Graph-based concept weighting for medical information retrieval

This paper presents a graph-based method to weight medical concepts in documents for the purposes of information retrieval. Medical concepts are extracted from free-text documents using a state-of-the-art technique that maps n-grams to concepts from the SNOMED CT medical ontology. In our graph-based concept representation, concepts are vertices in a graph built from a document, edges represent associations between concepts. This representation naturally captures dependencies between concepts, an important requirement for interpreting medical text, and a feature lacking in bag-of-words representations. We apply existing graph-based term weighting methods to weight medical concepts. Using concepts rather than terms addresses vocabulary mismatch as well as encapsulates terms belonging to a single medical entity into a single concept. In addition, we further extend previous graph-based approaches by injecting domain knowledge that estimates the importance of a concept within the global medical domain. Retrieval experiments on the TREC Medical Records collection show our method outperforms both term and concept baselines. More generally, this work provides a means of integrating background knowledge contained in medical ontologies into data-driven information retrieval approaches.

Facebook, Twitter, SMS and YouTube : the ramifications and risks for surgeons

Social media revolution has impacted on how people interact with one another. This has been a worldwide phenomenon. Whilst social media had its genesis in the personal and private realm its use has expanded exponentially to professional and business contexts, as well as being adopted by governments, politicians, journalists – everyone in just about every walk of life. Although at first the uptake was slow, surgeons and other health professionals are now using social media in their professional as well as personal capacity. This comes with significant advantages and opportunities for improving surgical practice and for facilitating attending communication, but it also comes with certain risks, including legal liability. This paper outlines the ways in which social media including, Facebook, Twitter, YouTube and SMS, is increasingly being employed in surgical practice and explains the legal and ethical consequences that may inadvertently arise in its official, as well as, unofficial use.

The development of a Monte Carlo system to verify radiotherapy treatment dose calculations

Recent advances in the planning and delivery of radiotherapy treatments have resulted in improvements in the accuracy and precision with which therapeutic radiation can be administered. As the complexity of the treatments increases it becomes more difficult to predict the dose distribution in the patient accurately. Monte Carlo methods have the potential to improve the accuracy of the dose calculations and are increasingly being recognised as the “gold standard” for predicting dose deposition in the patient. In this study, software has been developed that enables the transfer of treatment plan information from the treatment planning system to a Monte Carlo dose calculation engine. A database of commissioned linear accelerator models (Elekta Precise and Varian 2100CD at various energies) has been developed using the EGSnrc/BEAMnrc Monte Carlo suite. Planned beam descriptions and CT images can be exported from the treatment planning system using the DICOM framework. The information in these files is combined with an appropriate linear accelerator model to allow the accurate calculation of the radiation field incident on a modelled patient geometry. The Monte Carlo dose calculation results are combined according to the monitor units specified in the exported plan. The result is a 3D dose distribution that could be used to verify treatment planning system calculations. The software, MCDTK (Monte Carlo Dicom ToolKit), has been developed in the Java programming language and produces BEAMnrc and DOSXYZnrc input files, ready for submission on a high-performance computing cluster. The code has been tested with the Eclipse (Varian Medical Systems), Oncentra MasterPlan (Nucletron B.V.) and Pinnacle3 (Philips Medical Systems) planning systems. In this study the software was validated against measurements in homogenous and heterogeneous phantoms. Monte Carlo models are commissioned through comparison with quality assurance measurements made using a large square field incident on a homogenous volume of water. This study aims to provide a valuable confirmation that Monte Carlo calculations match experimental measurements for complex fields and heterogeneous media.

Nurse staffing levels and the incidence of mortality and morbidity in the adult intensive care unit : a literature review

BACKGROUND: Studies have shown that nurse staffing levels, among many other factors in the hospital setting, contribute to adverse patient outcomes. Concerns about patient safety and quality of care have resulted in numerous studies being conducted to examine the relationship between nurse staffing levels and the incidence of adverse patient events in both general wards and intensive care units. AIM: The aim of this paper is to review literature published in the previous 10 years which examines the relationship between nurse staffing levels and the incidence of mortality and morbidity in adult intensive care unit patients. METHODS: A literature search from 2002 to 2011 using the MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, and Australian digital thesis databases was undertaken. The keywords used were: intensive care; critical care; staffing; nurse staffing; understaffing; nurse-patient ratios; adverse outcomes; mortality; ventilator-associated pneumonia; ventilator-acquired pneumonia; infection; length of stay; pressure ulcer/injury; unplanned extubation; medication error; readmission; myocardial infarction; and renal failure. A total of 19 articles were included in the review. Outcomes of interest are patient mortality and morbidity, particularly infection and pressure ulcers. RESULTS: Most of the studies were observational in nature with variables obtained retrospectively from large hospital databases. Nurse staffing measures and patient outcomes varied widely across the studies. While an overall statistical association between increased nurse staffing levels and decreased adverse patient outcomes was not found in this review, most studies concluded that a trend exists between increased nurse staffing levels and decreased adverse events. CONCLUSION: While an overall statistical association between increased nurse staffing levels and decreased adverse patient outcomes was not found in this review, most studies demonstrated a trend between increased nurse staffing levels and decreased adverse patient outcomes in the intensive care unit which is consistent with previous literature. While further more robust research methodologies need to be tested in order to more confidently demonstrate this association and decrease the influence of the many other confounders to patient outcomes; this would be difficult to achieve in this field of research.

Skill development and social inclusion via peer assisted learning in first-year higher education : an evaluation of student experiences across two law units

Because professions seek graduates who can 'collaborate, share skills and knowledge, and communicate' (Kruck and Reif, 2001, p 37), it is important that university graduates are not equipped solely with the content knowledge of their discipline, but also with prospective employment skills. Furthermore, when students 'interact more in positive ways with their teachers and peers, they gain more in terms of essential skills and competencies, such as critical thinking, problem~solving [and] effective communication' (NSSE, 2000, p 2)./n this way, peer assisted fellowing has the potential to enhance students' professional development, and provide the social inclusion and engagement necessary for effective learning. This session describes two peer assisted learning models embedded within first year QUT Faculty of Law units. Through a partnership between teaching staff, student mentors and mentees, the models aim to facilitate student socialisation whilst supplementing understanding of substantive law with the development of academic and work·related skills. Mentor and mentee perceptions, and program implications, are considered.

An evaluation of corpus-driven measures of medical concept similarity for information retrieval

Measures of semantic similarity between medical concepts are central to a number of techniques in medical informatics, including query expansion in medical information retrieval. Previous work has mainly considered thesaurus-based path measures of semantic similarity and has not compared different corpus-driven approaches in depth. We evaluate the effectiveness of eight common corpus-driven measures in capturing semantic relatedness and compare these against human judged concept pairs assessed by medical professionals. Our results show that certain corpus-driven measures correlate strongly (approx 0.8) with human judgements. An important finding is that performance was significantly affected by the choice of corpus used in priming the measure, i.e., used as evidence from which corpus-driven similarities are drawn. This paper provides guidelines for the implementation of semantic similarity measures for medical informatics and concludes with implications for medical information retrieval.

Gender and the capacity of women with NIDDM to implement medical advice

This qualitative study of women with non-insulin dependent diabetes mellitus (NIDDM) examined constructions of their diabetes management and socio-familial relationships as potential sources of support. Semi-structured interview data was collected from 16 women. The transcripts were analysed with the aim of examining the ways in which Sender relations structured women's accounts of health-related behaviours. Women talked about themselves as wives, mothers, being pregnant and parenting, and friends of other women in ways that demonstrated how caring for others impeded their capacity to care for themselves. Meeting the food preferences of husbands and dietary requirements of diabetic husbands were dominant themes in women's accounts of marriage, and in various ways women justified their husbands' lack of support. Furthermore, the care of others during pregnancy and parenting was also an obstacle to women caring for themselves. An awareness of the gender politics inherent within social and family contexts is crucial to improving the effectiveness of medical advice for diabetes management.

Support for patients with hepatitis C : An exploratory qualitative study of medical specialists’ perceptions

Objective: To explore the range of meanings about the role of support for patients with hepatitis C by examining medical specialists' perceptions. Method: The study employed a qualitative, open-ended interview design and was conducted in four major teaching hospitals in Adelaide, South Australia. Eight participants (three infectious disease physicians, four gastroenterologists, one hepatologist), selected through purposive sampling, were interviewed about general patient support, their role in support provision, the role of non-medical support and their reasons for not using support services. Results: Main themes included a focus on support as information provision and that patient education is best carried out by a medical specialist. The use of support services was defined as the patient's decision. Participants identified four key periods when patients would benefit from support; during diagnosis, failure to meet treatment criteria, during interferon treatment and following treatment failure. Conclusions: It was concluded that while barriers exist to the establishment of partnerships between specialists and other support services, this study has identified clear points at which future partnerships could be established. Implications: A partnership approach to developing support for patients with hepatitis C offers a systematic framework to facilitate the participation of health professionals and the community in an important area of public health.

Prostate gland and extra-capsular tissue 3D reconstruction and measurement

Currently there are little objective parameters that can quantify the success of one form of prostate surgical removal over another. Accordingly, at Old Dominion University (ODU) we have been developing a process resulting in the use of software algorithms to assess the coverage and depth of extra-capsular soft tissue removed with the prostate by the various surgical approaches. Parameters such as the percent of capsule that is bare of soft tissue and where present the depth and extent of coverage have been assessed. First, visualization methods and tools are developed for images of prostate slices that are provided to ODU by the Pathology Department at Eastern Virginia Medical School (EVMS). The visualization tools interpolate and present 3D models of the prostates. Measurement algorithms are then applied to determine statistics about extra-capsular tissue coverage. This paper addresses the modeling, visualization, and analysis of prostate gland tissue to aid in quantifying prostate surgery success. Particular attention is directed towards the accuracy of these measurements and is addressed in the analysis discussions.

Surgical site infection prevention following total hip arthroplasty in Australia : a cost-effectiveness analysis

Background: Surgical site infection (SSI) is associated with substantial costs for health services, reduced quality of life, and functional outcomes. The aim of this study was to evaluate the cost-effectiveness of strategies claiming to reduce the risk of SSI in hip arthroplasty in Australia. Methods: Baseline use of antibiotic prophylaxis (AP) was compared with no antibiotic prophylaxis (no AP), antibiotic-impregnated cement (AP þ ABC), and laminar air operating rooms (AP þ LOR). A Markov model was used to simulate long-term health and cost outcomes of a hypothetical cohort of 30,000 total hip arthroplasty patients from a health services perspective. Model parameters were informed by the best available evidence. Uncertainty was explored in probabilistic sensitivity and scenario analyses. Results: Stopping the routine use of AP resulted in over Australian dollars (AUD) $1.5 million extra costs and a loss of 163 quality-adjusted life years (QALYs). Using antibiotic cement in addition to AP (AP þ ABC)generated an extra 32 QALYs while saving over AUD $123,000. The use of laminar air operating rooms combined with routine AP (AP þ LOR) resulted in an AUD $4.59 million cost increase and 127 QALYs lost compared with the baseline comparator. Conclusion: Preventing deep SSI with antibiotic prophylaxis and antibiotic-impregnated cement has shown to improve health outcomes among hospitalized patients, save lives, and enhance resource allocation. Based on this evidence, the use of laminar air operating rooms is not recommended.

Narrative review of changing medical and feminist perspectives on menopause : from femininity and ageing to risk and choice

Meanings and descriptions of menopause have shifted focus over the past century and a half; more particularly the past sixty years has seen a shift from descriptions of hormone decline and its relation to ageing, femininity and symptoms of menopause since the 1960's to the possibility for preventive medicine afforded by menopause. Medicine is not a static field in its construction of menopause. It has changed, not least by its engagement (positively or negatively) with critique from both within (epidemiological) and without (feminist and social sciences). In this review we identify three recent changes: (1) Increasing concern with women's decision-making. (2) The emergence from within medicine of the rejection of the use of language which defines menopause as a condition of deficiency. (3) New insights from postmodern and poststructural analyses of menopause that examine the epistemological foundations of medical and feminist concepts of menopause and contest fixed descriptions of the experience of menopause. Key aspects of a ‘medical menopause’ nevertheless remain constant: menopause is a loss of hormones that results in predictable effects and risks and may be ameliorated by hormone replacement therapy. A question therefore emerges about how and to what effect medical practitioners have engaged with critiques of the medical menopause?

Feminist ethics and menopause : autonomy and decision-making in primary medical care

The construction of menopause as a long-term risk to health and the adoption of discourses of prevention has made necessary a decision by women about medical treatment; specifically regarding the use of hormone replacement therapy. In a study of general practitioners’ accounts of menopause and treatment in Australia, women's ‘choice’, ‘informed decision-making’ and ‘empowerment’ were key themes through which primary medical care for women at menopause was presented. These accounts create a position for women defined by the concept of individual choice and an ethic of autonomy. These data are a basis for theorising more generally in this paper. We critically examine the construct of ‘informed decision-making’ in relation to several approaches to ethics including bioethics and a range of feminist ethics. We identify the intensification of power relations produced by an ethic of autonomy and discuss the ways these considerations inform a feminist ethics of decision-making by women. We argue that an ‘ethic of autonomy’ and an ‘offer of choice’ in relation to health care for women at menopause, far from being emancipatory, serves to intensify power relations. The dichotomy of choice, to take or not to take hormone replacement therapy, is required to be a choice and is embedded in relations of power and bioethical discourse that construct meanings about what constitutes decision-making at menopause. The deployment of the principle of autonomy in medical practice limits decision-making by women precisely because it is detached from the construction of meaning and the self and makes invisible the relations of power of which it is a part.

The appearance and effects of metallic implants in CT images

Contemporary 3D radiotherapy treatment planning relies upon the use of 3D electron density maps derived from computed tomography (CT) scans of patient anatomy, to evaluate the effects of that anatomy on radiation dose distributions. Production of these electron density maps requires that the CT numbers (Hounsfield units) that quantify the attenuation of the x-ray beam by the patient’s anatomy must be reliably converted into electron densities, using a stable calibration relationship. This study investigates the fidelity of electron density assignment in the presence of metallic prostheses and implants.