Convex optimization problem prototyping for image reconstruction in computed tomography with the Chambolle-Pock algorithm

The primal-dual optimization algorithm developed in Chambolle and Pock (CP), 2011 is applied to various convex optimization problems of interest in computed tomography (CT) image reconstruction. This algorithm allows for rapid prototyping of optimization problems for the purpose of designing iterative image reconstruction algorithms for CT. The primal-dual algorithm is briefly summarized in the article, and its potential for prototyping is demonstrated by explicitly deriving CP algorithm instances for many optimization problems relevant to CT. An example application modeling breast CT with low-intensity X-ray illumination is presented.Comment: Resubmitted to Physics in Medicine and Biology. Text has been modified according to referee comments, and typos in the equations have been correcte

The electronic absorption spectrum of crystallinechromyl chloride at 1.7[deg]K

The spectrum of chromyl chloride, CrO2Cl2 , in the region 6000 A-3800 A hasbeen obtained for the crystalline substance at temperatures down to 1.7[deg]K. Three absorption systems have been observed, together with the start of a fourth system at [lambda] < 3800 A. One of the systems has been analyzed in some detail and shown to be in agreement with conclusions drawn from the spectrum of the vapor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33234/1/0000624.pd

A comprehensive study on the relationship between image quality and imaging dose in low-dose cone beam CT

While compressed sensing (CS) based reconstructions have been developed for low-dose CBCT, a clear understanding on the relationship between the image quality and imaging dose at low dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot image quality and imaging dose together as functions of number of projections and mAs per projection over the whole clinically relevant range. A clear understanding on the tradeoff between image quality and dose can be achieved and optimal low-dose CBCT scan protocols can be developed for various imaging tasks in IGRT. Main findings of this work include: 1) Under the CS framework, image quality has little degradation over a large dose range, and the degradation becomes evident when the dose < 100 total mAs. A dose < 40 total mAs leads to a dramatic image degradation. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 total mAs, depending on the specific IGRT applications. 2) Among different scan protocols at a constant low-dose level, the super sparse-view reconstruction with projection number less than 50 is the most challenging case, even with strong regularization. Better image quality can be acquired with other low mAs protocols. 3) The optimal scan protocol is the combination of a medium number of projections and a medium level of mAs/view. This is more evident when the dose is around 72.8 total mAs or below and when the ROI is a low-contrast or high-resolution object. Based on our results, the optimal number of projections is around 90 to 120. 4) The clinically acceptable lowest dose level is task dependent. In our study, 72.8mAs is a safe dose level for visualizing low-contrast objects, while 12.2 total mAs is sufficient for detecting high-contrast objects of diameter greater than 3 mm.Comment: 19 pages, 12 figures, submitted to Physics in Medicine and Biolog

EULAR recommendations for the non-pharmacological management of systemic lupus erythematosus and systemic sclerosis

Objective To develop evidence-based recommendations for the non-pharmacological management of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). Methods A task force comprising 7 rheumatologists, 15 other healthcare professionals and 3 patients was established. Following a systematic literature review performed to inform the recommendations, statements were formulated, discussed during online meetings and graded based on risk of bias assessment, level of evidence (LoE) and strength of recommendation (SoR; scale A–D, A comprising consistent LoE 1 studies, D comprising LoE 4 or inconsistent studies), following the European Alliance of Associations for Rheumatology standard operating procedure. Level of agreement (LoA; scale 0–10, 0 denoting complete disagreement, 10 denoting complete agreement) was determined for each statement through online voting. Results Four overarching principles and 12 recommendations were developed. These concerned common and disease-specific aspects of non-pharmacological management. SoR ranged from A to D. The mean LoA with the overarching principles and recommendations ranged from 8.4 to 9.7. Briefly, non-pharmacological management of SLE and SSc should be tailored, person-centred and participatory. It is not intended to preclude but rather complement pharmacotherapy. Patients should be offered education and support for physical exercise, smoking cessation and avoidance of cold exposure. Photoprotection and psychosocial interventions are important for SLE patients, while mouth and hand exercises are important in SSc. Conclusions The recommendations will guide healthcare professionals and patients towards a holistic and personalised management of SLE and SSc. Research and educational agendas were developed to address needs towards a higher evidence level, enhancement of clinician–patient communication and improved outcomes

Educational readiness among health professionals in rheumatology: low awareness of EULAR offerings and unfamiliarity with the course content as major barriers: results of a EULAR-funded European survey

Background: Ongoing education of health professionals in rheumatology (HPR) is critical for high-quality care. An essential factor is education readiness and a high quality of educational offerings. We explored which factors contributed to education readiness and investigated currently offered postgraduate education, including the European Alliance of Associations for Rheumatology (EULAR) offerings. Methods and participants: We developed an online questionnaire, translated it into 24 languages and distributed it in 30 European countries. We used natural language processing and the Latent Dirichlet Allocation to analyse the qualitative experiences of the participants as well as descriptive statistics and multiple logistic regression to determine factors influencing postgraduate educational readiness. Reporting followed the Checklist for Reporting Results of Internet E-Surveys guideline. Results: The questionnaire was accessed 3589 times, and 667 complete responses from 34 European countries were recorded. The highest educational needs were 'professional development', 'prevention and lifestyle intervention'. Older age, more working experience in rheumatology and higher education levels were positively associated with higher postgraduate educational readiness. While more than half of the HPR were familiar with EULAR as an association and the respondents reported an increased interest in the content of the educational offerings, the courses and the annual congress were poorly attended due to a lack of awareness, comparatively high costs and language barriers. Conclusions: To promote the uptake of EULAR educational offerings, attention is needed to increase awareness among national organisations, offer accessible participation costs, and address language barriers.Orthopaedics, Trauma Surgery and Rehabilitatio

EULAR recommendations for the non-pharmacological management of systemic lupus erythematosus and systemic sclerosis

Objective To develop evidence-based recommendations for the non-pharmacological management of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). Methods A task force comprising 7 rheumatologists, 15 other healthcare professionals and 3 patients was established. Following a systematic literature review performed to inform the recommendations, statements were formulated, discussed during online meetings and graded based on risk of bias assessment, level of evidence (LoE) and strength of recommendation (SoR; scale AD , A comprising consistent LoE 1 studies, D comprising LoE 4 or inconsistent studies), following the European Alliance of Associations for Rheumatology standard operating procedure. Level of agreement (LoA; scale 0-10, 0 denoting complete disagreement, 10 denoting complete agreement) was determined for each statement through online voting. Results Four overarching principles and 12 recommendations were developed. These concerned common and disease-specific aspects of non-pharmacological management. SoR ranged from A to D. The mean LoA with the overarching principles and recommendations ranged from 8.4 to 9.7. Briefly, non-pharmacological management of SLE and SSc should be tailored, person-centred and participatory. It is not intended to preclude but rather complement pharmacotherapy. Patients should be offered education and support for physical exercise, smoking cessation and avoidance of cold exposure. Photoprotection and psychosocial interventions are important for SLE patients, while mouth and hand exercises are important in SSc. Conclusions The recommendations will guide healthcare professionals and patients towards a holistic and personalised management of SLE and SSc. Research and educational agendas were developed to address needs towards a higher evidence level, enhancement of clinician-patient communication and improved outcomes

The Normative Problem of Merit Goods in Perspective

In his Theory of Public Finance (1959), Musgrave invented the concept of merit wants to describe public wants that are satisfied by goods provided by the government in violation of the principle of consumer sovereignty. Starting from Musgrave’s mature discussion (1987), I construct two categories to classify the explanations of merit goods. The first strand of thought attempts to justify merit goods within the New welfare economics, by modifying its assumptions to accommodate irrationality, uncertainty, lack of information, and psychic externalities. The second category encompasses more radical departures from consumer sovereignty, drawn from philosophical critiques of economics. In the third part of the paper, I argue that the two strands might be represented by a non-individualistic social welfare function. I also show how this solution echoes Musgrave’s early views on public expenditures before he coined the concept of merit wants. From an historical perspective, the survival of the concept highlights the persistence of a social point of view in welfare economics