Beukenlaan 137
5616 VD Eindhoven
The Netherlands
+31 85064 55 82
info@interhospi.com
PanGlobal Media IS not responsible for any error or omission that might occur in the electronic display of product or company data.
Featured Articles
Digital tomosynthesis at a glance: a scientific review
X-ray based imaging techniques include a variety of different implementations and applications: computed radiography (CR), digital radiography (DR) and variations of computed tomography (CT): clinical CT, C-arm, tomosynthesis, micro-CT, industrial CT. These X-ray based methods are widely used not only for diagnostics and assistance in clinical practice but also for screening in security applications and for non-destructive material testing in industry, archeology and material science. The aim of this review paper is to give an introduction into a modern X-ray based tomographic imaging technique, called Digital Tomosynthesis (DT). DT is known as an attractive low-dose alternative to CT in medical (and non-medical) imaging applications.
by Yulia M. Levakhina, Thorsten M. Buzug
Historical overview: from radiostereoscopy to digital tomosynthesis
The history of X-ray imaging starts in 1985 when Wilhelm Conrad Roentgen discovered a new kind of radiation which he called X-rays. It was a breakthrough invention that allowed visualization of inner structures of the human body without surgical intervention.
Analogue imaging
A simple radiographic image contains the superposition of all three-dimensional structures in an object as a two-dimensional image. This means that is it impossible to recover the depth of information of any particular feature (e.g. tumour). At the beginning of the 1920s there were many attempts to erase superimposed shadows from X-ray images and to benefit from the use of X-rays for imaging of the human body. Owing to the fact that the communication between researchers from different countries was very limited at that time, many scientists were re-discovering similar imaging concepts. It resulted in a number of patent applications and scientific papers, which all discussed the same imaging technique where the X-ray tube and X-ray receptor move in parallel planes. The result of each acquisition was an analogue image showing sharply the only one plane located in focus while blurring all other planes. This technique was called stratigrafia by A. Vallebona, planigraphy by A. E. M. Bocage and B. G. Ziedses des Plantes or laminography by J. Kieffer. More information can be found e.g. in the historical article written by a curator of the Belgian Museum of Radiology, R. van Tiggelen.
Digital tomosynthesis or computed tomography?
The next step forward was the implementation of a device, where each measured radiographic image can be stored separately and processed after the examination instead of integrating the measurements directly on film. By doing this, it is possible to generate an arbitrary number of planes or laminograms through the object based on the limited number of measured radiographs. The total radiation dose can be reduced because only one examination is needed to produce images of the whole volume. This is essentially the main idea of modern tomosynthesis as it is known today. The word tomosynthesis was introduced by D. G. Grant in 1972. A number of further improvements of tomosynthesis, mainly focused on improving image quality and shortening acquisition time, have been proposed during the 1970s and 1980s. The review papers by Dobbins give a detailed overview of tomosynthesis research during the 1970s and 1980s.
In that same year (1972), there was an another development when Sir Godfrey Hounsfield and James Ambrose gave a talk on
Innovation in outpatient departments: the revolutionary vision of the Jeroen Bosch Hospital
Attention towards a more efficient and patient-centred outpatient care is increasing. This is due to a common interest in reducing the costs associated to long in-patient care stays. The Jeroen Bosch Ziekenhuis in the Netherlands adopted a non-conventional system of outpatient department: a hybrid system derived from the airport environment, where patients
Scientific literature: mechanical ventilation
As a special service to our readers, International Hospital presents a few recent literature abstracts chosen by our editorial board as being particularly worthy of attention.
A review of oral preventative strategies to reduce ventilator-associated pneumonia.
Andrews T, Steen C. Nurs Crit Care 2013; May18(3):116-22. Epub 2013 Jan 30.
This article evaluates the evidence for and efficacy of the use of mechanical hygiene and chlorhexidine in the prevention of ventilator-associated pneumonia (VAP). Search strategies included primary research articles; randomized controlled trials; systematic reviews and excluded quasi-experimental trials and opinion articles. VAP is the commonest infection found in critically ill patients who are mechanically ventilated. It is associated with increased mortality, increased length of stay in intensive care and increased costs. VAP is a health care-associated infection consistent with the presence of an endotracheal tube and mechanical ventilation for greater than 48 h. Efforts aimed at reducing infection rates include oral decontamination and mechanical hygiene to control the bacteria responsible, since there is an association between changes in bacteria found in the oropharynx and its development. Tooth brushing and the use of an oral antiseptic such as chlorhexidine gluconate are increasingly recommended in ventilator care bundles.
While there have been a number of studies conducted evaluating the efficacy of both approaches, there is limited evidence to support their use. The frequency of oral decontamination and mechanical hygiene interventions have not been established and chlorhexidine 2% seems to be more effective compared to weaker concentrations, but data is mainly confined to patients following cardiothoracic surgery.
Non-invasive positive pressure ventilation for treatment of respiratory failure due to severe acute exacerbations of asthma.
Lim WJ, Mohammed Akram R, Carson KV, Mysore S, Labiszewski NA, Wedzicha JA, Rowe BH, Smith BJ. Cochrane Database Syst Rev. 2012; Dec 12:12:CD004360.
Because of sub-optimal long-term care and delays in obtaining help during acute exacerbations, the mortality and morbidity related to asthma is still a major health concern. There is reason to believe that non-invasive positive pressure ventilation (NPPV) could be beneficial to patients with severe acute asthma; however, the evidence surrounding the efficacy of NPPV is unclear, despite its common use in clinical practice.
The objectives were to determine the efficacy of NPPV in adults with severe acute asthma in comparison to usual medical care with respect to mortality, tracheal intubation, changes in blood gases and hospital length of stay.
The search method consisted of a search in the Cochrane Airways Group Specialized Register of trials (July 2012). Following this, the bibliographies of included studies and review articles were searched for additional studies (July 2012). Included were randomized controlled trials of adults with severe acute asthma as the primary reason for presentation to the emergency department or for admission to hospital. Asthma diagnosis was defined by internationally accepted criteria. Studies were included if the intervention was usual medical care for the management of severe acute asthma plus NPPV applied through a nasal or facemask compared to usual medical care alone. Studies including patients with features of chronic obstructive pulmonary disease (COPD) were excluded unless data were provided separately for patients with asthma in studies recruiting both COPD and asthmatic patients. Five studies on 206 participants contributed data, while one study was available in abstract form only and was not fully incorporated into this review. For the primary outcome of endotracheal intubation there were two studies that contributed data: two intubations were needed in 45 participants on NPPV and no intubations in 41 control patients (risk ratio 4.48; 95% CI 0.23 to 89.13). There were no deaths in either of these studies. Length of hospital stay was reported in two studies, though meta-analysis was not possible. Hospitalisation was reported in one small study, in which there were three admissions out of 17 on NPPV and 10 admissions out of 16 in control patients (RR 0.28, 95% CI 0.09, 0.84).
This review of studies has highlighted the paucity of data that exist to support the use of NPPV in patients in status asthmaticus. As such this course of treatment remains controversial despite its continued use in current clinical practice. Larger, prospective randomized controlled trials of rigorous methodological design are needed to determine the role of NPPV in patients with asthma.
Protein catalysed capture agents for molecular imaging
There is a growing need for affinity agents for targeted molecular imaging of disease biomarkers. Protein catalysed capture agents (PCC agents) are assembled through target-guided in situ click chemistry and display low nanomolar affinity and specificity. The iterative design process, architecture, and composition of the resulting multi-ligands make this a promising technology for imaging agent development.
by Dr Steven W. Millward, Dr Heather D. Agnew, Dr Suresh Pitram, Dr Bert T. Lai, Dr Rosemary D. Rohde and Dr Norman Hardman
Personalized medicine is increasingly becoming a major component of cancer treatment and management. Many of the advances in personalized medicine have come from high throughput genomic sequencing and multiplexed proteomic analysis of tumour and tissue specimens. While these technologies have dramatically increased our understanding of cancer and cancer heterogeneity at the molecular level, translation of this knowledge into clinical imaging agents to non-invasively characterize tumour phenotypes in vivo has lagged behind. While small molecules (e.g. FDG) have proven very useful for clinical measurement of metabolic activity, molecular imaging of cell surface and secreted biomarkers overexpressed in cancer (e.g. IGFR, EGFR, etc.) is largely confined to the preclinical and early clinical trial setting.
While groundbreaking work to determine the biological and therapeutic roles of these proteins has produced a wealth of high affinity antibodies, antibody fragments, and peptides, attempts to translate them into radiotracers for molecular imaging have produced mixed results. Antibody-based imaging agents suffer from three disadvantages in this setting:
1) Their long serum half-lives, while advantageous for therapeutic applications, result in high background signal in perfused tissue and lengthen the time between agent administration and image acquisition.
2) Antibody-based radiotracers often show accumulation and metabolic processing in the liver, increasing nonspecific signal and potentially obscuring critical tumour-specific signal in the abdominal cavity.
3) Antibodies are biologicals, and as such their high production costs and regulatory burdens are significant economic barriers to commercialization and clinical translation. Linear peptides derived from phage display represent a second class of potential imaging agents, however their rapid degradation in vivo typically results in nonspecific background signal and poor tumour uptake. An ideal targeted molecular imaging agent would combine the affinity and specificity of antibodies with the high bio-stability, tumour uptake, and clearance of small molecules.
PCC agent design
Protein catalysed capture (PCC) agent technology represents a novel approach to rapidly design ligands with high affinity and specificity that can be potentially adapted to a variety of research and in vivo clinical applications including molecular imaging. This technology was built upon the observation by K. Barry Sharpless and co-workers at The Scripps Research Institute that the azide-alkyne cycloaddition (a