discomfort during the exams and knowledge about the breast surgery. A fasting blood sample, clinical breast exam, mammography and breast sonography were performed. At mammography the following parameters were noted: density, technical quality, location of the prostheses, presence of any abnormalities and painfulness. At sonography the following parameters were recorded: density, presence of cysts, visualisation of retro-areolar ducts or any abnormalities. Twenty-three percent of patients are not aware of the type of breast implants and 79% do not know their position to the pectoral muscles. Patient satisfaction with the appearance of their breasts was rather high (7.94 on a scale of 0-10). Mean expected and experienced pain from mammography was low (4.37 and 2.00 respectively). There was no statistically significant difference in expected pain between those who already had mammography and those who did not. There was a significant positive correlation between the expected and the experienced pain. Mammography and breast sonography were technically feasible and no gross anomalies were detected. Since both exams were judged as nearly painless, 98% of transsexual women intended to come back if they would be invited. Since breast cancer risk in transsexual women is largely unknown and breast exams are very well accepted, breast screening habits in this population should not differ from those of biological women.

Mammography and breast sonography in transsexual women

Energy Technology Data Exchange (ETDEWEB)

Weyers, S., E-mail: steven.weyers@ugent.b [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium); Villeirs, G.; Vanherreweghe, E. [Department of Radiology, Ghent University Hospital, Ghent (Belgium); Verstraelen, H. [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium); Monstrey, S. [Department of Plastic Surgery, Ghent University Hospital, Ghent (Belgium); Van den Broecke, R.; Gerris, J. [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium)

2010-06-15

Data on the necessity of performing screening mammographies in transsexual women are lacking. The main objective of this study was to assess the possibility to perform mammography and breast sonography in transsexual women. Fifty Dutch-speaking transsexual women were interviewed about the following: attitude towards mammography and breast sonography, importance attributed to and satisfaction with breast appearance, opinion about the necessity of breast check-up, expectations regarding discomfort during the exams and knowledge about the breast surgery. A fasting blood sample, clinical breast exam, mammography and breast sonography were performed. At mammography the following parameters were noted: density, technical quality, location of the prostheses, presence of any abnormalities and painfulness. At sonography the following parameters were recorded: density, presence of cysts, visualisation of retro-areolar ducts or any abnormalities. Twenty-three percent of patients are not aware of the type of breast implants and 79% do not know their position to the pectoral muscles. Patient satisfaction with the appearance of their breasts was rather high (7.94 on a scale of 0-10). Mean expected and experienced pain from mammography was low (4.37 and 2.00 respectively). There was no statistically significant difference in expected pain between those who already had mammography and those who did not. There was a significant positive correlation between the expected and the experienced pain. Mammography and breast sonography were technically feasible and no gross anomalies were detected. Since both exams were judged as nearly painless, 98% of transsexual women intended to come back if they would be invited. Since breast cancer risk in transsexual women is largely unknown and breast exams are very well accepted, breast screening habits in this population should not differ from those of biological women.

Evaluation of breast symptoms with mammography and ultrasonography

Directory of Open Access Journals (Sweden)

Emine Devolli Disha

2011-12-01

Full Text Available Introduction: Aim of the study was to discern which are more frequent symptoms presented in malign and benign masses diagnosed by mammography and ultrasonography.Methods: Our study group consisted of 546 female patients, with breast symptoms such as palpable lumps (40.8%, pain in the breast (26%, localized lumpiness or nodularity (13.7%, nipple retraction (11.2%, nipplebloody discharge (5.1% and redness and swelling of the breast (3.1%. All 546 patients were examined by ultrasonography and mammography. Biopsy was performed according to the findings of mammography and ultrasonography.Results: In breast cancer detection ultrasonography showed an efficiency of 79.4% compared to 55.0% for mammography in detecting breast lump, in the case of nipple retraction mammography showed an efficiency of 89.1% compared to 80.4% for ultrasound, while the lowest efficiency for mammography was in the cases with localized lumpiness or nodularity 17.1% compared to 45.7% for ultrasound. In detecting fibrocystic changes where the most common symptoms was pain, ultrasonography showed an efficiency of 99.3 % compared to 84.2 % for mammography.Conclusions: Our study confirmed that breast lumps are detectable in the majority of patients with breast cancer. The most frequent symptoms in patient with benign lesions were pain or localized discomfort. The diagnostic accuracy for carcinomas of the breast and for benign lesions according to symptoms was higher for ultrasound than for mammography.

WE-DE-207B-01: Optimization for Contrast-Enhanced Spectral Mammography Based On Photon-Counting Detectors

Energy Technology Data Exchange (ETDEWEB)

Ding, H; Molloi, S [University of California, Irvine, CA (United States)

2016-06-15

Purpose: To investigate the feasibility of optimizing the imaging parameters for contrast-enhanced spectral mammography based on Si strip photon-counting detectors. Methods: A computer simulation model using polyenergetic spectra from a tungsten anode x-ray tube and a Si-based photon-counting detector was evaluated for contrast-enhanced spectral mammography. The simulation traces the emission of photons from the x-ray source, attenuation through the breast and subsequent absorption in the detector. The breast was modeled as a mixture of adipose and mammary gland tissues with a breast density of 30%. A 4 mm iodine signal with a concentration of 4 mg/ml was used to simulate the enhancement of a lesion. Quantum efficiency of the detector was calculated based on the effective attenuation length in the Si strips. The figure-of-merit (FOM), which was defined as the decomposed iodine signal-to-noise ratio (SNR) with respect to the square root of the mean glandular dose (MGD), was chosen to optimize the imaging parameters, in terms of beam energy, splitting energy, and pre-filtrations for breast of various thicknesses and densities. Results: The optimal imaging parameters, which lead to the highest FOM, were found at a beam energy of 45 kVp with a splitting energy at 34 keV for an averaged breast thickness of 4 cm with a standard 0.75 mm Al pre-filtration. The optimal tube voltage varied slightly from 46 to 44 kVp as the breast thickness increases from 2 to 8 cm. The optimal tube voltage decreased to 42 kVp when the Al pre-filtration was increased to 3 mm. Conclusion: This simulation study predicted the optimal imaging parameters for application of photon-counting spectral mammography to contrast-enhanced imaging. The simulation results laid the ground work for future phantom and clinical studies. Grant funding from Philips Medical Systems.

Analyzing the financial crisis using the entropy density function

Science.gov (United States)

Oh, Gabjin; Kim, Ho-yong; Ahn, Seok-Won; Kwak, Wooseop

2015-02-01

The risk that is created by nonlinear interactions among subjects in economic systems is assumed to increase during an abnormal state of a financial market. Nevertheless, investigating the systemic risk in financial markets following the global financial crisis is not sufficient. In this paper, we analyze the entropy density function in the return time series for several financial markets, such as the S&P500, KOSPI, and DAX indices, from October 2002 to December 2011 and analyze the variability in the entropy value over time. We find that the entropy density function of the S&P500 index during the subprime crisis exhibits a significant decrease compared to that in other periods, whereas the other markets, such as those in Germany and Korea, exhibit no significant decrease during the market crisis. These findings demonstrate that the S&P500 index generated a regular pattern in the return time series during the financial crisis.

Entropy-Based Video Steganalysis of Motion Vectors

Directory of Open Access Journals (Sweden)

Elaheh Sadat Sadat

2018-04-01

Full Text Available In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and the irregularity of each block increases the precision of the final video classification into cover and stego classes.

Parameterized entropy analysis of EEG following hypoxic-ischemic brain injury

International Nuclear Information System (INIS)

Tong Shanbao; Bezerianos, Anastasios; Malhotra, Amit; Zhu Yisheng; Thakor, Nitish

2003-01-01

In the present study Tsallis and Renyi entropy methods were used to study the electric activity of brain following hypoxic-ischemic (HI) injury. We investigated the performances of these parameterized information measures in describing the electroencephalogram (EEG) signal of controlled experimental animal HI injury. The results show that (a): compared with Shannon and Renyi entropy, the parameterized Tsallis entropy acts like a spatial filter and the information rate can either tune to long range rhythms or to short abrupt changes, such as bursts or spikes during the beginning of recovery, by the entropic index q; (b): Renyi entropy is a compact and predictive indicator for monitoring the physiological changes during the recovery of brain injury. There is a reduction in the Renyi entropy after brain injury followed by a gradual recovery upon resuscitation

Characterizing brain structures and remodeling after TBI based on information content, diffusion entropy.

Science.gov (United States)

Fozouni, Niloufar; Chopp, Michael; Nejad-Davarani, Siamak P; Zhang, Zheng Gang; Lehman, Norman L; Gu, Steven; Ueno, Yuji; Lu, Mei; Ding, Guangliang; Li, Lian; Hu, Jiani; Bagher-Ebadian, Hassan; Hearshen, David; Jiang, Quan

2013-01-01

To overcome the limitations of conventional diffusion tensor magnetic resonance imaging resulting from the assumption of a Gaussian diffusion model for characterizing voxels containing multiple axonal orientations, Shannon's entropy was employed to evaluate white matter structure in human brain and in brain remodeling after traumatic brain injury (TBI) in a rat. Thirteen healthy subjects were investigated using a Q-ball based DTI data sampling scheme. FA and entropy values were measured in white matter bundles, white matter fiber crossing areas, different gray matter (GM) regions and cerebrospinal fluid (CSF). Axonal densities' from the same regions of interest (ROIs) were evaluated in Bielschowsky and Luxol fast blue stained autopsy (n = 30) brain sections by light microscopy. As a case demonstration, a Wistar rat subjected to TBI and treated with bone marrow stromal cells (MSC) 1 week after TBI was employed to illustrate the superior ability of entropy over FA in detecting reorganized crossing axonal bundles as confirmed by histological analysis with Bielschowsky and Luxol fast blue staining. Unlike FA, entropy was less affected by axonal orientation and more affected by axonal density. A significant agreement (r = 0.91) was detected between entropy values from in vivo human brain and histologically measured axonal density from post mortum from the same brain structures. The MSC treated TBI rat demonstrated that the entropy approach is superior to FA in detecting axonal remodeling after injury. Compared with FA, entropy detected new axonal remodeling regions with crossing axons, confirmed with immunohistological staining. Entropy measurement is more effective in distinguishing axonal remodeling after injury, when compared with FA. Entropy is also more sensitive to axonal density than axonal orientation, and thus may provide a more accurate reflection of axonal changes that occur in neurological injury and disease.

Characterizing Brain Structures and Remodeling after TBI Based on Information Content, Diffusion Entropy

Science.gov (United States)

Fozouni, Niloufar; Chopp, Michael; Nejad-Davarani, Siamak P.; Zhang, Zheng Gang; Lehman, Norman L.; Gu, Steven; Ueno, Yuji; Lu, Mei; Ding, Guangliang; Li, Lian; Hu, Jiani; Bagher-Ebadian, Hassan; Hearshen, David; Jiang, Quan

2013-01-01

Background To overcome the limitations of conventional diffusion tensor magnetic resonance imaging resulting from the assumption of a Gaussian diffusion model for characterizing voxels containing multiple axonal orientations, Shannon's entropy was employed to evaluate white matter structure in human brain and in brain remodeling after traumatic brain injury (TBI) in a rat. Methods Thirteen healthy subjects were investigated using a Q-ball based DTI data sampling scheme. FA and entropy values were measured in white matter bundles, white matter fiber crossing areas, different gray matter (GM) regions and cerebrospinal fluid (CSF). Axonal densities' from the same regions of interest (ROIs) were evaluated in Bielschowsky and Luxol fast blue stained autopsy (n = 30) brain sections by light microscopy. As a case demonstration, a Wistar rat subjected to TBI and treated with bone marrow stromal cells (MSC) 1 week after TBI was employed to illustrate the superior ability of entropy over FA in detecting reorganized crossing axonal bundles as confirmed by histological analysis with Bielschowsky and Luxol fast blue staining. Results Unlike FA, entropy was less affected by axonal orientation and more affected by axonal density. A significant agreement (r = 0.91) was detected between entropy values from in vivo human brain and histologically measured axonal density from post mortum from the same brain structures. The MSC treated TBI rat demonstrated that the entropy approach is superior to FA in detecting axonal remodeling after injury. Compared with FA, entropy detected new axonal remodeling regions with crossing axons, confirmed with immunohistological staining. Conclusions Entropy measurement is more effective in distinguishing axonal remodeling after injury, when compared with FA. Entropy is also more sensitive to axonal density than axonal orientation, and thus may provide a more accurate reflection of axonal changes that occur in neurological injury and disease

Investigating dynamical complexity in the magnetosphere using various entropy measures

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Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Kalimeri, Maria; Anastasiadis, Anastasios; Eftaxias, Konstantinos

2009-09-01

The complex system of the Earth's magnetosphere corresponds to an open spatially extended nonequilibrium (input-output) dynamical system. The nonextensive Tsallis entropy has been recently introduced as an appropriate information measure to investigate dynamical complexity in the magnetosphere. The method has been employed for analyzing Dst time series and gave promising results, detecting the complexity dissimilarity among different physiological and pathological magnetospheric states (i.e., prestorm activity and intense magnetic storms, respectively). This paper explores the applicability and effectiveness of a variety of computable entropy measures (e.g., block entropy, Kolmogorov entropy, T complexity, and approximate entropy) to the investigation of dynamical complexity in the magnetosphere. We show that as the magnetic storm approaches there is clear evidence of significant lower complexity in the magnetosphere. The observed higher degree of organization of the system agrees with that inferred previously, from an independent linear fractal spectral analysis based on wavelet transforms. This convergence between nonlinear and linear analyses provides a more reliable detection of the transition from the quiet time to the storm time magnetosphere, thus showing evidence that the occurrence of an intense magnetic storm is imminent. More precisely, we claim that our results suggest an important principle: significant complexity decrease and accession of persistency in Dst time series can be confirmed as the magnetic storm approaches, which can be used as diagnostic tools for the magnetospheric injury (global instability). Overall, approximate entropy and Tsallis entropy yield superior results for detecting dynamical complexity changes in the magnetosphere in comparison to the other entropy measures presented herein. Ultimately, the analysis tools developed in the course of this study for the treatment of Dst index can provide convenience for space weather

A new entropy based method for computing software structural complexity

International Nuclear Information System (INIS)

Roca, Jose L.

2002-01-01

In this paper a new methodology for the evaluation of software structural complexity is described. It is based on the entropy evaluation of the random uniform response function associated with the so called software characteristic function SCF. The behavior of the SCF with the different software structures and their relationship with the number of inherent errors is investigated. It is also investigated how the entropy concept can be used to evaluate the complexity of a software structure considering the SCF as a canonical representation of the graph associated with the control flow diagram. The functions, parameters and algorithms that allow to carry out this evaluation are also introduced. After this analytic phase follows the experimental phase, verifying the consistency of the proposed metric and their boundary conditions. The conclusion is that the degree of software structural complexity can be measured as the entropy of the random uniform response function of the SCF. That entropy is in direct relationship with the number of inherent software errors and it implies a basic hazard failure rate for it, so that a minimum structure assures a certain stability and maturity of the program. This metric can be used, either to evaluate the product or the process of software development, as development tool or for monitoring the stability and the quality of the final product. (author)

Mammography accreditation program

Energy Technology Data Exchange (ETDEWEB)

Wilcox, P.

1993-12-31

In the mid-1980`s, the movement toward the use of dedicated mammography equipment provided significant improvement in breast cancer detection. However, several studies demonstrated that this change was not sufficient to ensure optimal image quality at a low radiation dose. In particular, the 1985 Nationwide Evaluation of X-ray Trends identified the wide variations in image quality and radiation dose, even from dedicated units. During this time period, the American Cancer Society (ACS) launched its Breast Cancer Awareness Screening Campaign. However, there were concerns about the ability of radiology to respond to the increased demand for optimal screening examinations that would result from the ACS program. To respond to these concerns, the ACS and the American College of Radiology (ACR) established a joint committee on mammography screening in 1986. After much discussion, it was decided to use the ACR Diagnostic Practice Accreditation Program as a model for the development of a mammography accreditation program. However, some constraints were required in order to make the program meet the needs of the ACS. This voluntary, peer review program had to be timely and cost effective. It was determined that the best way to address these needs would be to conduct the program by mail. Finally, by placing emphasis on the educational nature of the program, it would provide an even greater opportunity for improving mammographic quality. The result of this effort was that, almost six years ago, in May 1987, the pilot study for the ACR Mammography Accreditation Program (MAP) began, and in August of that year, the first applications were received. In November 1987, the first 3-year accreditation certificates were awarded.

Mammography accreditation program

International Nuclear Information System (INIS)

Wilcox, P.

1993-01-01

In the mid-1980's, the movement toward the use of dedicated mammography equipment provided significant improvement in breast cancer detection. However, several studies demonstrated that this change was not sufficient to ensure optimal image quality at a low radiation dose. In particular, the 1985 Nationwide Evaluation of X-ray Trends identified the wide variations in image quality and radiation dose, even from dedicated units. During this time period, the American Cancer Society (ACS) launched its Breast Cancer Awareness Screening Campaign. However, there were concerns about the ability of radiology to respond to the increased demand for optimal screening examinations that would result from the ACS program. To respond to these concerns, the ACS and the American College of Radiology (ACR) established a joint committee on mammography screening in 1986. After much discussion, it was decided to use the ACR Diagnostic Practice Accreditation Program as a model for the development of a mammography accreditation program. However, some constraints were required in order to make the program meet the needs of the ACS. This voluntary, peer review program had to be timely and cost effective. It was determined that the best way to address these needs would be to conduct the program by mail. Finally, by placing emphasis on the educational nature of the program, it would provide an even greater opportunity for improving mammographic quality. The result of this effort was that, almost six years ago, in May 1987, the pilot study for the ACR Mammography Accreditation Program (MAP) began, and in August of that year, the first applications were received. In November 1987, the first 3-year accreditation certificates were awarded

Application of multi-scale (cross-) sample entropy for structural health monitoring

Science.gov (United States)

Lin, Tzu-Kang; Liang, Jui-Chang

2015-08-01

This study proposes an information-theoretic structural health monitoring (SHM) system based on multi-scale entropy (MSE) and multi-scale cross-sample entropy (MSCE). By measuring the ambient vibration signal from a structure, the damage condition can be rapidly evaluated via MSE analysis. The damage location can then be detected by analyzing the signals of different floors under the same damage condition via MSCE analysis. Moreover, a damage index is proposed to efficiently quantify the SHM process. Unlike some existing SHM methods, no experimental database or numerical model is required. Instead, a reference measurement of the current stage can initiate and launch the SHM system. A numerical simulation of a four-story steel structure is used to verify that the damage location and condition can be detected by the proposed SHM algorithm, and the location can be efficiently quantified by the damage index. A seven-story scaled-down benchmark structure is then employed for experimental verification. Based on the results, the damage condition can be correctly assessed, and average accuracy rates of 63.4 and 86.6% for the damage location can be achieved using the MSCE and damage index methods, respectively. As only the ambient vibration signal is required with a set of initial reference measurements, the proposed SHM system can be implemented practically with low cost.

Prospective study aiming to compare 2D mammography and tomosynthesis + synthesized mammography in terms of cancer detection and recall. From double reading of 2D mammography to single reading of tomosynthesis.

Science.gov (United States)

Romero Martín, Sara; Raya Povedano, Jose Luis; Cara García, María; Santos Romero, Ana Luz; Pedrosa Garriguet, Margarita; Álvarez Benito, Marina

2018-06-01

To evaluate tomosynthesis compared with 2D-mammography in cancer detection and recalls in a screening-programme, and assess performing synthesized instead of 2D, and compare double reading of 2D with single reading of tomosynthesis. Women (age 50-69 years) participating in the screening-programme were included. 2D-mammography and tomosynthesis were performed. There were four reading models: 2D-mammography (first); 2D-mammography (second); tomosynthesis + synthesized (third); tomosynthesis + synthesized + 2D (fourth reading). Paired double reading of 2D (first+second) and tomosynthesis (third+fourth) were analysed. In 16,067 participants, there were 98 cancers and 1,196 recalls. Comparing double reading of 2D with single reading of tomosynthesis, there was an increase of 12.6 % in cancer detection with the third reading (p= 0.043) and 6.9 % with the fourth reading (p=0.210), and a decrease in recalls of 40.5 % (ptomosynthesis. Single reading of tomosynthesis plus synthesized increased cancer detection and decreased recalls compared with double reading 2D. 2D did not improve results when added to tomosynthesis. • Tomosynthesis increases cancer detection and decreases recall rates versus 2D mammography. • Synthesized-mammography avoids performing 2D, showing higher cancer detection. • Single reading of tomosynthesis + synthesized is feasible as a new practice.

Contrast-enhanced spectral mammography: comparison with conventional mammography and histopathology in 152 women.

Science.gov (United States)

Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

2014-01-01

The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an "iodine" image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p mammography.

A High-Precision Time-Frequency Entropy Based on Synchrosqueezing Generalized S-Transform Applied in Reservoir Detection

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Hui Chen

2018-06-01

Full Text Available According to the fact that high frequency will be abnormally attenuated when seismic signals travel across reservoirs, a new method, which is named high-precision time-frequency entropy based on synchrosqueezing generalized S-transform, is proposed for hydrocarbon reservoir detection in this paper. First, the proposed method obtains the time-frequency spectra by synchrosqueezing generalized S-transform (SSGST, which are concentrated around the real instantaneous frequency of the signals. Then, considering the characteristics and effects of noises, we give a frequency constraint condition to calculate the entropy based on time-frequency spectra. The synthetic example verifies that the entropy will be abnormally high when seismic signals have an abnormal attenuation. Besides, comparing with the GST time-frequency entropy and the original SSGST time-frequency entropy in field data, the results of the proposed method show higher precision. Moreover, the proposed method can not only accurately detect and locate hydrocarbon reservoirs, but also effectively suppress the impact of random noises.

On the possibility of reducing doses received by patients during mammography screening

International Nuclear Information System (INIS)

Tolwinski, J.; Fabiszewska, E.; Gwiazdowska, B.; Bulski, W.

2005-01-01

The aim of the study was to collect and to evaluate a set of data of a large group of patients examined with different mammography units, and to compare the individual doses (Di) with the standard average glandular dose (standard AGD) established for a particular mammography unit. The comparison was intended to allow to formulate recommendations of procedures in order to limit the exposure of patients, procedures which are beyond the scope of routine testing of mammography facilities. The presented analysis bases on the results of the measurements of the standard AGD, taken from 82 protocols of quality control of mammography equipment; - 16 histograms of dose distribution for individual patients (Di) examined with 16 different mammography units; - 2 histograms for patients examined with one mammography unit by the radiographer before and after training; - histograms of individual doses (Di), corresponding high-voltage (kV) and tube-loading (mAs) values, for one mammography unit (Elscint-Glory 2001) which was equipped with an automatic optimisation of contrast (AOC) system. The measurements were carried out according to the procedures of the American College of Radiology (ACR). Basing upon the constructed histograms we performed a comparison of the standard AGD values with the individual doses (Di). The frequency distribution of the standard AGDs (Figure 1) shows a considerable dispersion of values, ranging between 0.5 and 2.5 mGy. The histograms of the individual glandular doses (Di) calculated for individual patients, examined with different units (Figure 2) suggest that the choice of high voltage made by the radiographers may be incorrect i.e. the high voltage was not increased sufficiently with the increase of breast thickness. The incorrect value of the high voltage (low value) may be also set up by the AOC system (Figure 4). Two histograms for patients examined with one mammography unit by the radiographer before and after training (Figure 3) indicate the

Mammography in women under 35

International Nuclear Information System (INIS)

Panzarola, P.; Bellucci, M.C.

1991-01-01

The detection of breast cancer in women under 35 is quite an uncommon event, accounting only for 3.2-3.4% of all breast cancers. To determine the indications for mammography in women under 35, the authors correlated clinical, mammographic, and US findings with fine-needle aspiration/surgical biopsy and follow-up results in 1040 symptomatic women examined at the Center of Senology of the Istitute of Radiology - University of Perugia, Italy, from 1984 to June 1990. Of 1040 women, 482 (41.6%) had normal findings; benign disease was diagnosed in 558 (53.7%) cases, and malignant disease in 49 (4.7%). Mammography was very useful to diagnose malignancy in palpable breast lesions, as well as to suggest the need for biopsy, to detect metachronous cancer and to define lesion sizes. In inflammatory process - e.g., mastitis and abscesses - both mammography and US were capable as its remission after therapy. Galactography had a specific role in the evaluation of the mammary duct and demonstrated intraductal pathologic conditions. In the authors'experiences, mammography never showed occult breast cancers in women with no palpable breast lesions or hematic nipple discharge

Quality control: comparison of images quality with screen film system and digital mammography CR

International Nuclear Information System (INIS)

Alvarenga, Frederico L.; Nogueira, Maria do Socorro

2008-01-01

The mammography screen film system should be used as part of processing chemicals, revelation process, equipment and this system has have a progressive replacing by the digital technology Full Field Digital Mammography FFDM, Computed Radiography (CR) Mammography and hardcopy. This new acquisition process of medical images has improved radiology section; however it is necessary efficient means for evaluating of the quality parameters. It should be considered taking into account the adaptation of the existent equipment and that procedures adopted for the exam, as well the adaptation of the new mammography films, the radiologist view box constitutes a part of the quality control program. This program aims at obtaining radiography with good quality that allows obtaining more information for the diagnosis and decreases the patient dose. For evaluation the quality image, this article is focused on presenting the differences regarding the acquired images through simulator mammography radiographic PMMA (Poly methyl methacrylate) in CR Mammography system and screen film system. The tests were accomplished at the same equipment of Mammography with the Automatic Exposure Control using a tension of 28 kV for both systems. The quality tests evaluated the spatial resolution, the own structures of the phantom, artifacts, optical density and contrast with conventional and laser films by mammography system. The installation for the accomplishment of the test has a quality control program. The evaluation was based on the pattern developed by the competent organ of the State of Minas Gerais. In this study, it was verified that the suitable Phantom Mama used by the Brazilian School of Radiology for conventional mammography did not obtain satisfactory result for Spatial Resolution in the digital mammography system CR. The final aim of this work is to obtain parameters to characterize the reference phantom quality image in an objective way. These parameters will be used to compare

3-T breast magnetic resonance imaging in patients with suspicious microcalcifications on mammography

Energy Technology Data Exchange (ETDEWEB)

Stehouwer, B.L.; Merckel, L.G.; Verkooijen, H.M.; Peters, N.H.G.M.; Mali, W.P.T.M.; Veldhuis, W.B.; Bosch, M.A.A.J. van den [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Mann, R.M. [University Medical Center St Radboud, Departement of Radiology, Nijmegen (Netherlands); Duvivier, K.M. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); VU University Medical Center, Department of Radiology, Amsterdam (Netherlands); Peeters, P.H.M. [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands)

2014-03-15

To investigate the diagnostic value of 3-Tesla (T) breast MRI in patients presenting with microcalcifications on mammography. Between January 2006 and May 2009, 123 patients with mammographically detected BI-RADS 3-5 microcalcifications underwent 3-T breast MRI before undergoing breast biopsy. All MRIs of the histopathologically confirmed index lesions were reviewed by two breast radiologists. The detection rate of invasive carcinoma and ductal carcinoma in situ (DCIS) was evaluated, as well as the added diagnostic value of MRI over mammography and breast ultrasound. At pathology, 40/123 (33 %) lesions proved malignant; 28 (70 %) DCIS and 12 (30 %) invasive carcinoma. Both observers detected all invasive malignancies at MRI, as well as 79 % (observer 1) and 86 % (observer 2) of in situ lesions. MRI in addition to conventional imaging led to a significant increase in area under the receiver operating characteristic (ROC) curve from 0.67 (95 % CI 0.56-0.79) to 0.79 (95 % CI 0.70-0.88, observer 1) and to 0.80 (95 % CI 0.71-0.89, observer 2), respectively. 3-T breast MRI was shown to add significant value to conventional imaging in patients presenting with suspicious microcalcifications on mammography. (orig.)

Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

OpenAIRE

Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

2014-01-01

Objective The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. Materials and Methods The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body...

Digital mammography in breast cancer screening: Evaluation and innovation

NARCIS (Netherlands)

Bluekens, A.M.J.

2015-01-01

With all other imaging modalities in radiology being digitised and conventional mammography being ready to phase out the transition to digital mammography was inevitable. This thesis describes the performance of digital screening mammography and the consequences of implementation in a

CONTRAST ENHANCED SPECTRAL MAMMOGRAPHY (CESM (REVIEW

Directory of Open Access Journals (Sweden)

N. I. Rozhkova

2015-01-01

Full Text Available The problem of early diagnosis of a breast cancer is extremely actual. Growth of incidence at women from 19 to 39 years increased for 34% over the last 10 years. It defines need of acceleration of development and deployment of the latest technologies of identification of the earliest symptoms of diseases. The x-ray mammography is the conducting method among of all radiological methods of diagnostics. Nevertheless a number of restrictions of method reduces its efficiency. The technologies increasing informational content of x-ray mammography – the leading method of screening – due to use of artificial contrasting and advantages of digital technologies are constantly developed. In this review it is described works, in which the authors having clinical experience of application of CESM – contrastenhanced spectral mammography on representative group of women. Positive sides and restrictions of new technology in comparison with mammography, ultrasonography and MRT are shown in this article.

Heavy-ion mammography and breast cancer

International Nuclear Information System (INIS)

Fabrikant, J.I.; Tobias, C.A.; Capp, M.P.; Holley, W.R.; Woodruff, K.H.; Sickles, E.A.

1980-01-01

Heavy-ion radiography is a new diagnostic imaging technique developed in our laboratory that produces superior density resolution at low radiation doses. Heavy-ion mammography has now emerged as a low-dose, safe, reliable, noninvasive diagnostic radiological procedure that can quantitate and image very small differences in soft tissue densities in the breast tissues of patients with clinical breast disease. The improved density resolution of heavy-ion mammography over conventional X-ray mammography and breast xerography provides the potential of detecting small breast cancers of less than 1 cm diameter. The radiation dose to the breast from carbon-ion mammorgraphy is about 50 mrad or less, and can potentially be only a fraction of this level. The results of the present clinical trial in progress of heavy-ion mammography in 37 patients, thus far studied, are extremely encouraging, and warrant continued study for application to the early diagnosis of breast cancer in women

Entropy in molecular recognition by proteins.

Science.gov (United States)

Caro, José A; Harpole, Kyle W; Kasinath, Vignesh; Lim, Jackwee; Granja, Jeffrey; Valentine, Kathleen G; Sharp, Kim A; Wand, A Joshua

2017-06-20

Molecular recognition by proteins is fundamental to molecular biology. Dissection of the thermodynamic energy terms governing protein-ligand interactions has proven difficult, with determination of entropic contributions being particularly elusive. NMR relaxation measurements have suggested that changes in protein conformational entropy can be quantitatively obtained through a dynamical proxy, but the generality of this relationship has not been shown. Twenty-eight protein-ligand complexes are used to show a quantitative relationship between measures of fast side-chain motion and the underlying conformational entropy. We find that the contribution of conformational entropy can range from favorable to unfavorable, which demonstrates the potential of this thermodynamic variable to modulate protein-ligand interactions. For about one-quarter of these complexes, the absence of conformational entropy would render the resulting affinity biologically meaningless. The dynamical proxy for conformational entropy or "entropy meter" also allows for refinement of the contributions of solvent entropy and the loss in rotational-translational entropy accompanying formation of high-affinity complexes. Furthermore, structure-based application of the approach can also provide insight into long-lived specific water-protein interactions that escape the generic treatments of solvent entropy based simply on changes in accessible surface area. These results provide a comprehensive and unified view of the general role of entropy in high-affinity molecular recognition by proteins.

Distance-Based Configurational Entropy of Proteins from Molecular Dynamics Simulations.

Science.gov (United States)

Fogolari, Federico; Corazza, Alessandra; Fortuna, Sara; Soler, Miguel Angel; VanSchouwen, Bryan; Brancolini, Giorgia; Corni, Stefano; Melacini, Giuseppe; Esposito, Gennaro

2015-01-01

Estimation of configurational entropy from molecular dynamics trajectories is a difficult task which is often performed using quasi-harmonic or histogram analysis. An entirely different approach, proposed recently, estimates local density distribution around each conformational sample by measuring the distance from its nearest neighbors. In this work we show this theoretically well grounded the method can be easily applied to estimate the entropy from conformational sampling. We consider a set of systems that are representative of important biomolecular processes. In particular: reference entropies for amino acids in unfolded proteins are obtained from a database of residues not participating in secondary structure elements;the conformational entropy of folding of β2-microglobulin is computed from molecular dynamics simulations using reference entropies for the unfolded state;backbone conformational entropy is computed from molecular dynamics simulations of four different states of the EPAC protein and compared with order parameters (often used as a measure of entropy);the conformational and rototranslational entropy of binding is computed from simulations of 20 tripeptides bound to the peptide binding protein OppA and of β2-microglobulin bound to a citrate coated gold surface. This work shows the potential of the method in the most representative biological processes involving proteins, and provides a valuable alternative, principally in the shown cases, where other approaches are problematic.

Ranking DMUs by Comparing DEA Cross-Efficiency Intervals Using Entropy Measures

Directory of Open Access Journals (Sweden)

Tim Lu

2016-12-01

Full Text Available Cross-efficiency evaluation, an extension of data envelopment analysis (DEA, can eliminate unrealistic weighing schemes and provide a ranking for decision making units (DMUs. In the literature, the determination of input and output weights uniquely receives more attentions. However, the problem of choosing the aggressive (minimal or benevolent (maximal formulation for decision-making might still remain. In this paper, we develop a procedure to perform cross-efficiency evaluation without the need to make any specific choice of DEA weights. The proposed procedure takes into account the aggressive and benevolent formulations at the same time, and the choice of DEA weights can then be avoided. Consequently, a number of cross-efficiency intervals is obtained for each DMU. The entropy, which is based on information theory, is an effective tool to measure the uncertainty. We then utilize the entropy to construct a numerical index for DMUs with cross-efficiency intervals. A mathematical program is proposed to find the optimal entropy values of DMUs for comparison. With the derived entropy value, we can rank DMUs accordingly. Two examples are illustrated to show the effectiveness of the idea proposed in this paper.

A Dynamic and Adaptive Selection Radar Tracking Method Based on Information Entropy

Directory of Open Access Journals (Sweden)

Ge Jianjun

2017-12-01

Full Text Available Nowadays, the battlefield environment has become much more complex and variable. This paper presents a quantitative method and lower bound for the amount of target information acquired from multiple radar observations to adaptively and dynamically organize the detection of battlefield resources based on the principle of information entropy. Furthermore, for minimizing the given information entropy’s lower bound for target measurement at every moment, a method to dynamically and adaptively select radars with a high amount of information for target tracking is proposed. The simulation results indicate that the proposed method has higher tracking accuracy than that of tracking without adaptive radar selection based on entropy.

Statistical Texture Model for mass Detection in Mammography

Directory of Open Access Journals (Sweden)

Nicolás Gallego-Ortiz

2013-12-01

Full Text Available In the context of image processing algorithms for mass detection in mammography, texture is a key feature to be used to distinguish abnormal tissue from normal tissue. Recently, a texture model based on a multivariate Gaussian mixture was proposed, of which the parameters are learned in an unsupervised way from the pixel intensities of images. The model produces images that are probabilistic maps of texture normality and it was proposed as a visualization aid for diagnostic by clinical experts. In this paper, the usability of the model is studied for automatic mass detection. A segmentation strategy is proposed and evaluated using 79 mammography cases.

Analysis of financial time series using multiscale entropy based on skewness and kurtosis

Science.gov (United States)

Xu, Meng; Shang, Pengjian

2018-01-01

There is a great interest in studying dynamic characteristics of the financial time series of the daily stock closing price in different regions. Multi-scale entropy (MSE) is effective, mainly in quantifying the complexity of time series on different time scales. This paper applies a new method for financial stability from the perspective of MSE based on skewness and kurtosis. To better understand the superior coarse-graining method for the different kinds of stock indexes, we take into account the developmental characteristics of the three continents of Asia, North America and European stock markets. We study the volatility of different financial time series in addition to analyze the similarities and differences of coarsening time series from the perspective of skewness and kurtosis. A kind of corresponding relationship between the entropy value of stock sequences and the degree of stability of financial markets, were observed. The three stocks which have particular characteristics in the eight piece of stock sequences were discussed, finding the fact that it matches the result of applying the MSE method to showing results on a graph. A comparative study is conducted to simulate over synthetic and real world data. Results show that the modified method is more effective to the change of dynamics and has more valuable information. The result is obtained at the same time, finding the results of skewness and kurtosis discrimination is obvious, but also more stable.

Fault Detection and Diagnosis for Gas Turbines Based on a Kernelized Information Entropy Model

Directory of Open Access Journals (Sweden)

Weiying Wang

2014-01-01

Full Text Available Gas turbines are considered as one kind of the most important devices in power engineering and have been widely used in power generation, airplanes, and naval ships and also in oil drilling platforms. However, they are monitored without man on duty in the most cases. It is highly desirable to develop techniques and systems to remotely monitor their conditions and analyze their faults. In this work, we introduce a remote system for online condition monitoring and fault diagnosis of gas turbine on offshore oil well drilling platforms based on a kernelized information entropy model. Shannon information entropy is generalized for measuring the uniformity of exhaust temperatures, which reflect the overall states of the gas paths of gas turbine. In addition, we also extend the entropy to compute the information quantity of features in kernel spaces, which help to select the informative features for a certain recognition task. Finally, we introduce the information entropy based decision tree algorithm to extract rules from fault samples. The experiments on some real-world data show the effectiveness of the proposed algorithms.

Fault detection and diagnosis for gas turbines based on a kernelized information entropy model.

Science.gov (United States)

Wang, Weiying; Xu, Zhiqiang; Tang, Rui; Li, Shuying; Wu, Wei

2014-01-01

Gas turbines are considered as one kind of the most important devices in power engineering and have been widely used in power generation, airplanes, and naval ships and also in oil drilling platforms. However, they are monitored without man on duty in the most cases. It is highly desirable to develop techniques and systems to remotely monitor their conditions and analyze their faults. In this work, we introduce a remote system for online condition monitoring and fault diagnosis of gas turbine on offshore oil well drilling platforms based on a kernelized information entropy model. Shannon information entropy is generalized for measuring the uniformity of exhaust temperatures, which reflect the overall states of the gas paths of gas turbine. In addition, we also extend the entropy to compute the information quantity of features in kernel spaces, which help to select the informative features for a certain recognition task. Finally, we introduce the information entropy based decision tree algorithm to extract rules from fault samples. The experiments on some real-world data show the effectiveness of the proposed algorithms.

Pain and discomfort during mammography

DEFF Research Database (Denmark)

Aro, A R; Absetz-Ylöstalo, P; Eerola, T

1996-01-01

was the most powerful factor explaining pain and discomfort among women with earlier mammography. However, it had no effect among women without earlier mammography, for whom screening-related nervousness and perceptions of staff were crucial. Suggested interventions include better information before screening......The aim of this prospective study was to investigate associations of mammography pain and discomfort with sociodemographics, personal history and psychological and situational factors. Subjects were women with a negative screening finding (n = 883) from a random sample of 50-year-old Finnish women...... attending their first breast cancer screening. Questionnaires were sent 1 month before the screening invitation and 2 months after screening. Sixty-one per cent reported painful and 59% uncomfortable mammograms (4% severely). Linear regression analyses showed that anticipation of pain and discomfort...

Mammography quality assurance in Morocco

International Nuclear Information System (INIS)

Zaoui, F.; Talsmat, K.; Lalaoui, K.

2001-01-01

The 'Centre National de l'Energie, des Sciences et des Techniques Nucleaires' (CNESTEN) realised, from February 1999 to March 2000, a quality control of 41 mammography facilities in Morocco. The protocol and standards adopted for achieving the control of elements constituting the mammography chain are those elaborated by GIM and Qualix association. Statistics and conformities results are presented. The program was performed in order to demonstrate to the practitioners in mammography field, the utility and necessity to have a national quality assurance policy. The main objective of CNESTEN is to be accredited by the Moroccan government as a reference laboratory in quality control and dose evaluation in medical imaging and radiotherapy. To achieve this goal the CNESTEN has set up Medical Physic Unit well trained and equipped with the necessary instruments. (author)

Breast cancer screening using tomosynthesis in combination with digital mammography.

Science.gov (United States)

Friedewald, Sarah M; Rafferty, Elizabeth A; Rose, Stephen L; Durand, Melissa A; Plecha, Donna M; Greenberg, Julianne S; Hayes, Mary K; Copit, Debra S; Carlson, Kara L; Cink, Thomas M; Barke, Lora D; Greer, Linda N; Miller, Dave P; Conant, Emily F

2014-06-25

Mammography plays a key role in early breast cancer detection. Single-institution studies have shown that adding tomosynthesis to mammography increases cancer detection and reduces false-positive results. To determine if mammography combined with tomosynthesis is associated with better performance of breast screening programs in the United States. Retrospective analysis of screening performance metrics from 13 academic and nonacademic breast centers using mixed models adjusting for site as a random effect. Period 1: digital mammography screening examinations 1 year before tomosynthesis implementation (start dates ranged from March 2010 to October 2011 through the date of tomosynthesis implementation); period 2: digital mammography plus tomosynthesis examinations from initiation of tomosynthesis screening (March 2011 to October 2012) through December 31, 2012. Recall rate for additional imaging, cancer detection rate, and positive predictive values for recall and for biopsy. A total of 454,850 examinations (n=281,187 digital mammography; n=173,663 digital mammography + tomosynthesis) were evaluated. With digital mammography, 29,726 patients were recalled and 5056 biopsies resulted in cancer diagnosis in 1207 patients (n=815 invasive; n=392 in situ). With digital mammography + tomosynthesis, 15,541 patients were recalled and 3285 biopsies resulted in cancer diagnosis in 950 patients (n=707 invasive; n=243 in situ). Model-adjusted rates per 1000 screens were as follows: for recall rate, 107 (95% CI, 89-124) with digital mammography vs 91 (95% CI, 73-108) with digital mammography + tomosynthesis; difference, -16 (95% CI, -18 to -14; P tomosynthesis; difference, 1.3 (95% CI, 0.4-2.1; P = .004); for cancer detection, 4.2 (95% CI, 3.8-4.7) with digital mammography vs 5.4 (95% CI, 4.9-6.0) with digital mammography + tomosynthesis; difference, 1.2 (95% CI, 0.8-1.6; P tomosynthesis; difference, 1.2 (95% CI, 0.8-1.6; P tomosynthesis was associated with an increase

An entropy-based improved k-top scoring pairs (TSP) method for ...

African Journals Online (AJOL)

An entropy-based improved k-top scoring pairs (TSP) (Ik-TSP) method was presented in this study for the classification and prediction of human cancers based on gene-expression data. We compared Ik-TSP classifiers with 5 different machine learning methods and the k-TSP method based on 3 different feature selection ...

Entrance surface dose measurements in mammography using thermoluminescence technique

International Nuclear Information System (INIS)

Rivera, T.; Vega C, H.R.; Manzanares A, E; Azorin, J.; Gonzalez, P.R.

2007-01-01

Full text: Of the various techniques that can be used for personnel dosimetry, thermoluminescence dosimetry (TLD) has emerged as a superior technique due to its manifold advantages over other methods of dose estimation. Various phosphors have been therefore investigated regarding their suitability for dosimetry. In this paper, a dosimetry system based on thermally stimulated luminescence (TSL) from zirconium oxide phosphors embedded in polytetrafluorethylene (ZrO 2 +PTFE) was developed for entrance surface doses (ES) measurements in mammography. Small ZrO 2 pellets of 5 mm in diameter and 0.8 mm in thickness were used. The reproducibility of measurements and linearity of ZrO 2 were also studied. The results were compared with those obtained from LiF:Mg,Cu,P usually used for the determination of absorbed dose in mammography. Measurements both per unit air kerma and In vivo were performed using a mammography unit model DMR (General Electric). The results showed that ZrO 2 TLDs can be used for the same X-ray dosimetry applications as LiF:Mg,Cu,P, with each type having the disadvantage of a response dependent on energy, particularly at low energies. These results indicate a considerable potential for use in routine control and In vivo ES measurements in mammography. (Author)

Influence of breast compression pressure on the performance of population-based mammography screening.

Science.gov (United States)

Holland, Katharina; Sechopoulos, Ioannis; Mann, Ritse M; den Heeten, Gerard J; van Gils, Carla H; Karssemeijer, Nico

2017-11-28

In mammography, breast compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast compression is needed to ensure acceptable image quality, guidelines remain vague about how much compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of compression is not available. Consequently, little is known about the relationship between the amount of breast compression and breast cancer detectability. The purpose of this study is to determine the effect of breast compression pressure in mammography on breast cancer screening outcomes. We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the compression force by the area of the contact surface between breast and compression paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p = 0.034). Specificity was lower in the

Studies on the calibration of mammography automatic exposure mode with computed radiology

International Nuclear Information System (INIS)

Zhu Hongzhou; Shao Guoliang; Shi Lei; Liu Qing

2010-01-01

Objective: To realize the optimization of image quality and radiation dose by correcting mammography automatic exposure, according to automatic exposure controlled mode of mammography film-screen system. Methods: The film-screen system (28 kV) was applied to perform automatic exposure of plexiglass (40 mm) and get the standard dose of exposure, the exposure mode of CR base on LgM=2.0 was rectified, which was divided into 10 steps. Mammary glands pattern (Fluke NA18-220) were examined with CR (26, 28, and 30 kV) by the automatic exposure mode corrected. The exposure values (mAs) were recorded. CR image was diagnosed and evaluated in double blind way by 4 radiologists according to American Collage of Radiology (ACR) standard. Results: Based on the standard of CR automatic exposure with the dose higher than the traditional exposure of film-screen system, the calibration of mammography automatic exposure was accomplished. The test results of the calibrated mode was better than the scoring system of ACR. Conclusions: Comparative study showed improvement in acquiring high-quality image and reduction of radiation dose. The corrected mammography automatic exposure mode might be a better method for clinical use. (authors)

TL dosimetry for quality control of CR mammography imaging systems

Science.gov (United States)

Gaona, E.; Nieto, J. A.; Góngora, J. A. I. D.; Arreola, M.; Enríquez, J. G. F.

The aim of this work is to estimate the average glandular dose with thermoluminescent (TL) dosimetry and comparison with quality imaging in computed radiography (CR) mammography. For a measuring dose, the Food and Drug Administration (FDA) and the American College of Radiology (ACR) use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, full field digital mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium flourohalideE We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated X-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose greater than 3.0 mGy without demonstrating improved image quality. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement for X-rays with a HVL (0.35-0.38 mmAl) and kVp (24-26) used in quality control procedures with ACR Mammography Accreditation Phantom.

Evaluation of the minimum iodine concentration for contrast-enhanced subtraction mammography

International Nuclear Information System (INIS)

Baldelli, P; Bravin, A; Maggio, C Di; Gennaro, G; Sarnelli, A; Taibi, A; Gambaccini, M

2006-01-01

Early manifestation of breast cancer is often very subtle and is displayed in a complex and variable pattern of normal anatomy that may obscure the disease. The use of dual-energy techniques, that can remove the structural noise, and contrast media, that enhance the region surrounding the tumour, could help us to improve the detectability of the lesions. The aim of this work is to investigate the use of an iodine-based contrast medium in mammography with two different double exposure techniques: K-edge subtraction mammography and temporal subtraction mammography. Both techniques have been investigated by using an ideal source, like monochromatic beams produced at a synchrotron radiation facility and a clinical digital mammography system. A dedicated three-component phantom containing cavities filled with different iodine concentrations has been developed and used for measurements. For each technique, information about the minimum iodine concentration, which provides a significant enhancement of the detectability of the pathology by minimizing the risk due to high dose and high concentration of contrast medium, has been obtained. In particular, for cavities of 5 and 8 mm in diameter filled with iodine solutions, the minimum concentration needed to obtain a contrast-to-noise ratio of 5 with a mean glandular dose of 2 mGy has been calculated. The minimum concentrations estimated with monochromatic beams and K-edge subtraction mammography are 0.9 mg ml -1 and 1.34 mg ml -1 for the biggest and smallest details, respectively, while for temporal subtraction mammography they are 0.84 mg ml -1 and 1.31 mg ml -1 . With the conventional clinical system the minimum concentrations for the K-edge subtraction mammography are 4.13 mg ml -1 (8 mm diameter) and 5.75 mg ml -1 (5 mm diameter), while for the temporal subtraction mammography they are 1.01 mg ml -1 (8 mm diameter) and 1.57 mg ml -1 (5 mm diameter)

Radiogenic breast cancer risk and mammography

International Nuclear Information System (INIS)

Jayaprakash, Shobha; Nair, C.P.R.; Rao, B.S.; Sawant, S.G.

2001-01-01

There is a general concern that the risks from mammography screening in inducting radiogenic breast cancer may outweigh the possible benefits to be derived from it. A review of epidemiological, case-control and cohort studies of radiogenic breast cancer, age-specific incidence and dose and dose-rate relationship reveals that such a fear is unfounded. The dose to the breast tissues in a quality assured mammography screening programme falls far below the levels that were observed to produce increased relative risk. The age-specific incidence rates also indicate that the need for mammography is for the women of age at which the relative risk is minimum

Digital mammography in a screening programme and its implications for pathology: a comparative study.

LENUS (Irish Health Repository)

Feeley, Linda

2011-03-01

Most studies comparing full-field digital mammography (FFDM) with conventional screen-film mammography (SFM) have been radiology-based. The pathological implications of FFDM have received little attention in the literature, especially in the context of screening programmes. The primary objective of this retrospective study is to compare FFDM with SFM in a population-based screening programme with regard to a number of pathological parameters.

Feedback structure based entropy approach for multiple-model estimation

Institute of Scientific and Technical Information of China (English)

Shen-tu Han; Xue Anke; Guo Yunfei

2013-01-01

The variable-structure multiple-model (VSMM) approach, one of the multiple-model (MM) methods, is a popular and effective approach in handling problems with mode uncertainties. The model sequence set adaptation (MSA) is the key to design a better VSMM. However, MSA methods in the literature have big room to improve both theoretically and practically. To this end, we propose a feedback structure based entropy approach that could find the model sequence sets with the smallest size under certain conditions. The filtered data are fed back in real time and can be used by the minimum entropy (ME) based VSMM algorithms, i.e., MEVSMM. Firstly, the full Markov chains are used to achieve optimal solutions. Secondly, the myopic method together with particle filter (PF) and the challenge match algorithm are also used to achieve sub-optimal solutions, a trade-off between practicability and optimality. The numerical results show that the proposed algorithm provides not only refined model sets but also a good robustness margin and very high accuracy.

Entropy-based derivation of generalized distributions for hydrometeorological frequency analysis

Science.gov (United States)

Chen, Lu; Singh, Vijay P.

2018-02-01

Frequency analysis of hydrometeorological and hydrological extremes is needed for the design of hydraulic and civil infrastructure facilities as well as water resources management. A multitude of distributions have been employed for frequency analysis of these extremes. However, no single distribution has been accepted as a global standard. Employing the entropy theory, this study derived five generalized distributions for frequency analysis that used different kinds of information encoded as constraints. These distributions were the generalized gamma (GG), the generalized beta distribution of the second kind (GB2), and the Halphen type A distribution (Hal-A), Halphen type B distribution (Hal-B) and Halphen type inverse B distribution (Hal-IB), among which the GG and GB2 distribution were previously derived by Papalexiou and Koutsoyiannis (2012) and the Halphen family was first derived using entropy theory in this paper. The entropy theory allowed to estimate parameters of the distributions in terms of the constraints used for their derivation. The distributions were tested using extreme daily and hourly rainfall data. Results show that the root mean square error (RMSE) values were very small, which indicated that the five generalized distributions fitted the extreme rainfall data well. Among them, according to the Akaike information criterion (AIC) values, generally the GB2 and Halphen family gave a better fit. Therefore, those general distributions are one of the best choices for frequency analysis. The entropy-based derivation led to a new way for frequency analysis of hydrometeorological extremes.

A Case-Control Study to Estimate the Impact of the Icelandic Population-Based Mammography Screening Program on Breast Cancer Death

Energy Technology Data Exchange (ETDEWEB)

Gabe, R.; Tryggvadottir, L.; Sigfusson, B.F.; Olafsdottir, G.H.; Sigurarsson , K. [Icelandic Cancer Society (Krabbameinsfelag Islands), Reykjavik (Iceland); Duffy, S.W. [Cancer Research UK, Centre for Epidemiology, Mathematics and Stati stics, Wolfson Inst. of Preventive Medicine, London (United Kingdom)

2007-11-15

Background: The Icelandic breast cancer screening program, initiated November 1987 in Reykjavik and covering the whole country from December 1989, comprises biennial invitation to mammography for women aged 40-69 years old. Purpose: To estimate the impact of mammography service screening in Iceland on deaths from breast cancer. Material and Methods: Cases were deaths from breast cancer from 1990 onwards in women aged 40 and over at diagnosis, during the period November 1987 to December 31, 2002. Age- and screening-area-matched, population-based controls were women who had also been invited to screening but were alive at the time their case died. Results: Using conditional logistic regression on the data from 226 cases and 902 controls, the odds ratio for the risk of death from breast cancer in those attending at least one screen compared to those never screened was 0.59 (95% CI 0.41-0.84). After adjustment for healthy-volunteer bias and screening-opportunity bias, the odds ratio was 0.65 (95% CI 0.39-1.09). Conclusion: These results indicate a 35-40% reduction in breast cancer deaths by attending the Icelandic breast cancer screening program. These results are consistent with the overall evidence from other observational evaluations of mammography-based programs.

A Case-Control Study to Estimate the Impact of the Icelandic Population-Based Mammography Screening Program on Breast Cancer Death

International Nuclear Information System (INIS)

Gabe, R.; Tryggvadottir, L.; Sigfusson, B.F.; Olafsdottir, G.H.; Sigurarsson, K.; Duffy, S.W.

2007-01-01

Background: The Icelandic breast cancer screening program, initiated November 1987 in Reykjavik and covering the whole country from December 1989, comprises biennial invitation to mammography for women aged 40-69 years old. Purpose: To estimate the impact of mammography service screening in Iceland on deaths from breast cancer. Material and Methods: Cases were deaths from breast cancer from 1990 onwards in women aged 40 and over at diagnosis, during the period November 1987 to December 31, 2002. Age- and screening-area-matched, population-based controls were women who had also been invited to screening but were alive at the time their case died. Results: Using conditional logistic regression on the data from 226 cases and 902 controls, the odds ratio for the risk of death from breast cancer in those attending at least one screen compared to those never screened was 0.59 (95% CI 0.41-0.84). After adjustment for healthy-volunteer bias and screening-opportunity bias, the odds ratio was 0.65 (95% CI 0.39-1.09). Conclusion: These results indicate a 35-40% reduction in breast cancer deaths by attending the Icelandic breast cancer screening program. These results are consistent with the overall evidence from other observational evaluations of mammography-based programs

Entropy and Economics

Directory of Open Access Journals (Sweden)

John Scales Avery

2012-04-01

Full Text Available In this essay, human society is regarded as a “superorganism”, analogous to colonies of social insects. The digestive system of the human superorganism is the global economy, which ingests both free energy and resources, and later excretes them in a degraded form. This process involves an increase in entropy. Early in the 20th century, both Frederick Soddy and Nicholas Georgescu-Roegen discussed the relationship between entropy and economics. Soddy called for an index system to regulate the money supply and a reform of the fractional reserve banking system, while Georgescu-Roegen pointed to the need for Ecological Economics, a steady-state economy, and population stabilization. As we reach the end of the fossil fuel era and as industrial growth falters, massive unemployment can only be avoided by responsible governmental action. The necessary steps include shifting labor to projects needed for a sustainable economy, dividing the available work fairly among those seeking employment, and reforming the practices of the financial sector.

A study of some technical essentials of X-ray mammography

International Nuclear Information System (INIS)

Cao Houde; Jiang Qin

2000-01-01

Objective: To improve the quality of mammography and diagnostic accuracy by analyzing and studying some of the technical essentials of X-ray mammography. Methods: The mammography quality of 21 hospitals were investigated. The image quality of normal intensifying screen-film combination was tested and compared with computerized mammography. The filming positions and operating skills were studied. Results: The important mammography details that were displayed have low conformity with the diagnostic requirements, mainly due to non-conformity of these equipment to the requirements. The optimal pressure suitable for mammography of the Chinese women was around 12 kg. Conclusion: Necessary attention must be paid to the improvement of imaging features of these equipment. The improved operating skills will greatly raise the detecting percentage of pathological changes of breasts

Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

Energy Technology Data Exchange (ETDEWEB)

Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia [Department of Radiology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Blecharz, Pawel [Department of Gynecologic Oncology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Rys, Janusz [Department of Tumour Pathology, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland); Reinfuss, Marian [Department of Radiotherapy, Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow 31-115 (Poland)

2014-07-01

The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an 'iodine' image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p < 0.001). CESM may provide higher sensitivity for breast cancer detection and greater diagnostic accuracy than conventional mammography.

Contrast-Enhanced Spectral Mammography: Comparison with Conventional Mammography and Histopathology in 152 Women

International Nuclear Information System (INIS)

Luczyńska, Elzbieta; Heinze-Paluchowska, Sylwia; Dyczek, Sonia; Blecharz, Pawel; Rys, Janusz; Reinfuss, Marian

2014-01-01

The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women. The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an 'iodine' image which outlined contrast up-take in the breast. MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p < 0.001). CESM may provide higher sensitivity for breast cancer detection and greater diagnostic accuracy than conventional mammography

Anomalies of the entanglement entropy in chiral theories

Energy Technology Data Exchange (ETDEWEB)

Iqbal, Nabil [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, 1090 GL Amsterdam (Netherlands); Wall, Aron C. [School of Natural Sciences, Institute for Advanced Study,Princeton, New Jersey 08540 (United States)

2016-10-20

We study entanglement entropy in theories with gravitational or mixed U(1) gauge-gravitational anomalies in two, four and six dimensions. In such theories there is an anomaly in the entanglement entropy: it depends on the choice of reference frame in which the theory is regulated. We discuss subtleties regarding regulators and entanglement entropies in anomalous theories. We then study the entanglement entropy of free chiral fermions and self-dual bosons and show that in sufficiently symmetric situations this entanglement anomaly comes from an imbalance in the flux of modes flowing through the boundary, controlled by familiar index theorems. In two and four dimensions we use anomalous Ward identities to find general expressions for the transformation of the entanglement entropy under a diffeomorphism. (In the case of a mixed anomaly there is an alternative presentation of the theory in which the entanglement entropy is not invariant under a U(1) gauge transformation. The free-field manifestation of this phenomenon involves a novel kind of fermion zero mode on a gravitational background with a twist in the normal bundle to the entangling surface.) We also study d-dimensional anomalous systems as the boundaries of d+1 dimensional gapped Hall phases. Here the full system is non-anomalous, but the boundary anomaly manifests itself in a change in the entanglement entropy when the boundary metric is sheared relative to the bulk.

Newly Diagnosed Breast Cancer: Comparison of Contrast-enhanced Spectral Mammography and Breast MR Imaging in the Evaluation of Extent of Disease.

Science.gov (United States)

Lee-Felker, Stephanie A; Tekchandani, Leena; Thomas, Mariam; Gupta, Esha; Andrews-Tang, Denise; Roth, Antoinette; Sayre, James; Rahbar, Guita

2017-11-01

Purpose To compare the diagnostic performances of contrast material-enhanced spectral mammography and breast magnetic resonance (MR) imaging in the detection of index and secondary cancers in women with newly diagnosed breast cancer by using histologic or imaging follow-up as the standard of reference. Materials and Methods This institutional review board-approved, HIPAA-compliant, retrospective study included 52 women who underwent breast MR imaging and contrast-enhanced spectral mammography for newly diagnosed unilateral breast cancer between March 2014 and October 2015. Of those 52 patients, 46 were referred for contrast-enhanced spectral mammography and targeted ultrasonography because they had additional suspicious lesions at MR imaging. In six of the 52 patients, breast cancer had been diagnosed at an outside institution. These patients were referred for contrast-enhanced spectral mammography and targeted US as part of diagnostic imaging. Images from contrast-enhanced spectral mammography were analyzed by two fellowship-trained breast imagers with 2.5 years of experience with contrast-enhanced spectral mammography. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated for both imaging modalities and compared by using the Bennett statistic. Results Fifty-two women with 120 breast lesions were included for analysis (mean age, 50 years; range, 29-73 years). Contrast-enhanced spectral mammography had similar sensitivity to MR imaging (94% [66 of 70 lesions] vs 99% [69 of 70 lesions]), a significantly higher PPV than MR imaging (93% [66 of 71 lesions] vs 60% [69 of 115 lesions]), and fewer false-positive findings than MR imaging (five vs 45) (P contrast-enhanced spectral mammography depicted 11 of the 11 secondary cancers (100%) and MR imaging depicted 10 (91%). Conclusion Contrast-enhanced spectral mammography is potentially as sensitive as MR imaging in the evaluation of extent of disease in newly diagnosed

ACR BI-RADS Assessment Category 4 Subdivisions in Diagnostic Mammography: Utilization and Outcomes in the National Mammography Database.

Science.gov (United States)

Elezaby, Mai; Li, Geng; Bhargavan-Chatfield, Mythreyi; Burnside, Elizabeth S; DeMartini, Wendy B

2018-05-01

Purpose To determine the utilization and positive predictive value (PPV) of the American College of Radiology (ACR) Breast Imaging Data and Reporting System (BI-RADS) category 4 subdivisions in diagnostic mammography in the National Mammography Database (NMD). Materials and Methods This study involved retrospective review of diagnostic mammography data submitted to the NMD from January 1, 2008 to December 30, 2014. Utilization rates of BI-RADS category 4 subdivisions were compared by year, facility (type, location, census region), and examination (indication, finding type) characteristics. PPV3 (positive predictive value for biopsies performed) was calculated overall and according to category 4 subdivision. The χ 2 test was used to test for significant associations. Results Of 1 309 950 diagnostic mammograms, 125 447 (9.6%) were category 4, of which 33.3% (41 841 of 125 447) were subdivided. Subdivision utilization rates were higher (P use, subdivisions were utilized in the minority (33.3% [41 841 of 125 447]) of category 4 diagnostic mammograms, with variability based on facility and examination characteristics. When subdivisions were used, PPV3s were in BI-RADS-specified malignancy ranges. This analysis supports the use of subdivisions in broad practice and, given benefits for patient care, should motivate increased utilization. © RSNA, 2018 Online supplemental material is available for this article.

Prediction of Protein Configurational Entropy (Popcoen).

Science.gov (United States)

Goethe, Martin; Gleixner, Jan; Fita, Ignacio; Rubi, J Miguel

2018-03-13

A knowledge-based method for configurational entropy prediction of proteins is presented; this methodology is extremely fast, compared to previous approaches, because it does not involve any type of configurational sampling. Instead, the configurational entropy of a query fold is estimated by evaluating an artificial neural network, which was trained on molecular-dynamics simulations of ∼1000 proteins. The predicted entropy can be incorporated into a large class of protein software based on cost-function minimization/evaluation, in which configurational entropy is currently neglected for performance reasons. Software of this type is used for all major protein tasks such as structure predictions, proteins design, NMR and X-ray refinement, docking, and mutation effect predictions. Integrating the predicted entropy can yield a significant accuracy increase as we show exemplarily for native-state identification with the prominent protein software FoldX. The method has been termed Popcoen for Prediction of Protein Configurational Entropy. An implementation is freely available at http://fmc.ub.edu/popcoen/ .

Quality control in digital mammography: the noise components

Energy Technology Data Exchange (ETDEWEB)

Leyton, Fernando [Universidade de Tarapaca, Arica (Chile). Centro de Estudios en Ciencias Radiologicas; Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nogueira, Maria do Socorro, E-mail: mnogue@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Duran, Maria Paz [Clinica Alemana, Santiago (Chile). Dept. de Radiologia; Dantas, Marcelino, E-mail: marcelino@inb.gov.b [Industrias Nucleares do Brasil (INB), Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Ubeda, Carlos, E-mail: cubeda@uta.c [Universidade de Tarapaca, Arica (Chile). Fac. de Ciencias de la Salud

2011-07-01

To measure the linearity of the detector and determine the noise components (quantum, electronic and structural noise) that contributed to losing image quality and to determine the signal noise ratio (SNR) and contrast noise ratio (CNR). This paper describes the results of the implementation of a protocol for quality control in digital mammography performed in two direct digital mammography equipment (Hologic, Selenia) in Santiago of Chile. Shows the results of linearity and noise analysis of the images which establishes the main cause of noise in the image of the mammogram to ensure the quality and optimize procedures. The study evaluated two digital mammography's Selenia, Hologic (DR) from Santiago, Chile. We conducted the assessment of linearity of the detector, the signal noise ratio, contrast noise ratio and was determined the contribution of different noise components (quantum, electronics and structural noise). Used different thicknesses used in clinical practice according to the protocol for quality control in digital mammography of Spanish society of medical physics and NHSBSP Equipment Report 0604 Version 3. The Selenia mammography software was used for the analysis of images and Unfors Xi detector for measuring doses. The mammography detector has a linear performance, the CNR and SNR did not comply with the Protocol for the thicknesses of 60 and 70 mm. The main contribution of the noise corresponds to the quantum noise, therefore it is necessary to adjust and optimize the mammography system. (author)

Quality control in digital mammography: the noise components

International Nuclear Information System (INIS)

Leyton, Fernando; Nogueira, Maria do Socorro; Duran, Maria Paz; Dantas, Marcelino; Ubeda, Carlos

2011-01-01

To measure the linearity of the detector and determine the noise components (quantum, electronic and structural noise) that contributed to losing image quality and to determine the signal noise ratio (SNR) and contrast noise ratio (CNR). This paper describes the results of the implementation of a protocol for quality control in digital mammography performed in two direct digital mammography equipment (Hologic, Selenia) in Santiago of Chile. Shows the results of linearity and noise analysis of the images which establishes the main cause of noise in the image of the mammogram to ensure the quality and optimize procedures. The study evaluated two digital mammography's Selenia, Hologic (DR) from Santiago, Chile. We conducted the assessment of linearity of the detector, the signal noise ratio, contrast noise ratio and was determined the contribution of different noise components (quantum, electronics and structural noise). Used different thicknesses used in clinical practice according to the protocol for quality control in digital mammography of Spanish society of medical physics and NHSBSP Equipment Report 0604 Version 3. The Selenia mammography software was used for the analysis of images and Unfors Xi detector for measuring doses. The mammography detector has a linear performance, the CNR and SNR did not comply with the Protocol for the thicknesses of 60 and 70 mm. The main contribution of the noise corresponds to the quantum noise, therefore it is necessary to adjust and optimize the mammography system. (author)

Statistical methods for determining the effect of mammography screening

DEFF Research Database (Denmark)

Lophaven, Søren

2016-01-01

In an overview of five randomised controlled trials from Sweden, a reduction of 29% was found in breast cancer mortality in women aged 50-69 at randomisation after a follow up of 5-13 years. Organised, population based, mammography service screening was introduced on the basis of these resultsin...... in 2007-2008. Women aged 50-69 were invited to screening every second year. Taking advantage of the registers of population and health, we present statistical methods for evaluating the effect of mammography screening on breast cancer mortality (Olsen et al. 2005, Njor et al. 2015 and Weedon-Fekjær etal...

Quality control for the mammography screening program in Serbia: Physical and technical aspects

International Nuclear Information System (INIS)

Ciraj-Bjelac, O.; Bozovic, P.; Lazarevic, D.; Arandjic, D.; Kosutic, D.

2012-01-01

Breast cancer is the major cause of mortality among female population in Serbia. It is presumed that the introduction of screening programme will reduce mortality and therefore, 47 new mammography units were installed for the purpose of population-based screening program in 2011. In parallel, Quality assurance and Quality control (QC) in mammography has received increasing attention as an essential element of the successful breast cancer campaign that is for the first time initialed in Serbia. The purpose of this study is to investigate the need for and the possible implementation of the comprehensive QC programme for the mammography screening in Serbia, with special focus on physical and technical aspect. In the first phase, a QC protocols containing list of parameters, methodology, frequency of tests and reference values for screen-film, computed radiography and full-filed digital mammography) units, were developed. The second phase is focused on the initial implementation of these protocols. The paper presents results of tests of the selected parameters in 35 mammography units, with special emphasis on patient dose and image quality descriptors. After initial implementation at the beginning of the population based breast cancer screening campaign, it is essential to establish system of regular and periodic QC equipment monitoring and to ensure high quality mammograms with minimal possible radiation dose to population included in the screening. (authors)

Entropy Coherent and Entropy Convex Measures of Risk

NARCIS (Netherlands)

Laeven, R.J.A.; Stadje, M.A.

2011-01-01

We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. We prove that convex, entropy convex and entropy coherent measures of risk emerge as certainty equivalents under variational, homothetic and multiple priors preferences,

A review of entropy generation in microchannels

Directory of Open Access Journals (Sweden)

Mohamed M Awad

2015-12-01

Full Text Available In this study, a critical review of thermodynamic optimum of microchannels based on entropy generation analysis is presented. Using entropy generation analysis as evaluation parameter of microchannels has been reported by many studies in the literature. In these studies, different working fluids such as nanofluids, air, water, engine oil, aniline, ethylene glycol, and non-Newtonian fluids have been used. For the case of nanofluids, “nanoparticles” has been used in various kinds such as Al2O3 and Cu, and “base fluid” has been used in various kinds such as water and ethylene glycol. Furthermore, studies on thermodynamic optimum of microchannels based on entropy generation analysis are summarized in a table. At the end, recommendations of future work for thermodynamic optimum of microchannels based on entropy generation analysis are given. As a result, this article can not only be used as the starting point for the researcher interested in entropy generation in microchannels, but it also includes recommendations for future studies on entropy generation in microchannels.

AUTHOR INDEX

Indian Academy of Sciences (India)

a granitic terrain of southern India using factor analysis and GIS. 1059. Radhakrishna M see Dev Sheena V .... Landslide susceptibility analysis using Probabilistic. Certainty Factor ... index via entropy-difference analysis. 687. Yidana Sandow ...

Particle swarm optimization-based local entropy weighted histogram equalization for infrared image enhancement

Science.gov (United States)

Wan, Minjie; Gu, Guohua; Qian, Weixian; Ren, Kan; Chen, Qian; Maldague, Xavier

2018-06-01

Infrared image enhancement plays a significant role in intelligent urban surveillance systems for smart city applications. Unlike existing methods only exaggerating the global contrast, we propose a particle swam optimization-based local entropy weighted histogram equalization which involves the enhancement of both local details and fore-and background contrast. First of all, a novel local entropy weighted histogram depicting the distribution of detail information is calculated based on a modified hyperbolic tangent function. Then, the histogram is divided into two parts via a threshold maximizing the inter-class variance in order to improve the contrasts of foreground and background, respectively. To avoid over-enhancement and noise amplification, double plateau thresholds of the presented histogram are formulated by means of particle swarm optimization algorithm. Lastly, each sub-image is equalized independently according to the constrained sub-local entropy weighted histogram. Comparative experiments implemented on real infrared images prove that our algorithm outperforms other state-of-the-art methods in terms of both visual and quantized evaluations.

New Fault Recognition Method for Rotary Machinery Based on Information Entropy and a Probabilistic Neural Network.

Science.gov (United States)

Jiang, Quansheng; Shen, Yehu; Li, Hua; Xu, Fengyu

2018-01-24

Feature recognition and fault diagnosis plays an important role in equipment safety and stable operation of rotating machinery. In order to cope with the complexity problem of the vibration signal of rotating machinery, a feature fusion model based on information entropy and probabilistic neural network is proposed in this paper. The new method first uses information entropy theory to extract three kinds of characteristics entropy in vibration signals, namely, singular spectrum entropy, power spectrum entropy, and approximate entropy. Then the feature fusion model is constructed to classify and diagnose the fault signals. The proposed approach can combine comprehensive information from different aspects and is more sensitive to the fault features. The experimental results on simulated fault signals verified better performances of our proposed approach. In real two-span rotor data, the fault detection accuracy of the new method is more than 10% higher compared with the methods using three kinds of information entropy separately. The new approach is proved to be an effective fault recognition method for rotating machinery.

Descriptive study of the quality control in mammography

International Nuclear Information System (INIS)

Gaona, E.; Perdigon C, G.M.; Casian C, G.A.; Azorin N, J.; Diaz G, J.A.I.; Arreola, M.

2005-01-01

The goal of mammography is to provide contrast between a lesion that is possible residing within the breast and normal surrounding tissue. Quality control is essential for maintaining the contrast imaging performance of a mammography system and incorporate tests that are relevant in that they are predictive of future degradation of contrast imaging performance. These tests will also be done at frequency that is high enough to intercept most drifts in quality imaging or performance before they become diagnostically significant. The quality control study has as objective to describe the results of the assessment of quality imaging elements (film optical density, contrast (density difference), uniformity, resolution and noise) of 62 mammography departments without quality control program and comparison these results with a mammography reference department with a quality control program. When comparing the results they allow seeing the clinical utility of to have a quality control program to reduce the errors of mammography interpretation. (Author)

Entropy coherent and entropy convex measures of risk

NARCIS (Netherlands)

Laeven, Roger; Stadje, M.A.

2010-01-01

We introduce entropy coherent and entropy convex measures of risk and prove a collection of axiomatic characterization and duality results. We show in particular that entropy coherent and entropy convex measures of risk emerge as negative certainty equivalents in (the regular and a generalized

Implications of Overdiagnosis: Impact on Screening Mammography Practices

Science.gov (United States)

Morris, Elizabeth; Feig, Stephen A.; Drexler, Madeline

2015-01-01

Abstract This review article explores the issue of overdiagnosis in screening mammography. Overdiagnosis is the screen detection of a breast cancer, histologically confirmed, that might not otherwise become clinically apparent during the lifetime of the patient. While screening mammography is an imperfect tool, it remains the best tool we have to diagnose breast cancer early, before a patient is symptomatic and at a time when chances of survival and options for treatment are most favorable. In 2015, an estimated 231,840 new cases of breast cancer (excluding ductal carcinoma in situ) will be diagnosed in the United States, and some 40,290 women will die. Despite these data, screening mammography for women ages 40–69 has contributed to a substantial reduction in breast cancer mortality, and organized screening programs have led to a shift from late-stage diagnosis to early-stage detection. Current estimates of overdiagnosis in screening mammography vary widely, from 0% to upwards of 30% of diagnosed cancers. This range reflects the fact that measuring overdiagnosis is not a straightforward calculation, but usually one based on different sets of assumptions and often biased by methodological flaws. The recent development of tomosynthesis, which creates high-resolution, three-dimensional images, has increased breast cancer detection while reducing false recalls. Because the greatest harm of overdiagnosis is overtreatment, the key goal should not be less diagnosis but better treatment decision tools. (Population Health Management 2015;18:S3–S11) PMID:26414384

Entropy: From Thermodynamics to Hydrology

Directory of Open Access Journals (Sweden)

Demetris Koutsoyiannis

2014-02-01

Full Text Available Some known results from statistical thermophysics as well as from hydrology are revisited from a different perspective trying: (a to unify the notion of entropy in thermodynamic and statistical/stochastic approaches of complex hydrological systems and (b to show the power of entropy and the principle of maximum entropy in inference, both deductive and inductive. The capability for deductive reasoning is illustrated by deriving the law of phase change transition of water (Clausius-Clapeyron from scratch by maximizing entropy in a formal probabilistic frame. However, such deductive reasoning cannot work in more complex hydrological systems with diverse elements, yet the entropy maximization framework can help in inductive inference, necessarily based on data. Several examples of this type are provided in an attempt to link statistical thermophysics with hydrology with a unifying view of entropy.

Value of mammography and breast ultrasound in male patients with nipple discharge.

Science.gov (United States)

Muñoz Carrasco, Rafaela; Álvarez Benito, Marina; Rivin del Campo, Eleonor

2013-03-01

To assess the contribution of mammography and ultrasound in men with nipple discharge. All men with nipple discharge who underwent mammography and/or ultrasound between 1993 and 2011 in our hospital were retrospectively evaluated. Radiological findings were classified according to BI-RADS lexicon. The final diagnosis was made based on histopathological results or clinical-radiological follow-up. The diagnostic performance of physical examination, mammography and ultrasound was calculated and compared. 26 men with 21 mammograms and 19 ultrasounds were reviewed. The final diagnoses were: 6 carcinomas (23.1%), 10 gynaecomastias, 2 pseudogynaecomastias and 8 normal breast tissues. Mammograms and ultrasounds performed on all five patients with infiltrating carcinoma showed a mass (categories 4 and 5). In all these patients except one, a breast mass was also noted and the physical examination was positive or suspected malignancy. In the patient with carcinoma in situ, the only conspicuous clinical sign was bloody nipple discharge and the mammography showed calcifications (category 4) that were not visible on ultrasound. Radiological findings of all patients without malignancy were classified as categories 1 and 2. The diagnostic performance of physical examination was lower than mammography and ultrasound (P>0.05). Mammography was more sensitive than ultrasound (100% vs. 83.3%). Both techniques showed the same specificity (100%). Men with nipple discharge have a high incidence of breast carcinoma. Nipple discharge may be the only clinical sign of carcinoma in situ. Mammography and ultrasound are useful in the evaluation of men with nipple discharge, diagnosing carcinoma in initial stages, avoiding unnecessary biopsies. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Harmonic analysis of electric locomotive and traction power system based on wavelet singular entropy

Science.gov (United States)

Dun, Xiaohong

2018-05-01

With the rapid development of high-speed railway and heavy-haul transport, the locomotive and traction power system has become the main harmonic source of China's power grid. In response to this phenomenon, the system's power quality issues need timely monitoring, assessment and governance. Wavelet singular entropy is an organic combination of wavelet transform, singular value decomposition and information entropy theory, which combines the unique advantages of the three in signal processing: the time-frequency local characteristics of wavelet transform, singular value decomposition explores the basic modal characteristics of data, and information entropy quantifies the feature data. Based on the theory of singular value decomposition, the wavelet coefficient matrix after wavelet transform is decomposed into a series of singular values that can reflect the basic characteristics of the original coefficient matrix. Then the statistical properties of information entropy are used to analyze the uncertainty of the singular value set, so as to give a definite measurement of the complexity of the original signal. It can be said that wavelet entropy has a good application prospect in fault detection, classification and protection. The mat lab simulation shows that the use of wavelet singular entropy on the locomotive and traction power system harmonic analysis is effective.

A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

Directory of Open Access Journals (Sweden)

Yongxin Chou

2017-01-01

Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

Mammography calibration qualities establishment in a Mo-Mo clinical system

International Nuclear Information System (INIS)

Correa, E.L.; Santos, L.R. dos; Vivolo, V.; Potiens, M.P.A.

2015-01-01

In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained. (author)

Mammography calibration qualities establishment in a Mo-Mo clinical system

Energy Technology Data Exchange (ETDEWEB)

Correa, E.L.; Santos, L.R. dos; Vivolo, V.; Potiens, M.P.A., E-mail: educorrea1905@gmail.com [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained. (author)

Mammography parameters: compression, dose, and discomfort

International Nuclear Information System (INIS)

Blanco, S.; Di Risio, C.; Andisco, D.; Rojas, R.R.; Rojas, R.M.

2017-01-01

Objective: To confirm the importance of compression in mammography and relate it to the discomfort expressed by the patients. Materials and methods: Two samples of 402 and 268 mammographies were obtained from two diagnostic centres that use the same mammographic equipment, but different compression techniques. The patient age range was from 21 to 50 years old. (authors) [es

Entropy coherent and entropy convex measures of risk

NARCIS (Netherlands)

Laeven, R.J.A.; Stadje, M.

2013-01-01

We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. Entropy coherent and entropy convex measures of risk are special cases of φ-coherent and φ-convex measures of risk. Contrary to the classical use of coherent and convex

Ditching the Disc: The Effects of Cloud-Based Image Sharing on Department Efficiency and Report Turnaround Times in Mammography.

Science.gov (United States)

Morgan, Matthew B; Young, Elizabeth; Harada, Scott; Winkler, Nicole; Riegert, Joanna; Jones, Tony; Hu, Nan; Stein, Matthew

2017-12-01

In screening mammography, accessing prior examination images is crucial for accurate diagnosis and avoiding false-positives. When women visit multiple institutions for their screens, these "outside" examinations must be retrieved for comparison. Traditionally, prior images are obtained by faxing requests to other institutions and waiting for standard mail (film or CD-ROM), which can greatly delay report turnaround times. Recently, advancements in cloud-based image transfer technology have opened up more efficient options for examination transfer between institutions. The objective of this study was to evaluate the effect of cloud-based image transfer on mammography department workflow, time required to obtain prior images, and report turnaround times. Sixty screening examinations requiring prior images were placed into two groups (30 each). The control group used the standard institutional protocol for requesting prior images: faxing requests and waiting for mailed examinations. The experimental group used a cloud-based transfer for both requesting and receiving examinations. The mean number of days between examination request and examination receipt was measured for both groups and compared. The mean number of days from examination request to receipt was 6.08 days (SD 3.50) in the control group compared with 3.16 days (SD 3.95) in the experimental group. Using a cloud-based image transfer to obtain prior mammograms resulted in an average reduction of 2.92 days (P = .0361; 95% confidence interval 0.20-5.65) between examination request and receipt. This improvement in system efficiency is relevant for interpreting radiologists working to improve reporting times and for patients anxious to receive their mammography results. Copyright © 2017 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Performance of clinical mammography: a nationwide study from Denmark

DEFF Research Database (Denmark)

Jensen, Allan; Vejborg, Ilse; Severinsen, Niels

2006-01-01

that clinical mammography worked best in patient populations of purely symptomatic women. Our data indicate that to increase the accuracy of clinical mammography at the community level, the presence of an experienced radiologist should be prioritized ahead of raising the clinic size.......Clinical mammography is the key tool for breast cancer diagnosis, but little is known about the impact of the organisational set-up on the performance. We evaluated whether organisational factors influence the performance of clinical mammography. Clinical mammography data from all clinics...... in Denmark in the year 2000 were collected and linked to cancer outcome. Use of the National Institute of Radiation Hygiene register for identification of radiology clinics ensured comprehensive nationwide registration. We used the final mammographic assessment at the end of the imaging work-up to determine...

Application of different entropy formalisms in a neural network for novel word learning

Science.gov (United States)

Khordad, R.; Rastegar Sedehi, H. R.

2015-12-01

In this paper novel word learning in adults is studied. For this goal, four entropy formalisms are employed to include some degree of non-locality in a neural network. The entropy formalisms are Tsallis, Landsberg-Vedral, Kaniadakis, and Abe entropies. First, we have analytically obtained non-extensive cost functions for the all entropies. Then, we have used a generalization of the gradient descent dynamics as a learning rule in a simple perceptron. The Langevin equations are numerically solved and the error function (learning curve) is obtained versus time for different values of the parameters. The influence of index q and number of neuron N on learning is investigated for the all entropies. It is found that learning is a decreasing function of time for the all entropies. The rate of learning for the Landsberg-Vedral entropy is slower than other entropies. The variation of learning with time for the Landsberg-Vedral entropy is not appreciable when the number of neurons increases. It is said that entropy formalism can be used as a means for studying the learning.

Multiwavelet packet entropy and its application in transmission line fault recognition and classification.

Science.gov (United States)

Liu, Zhigang; Han, Zhiwei; Zhang, Yang; Zhang, Qiaoge

2014-11-01

Multiwavelets possess better properties than traditional wavelets. Multiwavelet packet transformation has more high-frequency information. Spectral entropy can be applied as an analysis index to the complexity or uncertainty of a signal. This paper tries to define four multiwavelet packet entropies to extract the features of different transmission line faults, and uses a radial basis function (RBF) neural network to recognize and classify 10 fault types of power transmission lines. First, the preprocessing and postprocessing problems of multiwavelets are presented. Shannon entropy and Tsallis entropy are introduced, and their difference is discussed. Second, multiwavelet packet energy entropy, time entropy, Shannon singular entropy, and Tsallis singular entropy are defined as the feature extraction methods of transmission line fault signals. Third, the plan of transmission line fault recognition using multiwavelet packet entropies and an RBF neural network is proposed. Finally, the experimental results show that the plan with the four multiwavelet packet energy entropies defined in this paper achieves better performance in fault recognition. The performance with SA4 (symmetric antisymmetric) multiwavelet packet Tsallis singular entropy is the best among the combinations of different multiwavelet packets and the four multiwavelet packet entropies.

Entropy Production of Stars

Directory of Open Access Journals (Sweden)

Leonid M. Martyushev

2015-06-01

Full Text Available The entropy production (inside the volume bounded by a photosphere of main-sequence stars, subgiants, giants, and supergiants is calculated based on B–V photometry data. A non-linear inverse relationship of thermodynamic fluxes and forces as well as an almost constant specific (per volume entropy production of main-sequence stars (for 95% of stars, this quantity lies within 0.5 to 2.2 of the corresponding solar magnitude is found. The obtained results are discussed from the perspective of known extreme principles related to entropy production.

Properties of Risk Measures of Generalized Entropy in Portfolio Selection

Directory of Open Access Journals (Sweden)

Rongxi Zhou

2017-12-01

Full Text Available This paper systematically investigates the properties of six kinds of entropy-based risk measures: Information Entropy and Cumulative Residual Entropy in the probability space, Fuzzy Entropy, Credibility Entropy and Sine Entropy in the fuzzy space, and Hybrid Entropy in the hybridized uncertainty of both fuzziness and randomness. We discover that none of the risk measures satisfy all six of the following properties, which various scholars have associated with effective risk measures: Monotonicity, Translation Invariance, Sub-additivity, Positive Homogeneity, Consistency and Convexity. Measures based on Fuzzy Entropy, Credibility Entropy, and Sine Entropy all exhibit the same properties: Sub-additivity, Positive Homogeneity, Consistency, and Convexity. These measures based on Information Entropy and Hybrid Entropy, meanwhile, only exhibit Sub-additivity and Consistency. Cumulative Residual Entropy satisfies just Sub-additivity, Positive Homogeneity, and Convexity. After identifying these properties, we develop seven portfolio models based on different risk measures and made empirical comparisons using samples from both the Shenzhen Stock Exchange of China and the New York Stock Exchange of America. The comparisons show that the Mean Fuzzy Entropy Model performs the best among the seven models with respect to both daily returns and relative cumulative returns. Overall, these results could provide an important reference for both constructing effective risk measures and rationally selecting the appropriate risk measure under different portfolio selection conditions.

Mammography screening services: market segments and messages.

Science.gov (United States)

Scammon, D L; Smith, J A; Beard, T

1991-01-01

Mammography has become a vital tool for the early detection of breast cancer. Although many organizations and health care facilities are working to educate and motivate women to take advantage of the life saving opportunity that is offered through screening mammography, only twenty percent of women who should be screened actually have the procedure performed. In order to reach women who have not been screened, it is important to learn which factors most strongly motivate those women who do choose to have a mammogram. Depth interviews with 18 women attending a mobile mammography unit were conducted to explore the decision making process of women obtaining mammography screening services and to develop a profile of prevalent emotions, attitudes, and feelings associated with receiving breast cancer screening services. Analysis of the interview transcripts revealed several important themes to which health care professionals can direct marketing and health promotion strategies.

Enthalpy-entropy compensation in protein unfolding

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

Enthalpy-entropy compensation was found to be a universal law in protein unfolding based on over 3 000 experimental data. Water molecular reorganization accompanying the protein unfolding was suggested as the origin of the enthalpy-entropy compensation in protein unfolding. It is indicated that the enthalpy-entropy compensation constitutes the physical foundation that satisfies the biological need of the small free energy changes in protein unfolding, without the sacrifice of the bio-diversity of proteins. The enthalpy-entropy compensation theory proposed herein also provides valuable insights into the Privalov's puzzle of enthalpy and entropy convergence in protein unfolding.

Black hole entropy functions and attractor equations

International Nuclear Information System (INIS)

Lopes Cardoso, Gabriel; Wit, Bernard de; Mahapatra, Swapna

2007-01-01

The entropy and the attractor equations for static extremal black hole solutions follow from a variational principle based on an entropy function. In the general case such an entropy function can be derived from the reduced action evaluated in a near-horizon geometry. BPS black holes constitute special solutions of this variational principle, but they can also be derived directly from a different entropy function based on supersymmetry enhancement at the horizon. Both functions are consistent with electric/magnetic duality and for BPS black holes their corresponding OSV-type integrals give identical results at the semi-classical level. We clarify the relation between the two entropy functions and the corresponding attractor equations for N = 2 supergravity theories with higher-derivative couplings in four space-time dimensions. We discuss how non-holomorphic corrections will modify these entropy functions

Brain tissue segmentation using q-entropy in multiple sclerosis magnetic resonance images

International Nuclear Information System (INIS)

Diniz, P.R.B.; Brum, D.G.; Santos, A. C.; Murta-Junior, L.O.; Araujo, D.B. de

2010-01-01

The loss of brain volume has been used as a marker of tissue destruction and can be used as an index of the progression of neurodegenerative diseases, such as multiple sclerosis. In the present study, we tested a new method for tissue segmentation based on pixel intensity threshold using generalized Tsallis entropy to determine a statistical segmentation parameter for each single class of brain tissue. We compared the performance of this method using a range of different q parameters and found a different optimal q parameter for white matter, gray matter, and cerebrospinal fluid. Our results support the conclusion that the differences in structural correlations and scale invariant similarities present in each tissue class can be accessed by generalized Tsallis entropy, obtaining the intensity limits for these tissue class separations. In order to test this method, we used it for analysis of brain magnetic resonance images of 43 patients and 10 healthy controls matched for gender and age. The values found for the entropic q index were 0.2 for cerebrospinal fluid, 0.1 for white matter and 1.5 for gray matter. With this algorithm, we could detect an annual loss of 0.98% for the patients, in agreement with literature data. Thus, we can conclude that the entropy of Tsallis adds advantages to the process of automatic target segmentation of tissue classes, which had not been demonstrated previously. (author)

Brain tissue segmentation using q-entropy in multiple sclerosis magnetic resonance images

Energy Technology Data Exchange (ETDEWEB)

Diniz, P.R.B.; Brum, D.G. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Neurociencias e Ciencias do Comportamento; Santos, A. C. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Clinica Medica; Murta-Junior, L.O.; Araujo, D.B. de, E-mail: murta@usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

2010-01-15

The loss of brain volume has been used as a marker of tissue destruction and can be used as an index of the progression of neurodegenerative diseases, such as multiple sclerosis. In the present study, we tested a new method for tissue segmentation based on pixel intensity threshold using generalized Tsallis entropy to determine a statistical segmentation parameter for each single class of brain tissue. We compared the performance of this method using a range of different q parameters and found a different optimal q parameter for white matter, gray matter, and cerebrospinal fluid. Our results support the conclusion that the differences in structural correlations and scale invariant similarities present in each tissue class can be accessed by generalized Tsallis entropy, obtaining the intensity limits for these tissue class separations. In order to test this method, we used it for analysis of brain magnetic resonance images of 43 patients and 10 healthy controls matched for gender and age. The values found for the entropic q index were 0.2 for cerebrospinal fluid, 0.1 for white matter and 1.5 for gray matter. With this algorithm, we could detect an annual loss of 0.98% for the patients, in agreement with literature data. Thus, we can conclude that the entropy of Tsallis adds advantages to the process of automatic target segmentation of tissue classes, which had not been demonstrated previously. (author)

Multivariate refined composite multiscale entropy analysis

International Nuclear Information System (INIS)

Humeau-Heurtier, Anne

2016-01-01

Multiscale entropy (MSE) has become a prevailing method to quantify signals complexity. MSE relies on sample entropy. However, MSE may yield imprecise complexity estimation at large scales, because sample entropy does not give precise estimation of entropy when short signals are processed. A refined composite multiscale entropy (RCMSE) has therefore recently been proposed. Nevertheless, RCMSE is for univariate signals only. The simultaneous analysis of multi-channel (multivariate) data often over-performs studies based on univariate signals. We therefore introduce an extension of RCMSE to multivariate data. Applications of multivariate RCMSE to simulated processes reveal its better performances over the standard multivariate MSE. - Highlights: • Multiscale entropy quantifies data complexity but may be inaccurate at large scale. • A refined composite multiscale entropy (RCMSE) has therefore recently been proposed. • Nevertheless, RCMSE is adapted to univariate time series only. • We herein introduce an extension of RCMSE to multivariate data. • It shows better performances than the standard multivariate multiscale entropy.

Future of mammography-based imaging; Zukunft mammographiebasierter Bildgebung

Energy Technology Data Exchange (ETDEWEB)

Schulz-Wendtland, R.; Brehm, B.; Meier-Meitinger, M.; Uder, M. [Klinikum der Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Gynaekologische Radiologie, Radiologisches Institut, Erlangen (Germany); Wittenberg, T. [Fraunhofer-Institut fuer Integrierte Schaltkreise IIS, Erlangen (Germany); Michel, T.; Anton, G. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Hartmann, A. [Klinikum der Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Institut fuer Pathologie, Erlangen (Germany); Beckmann, M.W.; Rauh, C.; Jud, S.M.; Fasching, P.A. [Klinikum der Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Frauenklinik, Comprehensive Cancer Center Erlangen-EMN, Erlangen (Germany)

2014-03-15

Mammography is the central diagnostic method for clinical diagnostics of breast cancer and the breast cancer screening program. In the clinical routine complementary methods, such as ultrasound, tomosynthesis and optional magnetic resonance imaging (MRI) are already combined for the diagnostic procedure. Future developments will utilize investigative procedures either as a hybrid (combination of several different imaging modalities in one instrument) or as a fusion method (the technical fusion of two or more of these methods) to implement fusion imaging into diagnostic algorithms. For screening there are reasonable hypotheses to aim for studies that individualize the diagnostic process within the screening procedure. Individual breast cancer risk prediction and individualized knowledge about sensitivity and specificity for certain diagnostic methods could be tested. The clinical implementation of these algorithms is not yet in sight. (orig.) [German] Die Mammographie ist die zentrale diagnostische Methode der klinischen symptombezogenen Abklaerung von Brusterkrankungen und des Brustkrebsscreenings. In der klinischen Diagnostik wird sie heute schon oft durch zusaetzliche Untersuchungsmethoden wie dem Ultraschall, der Tomosynthese und ggf. auch der MRT-Bildgebung unterstuetzt. Zukuenftige Entwicklungen gehen in die Richtung, dass diese Kombination aus 2 oder mehr Untersuchungsverfahren entweder in Hybrid- (Aufnahme mehrerer unterschiedlicher Bildmodalitaeten in einem einzigen Geraet) oder in Fusionsmethoden (Zusammenfuehrung und Registrierung von Bilddaten aus verschiedenen Modalitaeten) technisch professionalisiert werden. Des Weiteren koennten an subgruppenbezogene Erkrankungsrisiken und individuelle Sensitivitaeten und Spezifitaeten angepasste Diagnostikkombinationen fuer eine Screeningdiagnostik Gegenstand kuenftiger Studien sein. Wir stellen die aktuellen Entwicklungen auf diesen Gebieten und deren momentane Relevanz fuer die klinische Praxis und

Quality control tests for conventional mammography

International Nuclear Information System (INIS)

Dawod, Alnazer Ahmed Ibrahim

2014-12-01

Mammography is this the test that allows the radiologist to look at images of the inside of the breasts. Mammograms help detect breast cancer early successful treatment of breast cancer depends on that early diagnosis. Breast cancer is a very common condition. About one in every nine women develops breast cancer by the age of eighty. In addition to the clinical examination and self-examination, mammography plays important role in the detection of breast cancer before they become clinically visible tumors. The mammography is the most common test for early detection of breast cancer. Quality control techniques that done ensured importance of this programme to produce images with good diagnostic values and help radiologist to diagnose breast discase easily and avoid exposing patient to radiation hazards.(Author)

Identification of Breast Cancer Using Integrated Information from MRI and Mammography.

Directory of Open Access Journals (Sweden)

Shih-Neng Yang

Full Text Available Integration of information from corresponding regions between the breast MRI and an X-ray mammogram could benefit the detection of breast cancer in clinical diagnosis. We aimed to provide a framework of registration from breast MRI to mammography and to evaluate the diagnosis using the combined information.43 patients with 46 lesions underwent both MRI and mammography scans, and the interval between the two examinations was around one month. The distribution of malignant to benign lesions was 31/46 based on histological results. Maximum intensity projection and thin-plate spline methods were applied for image registration for MRI to mammography. The diagnosis using integrated information was evaluated using results of histology as the reference. The assessment of annotations and statistical analysis were performed by the two radiologists.For the cranio-caudal view, the mean post-registration error between MRI and mammography was 2.2±1.9 mm. For the medio-lateral oblique view, the proposed approach performed even better with a mean error of 3.0±2.4 mm. In the diagnosis using MRI assessment with information of mammography, the sensitivity was 91.9±2.3% (29/31, 28/31, specificity 70.0±4.7% (11/15, 10/15, accuracy 84.8±3.1% (40/46, 38/46, positive predictive value 86.4±2.1% (29/33, 28/33 and negative predictive value 80.8±5.4% (11/13, 10/13.MRI with the aid of mammography shows potential improvements of sensitivity, specificity, accuracy, PPV and NPV in clinical breast cancer diagnosis compared to the use of MRI alone.

Activity-Based Approach for Teaching Aqueous Solubility, Energy, and Entropy

Science.gov (United States)

Eisen, Laura; Marano, Nadia; Glazier, Samantha

2014-01-01

We describe an activity-based approach for teaching aqueous solubility to introductory chemistry students that provides a more balanced presentation of the roles of energy and entropy in dissolution than is found in most general chemistry textbooks. In the first few activities, students observe that polar substances dissolve in water, whereas…

Trajectories entropy in dynamical graphs with memory

Directory of Open Access Journals (Sweden)

Francesco eCaravelli

2016-04-01

Full Text Available In this paper we investigate the application of non-local graph entropy to evolving and dynamical graphs. The measure is based upon the notion of Markov diffusion on a graph, and relies on the entropy applied to trajectories originating at a specific node. In particular, we study the model of reinforcement-decay graph dynamics, which leads to scale free graphs. We find that the node entropy characterizes the structure of the network in the two parameter phase-space describing the dynamical evolution of the weighted graph. We then apply an adapted version of the entropy measure to purely memristive circuits. We provide evidence that meanwhile in the case of DC voltage the entropy based on the forward probability is enough to characterize the graph properties, in the case of AC voltage generators one needs to consider both forward and backward based transition probabilities. We provide also evidence that the entropy highlights the self-organizing properties of memristive circuits, which re-organizes itself to satisfy the symmetries of the underlying graph.

Configurational entropy of polar glass formers and the effect of electric field on glass transition

Energy Technology Data Exchange (ETDEWEB)

Matyushov, Dmitry V., E-mail: dmitrym@asu.edu [Department of Physics and School of Molecular Sciences, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287 (United States)

2016-07-21

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ{sup γ}/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for excess (over the crystal state) thermodynamics of molecular glass formers. We suggest that the Kauzmann entropy crisis might be a signature of vanishing configurational entropy of a subset of degrees of freedom, multipolar rotations in our model. This scenario has observable consequences: (i) a dynamical crossover of the relaxation time and (ii) the fragility index defined by the ratio of the excess heat capacity and excess entropy at the glass transition. The Kauzmann temperature of vanishing configurational entropy and the corresponding glass transition temperature shift upward when the electric field is applied. The temperature shift scales quadratically with the field strength.

Configurational entropy of polar glass formers and the effect of electric field on glass transition.

Science.gov (United States)

Matyushov, Dmitry V

2016-07-21

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ(γ)/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for excess (over the crystal state) thermodynamics of molecular glass formers. We suggest that the Kauzmann entropy crisis might be a signature of vanishing configurational entropy of a subset of degrees of freedom, multipolar rotations in our model. This scenario has observable consequences: (i) a dynamical crossover of the relaxation time and (ii) the fragility index defined by the ratio of the excess heat capacity and excess entropy at the glass transition. The Kauzmann temperature of vanishing configurational entropy and the corresponding glass transition temperature shift upward when the electric field is applied. The temperature shift scales quadratically with the field strength.

Time Dependence of Entropy Flux and Entropy Production of a Dissipative Dynamical System Driven by Non-Gaussian Noise

International Nuclear Information System (INIS)

Guo Yongfeng; Xu Wei; Li Dongxi; Xie Wenxian

2008-01-01

A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition of Shannon's information entropy, the exact time dependence of entropy flux and entropy production of the system is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculation can be used to interpret the interplay of the dissipative constant and non-Gaussian noise on the entropy flux and entropy production

Mammography: an update of the EUSOBI recommendations on information for women.

Science.gov (United States)

Sardanelli, Francesco; Fallenberg, Eva M; Clauser, Paola; Trimboli, Rubina M; Camps-Herrero, Julia; Helbich, Thomas H; Forrai, Gabor

2017-02-01

This article summarises the information to be offered to women about mammography. After a delineation of the aim of early diagnosis of breast cancer, the difference between screening mammography and diagnostic mammography is explained. The need to bring images and reports from the previous mammogram (and from other recent breast imaging examinations) is highlighted. Mammography technique and procedure are described with particular attention to discomfort and pain experienced by a small number of women who undergo the test. Information is given on the recall during a screening programme and on the request for further work-up after a diagnostic mammography. The logic of the mammography report and of classification systems such as R1-R5 and BI-RADS is illustrated, and brief but clear information is given about the diagnostic performance of the test, with particular reference to interval cancers, i.e., those cancers that are missed at screening mammography. Moreover, the breast cancer risk due to radiation exposure from mammography is compared to the reduction in mortality obtained with the test, and the concept of overdiagnosis is presented with a reliable estimation of its extent. Information about new mammographic technologies (tomosynthesis and contrast-enhanced spectral mammography) is also given. Finally, frequently asked questions are answered. • Direct digital mammography should be preferred to film-screen or phosphor plates. • Screening (in asymptomatic women) should be distinguished from diagnosis (in symptomatic women). • A breast symptom has to be considered even after a negative mammogram. • Digital breast tomosynthesis increases cancer detection and decreases the recall rate. • Contrast-enhanced spectral mammography can help in cancer detection and lesion characterisation.

Application of the entropy generation minimization method to a solar heat exchanger: A pseudo-optimization design process based on the analysis of the local entropy generation maps

International Nuclear Information System (INIS)

Giangaspero, Giorgio; Sciubba, Enrico

2013-01-01

This paper presents an application of the entropy generation minimization method to the pseudo-optimization of the configuration of the heat exchange surfaces in a Solar Rooftile. An initial “standard” commercial configuration is gradually improved by introducing design changes aimed at the reduction of the thermodynamic losses due to heat transfer and fluid friction. Different geometries (pins, fins and others) are analysed with a commercial CFD (Computational Fluid Dynamics) code that also computes the local entropy generation rate. The design improvement process is carried out on the basis of a careful analysis of the local entropy generation maps and the rationale behind each step of the process is discussed in this perspective. The results are compared with other entropy generation minimization techniques available in the recent technical literature. It is found that the geometry with pin-fins has the best performance among the tested ones, and that the optimal pin array shape parameters (pitch and span) can be determined by a critical analysis of the integrated and local entropy maps and of the temperature contours. - Highlights: ► An entropy generation minimization method is applied to a solar heat exchanger. ► The approach is heuristic and leads to a pseudo-optimization process with CFD as main tool. ► The process is based on the evaluation of the local entropy generation maps. ► The geometry with pin-fins in general outperforms all other configurations. ► The entropy maps and temperature contours can be used to determine the optimal pin array design parameters

Mammography practices for radiation protection in Kenya

International Nuclear Information System (INIS)

Shadrack, Anthony K.

2008-01-01

All mammography units in the country, totaling fourteen in number at the time, were evaluated on the basis of performance and practice to come up with useful data for summing up the mammography practice in Kenya. The study was carried out by performing hands-on quality control tests on the units using internationally established protocols. Image quality and dose measurement data were generated in all the centers and clearly indicated that the practice of mammography, more so on optimization viewpoint is so much varied. A standard method was used to obtain these data by use of mammography accreditation phantom. Data from actual patients was also collected in three major centers in Nairobi. On the criteria used for evaluating phantom image quality, ten out of fourteen units did satisfy the set criterion. The average glandular dose was 2.79 mGy per cranio caudal (cc) view of the phantom and 3.27 mGy per cc view for the sampled patients. The internationally recommended dose level for such a view is 3.0 mGy. One worrying observation made was that most units failed on one of the easiest test of mammographic unit assembly. Of most concern was the lack of technique charts for the practice detailing the imaging parameters being employed for the procedure. Most centers do not take the servicing of equipment seriously and others merely ignore even the crucial issues of equipment performance like the automatic exposure control and viewing conditions of the reporting areas.The results of this study calls for the setting up of a programme of optimization of radiological protection in mammography using the experience of other countries that have put in place quality assurance programs, setting and adoption of Dose Reference Levels (DRLs) as part of Quality Assurance (QA). This practice needs an effective quality control program which should start with the selection of appropriate equipment for mammography and the use of qualified personnel including the radiologist, radiographer

Risks, radiation dose and image quality of mammography

International Nuclear Information System (INIS)

Menges, V.

1979-01-01

For some time to come, early detection of breast cancer will remain the only way to improve the therapeutical success. Mammography is an absolutely indispensible way to take advantage of this opportunity. Today, mammography is undoubtedly the most reliable method of examination for an early detection of breast cancer. Only mammography can detect carcinomas smaller than the critical tumour size of 1cm. If carried out properly and with present dose levels, it involves hardly any radiation risk. (orig.) [de

Computer-aided diagnosis in routine mammography

International Nuclear Information System (INIS)

Sittek, H.; Perlet, C.; Helmberger, R.; Linsmeier, E.; Kessler, M.; Reiser, M.

1998-01-01

Purpose: Computer-aided diagnosis in mammography is a topic many study groups have been concerned with since the first presentation of a system for computer-aided interpretation in 1967. Currently, there is only one system avilable for clinical use in mammography, the CAD-System Image Checker (R2 Technology). The purpose of our prospective study was to evaluate whether the integration of the CAD-system into the routine of a radiological breast diagnosis unit is feasible. Results: After the installation of the CAD-system, 300 patients with 1110 mammograms were included for evaluation in the present study. In 54 of these cases histological examination was indicated due to suspect criteria on conventional mammography. In 39 of 54 cases (72,2%) malignancy could be proven histologically. The CAD-system marked 82,1% of the histologically verified carcinomas correctly 94,3% of all 1797 marks made by the CAD-system indicated normal or benign structures. Routinely performed CAD analysis prolonged patients waiting time by about 15 min because the marks of the CAD system had to be interpreted in addition to the routine diagnostic investigations. Conclusion: Our experience with the use of the CAD-system in daily routine showed that CAD analysis can easily be integrated into a preexisting mammography unit. However, the diagnostic benefit is not yet clearly established. Since the rate of false negative marks by the CAD-system Image Checker is still high, the results of CAD analysis must be checked and corrected by an observer well experienced in mammography reading. (orig.) [de

Mammography

International Nuclear Information System (INIS)

1975-01-01

This patent reveals a method and instrument for the detection and registration of breast cancer with the aid of X-radiation, i.e. mammography. The breast is irradiated with soft X-rays whereby the radiation beam is scanned with a moving 'stripform' screen and whereby the picture from the 'stripform' screen is recorded by a television camera that moves simultaneously with the strip. The image is then projected on a monitor

Microscopic insights into the NMR relaxation based protein conformational entropy meter

Science.gov (United States)

Kasinath, Vignesh; Sharp, Kim A.; Wand, A. Joshua

2013-01-01

Conformational entropy is a potentially important thermodynamic parameter contributing to protein function. Quantitative measures of conformational entropy are necessary for an understanding of its role but have been difficult to obtain. An empirical method that utilizes changes in conformational dynamics as a proxy for changes in conformational entropy has recently been introduced. Here we probe the microscopic origins of the link between conformational dynamics and conformational entropy using molecular dynamics simulations. Simulation of seven pro! teins gave an excellent correlation with measures of side-chain motion derived from NMR relaxation. The simulations show that the motion of methyl-bearing side-chains are sufficiently coupled to that of other side chains to serve as excellent reporters of the overall side-chain conformational entropy. These results tend to validate the use of experimentally accessible measures of methyl motion - the NMR-derived generalized order parameters - as a proxy from which to derive changes in protein conformational entropy. PMID:24007504

Information on mammography-screening - from deception to insight

International Nuclear Information System (INIS)

Muehlhauser, I.; Hoeldke, B.

2002-01-01

Information about mammography-screening as a basis for informed-decision making has to be evidence-based and presented in an unbiased format. This includes communication of results about effectiveness/lack of effectiveness of screening programmes (breast cancer mortality, total mortality), the quality of mammography as a screening test (sensitivity, specificity, positive and negative predictive values), and possible harm (consequences of false positive and false negative results, overdiagnosis of breast cancer, overtreatment). Outcome data have to be communicated as natural frequencies rather than relative differences. In order to avoid framing of data equal emphasis has to be put on the proportion of persons who are likely to benefit and those who are unlikely to benefit or likely to be harmed. (orig.) [de

Mammography discomfort: a holistic perspective derived from women's experiences

International Nuclear Information System (INIS)

Poulos, Ann; Llewellyn, Gwynnyth

2005-01-01

Purpose: Mammography discomfort has the potential to deter women from attending for regular breast screening. Previous studies have focussed on the pain/discomfort of the mammography procedure itself. The purpose of this study was to consider discomfort from a holistic perspective of the mammography experience derived from the women themselves. Methods: Qualitative research methods were employed. Using theoretical sampling, 12 women who had recently experienced mammography were interviewed. The interview questions aimed to explore the experience of women attending for a mammogram from arrival to departure and beyond in order to identify aspects which potentially increase discomfort. Data analysis involved coding and categorisation and identification of key concepts and their relationships. Results: A conceptual framework was developed that demonstrates the contributors to mammography discomfort and the relationships between these as identified by the women. Conclusions: The conceptual framework has important implications for clinical practice and future research

Interdisciplinary group of mammography (IGM). Quality assurance in mammography

International Nuclear Information System (INIS)

Anon.

1994-01-01

Assurance quality must be a preoccupation of each day in mammography. To be efficient and of low cost it must be discussed between radiologists and physicists; some countries like Federal Republic of Germany, Belgium, United Kingdom, Scandinavia and Netherlands engaged actions to make assurance quality a daily practice

ENTROPY FUNCTIONAL FOR CONTINUOUS SYSTEMS OF FINITE ENTROPY

Institute of Scientific and Technical Information of China (English)

M. Rahimi A. Riazi

2012-01-01

In this article,we introduce the concept of entropy functional for continuous systems on compact metric spaces,and prove some of its properties.We also extract the Kolmogorov entropy from the entropy functional.

COLLAGE-BASED INVERSE PROBLEMS FOR IFSM WITH ENTROPY MAXIMIZATION AND SPARSITY CONSTRAINTS

Directory of Open Access Journals (Sweden)

Herb Kunze

2013-11-01

Full Text Available We consider the inverse problem associated with IFSM: Given a target function f, find an IFSM, such that its invariant fixed point f is sufficiently close to f in the Lp distance. In this paper, we extend the collage-based method developed by Forte and Vrscay (1995 along two different directions. We first search for a set of mappings that not only minimizes the collage error but also maximizes the entropy of the dynamical system. We then include an extra term in the minimization process which takes into account the sparsity of the set of mappings. In this new formulation, the minimization of collage error is treated as multi-criteria problem: we consider three different and conflicting criteria i.e., collage error, entropy and sparsity. To solve this multi-criteria program we proceed by scalarization and we reduce the model to a single-criterion program by combining all objective functions with different trade-off weights. The results of some numerical computations are presented. Numerical studies indicate that a maximum entropy principle exists for this approximation problem, i.e., that the suboptimal solutions produced by collage coding can be improved at least slightly by adding a maximum entropy criterion.

Screening mammography uptake within Australia and Scotland in rural and urban populations.

Science.gov (United States)

Leung, Janni; Macleod, Catriona; McLaughlin, Deirdre; Woods, Laura M; Henderson, Robert; Watson, Angus; Kyle, Richard G; Hubbard, Gill; Mullen, Russell; Atherton, Iain

2015-01-01

To test the hypothesis that rural populations had lower uptake of screening mammography than urban populations in the Scottish and Australian setting. Scottish data are based upon information from the Scottish Breast Screening Programme Information System describing uptake among women residing within the NHS Highland Health Board area who were invited to attend for screening during the 2008 to 2010 round (N = 27,416). Australian data were drawn from the 2010 survey of the 1946-51 cohort of the Australian Longitudinal Study on Women's Health (N = 9890 women). Contrary to our hypothesis, results indicated that women living in rural areas were not less likely to attend for screening mammography compared to women living in urban areas in both Scotland (OR for rural = 1.17, 95% CI = 1.06-1.29) and Australia (OR for rural = 1.15, 95% CI = 1.01-1.31). The absence of rural-urban differences in attendance at screening mammography demonstrates that rurality is not necessarily an insurmountable barrier to screening mammography.

Entropy type complexity of quantum processes

International Nuclear Information System (INIS)

Watanabe, Noboru

2014-01-01

von Neumann entropy represents the amount of information in the quantum state, and this was extended by Ohya for general quantum systems [10]. Umegaki first defined the quantum relative entropy for σ-finite von Neumann algebras, which was extended by Araki, and Uhlmann, for general von Neumann algebras and *-algebras, respectively. In 1983 Ohya introduced the quantum mutual entropy by using compound states; this describes the amount of information correctly transmitted through the quantum channel, which was also extended by Ohya for general quantum systems. In this paper, we briefly explain Ohya's S-mixing entropy and the quantum mutual entropy for general quantum systems. By using structure equivalent class, we will introduce entropy type functionals based on quantum information theory to improve treatment for the Gaussian communication process. (paper)

Analysis of mammography on breast fibroadenoma

International Nuclear Information System (INIS)

Fu Xiaomin; Han Benyi; Zhao Yae

2009-01-01

Objective: To study the imaging characteristics of breast fibroadenoma on mammograms. Methods: Mammography of 70 patients with breast fibroadenoma confirmed by pathology were analyzed retrospectively. All patients took breast X-ray of mediolateral oblique projection and craniocaudal projection before operation. Results: In 70 cases with fibroadenoma, mammography revealed 74 foci (36 left breast, 38 right breast) of 62 cases, and failed to reveal lesions in 8 cases. The shape of the lesions was round or round-like lesion in 60(31%). The border was well-defined in 46 masses, partly well-outlined in 14 and ill-defined in 4. 'Membranoid sign' can be seen in 40 cases. Conclusion: Typical X-ray findings of breast fibroadenoma is very important, mammography is a good method of choice in diagnosis of fibroadenoma. (authors)

Implementation of Extended Statistical Entropy Analysis to the Effluent Quality Index of the Benchmarking Simulation Model No. 2

Directory of Open Access Journals (Sweden)

Alicja P. Sobańtka

2014-01-01

Full Text Available Extended statistical entropy analysis (eSEA is used to assess the nitrogen (N removal performance of the wastewater treatment (WWT simulation software, the Benchmarking Simulation Model No. 2 (BSM No. 2 . Six simulations with three different types of wastewater are carried out, which vary in the dissolved oxygen concentration (O2,diss. during the aerobic treatment. N2O emissions generated during denitrification are included in the model. The N-removal performance is expressed as reduction in statistical entropy, ΔH, compared to the hypothetical reference situation of direct discharge of the wastewater into the river. The parameters chemical and biological oxygen demand (COD, BOD and suspended solids (SS are analogously expressed in terms of reduction of COD, BOD, and SS, compared to a direct discharge of the wastewater to the river (ΔEQrest. The cleaning performance is expressed as ΔEQnew, the weighted average of ΔH and ΔEQrest. The results show that ΔEQnew is a more comprehensive indicator of the cleaning performance because, in contrast to the traditional effluent quality index (EQ, it considers the characteristics of the wastewater, includes all N-compounds and their distribution in the effluent, the off-gas, and the sludge. Furthermore, it is demonstrated that realistically expectable N2O emissions have only a moderate impact on ΔEQnew.

Barriers to Mammography among Inadequately Screened Women

Science.gov (United States)

Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

2015-01-01

Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

Fundamental Flaws In The Derivation Of Stevens' Law For Taste Within Norwich's Entropy Theory of Perception

International Nuclear Information System (INIS)

Nizami, Lance

2010-01-01

Norwich's Entropy Theory of Perception (1975-present) is a general theory of perception, based on Shannon's Information Theory. Among many bold claims, the Entropy Theory presents a truly astounding result: that Stevens' Law with an Index of 1, an empirical power relation of direct proportionality between perceived taste intensity and stimulus concentration, arises from theory alone. Norwich's theorizing starts with several extraordinary hypotheses. First, 'multiple, parallel receptor-neuron units' without collaterals 'carry essentially the same message to the brain', i.e. the rate-level curves are identical. Second, sensation is proportional to firing rate. Third, firing rate is proportional to the taste receptor's 'resolvable uncertainty'. Fourth, the 'resolvable uncertainty' is obtained from Shannon's Information Theory. Finally, 'resolvable uncertainty' also depends upon the microscopic thermodynamic density fluctuation of the tasted solute. Norwich proves that density fluctuation is density variance, which is proportional to solute concentration, all based on the theory of fluctuations in fluid composition from Tolman's classic physics text, 'The Principles of Statistical Mechanics'. Altogether, according to Norwich, perceived taste intensity is theoretically proportional to solute concentration. Such a universal rule for taste, one that is independent of solute identity, personal physiological differences, and psychophysical task, is truly remarkable and is well-deserving of scrutiny. Norwich's crucial step was the derivation of density variance. That step was meticulously reconstructed here. It transpires that the appropriate fluctuation is Tolman's mean-square fractional density fluctuation, not density variance as used by Norwich. Tolman's algebra yields a 'Stevens Index' of -1 rather than 1. As 'Stevens Index' empirically always exceeds zero, the Index of -1 suggests that it is risky to infer psychophysical laws of sensory response from information theory

Traceability and quality control in mammography: measurements and models

International Nuclear Information System (INIS)

Peixoto, Jose Guilherme Pereira

2002-10-01

The success of a treatment or diagnosis using radiation, depends on the optimization of the dose determination to be administered for the patient and on the beam radiation quality. It is recognized by the international guidelines that it is necessary to improve calibration services for mammography beams in order to improve the quality of clinical diagnosis. Major efforts have been made by several laboratories in order to establish an appropriate and traceable calibration infrastructure and to provide the basis for a quality control program in mammography. The contribution of the radiation metrology network to the mammography services is reviewed in this work. Steps required for the implementation of a mammography calibration system using a constant potential x-ray and a clinical mammography x-ray machine are presented. The various qualities of mammography radiation discussed in this work are in accordance with the IEC 61674 and the AAPM recommendations. This work also presents the methodology and the procedures to maintain and to disseminate the traceability at the x-ray mammography range, describing the interlaboratory comparison performed at LNMRI/IRD/CNEN and at the IPEN/CNEN using the secondary standard ionization chambers traceable with the international standard. It assesses the inter-laboratory comparison consistency and decides whether a questionable value should or not be accepted, using the residual method. This thesis discusses the uncertainties involved in all steps of the calibration chain in accord once with the ISO recommendations. (author)

Digital mammography with high-resolution storage plates (CR) versus full-field digital mammography (CCD) (DR) for microcalcifications and focal lesions - a retrospective clinical histologic analysis (n = 102)

International Nuclear Information System (INIS)

Schulz-Wendtland, R.; Lell, M.; Wenkel, E.; Boehner, C.; Dassel, M.S.; Bautz, W.

2005-01-01

Purpose: to determine the diagnostic accuracy of microcalcifications and focal lesions in a retrospective clinical-histological study using high-resolution digital phosphor storage plates (hard copy) and full-field digital mammography (hard copy). Materials and methods: from May 2003 to September 2003, 102 patients underwent digital storage plate mammography (CR), using a mammography unit (Mammomat 3000 N, Siemens) in combination with a high resolution (9 lp/mm) digital storage phosphor plate system (pixel size 50 μm) (Fuji/Siemens). After diagnosis and preoperative wire localization, full-field digital mammography (CCD) (DR) was performed with the same exposure parameters. The full-field digital mammography used a CCD-detector (SenoScan) (fisher imaging) with a resolution of 10 Ip/mm and a pixel size of 50 μm. Five investigators determined the diagnosis (BI-RADS trademark I-V) retrospectively after the operation from randomly distributed mediolateral views (hard copy reading). These results were correlated with the final histology. Results: the diagnostic accuracy of digital storage plate mammography (CR) and full-field digital mammography (CCD) (DR) was 73% and 71% for all findings (n = 102), 73% and 71% for microcalcifications (n = 51), and 72% and 70% for focal lesions (n = 51). The overall results showed no difference. Conclusion: our findings indicate the equivalence of high-resolution digital phosphor storage plate mammography (CR) and full-field digital mammography (CCD) (DR). (orig.)

Topological nearly entropy

Science.gov (United States)

Gulamsarwar, Syazwani; Salleh, Zabidin

2017-08-01

The purpose of this paper is to generalize the notions of Adler's topological entropy along with their several fundamental properties. A function f : X → Y is said to be R-map if f-1 (V) is regular open in X for every regular open set V in Y. Thus, we initiated a notion of topological nearly entropy for topological R-dynamical systems which is based on nearly compact relative to the space by using R-map.

Mammography in Norway: Image quality and total performance; Mammografivirksomhet i Norge: Bildekvalitet og totalytelse

Energy Technology Data Exchange (ETDEWEB)

Olsen, J.B.; Skretting, A. [Norske Radiumhospital, Oslo (Norway); Widmark, A. [Statens Straalevern, Oesteraas (Norway)

1997-04-01

This report describes a method for assessing the total performance in mammography based on Receiver Operating Characteristic (ROC) analysis. In the time period from December 1993 to March 1994 the method was applied to assess the total performance of all the 45 Norwegian mammography laboratories operative at that time. Image quality characteristics in each laboratory was established by use of well-known phantoms.

Barriers to Organized Mammography Screening Programs in Hungary: A Questionnaire-based Study of 3,313 Women.

Science.gov (United States)

Újhelyi, Mihály; Pukancsik, Dávid; Kelemen, Péter; Kovács, Eszter; Kenessey, István; Bak, Mihály; Kásler, Miklós; Kovács, Tibor; Mátrai, Zoltán

2018-03-01

Despite well-organized Hungarian invitational mammography screening, participation rates have never reached 50%. This is similar to rates in Central Eastern Europe. In order to reduce breast cancer mortality, the participation rate should be at least 70%. This questionnaire-based study assessed the barriers associated with low adherence rates. Women 45-65 years of age were interviewed by questionnaire containing 15 structured questions focused on socioeconomic status and barriers to screening. A total of 3,313 women completed the questionnaire. The main reasons for avoiding screening were work absenteeism (18.9%), fear of painful examination (18.39%), and poor understanding of mammography screening (14.94%). Education is required to increase awareness among women about the utility and availability of breast screening services. This report provides information on the appropriate level of intervention needed to increase screening participation in Hungary and other developing countries in Central Eastern Europe to reduce breast cancer-related mortality. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

A numerically research on energy loss evaluation in a centrifugal pump system based on local entropy production method

Directory of Open Access Journals (Sweden)

Hou Hucan

2017-01-01

Full Text Available Inspired by wide application of the second law of thermodynamics to flow and heat transfer devices, local entropy production analysis method was creatively introduced into energy assessment system of centrifugal water pump. Based on Reynolds stress turbulent model and energy equation model, the steady numerical simulation of the whole flow passage of one IS centrifugal pump was carried out. The local entropy production terms were calculated by user defined functions, mainly including wall entropy production, turbulent entropy production, and viscous entropy production. The numerical results indicated that the irreversible energy loss calculated by the local entropy production method agreed well with that calculated by the traditional method but with some deviations which were probably caused by high rotatability and high curvature of impeller and volute. The wall entropy production and turbulent entropy production took up large part of the whole entropy production about 48.61% and 47.91%, respectively, which indicated that wall friction and turbulent fluctuation were the major factors in affecting irreversible energy loss. Meanwhile, the entropy production rate distribution was discussed and compared with turbulent kinetic energy dissipation rate distribution, it showed that turbulent entropy production rate increased sharply at the near wall regions and both distributed more uniformly. The blade region in leading edge near suction side, trailing edge and volute tongue were the main regions to generate irreversible exergy loss. This research broadens a completely new view in evaluating energy loss and further optimizes pump using entropy production minimization.

A novel evaluation of heat-electricity cost allocation in cogenerations based on entropy change method

International Nuclear Information System (INIS)

Ye, Xuemin; Li, Chunxi

2013-01-01

As one of the most significant measures to improve energy utilization efficiency and save energy, cogeneration or combined heat and power (CHP) has been widely applied and promoted with positive motivations in many countries. A rational cost allocation model should indicate the performance of cogenerations and balance the benefits between electricity generation and heat production. Based on the second law of thermodynamics, the present paper proposes an entropy change method for cost allocation by choosing exhaust steam entropy as a datum point, and the new model works in conjunction with entropy change and irreversibility during energy conversion processes. The allocation ratios of heat cost with the present and existing methods are compared for different types of cogenerations. Results show that the allocation ratios with the entropy change method are more rational and the cost allocation model can make up some limitations involved in other approaches. The future energy policies and innovational directions for cogenerations and heat consumers should be developed. - Highlights: • A rational model of cogeneration cost allocation is established. • Entropy change method integrates the relation of entropy change and exergy losses. • The unity of measuring energy quality and quantity is materialized. • The benefits between electricity generation and heat production are balanced

Mammography screening among Arab American women in metropolitan Detroit.

Science.gov (United States)

Schwartz, Kendra; Fakhouri, Monty; Bartoces, Monina; Monsur, Joseph; Younis, Amani

2008-12-01

Mammography screening behavior has not been well studied among Middle Eastern immigrant women. We conducted a telephone survey of 365 Arab American women residing in metropolitan Detroit, home to one of the largest populations of Middle Eastern immigrants in the US, to determine prevalence of factors associated with mammography, and attitudes and beliefs regarding mammography screening. Of 365 participants, only five were born in the US. Mean age was 53.2 years (SD 10.8). Two hundred twelve (58.1%) reported having mammogram every 1-2 years; 70% ever had mammogram. Age 50-64 years, having health insurance, married status, being in the US over 10 years, and being Lebanese were associated with mammography every 1-2 years. After adjusting for demographic factors, perceived seriousness of disease, general health motivation, and having fewer barriers were associated with more frequent screening. Appropriate mammography screening is decreased in this group. Targeted outreach regarding screening is appropriate for this population; however, lack of insurance may prevent adequate follow-up.

A Systematic Methodology for Uncertainty Analysis of Group Contribution Based and Atom Connectivity Index Based Models for Estimation of Properties of Pure Components

DEFF Research Database (Denmark)

Hukkerikar, Amol; Sarup, Bent; Sin, Gürkan

, entropy of vaporization, surface tension, viscosity, flash point, auto ignition temperature, Hansen solubility parameters, Hildebrand solubility parameter, aqueous solubility, octanol/water partition coefficient, compressibility factor, molar volume, molar refraction, refractive index and lethal...

Entanglement entropy and differential entropy for massive flavors

International Nuclear Information System (INIS)

Jones, Peter A.R.; Taylor, Marika

2015-01-01

In this paper we compute the holographic entanglement entropy for massive flavors in the D3-D7 system, for arbitrary mass and various entangling region geometries. We show that the universal terms in the entanglement entropy exactly match those computed in the dual theory using conformal perturbation theory. We derive holographically the universal terms in the entanglement entropy for a CFT perturbed by a relevant operator, up to second order in the coupling; our results are valid for any entangling region geometry. We present a new method for computing the entanglement entropy of any top-down brane probe system using Kaluza-Klein holography and illustrate our results with massive flavors at finite density. Finally we discuss the differential entropy for brane probe systems, emphasising that the differential entropy captures only the effective lower-dimensional Einstein metric rather than the ten-dimensional geometry.

Diagnostic performance of dual-energy contrast-enhanced subtracted mammography in dense breasts compared to mammography alone: interobserver blind-reading analysis.

Science.gov (United States)

Cheung, Yun-Chung; Lin, Yu-Ching; Wan, Yung-Liang; Yeow, Kee-Min; Huang, Pei-Chin; Lo, Yung-Feng; Tsai, Hsiu-Pei; Ueng, Shir-Hwa; Chang, Chee-Jen

2014-10-01

To analyse the accuracy of dual-energy contrast-enhanced spectral mammography in dense breasts in comparison with contrast-enhanced subtracted mammography (CESM) and conventional mammography (Mx). CESM cases of dense breasts with histological proof were evaluated in the present study. Four radiologists with varying experience in mammography interpretation blindly read Mx first, followed by CESM. The diagnostic profiles, consistency and learning curve were analysed statistically. One hundred lesions (28 benign and 72 breast malignancies) in 89 females were analysed. Use of CESM improved the cancer diagnosis by 21.2 % in sensitivity (71.5 % to 92.7 %), by 16.1 % in specificity (51.8 % to 67.9 %) and by 19.8 % in accuracy (65.9 % to 85.8 %) compared with Mx. The interobserver diagnostic consistency was markedly higher using CESM than using Mx alone (0.6235 vs. 0.3869 using the kappa ratio). The probability of a correct prediction was elevated from 80 % to 90 % after 75 consecutive case readings. CESM provided additional information with consistent improvement of the cancer diagnosis in dense breasts compared to Mx alone. The prediction of the diagnosis could be improved by the interpretation of a significant number of cases in the presence of 6 % benign contrast enhancement in this study. • DE-CESM improves the cancer diagnosis in dense breasts compared with mammography. • DE-CESM shows greater consistency than mammography alone by interobserver blind reading. • Diagnostic improvement of DE-CESM is independent of the mammographic reading experience.

EEG artifacts reduction by multivariate empirical mode decomposition and multiscale entropy for monitoring depth of anaesthesia during surgery.

Science.gov (United States)

Liu, Quan; Chen, Yi-Feng; Fan, Shou-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

2017-08-01

Electroencephalography (EEG) has been widely utilized to measure the depth of anaesthesia (DOA) during operation. However, the EEG signals are usually contaminated by artifacts which have a consequence on the measured DOA accuracy. In this study, an effective and useful filtering algorithm based on multivariate empirical mode decomposition and multiscale entropy (MSE) is proposed to measure DOA. Mean entropy of MSE is used as an index to find artifacts-free intrinsic mode functions. The effect of different levels of artifacts on the performances of the proposed filtering is analysed using simulated data. Furthermore, 21 patients' EEG signals are collected and analysed using sample entropy to calculate the complexity for monitoring DOA. The correlation coefficients of entropy and bispectral index (BIS) results show 0.14 ± 0.30 and 0.63 ± 0.09 before and after filtering, respectively. Artificial neural network (ANN) model is used for range mapping in order to correlate the measurements with BIS. The ANN method results show strong correlation coefficient (0.75 ± 0.08). The results in this paper verify that entropy values and BIS have a strong correlation for the purpose of DOA monitoring and the proposed filtering method can effectively filter artifacts from EEG signals. The proposed method performs better than the commonly used wavelet denoising method. This study provides a fully adaptive and automated filter for EEG to measure DOA more accuracy and thus reduce risk related to maintenance of anaesthetic agents.

Mammography and ultrasound in the evaluation of male breast disease

Energy Technology Data Exchange (ETDEWEB)

Munoz Carrasco, Rafaela; Alvarez Benito, Marina; Raya Povedano, Jose Luis [Hospital Universitario ' Reina Sofia' , Radiology Department, Cordoba (Spain); Munoz Gomariz, Elisa [Hospital Universitario ' Reina Sofia' , Support Unit for Research, Cordoba (Spain); Martinez Paredes, Maria [University of Cordoba, Radiology and Physical Medicine Area, Cordoba (Spain)

2010-12-15

To assess clinical variables that may be useful in differentiating gynaecomastia from carcinoma and to analyse the contribution of mammography and ultrasound to the evaluation of male breast disease. All men who underwent mammography and/or ultrasound between 1993 and 2006 in our hospital were retrospectively evaluated. Clinical characteristics in patients with gynaecomastia and those with carcinoma were compared. Radiological findings were classified according to the BI-RADS (Breast Imaging Reporting and Data System) criteria. The diagnostic performance of physical examination, mammography and ultrasound was determined and compared. A total of 628 patients with 518 mammograms and 423 ultrasounds were reviewed. The final diagnoses were: 19 carcinomas, 526 gynaecomastias, 84 other benign conditions and 25 normal. There were statistically significant differences in age, bilateral involvement, clinical presentation and physical examination between patients with carcinoma and those with gynaecomastia. The diagnostic performance of physical examination was lower than that of mammography and ultrasound (p < 0.05 for specificity). Mammography was the most sensitive (94.7%) and ultrasound the most specific (95.3%) for detection of malignancy (p > 0.05). We propose an algorithm for the use of mammography and ultrasound in men. Mammography and ultrasound, with a negative predictive value close to 100%, make it possible to avoid very many unnecessary surgical procedures in men. (orig.)

Time dependence of entropy flux and entropy production for a dynamical system driven by noises with coloured cross-correlation

Institute of Scientific and Technical Information of China (English)

Xie Wen-Xian; Xu Wei; Cai Li

2007-01-01

This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon's information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.

Dynamic Cross-Entropy.

Science.gov (United States)

Aur, Dorian; Vila-Rodriguez, Fidel

2017-01-01

Complexity measures for time series have been used in many applications to quantify the regularity of one dimensional time series, however many dynamical systems are spatially distributed multidimensional systems. We introduced Dynamic Cross-Entropy (DCE) a novel multidimensional complexity measure that quantifies the degree of regularity of EEG signals in selected frequency bands. Time series generated by discrete logistic equations with varying control parameter r are used to test DCE measures. Sliding window DCE analyses are able to reveal specific period doubling bifurcations that lead to chaos. A similar behavior can be observed in seizures triggered by electroconvulsive therapy (ECT). Sample entropy data show the level of signal complexity in different phases of the ictal ECT. The transition to irregular activity is preceded by the occurrence of cyclic regular behavior. A significant increase of DCE values in successive order from high frequencies in gamma to low frequencies in delta band reveals several phase transitions into less ordered states, possible chaos in the human brain. To our knowledge there are no reliable techniques able to reveal the transition to chaos in case of multidimensional times series. In addition, DCE based on sample entropy appears to be robust to EEG artifacts compared to DCE based on Shannon entropy. The applied technique may offer new approaches to better understand nonlinear brain activity. Copyright © 2016 Elsevier B.V. All rights reserved.

Organization and standards of screening and diagnostic mammography

International Nuclear Information System (INIS)

Linderbraten, L.D.; Chikirdin, Eh.G.; Rozhkova, N.I.

1999-01-01

Problem of organizing and standards of the reference and diagnostic mammography in our country is discussed. Attention is paid to the terminology, accreditation of mammographic establishments and specialists, specifications of equipment, image quality, mammography results processing, radiation doses [ru

Chatter detection in milling process based on VMD and energy entropy

Science.gov (United States)

Liu, Changfu; Zhu, Lida; Ni, Chenbing

2018-05-01

This paper presents a novel approach to detect the milling chatter based on Variational Mode Decomposition (VMD) and energy entropy. VMD has already been employed in feature extraction from non-stationary signals. The parameters like number of modes (K) and the quadratic penalty (α) need to be selected empirically when raw signal is decomposed by VMD. Aimed at solving the problem how to select K and α, the automatic selection method of VMD's based on kurtosis is proposed in this paper. When chatter occurs in the milling process, energy will be absorbed to chatter frequency bands. To detect the chatter frequency bands automatically, the chatter detection method based on energy entropy is presented. The vibration signal containing chatter frequency is simulated and three groups of experiments which represent three cutting conditions are conducted. To verify the effectiveness of method presented by this paper, chatter feather extraction has been successfully employed on simulation signals and experimental signals. The simulation and experimental results show that the proposed method can effectively detect the chatter.

Epileptic seizure detection using DWT-based approximate entropy, Shannon entropy and support vector machine: a case study.

Science.gov (United States)

Sharmila, A; Aman Raj, Suman; Shashank, Pandey; Mahalakshmi, P

2018-01-01

In this work, we have used a time-frequency domain analysis method called discrete wavelet transform (DWT) technique. This method stand out compared to other proposed methods because of its algorithmic elegance and accuracy. A wavelet is a mathematical function based on time-frequency analysis in signal processing. It is useful particularly because it allows a weak signal to be recovered from a noisy signal without much distortion. A wavelet analysis works by analysing the image and converting it to mathematical function which is decoded by the receiver. Furthermore, we have used Shannon entropy and approximate entropy (ApEn) for extracting the complexities associated with electroencephalographic (EEG) signals. The ApEn is a suitable feature to characterise the EEGs because its value drops suddenly due to excessive synchronous discharge of neurons in the brain during epileptic activity in this study. EEG signals are decomposed into six EEG sub-bands namely D1-D5 and A5 using DWT technique. Non-linear features such as ApEn and Shannon entropy are calculated from these sub-bands and support vector machine classifiers are used for classification purpose. This scheme is tested using EEG data recorded from five healthy subjects and five epileptic patients during the inter-ictal and ictal periods. The data are acquired from University of Bonn, Germany. The proposed method is evaluated through 15 classification problems, and obtained high classification accuracy of 100% for two cases and it indicates the good classifying performance of the proposed method.

Symplectic entropy

International Nuclear Information System (INIS)

De Nicola, Sergio; Fedele, Renato; Man'ko, Margarita A; Man'ko, Vladimir I

2007-01-01

The tomographic-probability description of quantum states is reviewed. The symplectic tomography of quantum states with continuous variables is studied. The symplectic entropy of the states with continuous variables is discussed and its relation to Shannon entropy and information is elucidated. The known entropic uncertainty relations of the probability distribution in position and momentum of a particle are extended and new uncertainty relations for symplectic entropy are obtained. The partial case of symplectic entropy, which is optical entropy of quantum states, is considered. The entropy associated to optical tomogram is shown to satisfy the new entropic uncertainty relation. The example of Gaussian states of harmonic oscillator is studied and the entropic uncertainty relations for optical tomograms of the Gaussian state are shown to minimize the uncertainty relation

Mammography: an update of the EUSOBI recommendations on information for women

OpenAIRE

Sardanelli, Francesco; Fallenberg, Eva M.; Clauser, Paola; Trimboli, Rubina M.; Camps-Herrero, Julia; Helbich, Thomas H.; Forrai, Gabor

2016-01-01

Abstract This article summarises the information to be offered to women about mammography. After a delineation of the aim of early diagnosis of breast cancer, the difference between screening mammography and diagnostic mammography is explained. The need to bring images and reports from the previous mammogram (and from other recent breast imaging examinations) is highlighted. Mammography technique and procedure are described with particular attention to discomfort and pain experienced by a sma...

Time-dependent entropy evolution in microscopic and macroscopic electromagnetic relaxation

International Nuclear Information System (INIS)

Baker-Jarvis, James

2005-01-01

This paper is a study of entropy and its evolution in the time and frequency domains upon application of electromagnetic fields to materials. An understanding of entropy and its evolution in electromagnetic interactions bridges the boundaries between electromagnetism and thermodynamics. The approach used here is a Liouville-based statistical-mechanical theory. I show that the microscopic entropy is reversible and the macroscopic entropy satisfies an H theorem. The spectral entropy development can be very useful for studying the frequency response of materials. Using a projection-operator based nonequilibrium entropy, different equations are derived for the entropy and entropy production and are applied to the polarization, magnetization, and macroscopic fields. I begin by proving an exact H theorem for the entropy, progress to application of time-dependent entropy in electromagnetics, and then apply the theory to relevant applications in electromagnetics. The paper concludes with a discussion of the relationship of the frequency-domain form of the entropy to the permittivity, permeability, and impedance

Mammography image assessment; validity and reliability of current scheme

International Nuclear Information System (INIS)

Hill, C.; Robinson, L.

2015-01-01

Mammographers currently score their own images according to criteria set out by Regional Quality Assurance. The criteria used are based on the ‘Perfect, Good, Moderate, Inadequate’ (PGMI) marking criteria established by the National Health Service Breast Screening Programme (NHSBSP) in their Quality Assurance Guidelines of 2006 1 . This document discusses the validity and reliability of the current mammography image assessment scheme. Commencing with a critical review of the literature this document sets out to highlight problems with the national approach to the use of marking schemes. The findings suggest that ‘PGMI’ scheme is flawed in terms of reliability and validity and is not universally applied across the UK. There also appear to be differences in schemes used by trainees and qualified mammographers. Initial recommendations are to be made in collaboration with colleagues within the National Health Service Breast Screening Programme (NHSBSP), Higher Education Centres, College of Radiographers and the Royal College of Radiologists in order to identify a mammography image appraisal scheme that is fit for purpose. - Highlights: • Currently no robust evidence based marking tools in use for the assessment of images in mammography. • Is current system valid, reliable and robust? • How can the current image assessment tool be improved? • Should students and qualified mammographers use the same tool? • What marking criteria are available for image assessment?

Specialized software for optimization of the quality control of the mammography units

International Nuclear Information System (INIS)

Stoeva, M.; Vassileva, J.

2004-01-01

Quality control is essential to ensure the equipment used is reliable and consistent in order to maintain radiation does as low as reasonably achievable whilst optimizing image quality and performance in mammography. The effectiveness of mammographic screening is highly dependent on the consistent production of high quality diagnostic images. Mammography is highly dependent on the equipment status, which requires an effective Quality Control (QC) program to provide tools for continuous assessment of the equipment performance and also data storage and analysis of the protocols' data. The objective of this paper is to present the specialized software for Quality Control of the Mammography Units, as tool providing additional functionality for optimizations of the Mammography QC data storage and management. The PC program was developed according to the requirements stated in the European protocol for Quality Control of the Mammography Screening and the data collected as a result of its application in several Bulgarian hospitals. The Structured Analysis method was used in order to perform a case, which resulted in the development of the specialized software with a database module, providing the following functionality: Data Storage, Preliminary Data Processing and Post-Processing, Manual Data Entry, Data Import from XLS format, Data Export to XLS format, Printing, Data Filters, Automated Calculation, Automated Graphical Representation, Archiving The development of specialized QC software with a database for mammography units facilitates the process of QC data storage and handling and minimizes the errors. The electronic format for data storage is especially useful in case of long-term storage and periodical data analysis/access. The integrated data processing functionality and the automated import/export features based on standard platform increase the compatibility of the data. (authors)

Diagnostic accuracy and recall rates for digital mammography and digital mammography combined with one-view and two-view tomosynthesis: results of an enriched reader study.

Science.gov (United States)

Rafferty, Elizabeth A; Park, Jeong Mi; Philpotts, Liane E; Poplack, Steven P; Sumkin, Jules H; Halpern, Elkan F; Niklason, Loren T

2014-02-01

The purpose of this study was to compare two methods of combining tomosynthesis with digital mammography by assessing diagnostic accuracy and recall rates for digital mammography alone and digital mammography combined with one-view tomosynthesis and two-view tomosynthesis. Three hundred ten cases including biopsy-proven malignancies (51), biopsy-proven benign findings (47), recalled screening cases (138), and negative screening cases (74) were reviewed by 15 radiologists sequentially using digital mammography, adding one-view tomosynthesis, and then two-view tomosynthesis. Cases were assessed for recall and assigned a BI-RADS score and probability of malignancy for each imaging method. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analysis. Screening recall rates were compared using pooled logistical regression analysis. A p value of tomosynthesis, and DM plus two-view tomosynthesis was 0.828, 0.864, and 0.895, respectively. Both one-view and two-view tomosynthesis plus DM were significantly better than DM alone (Δ AUCs 0.036 [p = 0.009] and 0.068 [p tomosynthesis, and DM plus two-view tomosynthesis were 44.2%, 27.2%, and 24.0%, respectively. Combined with DM, one-view and two-view tomosynthesis both showed significantly lower noncancer recall rates than digital mammography alone (p tomosynthesis showed a significantly lower recall rate than digital mammography with one-view tomosynthesis (p tomosynthesis compared with digital mammography alone. Compared with digital mammography, diagnostic sensitivity for invasive cancers increased with the addition of both one-view (Δ12.0%, p tomosynthesis. The addition of one-view tomosynthesis to conventional digital mammography improved diagnostic accuracy and reduced the recall rate; however, the addition of two-view tomosynthesis provided twice the performance gain in diagnostic accuracy while further reducing the recall rate.

Controlling the Shannon Entropy of Quantum Systems

Science.gov (United States)

Xing, Yifan; Wu, Jun

2013-01-01

This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking. PMID:23818819

Controlling the Shannon Entropy of Quantum Systems

Directory of Open Access Journals (Sweden)

Yifan Xing

2013-01-01

Full Text Available This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking.

Entropy for Mechanically Vibrating Systems

Science.gov (United States)

Tufano, Dante

, which demonstrates the applicability of entropy-based approaches to real-world systems. Three systems are considered to demonstrate these findings: 1) a rod end-coupled to a simple oscillator, 2) two end-coupled rods, and 3) two end-coupled beams. The aforementioned work utilizes the weak coupling assumption to determine the entropy of composite systems. Following this discussion, a direct method of finding entropy is developed which does not rely on this limiting assumption. The resulting entropy provides a useful benchmark for evaluating the accuracy of the weak coupling approach, and is validated using systems of coupled oscillators. The later chapters of this work discuss Khinchin's entropy as applied to nonlinear and nonconservative systems, respectively. The discussion of entropy for nonlinear systems is motivated by the desire to expand the applicability of SEA techniques beyond the linear regime. The discussion of nonconservative systems is also crucial, since real-world systems interact with their environment, and it is necessary to confirm the validity of an entropy approach for systems that are relevant in the context of SEA. Having developed a mathematical framework for determining entropy under a number of previously unexplored cases, the relationship between thermodynamics and statistical vibroacoustics can be better understood. Specifically, vibroacoustic temperatures can be obtained for systems that are not necessarily linear or weakly coupled. In this way, entropy provides insight into how the power flow proportionality of statistical energy analysis (SEA) can be applied to a broader class of vibroacoustic systems. As such, entropy is a useful tool for both justifying and expanding the foundational results of SEA.

Control of quality in mammography

International Nuclear Information System (INIS)

2006-10-01

The present protocol of quality control/quality assurance in mammography is the result of the work of two regional projects realised in Latin America within the frame of ARCAL with the support of the IAEA. The first is ARCAL LV (RLA/6/043) project on quality assurance/quality control in mammography studies which analysed the present situation of the mammography in the member countries of the project which include: Bolivia, Colombia, Costa Rica, Cuba, El Salvador, Guatemala, Nicaragua, Panama, Paraguay, Peru, Dominican Republic and Republic of Venezuela and the second is ARCAL XLIX (RLA/9/035) project, whose members were Brazil, Colombia, Cuba, Chile, Mexico, and Peru, worked the application of Basic Safety Standards for the protection against ionising radiation with the aim to improve radiation protection in X-ray diagnosis medical practices through the implementation of the Basic Safety Standards (BSS) related to x-ray diagnosis in selected hospitals located in each country involved in the project. The work of both projects had been consolidated and harmonized in the present publication

Brain tissue segmentation using q-entropy in multiple sclerosis magnetic resonance images

Directory of Open Access Journals (Sweden)

P.R.B. Diniz

2010-01-01

Full Text Available The loss of brain volume has been used as a marker of tissue destruction and can be used as an index of the progression of neurodegenerative diseases, such as multiple sclerosis. In the present study, we tested a new method for tissue segmentation based on pixel intensity threshold using generalized Tsallis entropy to determine a statistical segmentation parameter for each single class of brain tissue. We compared the performance of this method using a range of different q parameters and found a different optimal q parameter for white matter, gray matter, and cerebrospinal fluid. Our results support the conclusion that the differences in structural correlations and scale invariant similarities present in each tissue class can be accessed by generalized Tsallis entropy, obtaining the intensity limits for these tissue class separations. In order to test this method, we used it for analysis of brain magnetic resonance images of 43 patients and 10 healthy controls matched for gender and age. The values found for the entropic q index were 0.2 for cerebrospinal fluid, 0.1 for white matter and 1.5 for gray matter. With this algorithm, we could detect an annual loss of 0.98% for the patients, in agreement with literature data. Thus, we can conclude that the entropy of Tsallis adds advantages to the process of automatic target segmentation of tissue classes, which had not been demonstrated previously.

Barriers to Mammography Screening: How to Overcome Them

Directory of Open Access Journals (Sweden)

Yasmin Hassoun

2015-10-01

Full Text Available Background: Screening mammography is an established intervention that leads to early breast cancer detection and reduced mortality. The Lebanese Ministry of Health has initiated yearly awareness campaigns and provided free mammography in multiple centers around the country. Methods: The study took place in two major areas of Lebanon - Beirut and South Lebanon. This cross-sectional survey aimed to assess knowledge about breast cancer screening and screening behaviors in the Lebanese population. The primary outcome of the study was to assess the reasons that prevented women from performing screening mammography based on our categories of questions: lack of knowledge about breast cancer, lack of access to screening facilities, failure of primary care physician to encourage screening behavior, and other reasons. Results: The major barriers to seek screening that had statistically significant P-values, in order of prevalence, included: lack of knowledge about breast cancer, followed by social reasons and lack of access. Conclusion: Given the prevalence of breast cancer in our population, it is important to understand the pitfalls that we experience in promoting awareness. Our study is the first study to reach out to the community to assess perceived barriers against screening and provide solutions for such barriers.

Cancer of the breast: induction by radiation and role of mammography

Energy Technology Data Exchange (ETDEWEB)

Simon, N

1977-10-01

Conflict in the management of cancer of the breast exists. Diagnosis by x-ray mammography provides early effective treatment, but x-ray exposure to the breast is cancerogenic. Prudence requires the use of low dose x-rays in mammography, and limits the use of x-ray mammography in the young. Guide lines for the indications for mammography are changing, and large scale population exposure to radiation should await results of demonstration projects in the United States.

Entanglement entropy in top-down models

Energy Technology Data Exchange (ETDEWEB)

Jones, Peter A.R.; Taylor, Marika [Mathematical Sciences and STAG Research Centre, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom)

2016-08-26

We explore holographic entanglement entropy in ten-dimensional supergravity solutions. It has been proposed that entanglement entropy can be computed in such top-down models using minimal surfaces which asymptotically wrap the compact part of the geometry. We show explicitly in a wide range of examples that the holographic entanglement entropy thus computed agrees with the entanglement entropy computed using the Ryu-Takayanagi formula from the lower-dimensional Einstein metric obtained from reduction over the compact space. Our examples include not only consistent truncations but also cases in which no consistent truncation exists and Kaluza-Klein holography is used to identify the lower-dimensional Einstein metric. We then give a general proof, based on the Lewkowycz-Maldacena approach, of the top-down entanglement entropy formula.

Entanglement entropy in top-down models

International Nuclear Information System (INIS)

Jones, Peter A.R.; Taylor, Marika

2016-01-01

We explore holographic entanglement entropy in ten-dimensional supergravity solutions. It has been proposed that entanglement entropy can be computed in such top-down models using minimal surfaces which asymptotically wrap the compact part of the geometry. We show explicitly in a wide range of examples that the holographic entanglement entropy thus computed agrees with the entanglement entropy computed using the Ryu-Takayanagi formula from the lower-dimensional Einstein metric obtained from reduction over the compact space. Our examples include not only consistent truncations but also cases in which no consistent truncation exists and Kaluza-Klein holography is used to identify the lower-dimensional Einstein metric. We then give a general proof, based on the Lewkowycz-Maldacena approach, of the top-down entanglement entropy formula.

Effectiveness of a Mobile Mammography Program.

Science.gov (United States)

Stanley, Elizabeth; Lewis, Madelene C; Irshad, Abid; Ackerman, Susan; Collins, Heather; Pavic, Dag; Leddy, Rebecca J

2017-12-01

Mobile mammography units have increasingly been used to address patient health care disparities; however, there are limited data comparing mobile units to stationary sites. This study aims to evaluate the characteristics of women who underwent mammography screening in a mobile unit versus those who underwent mammography screening at a cancer center. In this retrospective study, we analyzed all screening mammography examinations performed in a mobile unit in 2014 (n = 1433 examinations). For comparison, we randomized and reviewed an equivalent number of screening mammography examinations performed at our cancer center in 2014 (n = 1434 examinations). BI-RADS assessment, adherence to follow-up, biopsies performed, cancer detection rate, and sociodemographic variables were recorded. An independent-samples t test was conducted to identify potential differences in age between cancer center patients and mobile unit patients. Chi-square analyses were used to test for associations between location and factors such as health insurance, race, marital status, geographic area, adherence to screening guidelines, recall rate, adherence to follow-up, and cancer detection rates. Patients visiting our cancer center (mean = 57.74 years; SD = 10.55) were significantly older than those visiting the mobile unit (mean = 52.58 years; SD = 8.19; p mobile van (cancer center = 3.70%, mobile unit = 38.73%). There was a significant association between screening location and patient race (χ 2 = 118.75, p mobile unit = 33.30%), more black patients being screened in the mobile van (cancer center = 49.30%, mobile unit = 54.15%), and more Hispanic patients being screened in the mobile van (cancer center = 1.05%, mobile unit = 6.77%). There was a significant association between location and patient marital status (χ 2 = 135.61, p mobile unit = 38.31%), more single patients screened in the mobile van (cancer center = 25.17%, mobile unit = 34.47%), and more widowed patients being screened at the

Analyzing Multiple-Probe Microarray: Estimation and Application of Gene Expression Indexes

KAUST Repository

Maadooliat, Mehdi; Huang, Jianhua Z.; Hu, Jianhua

2012-01-01

model, which is similar to the additive model discussed in Irizarry et al. (2003a) at the logarithm scale. Along this line, Hu et al. (2006) proposed data transformation to improve expression index estimation based on an ad hoc entropy criteria and naive

Radiology Residents' Performance in Screening Mammography Interpretation

International Nuclear Information System (INIS)

Lee, Eun Hye; Lyou, Chae Yeon

2013-01-01

To evaluate radiology residents' performance in screening mammography interpretation and to analyze the factors affecting performance. We enrolled 203 residents from 21 institutions and performed mammography interpretation tests. Between the trainee and non-trainee groups, we compared the interpretation score, recall rate, sensitivity, positive predictive value (PPV) and false-positive rate (FPR). We estimated the training effect using the score differences between trainee and non-trainee groups. We analyzed the factors affecting performance between training-effective and non-effective groups. Trainees were superior to non-trainees regarding interpretation score (43.1 vs. 37.1), recall rate (11.0 vs. 15.5%), sensitivity (83.6 vs. 72.0%), PPV (53.0 vs. 32.4%) and FPR (13.5 vs. 25.5). The longer the training period, the better were the interpretation score, recall rate, sensitivity, PPV and FPR (rho = 0.486, -0.375, 0.343, 0.504, -0.446, respectively). The training affected an increase by an average of 6 points; however, 31.6% of institutions showed no effect. A difference was noted in the volume of mammography interpretation during a month (594.0 vs. 476.9) and dedication of breast staff (61.5 vs. 0%) between training-effective and non-effective groups. Trainees showed better performance in mammography interpretation compared to non-trainees. Moreover, performance was correlated with the training period. The factors affecting performance were the volume of mammography interpretation and the dedication of the breast staff.

Exposure and roentgen-area-product in xeromammography and conventional mammography

Energy Technology Data Exchange (ETDEWEB)

Baxt, J H; Bushong, S C; Glaze, S; Kothari, S [Baylor Univ., Houston, Tex. (USA). Coll. of Medicine

1976-01-01

X-ray mammography is assuming increasing importance in the early detection of breast cancer. The principal disadvantage to conventional mammography is high patient dose. Xeromammography offers three advantages over conventional mammography: (a) lower patient dose, (b) better image quality and (c) no special mammography tube required. A transmission ionization chamber and thermoluminescent dosimeters were used to measure the roentgen-area-product and the exposure for three view examination. Average roentgen-area-product values of 6500 and 4200 R-cm/sup 2/ were observed for conventional mammography and xeromammography respectively. The medial surface of the breast received the highest radiation exposure for both types of examinations and this was shown to be 11.5 and 5.1 R respectively. Omission of the axillary view from the examination reduces the patient dose in both types by approximately 60 %.

Quality assurance programme at Slovak mammography departments

International Nuclear Information System (INIS)

Horvathova, M.; Nikodemova, D.

2004-01-01

A co-ordinated research program (CRP) for optimisation of image quality in mammography in some Eastern European countries has been initiated by IAEA between 1999 and 2001 and the Slovak Republic took part in this program. The aim of this program was to implement the European QA/QC protocol in a sample of mammography departments and to achieve improvement of the image quality and patient dose reduction. On the national level 28 mammography units were chosen in accordance with equipment performance for quality control programme at this departments, for the first part of the mammography audit in the years 2002-2004. Realisation of CRP project contains: 1) Collection and evaluation of clinical images in agreement with EC criteria; 2) Evaluation of the image quality using mammography test phantom; 3) Measurements of the ESD at patients using TLD; 4) Intercomparison of TLD system calibration with IAEA laboratory; 5) Film reject analysis; 6) Implementation of QC program to the mammography units. The measurements of ESD on patients were performed with TLD (LiF 700 Harshaw). In the 6 month period were collected the results of measurements of: 1) object thickness compensation (measured weekly); 2) long time reproducibility (measured daily); 3) phantom image quality on the standard RMI 156 phantom (measured weekly); 4) ESD on phantom with TLD (once during the audit). Automatic Exposure Control compensation for the object thickness variation was measured by exposing different PMMA plates of thickness ranging from 20 to 60 mm, using the clinical settings. The long term reproducibility has been assessed from the measurements of the optical density and mAs product resulted from the exposure on the PMMA plates. In order to estimate the quality of the images the RMI 156 mammography accreditation phantom was chosen. The accreditation phantom contains test objects which simulate small structures seen in the breast (microcalcifications, fibrils, and tumor like masses). Results of

Problems in black-hole entropy interpretation

International Nuclear Information System (INIS)

Liberati, S.

1997-01-01

In this work some proposals for black-hole entropy interpretation are exposed and investigated. In particular, the author will firstly consider the so-called 'entanglement entropy' interpretation, in the framework of the brick wall model and the divergence problem arising in the one-loop calculations of various thermodynamical quantities, like entropy, internal energy and heat capacity. It is shown that the assumption of equality of entanglement entropy and Bekenstein-Hawking one appears to give inconsistent results. These will be a starting point for a different interpretation of black.hole entropy based on peculiar topological structures of manifolds with 'intrinsic' thermodynamical features. It is possible to show an exact relation between black-hole gravitational entropy and topology of these Euclidean space-times. the expression for the Euler characteristic, through the Gauss-Bonnet integral, and the one for entropy for gravitational instantons are proposed in a form which makes the relation between these self-evident. Using this relation he propose a generalization of the Bekenstein-Hawking entropy in which the former and Euler characteristic are related in the equation S = χA / 8. Finally, he try to expose some conclusions and hypotheses about possible further development of this research

The accuracy of digital breast tomosynthesis compared with coned compression magnification mammography in the assessment of abnormalities found on mammography

International Nuclear Information System (INIS)

Morel, J.C.; Iqbal, A.; Wasan, R.K.; Peacock, C.; Evans, D.R.; Rahim, R.; Goligher, J.; Michell, M.J.

2014-01-01

Aim: To compare the diagnostic accuracy of the digital breast tomosynthesis (DBT) with coned compression magnification mammography (CCMM). Materials and methods: The study design included two reading sessions completed by seven experienced radiologists. In the first session, all readers read bilateral standard two-view mammograms and a CCMM view of the lesion before giving a combined score for assessment. In the second session, readers read bilateral standard two-view mammograms plus one-view DBT. The two reading sessions of the experiment were separated by at least 2 weeks to reduce the chance of reader memory of the images read in the previous session from influencing the performance in the subsequent session. Results: Three hundred and fifty-four lesions were assessed and receiver-operative characteristic (ROC) analysis was used to evaluate the difference between the two modes. For standard two-view mammography plus CCMM, the area under the curve (AUC) was 0.87 [95% confidence interval (CI): 0.83–0.91] and for standard two-view mammography plus DBT the AUC was 0.93 (95% CI: 0.91–0.95). The difference between the AUCs was 0.06 with p-value of 0.0014. Conclusion: Two-view mammography with one-view DBT showed significantly improved accuracy compared to two-view mammography and CCMM in the assessment of mammographic abnormalities. These results show that DBT can be used effectively in the further evaluation of mammographic abnormalities found at screening and in symptomatic diagnostic practice. - Highlights: • Diagnostic accuracy of magnification mammography and digital breast tomosynthesis. • There is statistical difference between CCMM and DBT. • DBT has a role in evaluating mammographic abnormalities

Dose to population as a metric in the design of optimised exposure control in digital mammography

International Nuclear Information System (INIS)

Klausz, R.; Shramchenko, N.

2005-01-01

This paper describes a methods for automatic optimisation of parameter (AOP) in digital mammography systems. Using a model of the image chain, contrast to noise ratio (CNR) and average glandular dose (AGD) are computed for possible X-ray parameters and breast types. The optimisation process consists of the determination of the operating points providing the lowest possible AGD for each CNR level and breast type. The proposed metric for the dose used in the design of an AOP mode is the resulting dose to the population, computed by averaging the AGD values over the distribution of breast types in the population. This method has been applied to the automatic exposure control of new digital mammography equipment. Breast thickness and composition are estimated from a low dose pre-exposure and used to index tables containing sets of optimised operating points. The resulting average dose to the population ranges from a level comparable to state-of-the-art screen/film mammography to a reduction by a factor of two. Using this method, both CNR and dose are kept under control for all breast types, taking into consideration both individual and collective risk. (authors)

Validation of electrical impedance tomography qualitative and quantitative values and comparison of the numeric pain distress score against mammography.

Science.gov (United States)

Juliana, Norsham; Shahar, Suzana; Chelliah, Kanaga Kumari; Ghazali, Ahmad Rohi; Osman, Fazilah; Sahar, Mohd Azmani

2014-01-01

Electrical impedance tomography (EIT) is a potential supplement for mammogram screening. This study aimed to evaluate and feasibility of EIT as opposed to mammography and to determine pain perception with both imaging methods. Women undergoing screening mammography at the Radiology Department of National University of Malaysia Medical Centre were randomly selected for EIT imaging. All women were requested to give a pain score after each imaging session. Two independent raters were chosen to define the image findings of EIT. A total of 164 women in the age range from 40 to 65-year-old participated and were divided into two groups; normal and abnormal. EIT sensitivity and specificity for rater 1 were 69.4% and 63.3, whereas for rater 2 they were 55.3% and 57.0% respectively. The reliability for each rater ranged between good to very good (p<0.05). Quantitative values of EIT showed there were significant differences in all values between groups (ANCOVA, p<0.05). Interestingly, EIT scored a median pain score of 1.51±0.75 whereas mammography scored 4.15±0.87 (Mann Whitney U test, p<0.05). From these quantitative values, EIT has the potential as a health discriminating index. Its ability to replace image findings from mammography needs further investigation.

Entropy Measurement for Biometric Verification Systems.

Science.gov (United States)

Lim, Meng-Hui; Yuen, Pong C

2016-05-01

Biometric verification systems are designed to accept multiple similar biometric measurements per user due to inherent intrauser variations in the biometric data. This is important to preserve reasonable acceptance rate of genuine queries and the overall feasibility of the recognition system. However, such acceptance of multiple similar measurements decreases the imposter's difficulty of obtaining a system-acceptable measurement, thus resulting in a degraded security level. This deteriorated security needs to be measurable to provide truthful security assurance to the users. Entropy is a standard measure of security. However, the entropy formula is applicable only when there is a single acceptable possibility. In this paper, we develop an entropy-measuring model for biometric systems that accepts multiple similar measurements per user. Based on the idea of guessing entropy, the proposed model quantifies biometric system security in terms of adversarial guessing effort for two practical attacks. Excellent agreement between analytic and experimental simulation-based measurement results on a synthetic and a benchmark face dataset justify the correctness of our model and thus the feasibility of the proposed entropy-measuring approach.