Development of liquid xenon detectors for medical imaging

In the present paper, we report on our developments of liquid xenon detectors for medical imaging, positron emission tomography and single photon imaging, in particular. The results of the studies of several photon detectors (photomultiplier tubes and large area avalanche photodiode) suitable for detection of xenon scintillation are also briefly described.Comment: 13 pages, 5 figures, presented on the International Workshop on Techniques and Applications of Xenon Detectors (Xenon01), ICRR, Univ. of Tokyo, Kashiwa, Japan, December 3-4, 2001 (submitted to proceedings

Encephalopathy Associated with Autoimmune Thyroid Disease: A Potentially Reversible Condition

Autoimmune thyroid disease may occasionally associate with unspecific neurological symptoms, which are more commonly insidious, include cognitive or behavioural symptoms, and may associate with tremor, myoclonus, or ataxia. We report a 61-year-old female patient who presented with chronic headache, insidious mood, and cognitive disturbance which evolved in a few months to dementia associated with exuberant limb myoclonus. Diagnostic workup revealed high anti-thyroid peroxidase antibody titers and an inflammatory CSF profile, and it was negative for other possible etiologies. Treatment with steroids induced significant improvement. The diagnosis of encephalopathy associated with autoimmune thyroid disease is still controversial given the fact that the clinical presentation and diagnostic workup are unspecific, the pathophysiology is still undetermined, and the diagnosis is mostly of exclusion. No direct correlation is found between anti-thyroid antibody titers and clinical presentation, and it is currently speculated that other still unrecognized antibodies may be responsible for this clinical entity. It is extremely important to recognize this entity because it is potentially treatable with immunotherapies. It is also increasingly recognized that clinical improvement with first-line treatment with steroids may be absent or incomplete, and other immunotherapies as immunosuppressants, intravenous immunoglobulin, or plasma exchange must be attempted in the clinical suspicion of EEAT.info:eu-repo/semantics/publishedVersio

Spontaneous Intracranial Hypotension Treated with a Targeted CT-Guided Epidural Blood Patch

Spontaneous intracranial hypotension (SIH) is an important cause of new daily persistent headache. It is thought to be due to spontaneous spinal cerebrospinal fluid (CSF) leaks, which probably have a multifactorial etiology. The classic manifestation of SIH is an orthostatic headache, but other neurological symptoms may be present. An epidural blood patch is thought to be the most effective treatment, but a blind infusion may be ineffective. We describe the case of a young man who developed an acute severe headache, with pain worsening when assuming an upright posture and relief gained with recumbency. No history of previous headache, recent cranial or cervical trauma, or invasive procedures was reported. Magnetic resonance imaging showed pachymeningeal enhancement and other features consistent with SIH and pointed towards a cervical CSF leak site. After failure of conservative treatment, a targeted computer tomography-guided EBP was performed, with complete recovery.info:eu-repo/semantics/publishedVersio

Micropropagação de Epidendrum ibaguense efeito de reguladores de crescimento no desenvolvimento in vitro de plântulas.

O objetivo deste trabalho foi avaliar o efeito dos reguladores de crescimento BAP (benzilaminopurina) e AIB (ácido indolbutírico) no desenvolvimento in vitro de plântulas de E. ibaguense, visando ao estabelecimento de um protocolo eficiente de produção de mudas micropropagadas de plantas desta espécie.bitstream/CPAF-RO-2010/14500/1/105-epidendrum.pd

Spatial resolution on a small animal RPC-PET prototype operating under magnetic field

It has been demonstrated in previous work that the RPC-PET technology is able to deliver radioisotope image resolutions approaching the physical limits of the PET principle. Here we study, by simulation, the effect of the magnetic field on the positron range to evaluate whether the spatial resolution of the RPC-PET could be improved by using an intense magnetic field. Six positron emitters of interest to small animal PET imaging (18F, 11C, 15O, 68G, 62Cu and 86Y) are considered. Results suggest that a three-fold improvement on the spatial resolution may be obtained under a magnetic field of 10 T for the higher energy radioisotopes like 86Y or 62Cu, and by about 20% for the lower energy ones, like 18F or 11C.http://www.sciencedirect.com/science/article/B6TVD-4KV4MR8-15/1/efa4356ba16a85fd7740937bd0e672a

Very high position resolution gamma imaging with resistive plate chambers

In this study we present experimental results from a first prototype of a positron emission tomography system based on the resistive plate chamber (RPC) technology. The system is composed of two counting heads, each one containing 16 single-gap RPC detectors capable of detecting the photon interaction point in the transaxial plane. Uniformity studies were performed for image resolution and sensitivity, yielding a rather uniform image resolution close to 0.3 mm FWHM across the field of view. The contribution of the photons noncolinearity effect to the intrinsic spatial resolution was also studied, causing a variation from 0.52 to 0.63 mm when the system diameter ranges from 60 to 120 mm, in agreement with calculations.http://www.sciencedirect.com/science/article/B6TJM-4K5HV7F-9/1/7b655e08199d2b28acc8050106c2271

Classifying residential real estate based on their exposure to crime: a research agenda

Criminality and sense of security in residential areas are always present in the mind of citizens, and directly affect the work of police authorities, real estate agents and society at large. This study proposes the development of a multiple criteria model for the classification of residential areas based on their exposure to crime. By combining cognitive mapping with the Measuring Attractiveness by a Categorical Based Evaluation Technique (MACBETH), we also aim to increase transparency in the classification process of residential real estate, allowing improvement initiatives to be applied and crime rates to be reduced. The major difference between our proposal and the extant literature is the fact that the information collected from criminal, urbanism and real estate experts, who deal with crime adversities on a daily basis, will be analyzed and discussed during presential group meetings, allowing realism to be incorporated into the evaluation mechanism. The current proposal is a research agenda, and results will not yet be presented