Objective assessment of image quality in conventional and digital mammography taking into account dynamic range

The goal of this work is to develop a method to objectively compare the performance of a digital and a screen-film mammography system in terms of image quality. The method takes into account the dynamic range of the image detector, the detection of high and low contrast structures, the visualisation of the images and the observer response. A test object, designed to represent a compressed breast, was constructed from various tissue equivalent materials ranging from purely adipose to purely glandular composition. Different areas within the test object permitted the evaluation of low and high contrast detection, spatial resolution and image noise. All the images (digital and conventional) were captured using a CCD camera to include the visualisation process in the image quality assessment. A mathematical model observer (non-prewhitening matched filter), that calculates the detectability of high and low contrast structures using spatial resolution, noise and contrast, was used to compare the two technologies. Our results show that for a given patient dose, the detection of high and low contrast structures is significantly better for the digital system than for the conventional screen-film system studied. The method of using a test object with a large tissue composition range combined with a camera to compare conventional and digital imaging modalities can be applied to other radiological imaging techniques. In particular it could be used to optimise the process of radiographic reading of soft copy image

Diagnostic and interventional radiology: a strategy to introduce reference dose level taking into account the national practice

The purpose of this study is to present a strategy to define the reference dose levels for fluoroscopic, dose-intensive examinations. This work is a part of the project of the Federal Office of Public Health of Switzerland to translate the guidelines of the International Commission on Radiological Protection and the European Union into action. The study will also be used to set reference dose levels on the basis of a national survey. All the fluoroscopic units, involved in the survey, were equipped with a KAP (kerma-area product) meter. All KAP meters were first calibrated to ensure the comparability of the dose measurements. The doses and the dose rates together with subjective image quality measurements were acquired in all the centres. Eight types of examination were chosen by a panel of radiologists, and each of the five centres involved agreed to monitor 20 patients per examination type. A wide variation in the dose and the image quality in fixed geometry was observed. For example, the skin dose rate for abdominal examinations varied in the range of 12-42 mGy min−1 for comparable image quality. Average KAP values of 67, 178, 106, 102, 473, 205, 307 and 316 Gy cm2 were recorded for barium meal, abdominal angiography, cerebral angiography, barium enema, hepatic embolisation, biliary drainage, cerebral embolisation and femoral stenting, respectively. The values obtained in this limited study are generally higher than the ones available in the literature and strategies to optimise these studies have to be discussed. A strict control concerning the denomination of the examination type involved in such a study is mandatory to obtain reliable data. This can only be done through a close collaboration between physicians, radiographers and medical physicist

Management of patient dose and image noise in routine pediatric CT abdominal examinations

The aim was to propose a strategy for finding reasonable compromises between image noise and dose as a function of patient weight. Weighted CT dose index (CTDIw) was measured on a multidetector-row CT unit using CTDI test objects of 16, 24 and 32cm in diameter at 80, 100, 120 and 140kV. These test objects were then scanned in helical mode using a wide range of tube currents and voltages with a reconstructed slice thickness of 5mm. For each set of acquisition parameter image noise was measured and the Rose model observer was used to test two strategies for proposing a reasonable compromise between dose and low-contrast detection performance: (1) the use of a unique noise level for all test object diameters, and (2) the use of a unique dose efficacy level defined as the noise reduction per unit dose. Published data were used to define four weight classes and an acquisition protocol was proposed for each class. The protocols have been applied in clinical routine for more than one year. CTDIvol values of 6.7, 9.4, 15.9 and 24.5mGy were proposed for the following weight classes: 2.5-5, 5-15, 15-30 and 30-50kg with image noise levels in the range of 10-15HU. The proposed method allows patient dose and image noise to be controlled in such a way that dose reduction does not impair the detection of low-contrast lesions. The proposed values correspond to high- quality images and can be reduced if only high-contrast organs are assesse

Radiation exposure in dental radiology: a 1998 nationwide survey in Switzerland

OBJECTIVES: To measure the frequencies of dental radiological examinations in Switzerland and to determine the associated collective radiation doses. METHODS: To evaluate the frequencies, a sample of 376 dental practitioners and other institutions performing dental radiology were requested to fill in questionnaires designed to measure, amongst others, frequencies of dental radiodiagnoses according to type of examination, patient age and gender, dental specialty and type of surgery. The associated collective radiation doses were determined by multiplying the relevant frequencies with dose estimates obtained from recent measurements and calculations. RESULTS: The total number of dental examinations performed in Switzerland in 1998 was 4.1 million (581 per 1000 population). Periapical, bitewing and panoramic radiographs were the most frequent types of dental examinations. The collective dose associated with dental radiology was 71 person.Sv. This amounts to an annual average effective dose to the population of 10 muSv per caput, which is in agreement with the figures reported for countries of similar healthcare level. Various features such as the age distribution of the radiographed patients, the forms of collimators used, film consumption and the use of digital imaging systems are presented. CONCLUSIONS: Several recommendations for dose reduction are made. These include the re-evaluation of the patterns and justification for prescribing some particular types of dental examinations as well as the avoidance of unnecessary irradiation by the use of rectangular collimation and high sensitivity F-speed films. [Authors]]]> Radiation Dosage; Radiography, Dental eng oai:serval.unil.ch:BIB_D2DF3BCD7DC7 2022-05-07T01:27:40Z openaire documents urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_D2DF3BCD7DC7 Immigrants: A forgotten minority info:doi:10.1111/iops.12019 info:eu-repo/semantics/altIdentifier/doi/10.1111/iops.12019 Binggeli, S. Dietz, J. Krings, F. info:eu-repo/semantics/article article 2013 Industrial and Organizational Psychology: Perspectives on Science and Practice, vol. 6, no. 1, pp. 107-113 info:eu-repo/semantics/altIdentifier/pissn/1754-9426 eng https://serval.unil.ch/resource/serval:BIB_D2DF3BCD7DC7.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_D2DF3BCD7DC75 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_D2DF3BCD7DC75 info:eu-repo/semantics/submittedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_D2E0004859CE 2022-05-07T01:27:40Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_D2E0004859CE Personality and career interventions http://www.apa.org/pubs/books/4311514.aspx?tab=2 Rossier, J. info:eu-repo/semantics/bookPart incollection 2015 APA handbook of career intervention. Vol. 1 : Foundations, vol. 1, pp. 327-350 Hartung, P. J. (ed.) Savickas, M. L. (ed.) Walsh, W. B. (ed.) info:eu-repo/semantics/altIdentifier/isbn/978-1-4338-1753-3 <![CDATA[Career interventions for adults frequently include personality assessment. Personality in career counseling contexts should no longer be considered as vocational personality associated with personality interests but, rather, as a set of dispositions that has an impact on several vocational and career-related outcomes, such as work engagement, work satisfaction, job performance, etc. Although the relationship between personality and the vocational and career related outcomes is not direct, it might certainly be mediated by several regulatory processes, such as work adaptability, and moderated by contextual and environmental factors. Personality assessment initiates an individual's self-regulatory process and contributes to the overall effectiveness of career interventions when feedback is individualized and stimulates a deconstruction, reconstruction, and co-construction of the vocational or multiple self-concept. Personality assessments can also promote the reconstruction of a self-concept more aligned with the perception of the environment about the personality of the counselee, strengthening the reality principle allowing more rational and controlled choices. In addition, some specific personality profiles, such as having high levels of neuroticism and low levels of conscientiousness, can be considered as risk factors frequently leading to career decision-making difficulties. Moreover, people with low conscientiousness benefit less from career interventions, so special attention should be devoted to counselees having that characteristic. Two case studies are provided to illustrate these important aspects of personality assessment in career interventions

Impact of the introduction of 16-row MDCT on image quality and patient dose: phantom study and multi-centre survey

The purpose was to compare the image quality and patient dose between 4- and 16-row MDCT units and to evaluate the dispersion of the dose delivered for common clinical examinations. Four 4- and 16-row MDCT units were used in the study. Image noise levels from images of a CatPhan phantom were compared for all units using a given CTDIvol of 15.0±1.0mGy. Standard acquisition protocols from ten centres, shifted from 4- to 16-row MDCT (plus one additional centre for 16-row MDCT), were compared for cerebral angiography and standard chest and abdomen examinations. In addition, the protocols used with 16-row MDCT units for diagnosis of the unstable shoulder and for cardiac examinations were also compared. The introduction of 16-MSCT units did not reduce the performance of the detectors. Concerning the acquisition protocols, a wide range in practice was observed for standard examinations; DLP varied from 800 to 5,120mGy.cm, 130 to 860mGy.cm, 410 to 1,790mGy.cm and 850 to 2,500mGy.cm for cerebral angiography, standard chest, standard abdomen and heart examinations, respectively.The introduction of 16-row MDCT did not, on average, increase the patient dose for standard chest and abdominal examinations. However, a significant dose increase has been observed for cerebral angiography. There is a wide dispersion in the doses delivered, especially for cardiac imagin

The Reasons for Discrepancies in TargetVolume Delineation: A SASRO Study on Head-and-Neck and Prostate Cancers

Purpose: : To understand the reasons for differences in the delineation of target volumes between physicians. Material and Methods: : 18 Swiss radiooncology centers were invited to delineate volumes for one prostate and one head-and-neck case. In addition, a questionnaire was sent to evaluate the differences in the volume definition (GTV [gross tumor volume], CTV [clinical target volume], PTV [planning target volume]), the various estimated margins, and the nodes at risk. Coherence between drawn and stated margins by centers was calculated. The questionnaire also included a nonspecific series of questions regarding planning methods in each institution. Results: : Fairly large differences in the drawn volumes were seen between the centers in both cases and also in the definition of volumes. Correlation between drawn and stated margins was fair in the prostate case and poor in the head-and-neck case. The questionnaire revealed important differences in the planning methods between centers. Conclusion: : These large differences could be explained by (1) a variable knowledge/interpretation of ICRU definitions, (2) variable interpretations of the potential microscopic extent, (3) difficulties in GTV identification, (4) differences in the concept, and (5) incoherence between theory (i.e., stated margins) and practice (i.e., drawn margins

X-ray imaging of the chest in Switzerland in 1998: a nationwide survey

The use in Switzerland of three chest X-ray imaging modalities is studied. The frequency and dosimetric aspects associated with chest radiography, chest CT, and photofluorography are investigated and the Swiss figures are compared with those of other countries. The frequencies are established by means of a nationwide survey performed in 1998, whereas the doses are determined by modelling, based on the technical parameters of the examinations. The annual frequencies of chest radiography, chest CT, and photofluorography are 201, 7, and 7 per thousand population, respectively. The standard effective doses related to these three types of examinations are 0.057, 9, and 0.13 mSv, respectively. The collective dose associated with chest X-ray imaging amounts to 606 man.Sv, representing 8.5% of the total collective dose due to diagnostic and interventional radiology. The geographic and seasonal variations, as well as the distribution with the medical specialty and with the age of the patient, are established. The Swiss results compare well with the average data published in the literature for other countries of similar health care level. Chest radiography shows a significant decrease with time. It dropped by a factor of 2 in 20 years. The conformity of the indication of chest X-ray modalities with referral guidelines is also investigated. [Authors]]]> Health Care Surveys ; Photofluorography ; Radiography, Thoracic ; Tomography, X-Ray Computed eng oai:serval.unil.ch:BIB_8293F0966BFE 2022-05-07T01:21:40Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_8293F0966BFE L’éducation en train de vivre une expérience post-apocalyptique. Approche herméneutique du film Snowpiercer (Bong Joon-ho, 2013) https://halshs.archives-ouvertes.fr/halshs-03213656 Camille, Roelens info:eu-repo/semantics/conferenceObject inproceedings 2021-06 Colloque international de la Société Française de Philosophie de l’Éducation (SOFPHIED) : « Éduquer pour un avenir incertain : La fin de l’école Prométhéenne ? », Université de Nantes fre oai:serval.unil.ch:BIB_8294 2022-05-07T01:21:40Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_8294 Solid-State NMR for the Study of Membrane Systems : The Use of Anisotropic Interactions. Warschawski, DE Traika, M Devaux, PF Bodenhausen, G info:eu-repo/semantics/article article 1998 Biochimie, vol. 80, pp. 437-450 oai:serval.unil.ch:BIB_8294384C7E74 2022-05-07T01:21:40Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_8294384C7E74 Outcomes after accommodative bioanalogic intraocular lens implantation. info:doi:10.3928/1081597X-20140520-01 info:eu-repo/semantics/altIdentifier/doi/10.3928/1081597X-20140520-01 info:eu-repo/semantics/altIdentifier/pmid/24972406 Pallikaris, I.G. Portaliou, D.M. Kymionis, G.D. Panagopoulou, S.I. Kounis, G.A. info:eu-repo/semantics/article article 2014-06 Journal of refractive surgery, vol. 30, no. 6, pp. 402-406 info:eu-repo/semantics/altIdentifier/pissn/1081-597X urn:issn:1081-597X <![CDATA[To evaluate the outcomes after Wichterle Intraocular Lens-Continuous Focus (Medicem, Kamenné Zehrovice, Czech Republic) accommodative bioanalogic intraocular lens implantation. In this prospective case series, 50 eyes of 25 patients (mean age: 65.3 ± 8.4 years; range: 53 to 83 years) were included. All patients underwent routine cataract surgery and Wichterle Intraocular Lens-Continuous Focus implantation. Mean follow-up was 11.44 ± 2.46 months (range: 9 to 17 months). Both monocular uncorrected and corrected distance visual acuity statistically and significantly (P &lt; .05) improved from 0.31 ± 0.17 (20/63 Snellen) (range: counting fingers to 0.7) to 0.74 ± 0.19 (20/25 Snellen) (range: 0.2 to 1) and from 0.61 ± 0.19 (20/32 Snellen) (range: 0.2 to 1) to 0.82 ± 0.13 (20/25 Snellen) (range: 0.4 to 1), respectively. Target postoperative refraction was -0.5 diopters (D) and preoperative and 1-year postoperative spherical equivalent refraction were 0.72 ± 2.71 D (range: -7.25 to 2.37 D) and -0.24 ± 0.65 D (range: -1.0 to 1.0 D), respectively. No eyes lost lines of corrected distance visual acuity during the follow-up period, whereas 88% of patients gained one or more lines of corrected distance visual acuity. Uncorrected intermediate and near visual acuity were J2 (Snellen 20/25) or better in 72% of patients. No complications occurred intraoperatively or postoperatively. The evaluation of the mean values of root mean square of third and fourth order higher-order aberrations at 1 year postoperatively revealed a mean negative spherical aberration of -0.18 ± 0.13 μm. Wichterle Intraocular Lens-Continuous Focus accommodative bioanalogic IOL implantation provides satisfactory visual acuity for far, intermediate, and near distances and the promising results remain stable throughout the follow-up period

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of diseas

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of disease