Combined fast neutron - gamma ray computed tomography and radiography

The combination of real-time fast-neutron and γ-ray assessment for the purpose of tomography and radiography has been investigated using a number of complementary experimental techniques. The research described in this thesis comprises an extensive Monte Carlo simulation study and three experimental approaches, each of which is supported by computer simulations themselves. In the Monte Carlo study, computed by means of MCNP6, actinide materials such as plutonium metal, plutonium oxide, uranium metal, U3O8 and UC2, have been shielded with combinations of lead and high-density polyethylene, then investigated actively with a simulated beam of both fast neutrons and γ rays produced by an americium-beryllium source, and detected by an array of liquid scintillation detectors. This Monte Carlo study demonstrates that, in terms of relative image contrast, the combination of γ and neutron tomography yields to a better discrimination amongst plutonium metal, lead and polyethylene, as well as amongst uranium-based compounds, such as uranium metal and uranium carbide, with the same shielding materials. Less convincing contrast is instead obtained when plutonium oxide and U3O8 are concealed with the same shielding arrangement of lead and polyethylene. The study also shows that a combination of both fast neutron and γ radiation, in several cases, led to a better spatial resolution (order of a few mm) of that achieved using fast neutrons or γ rays in isolation. A similar approach was performed to investigate a variety of materials often associated with conventional explosives and a lithium-based polymer (LiPo). By means of neutron tomography, LiPo and water, hydrogen peroxide, acetone, RDX, TNT, NC have been discerned from one another; whilst the γ tomography approach helps to discern, for instance, RDX from acetone. Experimentally, this technique has been computed, albeit in terms of radiography rather than tomography, using a californium neutron source and single scintillation detector coupled to a real-time, pulse-shape discrimination system. A lithium ion laptop battery was scanned and compared with an X-ray radiograph of the battery itself. These experimental results show that the combined neutron-γ imaging spatial information is comparable to what obtained with the X-ray. In addition, the results show that higher level of image contrast is present in the proximity of the cell batteries, suggesting the potential to identify the spatial lithium polymer distribution within the cell batteries. Furthermore, an alternative approach to investigate a single material type subject to changes in dimension, hypothetically due to corrosion, has been explored. This was conducted assessing both the fast neutron and γ ray flux backscattered by irradiated steel slabs, as a function of their thickness. Such research, carried out with the objective to detect flaws in pipeline sections, not only showed the potential to estimate different thicknesses of steel in isolation, but also showed the potential to measure thicknesses of slabs covered by a layer of materials commonly used for pipelines insulation, such as polyethylene and concrete. Finally, a Monte Carlo study has been completed for an arrangement in which a particle accelerator has been used as the neutron source, with which to explore the potential benefits of combining high-resolution γ-ray spectroscopy, neutron tomography and γ-ray tomography in the same approach. The outcome of this study showed the possibility to identify and localise the distribution of different isotopes of metals, such as 56Fe and 63Cu in a sample. The research presented associated with this aspect of the thesis has potential applications in nuclear safeguards, homeland security, contraband detection and in fields where relatively quick and non-destructive inspections are needed

Porcelin and duplicated gallbladder associated with pancreatic cancer

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A hidden echocardiographic pitfall: the Gerbode defect

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NT pro BNP plasma level and atrial volume are linked to the severity of liver cirrhosis.

BACKGROUND AND AIMS: Plasma levels of NT-pro-BNP, a natriuretic peptide precursor, are raised in the presence of fluid retention of cardiac origin and can be used as markers of cardiac dysfunction. Recent studies showed high levels of NT pro BNP in patients with cirrhosis. We assessed NT pro-BNP and other parameters of cardiac dysfunction in patients with cirrhosis, with or without ascites, in order to determine whether the behaviour of NT pro BNP is linked to the stage of liver disease or to secondary cardiac dysfunction. METHODS: Fifty eight consecutive hospitalized patients mostly with viral or NAFLD-related cirrhosis were studied. All underwent abdominal ultrasound and upper GI endoscopy. Cardiac morpho-functional changes were evaluated by echocardiography and NT-pro-BNP plasma levels determined upon admission. Twenty-eight hypertensive patients, without evidence of liver disease served as controls. RESULTS: Fifty eight cirrhotic patients (72% men) with a median age of 62 years (11% with mild arterial hypertension and 31% with type 2 diabetes) had a normal renal function (mean creatinine 0.9 mg/dl, range 0.7-1.06). As compared to controls, cirrhotic patients had higher NT pro-BNP plasma levels (365.2±365.2 vs 70.8±70.6 pg/ml; p<0.001). Left atrial volume (LAV) (61.8±26.3 vs 43.5±14.1 ml; p = 0.001), and left ventricular ejection fraction (62.7±6.9 vs. 65.5±4%,; p = 0.05) were also altered in cirrhotic patients that in controls. Patients with F2-F3 oesophageal varices as compared to F0/F1, showed higher e' velocity (0.91±0.23 vs 0.66±0.19 m/s, p<0.001), and accordingly a higher E/A ratio (1.21±0.46 vs 0.89±0.33 m/s., p = 0.006). CONCLUSION: NT-pro-BNP plasma levels are increased proportionally to the stage of chronic liver disease. Advanced cirrhosis and high NT-pro-BNP levels are significantly associated to increased LAV and to signs of cardiac diastolic dysfunction. NT pro-BNP levels could hence be an useful prognostic indicators of early decompensation of cirrhosis

Simulating Ionising Radiation in Gazebo for Robotic Nuclear Inspection Challenges

From MDPI via Jisc Publications RouterHistory: accepted 2021-07-02, pub-electronic 2021-07-07Publication status: PublishedFunder: UK Research and Innovation; Grant(s): EP/P018505/1, EP/R026084/1Funder: Royal Academy of Engineering; Grant(s): CiET1819\13The utilisation of robots in hazardous nuclear environments has potential to reduce risk to humans. However, historical use has been largely limited to specific missions rather than broader industry-wide adoption. Testing and verification of robotics in realistic scenarios is key to gaining stakeholder confidence but hindered by limited access to facilities that contain radioactive materials. Simulations offer an alternative to testing with actual radioactive sources, provided they can readily describe the behaviour of robotic systems and ionising radiation within the same environment. This work presents a quick and easy way to generate simulated but realistic deployment scenarios and environments which include ionising radiation, developed to work within the popular robot operating system compatible Gazebo physics simulator. Generated environments can be evolved over time, randomly or user-defined, to simulate the effects of degradation, corrosion or to alter features of certain objects. Interaction of gamma radiation sources within the environment, as well as the response of simulated detectors attached to mobile robots, is verified against the MCNP6 Monte Carlo radiation transport code. The benefits these tools provide are highlighted by inclusion of three real-world nuclear sector environments, providing the robotics community with opportunities to assess the capabilities of robotic systems and autonomous functionalities

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

Beta-Blocker Use in Older Hospitalized Patients Affected by Heart Failure and Chronic Obstructive Pulmonary Disease: An Italian Survey From the REPOSI Register

Beta (β)-blockers (BB) are useful in reducing morbidity and mortality in patients with heart failure (HF) and concomitant chronic obstructive pulmonary disease (COPD). Nevertheless, the use of BBs could induce bronchoconstriction due to β2-blockade. For this reason, both the ESC and GOLD guidelines strongly suggest the use of selective β1-BB in patients with HF and COPD. However, low adherence to guidelines was observed in multiple clinical settings. The aim of the study was to investigate the BBs use in older patients affected by HF and COPD, recorded in the REPOSI register. Of 942 patients affected by HF, 47.1% were treated with BBs. The use of BBs was significantly lower in patients with HF and COPD than in patients affected by HF alone, both at admission and at discharge (admission, 36.9% vs. 51.3%; discharge, 38.0% vs. 51.7%). In addition, no further BB users were found at discharge. The probability to being treated with a BB was significantly lower in patients with HF also affected by COPD (adj. OR, 95% CI: 0.50, 0.37-0.67), while the diagnosis of COPD was not associated with the choice of selective β1-BB (adj. OR, 95% CI: 1.33, 0.76-2.34). Despite clear recommendations by clinical guidelines, a significant underuse of BBs was also observed after hospital discharge. In COPD affected patients, physicians unreasonably reject BBs use, rather than choosing a β1-BB. The expected improvement of the BB prescriptions after hospitalization was not observed. A multidisciplinary approach among hospital physicians, general practitioners, and pharmacologists should be carried out for better drug management and adherence to guideline recommendations

Pain and Frailty in Hospitalized Older Adults

Introduction: Pain and frailty are prevalent conditions in the older population. Many chronic diseases are likely involved in their origin, and both have a negative impact on quality of life. However, few studies have analysed their association. Methods: In light of this knowledge gap, 3577 acutely hospitalized patients 65&nbsp;years or older enrolled in the REPOSI register, an Italian network of internal medicine and geriatric hospital wards, were assessed to calculate the frailty index (FI). The impact of pain and some of its characteristics on the degree of frailty was evaluated using an ordinal logistic regression model after adjusting for age and gender. Results: The prevalence of pain was 24.7%, and among patients with pain, 42.9% was regarded as chronic pain. Chronic pain was associated with severe frailty (OR = 1.69, 95% CI 1.38–2.07). Somatic pain (OR = 1.59, 95% CI 1.23–2.07) and widespread pain (OR = 1.60, 95% CI 0.93–2.78) were associated with frailty. Osteoarthritis was the most common cause of chronic pain, diagnosed in 157 patients (33.5%). Polymyalgia, rheumatoid arthritis and other musculoskeletal diseases causing chronic pain were associated with a lower degree of frailty than osteoarthritis (OR = 0.49, 95%CI 0.28–0.85). Conclusions: Chronic and somatic pain negatively affect the degree of frailty. The duration and type of pain, as well as the underlying diseases associated with chronic pain, should be evaluated to improve the hospital management of frail older people

The multifaceted spectrum of liver cirrhosis in older hospitalised patients: Analysis of the REPOSI registry

Background: Knowledge on the main clinical and prognostic characteristics of older multimorbid subjects with liver cirrhosis (LC) admitted to acute medical wards is scarce. Objectives: To estimate the prevalence of LC among older patients admitted to acute medical wards and to assess the main clinical characteristics of LC along with its association with major clinical outcomes and to explore the possibility that well-distinguished phenotypic profiles of LC have classificatory and prognostic properties. Methods: A cohort of 6,193 older subjects hospitalised between 2010 and 2018 and included in the REPOSI registry was analysed. Results: LC was diagnosed in 315 patients (5%). LC was associated with rehospitalisation (age-sex adjusted hazard ratio, [aHR] 1.44; 95% CI, 1.10-1.88) and with mortality after discharge, independently of all confounders (multiple aHR, 2.1; 95% CI, 1.37-3.22), but not with in-hospital mortality and incident disability. Three main clinical phenotypes of LC patients were recognised: relatively fit subjects (FIT, N = 150), subjects characterised by poor social support (PSS, N = 89) and, finally, subjects with disability and multimorbidity (D&amp;M, N = 76). PSS subjects had an increased incident disability (35% vs 13%, P &lt; 0.05) compared to FIT. D&amp;M patients had a higher mortality (in-hospital: 12% vs 3%/1%, P &lt; 0.01; post-discharge: 41% vs 12%/15%, P &lt; 0.01) and less rehospitalisation (10% vs 32%/34%, P &lt; 0.01) compared to PSS and FIT. Conclusions: LC has a relatively low prevalence in older hospitalised subjects but, when present, accounts for worse post-discharge outcomes. Phenotypic analysis unravelled the heterogeneity of LC older population and the association of selected phenotypes with different clinical and prognostic features