Gamma Knife(A (R)) 3-D Dose Distribution Mapping by Magnetic Resonance Imaging

In medical processes where ionizing radiation is used, dose planning and dose delivery are the key elements to patient safety and treatment success, particularly, when the delivered dose in a single session of treatment can be an order of magnitude higher than the regular doses of radiotherapy. Therefore, the radiation dose should be well defined and precisely delivered to the target while minimizing radiation exposure to surrounding normal tissues [1]. Several methods have been proposed to obtain three-dimensional (3-D) dose distribution [2, 3]. In this paper, we propose an alternative method, which can be easily implemented in any stereotactic radiosurgery center with a magnetic resonance imaging (MRI) facility. A phantom with or without scattering centers filled with Fricke gel solution is irradiated with Gamma Knife(A (R)) system at a chosen spot. The phantom can be a replica of a human organ such as head, breast or any other organ. It can even be constructed from a real 3-D MR image of an organ of a patient using a computer-aided construction and irradiated at a specific region corresponding to the tumor position determined by MRI. The spin-lattice relaxation time T (1) of different parts of the irradiated phantom is determined by localized spectroscopy. The T (1)-weighted phantom images are used to correlate the image pixels intensity to the absorbed dose and consequently a 3-D dose distribution with a high resolution is obtained.

Determination of Very Slow Diffusion of Paramagnetic Ions by NMR Spectroscopy

In this paper, we propose a new method of measuring the very slow paramagnetic ion diffusion coefficient using a commercial high-resolution spectrometer. If there are distinct paramagnetic ions influencing the hydrogen nuclear magnetic relaxation time differently, their diffusion coefficients can be measured separately. A cylindrical phantom filled with Fricke xylenol gel solution and irradiated with gamma rays was used to validate the method. The Fricke xylenol gel solution was prepared with 270 Bloom porcine gelatin, the phantom was irradiated with gamma rays originated from a (60)Co source and a high-resolution 200 MHz nuclear magnetic resonance (NMR) spectrometer was used to obtain the phantom (1)H profile in the presence of a linear magnetic field gradient. By observing the temporal evolution of the phantom NMR profile, an apparent ferric ion diffusion coefficient of 0.50 mu m(2)/ms due to ferric ions diffusion was obtained. In any medical process where the ionizing radiation is used, the dose planning and the dose delivery are the key elements for the patient safety and success of treatment. These points become even more important in modern conformal radio therapy techniques, such as stereotactic radiosurgery, where the delivered dose in a single session of treatment can be an order of magnitude higher than the regular doses of radiotherapy. Several methods have been proposed to obtain the three-dimensional (3-D) dose distribution. Recently, we proposed an alternative method for the 3-D radiation dose mapping, where the ionizing radiation modifies the local relative concentration of Fe(2+)/Fe(3+) in a phantom containing Fricke gel and this variation is associated to the MR image intensity. The smearing of the intensity gradient is proportional to the diffusion coefficient of the Fe(3+) and Fe(2+) in the phantom. There are several methods for measurement of the ionic diffusion using NMR, however, they are applicable when the diffusion is not very slow.

MRI study of radiation effect on Fricke gel solutions

The quality control optimization of medical processes that use ionizing radiation in the treatment of diseases like cancer is a key element for patient safety and success of treatment. The major medical application of radiation is radiotherapy, i.e. the delivery of dose levels to well-defined target tissues of a patient with the purpose of eliminating a disease. The need of an accurate tumour-edge definition with the purpose of preserving healthy surrounding tissue demands rigorous radiation treatment planning. Dosimetric methods are used for dose distribution mapping region of interest to assure that the prescribed dose and the irradiated region are correct. The Fricke gel (FXG) is the main dosimeter that supplies visualization of the three-dimensional (3D) dose distribution. In this work the dosimetric characteristics of the modified Fricke dosimeter produced at the Radiation Metrology Centre of the Institute of Energetic and Nuclear Research (IPEN) such as gel concentration dose response dependence, xylenol orange addition influence, dose response between 5 and 50Gy and signal stability were evaluated by magnetic resonance imaging (MRI). Using the same gel solution, breast simulators (phantoms) were shaped and absorbed dose distributions were imaged by MRI at the Nuclear Resonance Laboratory of the Physics Institute of Sao Paulo University. (C) 2007 Elsevier Ltd. All rights reserved.

Cross-situational learning of object-word mapping using Neural Modeling Fields

The issue of how children learn the meaning of words is fundamental to developmental psychology. The recent attempts to develop or evolve efficient communication protocols among interacting robots or Virtual agents have brought that issue to a central place in more applied research fields, such as computational linguistics and neural networks, as well. An attractive approach to learning an object-word mapping is the so-called cross-situational learning. This learning scenario is based on the intuitive notion that a learner can determine the meaning of a word by finding something in common across all observed uses of that word. Here we show how the deterministic Neural Modeling Fields (NMF) categorization mechanism can be used by the learner as an efficient algorithm to infer the correct object-word mapping. To achieve that we first reduce the original on-line learning problem to a batch learning problem where the inputs to the NMF mechanism are all possible object-word associations that Could be inferred from the cross-situational learning scenario. Since many of those associations are incorrect, they are considered as clutter or noise and discarded automatically by a clutter detector model included in our NMF implementation. With these two key ingredients - batch learning and clutter detection - the NMF mechanism was capable to infer perfectly the correct object-word mapping. (C) 2009 Elsevier Ltd. All rights reserved.

Konstruktiva och destruktiva former av språklig kommunikation i moderna arbetsorganisationer : - En teoretisk undersökning med kompletterande fallstudier av Leksands vårdcentral och Mora vårdcentral

A main aim with the essay “Constructive and destructive forms of language communication in modern work organizations” is to try to develop methods which can be used to measure and classify different forms of language communication. Methods that hopefully also can be used for analysis of in which ways dominating language communication forms affects employees health in modern work organizations.Quantitative methods have chiefly been used in the essay. A questionnaire study based on sociological research and psychoterapeutic research and practice has been used to collect data around communication in two work organizations (community health centers). Then communication has been classified in two main forms: constructive and destructive language communication.Results in the essay indicate that there are tendencies to links between high illness-absence and destructive communication in a work organization. In the work organization with the highest illness-absence, during a chosen period of inquiry (2005), a larger share of the employees stated that the communications in their organization were destructive, compared to the employees in the organization which showed the lowest illness-absence. Statistically secured links between high illness-absence and destructive communication have however not been observed.

Kommunikation bortom orden : En etnografisk studie om hur lärares actio och ickeverbala kommunikation påverkar elevers motivation

Syftet med detta examensarbete är att få insikt i hur lärarens ickeverbala kommunikation och actio påverkar elevers motivation. Utifrån en etnografisk arbetsmetod observerades en svensklärare på en gymnasieskola under fyra lektionstimmar för att undersöka hur läraren kommunicerade med sina elever ickeverbalt. Parallellt med observationerna intervjuades både läraren och eleverna som deltog i undersökningen. Undersökningen visade att lärares ickeverbala kommunikation och actio har en stor påverkan på elevernas motivation, att denna påverkan sker omedelbart och att den kan förändras under en pågående lektion. När en lärare medvetandegör hur hon eller han kommunicerar med sina elever ickeverbalt kan aspekter som oavsiktlig och intuitiv kommunikation få en mindre påverkan på undervisningen. Detta bidrar i sin tur till att utveckla lärarens ickeverbala kompetens och på så sätt sin förmåga att motivera sina elever under hela lektionen.

Factors associated with evidence-based practice among registered nurses in Sweden : a national cross-sectional study

Background: Evidence-based practice (EBP) is emphasized to increase the quality of care and patient safety. EBP is often described as a process consisting of distinct activities including, formulating questions, searching for information, compiling the appraised information, implementing evidence, and evaluating the resulting practice. To increase registered nurses' (RNs') practice of EBP, variables associated with such activities need to be explored. The aim of the study was to examine individual and organizational factors associated with EBP activities among RNs 2 years post graduation. Methods: A cross-sectional design based on a national sample of RNs was used. Data were collected in 2007 from a cohort of RNs, included in the Swedish Longitudinal Analyses of Nursing Education/Employment study. The sample consisted of 1256 RNs (response rate 76%). Of these 987 RNs worked in healthcare at the time of the data collection. Data was self-reported and collected through annual postal surveys. EBP activities were measured using six single items along with instruments measuring individual and work-related variables. Data were analyzed using logistic regression models. Results: Associated factors were identified for all six EBP activities. Capability beliefs regarding EBP was a significant factor for all six activities (OR = 2.6 - 7.3). Working in the care of older people was associated with a high extent of practicing four activities (OR = 1.7 - 2.2). Supportive leadership and high collective efficacy were associated with practicing three activities (OR = 1.4 - 2.0). Conclusions: To be successful in enhancing EBP among newly graduated RNs, strategies need to incorporate both individually and organizationally directed factors.

Patienters upplevelser av vilka faktorer som har betydelse i vården på specialistsjuksköterskeledda hjärtsviktsmottagningar. : En kvalitativ studie

Bakgrund: Hjärtsvikt är ett vanligt och allvarligt tillstånd med hög dödlighet, sjuklighet och försämrad livskvalité. Det beräknas att omkring en kvarts miljon personer i Sverige har kronisk hjärtsvikt. Inrättandet av specialistsjuksköterskeledda hjärtsviktsmottagningar med läkarstöd har förbättrat behandlingen av patienter med hjärtsvikt. Syfte: Syftet med denna studie var att undersöka patienters upplevelser av vilka faktorer som har betydelse i vården på specialistsjuksköterskeledda hjärtsviktsmottagningar. Metod: En intervjustudie med semistrukturerade frågor har använts. En kvalitativ manifest innehållsanalys användes för att analysera det material som framkom vid intervjuerna. Informanterna valdes ut genom ett strategiskt urval. Resultat: Resultatet visade att en fungerande vårdrelation med sjukvården som representerades av specialistsjuksköterska på hjärtsviktsmottagningen samt information för att klara av sin egenvård var av betydelse för informanterna. En god vårdrelation beskrivs av informanterna i studien att den innehåller kontinuitet, tillit till specialistsjuksköterska, samarbete med vårdpersonal, ett bekräftande bemötande samt tillgänglighet vid behov. Konklusion: Vården på specialistsjuksköterskeledda hjärtsviktsmottagningar är betydelsefull för patienters trygghet. Det förefaller viktigt att få veta vem hjärtsviktspatienterna ska kontakta vid behov av stöd och hjälp för att hantera sin situation. Möjligheten att kontakta specialistsjuksköterska när behovet fanns upplevdes betydelsefull. Information om egenvård uppfattades av informanterna som viktigt och som ett stöd i det dagliga livet.

Unlicensed personnel administering medications to older persons living at home : a challenge for social and care services

BACKGROUND: Administration of medication to care recipients is delegated to home-care assistants working in the municipal social care, alongside responsibility for providing personal assistance for older people. Home-care assistants have practical administration skills, but lack formal medical knowledge. AIM: The aim of this study was to explore how home-care assistants perceive administration of medication to older people living at home, as delegated to them in the context of social care. METHODS: Four focus groups consisting of 19 home-care assistants were conducted. Data were analysed using qualitative content analysis. RESULTS: According to home-care assistants, health and social care depends on delegation arrangements to function effectively, but in the first place it relieves a burden for district nurses. Even when the delegation had expired, administration of medication continued, placing the statutes of regulation in a subordinate position. There was low awareness among home-care assistants about the content of the statutes of delegation. Accepting delegation to administer medications has become an implicit prerequisite for social care work in the municipality. CONCLUSIONS: Accepting the delegation to administer medication was inevitable and routine. In practice, the regulating statute is made subordinate and consequently patient safety can be threatened. The organisation of health and social care relies on the delegation arrangement to meet the needs of a growing number of older home-care recipients. IMPLICATIONS FOR PRACTICE: This is a crucial task which management within both the healthcare professions and municipal social care needs to address, to bridge the gap between statutes and practice, to create arenas for mutual collaboration in the care recipients' best interest and to ensure patient safety.

Estudo de caso para ensino: “Errar é humano: um desafio na busca da segurança do paciente em unidade pública de saúde.”

A preocupação com a segurança do paciente, fator importante na dimensão da qualidade do cuidado de saúde, é, atualmente, um tema de grande relevância entre pesquisadores do todo o mundo. Os “erros” ocorrem em qualquer local onde se prestam cuidados de saúde e na maioria das situações são passíveis de medidas preventivas. O objetivo deste estudo de caso para ensino é desvelar, através de uma revisão bibliográfica, o debate em torno do tema da segurança do paciente a partir do século XXI, enfocando sua relevância enquanto problema global de saúde pública. Além disso, este estudo discorre sobre os desafios relacionados às lacunas e perspectivas neste tema e sua abordagem na realidade brasileira. Os resultados da análise sugerem que a investigação sobre a segurança do paciente apresenta falhas nas suas abordagens a serem melhor definidas e estabelecidas. Foram identificadas ainda, as barreiras, como grande demanda dos prontos-socorros das grandes cidades, o medo do profissional que cometeu o erro, adesão de todos os profissionais e dos gestores, e desafios para serem enfrentados, como o desenvolvimento de estratégias e ações políticas de saúde específicas, tanto para a pesquisa na área de saúde quanto para a literatura de saúde pública em gestão pública.

Controle de qualidade físico-químico e biodisponibilidade relativa em ratos de suspensões orais de naproxeno sódico obtidas de farmácias de manipulação na cidade do Natal RN

Compounded medicines have been reported by the ANVISA due to decreased of the therapeutic response or toxicity of these formulations. The aim of this work was to investigate the physicochemical quality control among naproxen sodium oral suspensions 25 mg/mL obtained from six compounding pharmacies (A, B, C, D, E and F) and the manufactured suspension (R). In the quality control test, the tests of pH, content, homogeneity, volume and physical and organoleptic characteristics were performed according to the Brazilian Pharmacopoeia. The analytical method for determination of naproxen in suspensions was validate. This method showed excellent precision, accuracy, linearity and specificity. In the content test the suspensions B, C and E showed lower value and the F suspension showed a high value of the content. The products C and E were disapproved in the description of the physical and organoleptic characteristics test. In the pH test, three suspensions were outside specifications (C, E and F). Only the products R, A and D showed satisfactory results in these tests and therefore they were approved for relative bioavailability test. The R, A and D suspensions were orally administered to Wistar rats and the blood samples were taken at time intervals of 10, 20, 40, 60 min, 3, 4, 6, 24 and 48 h. The plasma samples were immediately stored at 80 ºC until analysis of HPLC. The bioanalytical method validation showed specificity, linearity (R2 0.9987), precision, accuracy, good recovery and stability. The chromatographic conditions were: flow rate of 1.2 mL.min-1 with a mobile phase of acetonitrile : sodium phosphate buffer pH 4.0 (50:50, v/v) at 280 nm, using a C18 column. The confidence interval of 90% for the Cmax and AUCt ratio was within the range of 80 - 125% proposed by the FDA. Only one suspension, obtained from the compounding pharmacy D, was considered bioequivalent to the rate of absorption under the conditions proposed by this study. Thus, the results indicate the need for strict supervision from the relevant authorities to ensure the patient safety and the quality of compounded drugs by pharmacies