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1.
Radiologia ; 58 Suppl 2: 92-103, 2016 May.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-27085511

RESUMO

It is essential to minimize exposure to ionizing radiation in children for various reasons. The risk of developing a tumor from exposure to a given dose of radiation is greater in childhood. Various strategies can be used to reduce exposure to ionizing radiation. It is fundamental to avoid unnecessary tests and tests that are not indicated, to choose an alternative test that does not use ionizing radiation, and/or to take a series of measures that minimize the dose of radiation that the patient receives, such as avoiding having to repeat tests, using the appropriate projections, using shields, adjusting the protocol (mAs, Kv, or pitch) to the patient's body volume, etc… When contrast agents are necessary, intracavitary ultrasound agents can be used, although the use of ultrasound agents is also being extended to include intravenous administration. In fluoroscopy, contrast agents with low osmolarity must be used, as in CT where we must adjust the dose and speed of injection to the patient's weight and to the caliber of the peripheral line, respectively. In MRI, only three types of contrast agents have been approved for pediatric use. It is sometimes necessary to use double doses or organ-specific contrast agents in certain clinical situations; the safety of contrast agents for these indications has not been proven, so they must be used off label.


Assuntos
Meios de Contraste , Diagnóstico por Imagem/métodos , Lesões por Radiação/prevenção & controle , Proteção Radiológica , Criança , Humanos , Guias de Prática Clínica como Assunto , Doses de Radiação , Tomografia Computadorizada por Raios X
2.
J Oral Rehabil ; 43(2): 111-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26404105

RESUMO

To compare the three-dimensional changes occurring in the maxillary arch during the use of modified pre-surgical nasoalveolar moulding (PNAM) and Hotz's plate. A clinical trial including 32 children with unilateral cleft lip and palate (UCLP), 16 treated with Hotz's plate and 16 with PNAM, was performed. Impressions of the maxillary arches were taken: A. prior to pre-surgical orthopaedics, B. before cheiloplasty and C. after cheiloplasty. Models were digitised using a stereophotogrammetric instrument, and geodesic distances were calculated: anterior, canine and posterior widths of the arch, and lengths and cleft depths of the larger and shorter segments. The time and treatment effects were assessed by two-factor anova. A significant effect of treatment was found for cleft depth at the larger segment: children treated with Hotz's plate had significantly deeper cleft than children treated with PNAM. All distances significantly changed during time: the anterior and canine widths decreased, while the posterior width, the lengths and depths of the cleft segments increased. Significant treatment per time interactions was found. The anterior and canine widths reduced more with PNAM between time points A and B while Hotz's treatment was more effective between B and C. The shorter segment depth increased more between B and C with PNAM, and between A and B with Hotz's plate. During pre-surgical orthopaedics, therapy with PNAM obtained the best results in reducing the width at the anterior segment of the cleft. This treatment gave a lower increase in cleft depth than treatment with Hotz's plate.


Assuntos
Processo Alveolar/cirurgia , Fenda Labial/cirurgia , Fissura Palatina/cirurgia , Procedimentos Ortopédicos/métodos , Obturadores Palatinos , Humanos , Imageamento Tridimensional , Lactente , Fotogrametria , Resultado do Tratamento
4.
Rev. med. nucl. Alasbimn j ; 7(28)apr. 2005. tab, graf
Artigo em Espanhol | LILACS | ID: lil-444065

RESUMO

El objetivo del presente trabajo es investigar como se modifica el comportamiento in vitro e in vivo (localización de sitios de infección experimental con Staphilococcus aureus (S.a.)) del UBI 29-41 cuando es marcado con 99mTc por cuatro métodos distintos: a) con borohidruro de potasio y pirofosfato de estaño, b) con hidróxido de sodio y cloruro estañoso (métodos directos), c) con NHS-MAG3 y d) con NHS-HYNIC (métodos indirectos). En segundo lugar comparar los valores PI/PN (Pata Infectada / Pata Normal) del 99mTc-UBI 29-41 (método a), con el 99mTc-scrambled (Sc) UBI 29-41 (péptido control) y con 99mTc-IgG (radiofármaco no específico para infecciones) en ratones infectados con S.a. viables; y los valores pata inflamada/ PN del 99mTc-UBI 29-41 99mTc (método a) con 99mTc-IgG en ratones con inflamación estéril. Cuando el 99mTc-UBI 29-41 fue obtenido por el método a, se obtuvieron los mejores resultados in vitro y las biodistribuciones mostraron la máxima acumulación en sitios con S.a. viables y muy baja acumulación en sitios con inflamación estéril, demostrando su potencial uso en el diagnóstico de infecciones.


Assuntos
Camundongos , Animais , Fragmentos de Peptídeos/farmacocinética , Infecções Estafilocócicas , Marcação por Isótopo/métodos , Compostos Radiofarmacêuticos/farmacologia , Tecnécio , Antibacterianos , Compostos de Organotecnécio/farmacocinética , Controle de Qualidade , Distribuição Tecidual , Estabilidade de Medicamentos , Meios de Cultura , Succinimidas/farmacocinética
5.
Rev. med. nucl. Alasbimn j ; 6(25)julio 2004. ilus, tab, graf
Artigo em Espanhol | LILACS | ID: lil-444054

RESUMO

El objetivo del presente trabajo es evaluar la capacidad del 99mTc-UBI 29-41 marcado por un método directo en la localización de sitios de infección experimental con Staphilococcus aureus (S.a.). En segundo lugar comparar los valores PI/PN (Pata Infectada / Pata Normal) de las biodistribuciones en ratones portadores de S.a. viables, S.a. no viables obtenidos por irradiación gamma y por calentamiento y en sitios de inflamación estéril y cuantificar las relaciones sitio infectado / sitio normal (SI / SN) através de autorradiografía digital. El UBI 29-41 es un fragmento sintético de la ubiquicidina y el scrambled (Sc) UBI 29-41 es el péptido control. 99mTc-IgG fue el control positivo para inflamaciones estériles. Cuando el 99mTc-UBI 29-41 fue obtenido por este método rápido y reproducible, se visualizaron sitios de infección a 2h p.i.. Las biodistribuciones mostraron mayor acumulación en sitios con S.a. viables que con S.a. irradiados y no hubo acumulación en inflamaciones estériles.


Assuntos
Camundongos , Animais , Compostos de Organotecnécio/farmacocinética , Fragmentos de Peptídeos/farmacocinética , Infecções Estafilocócicas/diagnóstico , Distribuição Tecidual , Intensificação de Imagem Radiográfica , Marcação por Isótopo , Peptídeos Catiônicos Antimicrobianos/farmacocinética
6.
Analyst ; 127(4): 466-71, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12022642

RESUMO

A planar high field asymmetric waveform ion mobility spectrometer (PFAIMS) with a micro-machined drift tube was characterized as a detector for capillary gas chromatography. The performance of the PFAIMS was compared directly to that of a flame ionization detector (FID) for the separation of a ketone mixture from butanone to decanone. Effluent from the column was continuously sampled by the detector and mobility scans could be obtained throughout the chromatographic analysis providing chemical inforrmation in mobility scans orthogonal to retention time. Limits of detection were approximately I ng for measurement of positive ions and were comparable or slightly better than those for the FID. Direct comparison of calibration curves for the FAIMS and the FID was possible over four orders of magnitude with a semi-log plot. The concentration dependence of the PFAIMS mobility scans showed the dependence between ion intensity and ion clustering, evident in other mobility spectrometers and atmospheric pressure ionization technologies. Ions were identified using mass spectrometry as the protonated monomer and the proton bound dimer of the ketones. Residence time for column effluent in the PFAIMS was calculated as approximately 1 ms and a 36% increase in extra-column broadening versus the FID occurred with the PFAIMS.


Assuntos
Cromatografia Gasosa/instrumentação , Butanonas , Cetonas/isolamento & purificação , Sensibilidade e Especificidade , Espectrofotometria/instrumentação
7.
Anal Chem ; 72(14): 3102-8, 2000 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-10939373

RESUMO

Improvements in the stability and performance of a capillary microwave-induced plasma-mass spectrometer (MIP-MS) were achieved by optimizing power transfer to the cavity using a tunable coaxial MIP. The MIP, operating at atmospheric pressure, was sustained with 30 mL/min He and 60 W of power. Measurement precision and sensitivity for the standard waveguide and coaxial systems were determined using 16 organochlorine pesticide solutions separated by gas chromatography (GC). The linear dynamic range obtained with the tunable MIP-MS extended over 3 orders of magnitude, a 10 time improvement with respect to the standard MIP. Detection limits were between 3 and 19 pg of Cl mol(-1) s(-1), 7 times lower than the detection limits obtained with the nontunable MIP-MS. Analysis of pesticides containing sulfur atoms was also possible, further demonstrating multielement MIP-MS detection. Excellent accuracy (10% recovery) and precision (5% RSD) were found for the detection of the pesticides in a petroleum-contaminated reference soil. By placing the GC column at the plasma expansion stage, molecular fragmentation of a mixture of volatile organic compounds was also demonstrated. With the MS operated in the selected ion monitoring mode, measurement sensitivity was approximately 500 pg/s per compound.


Assuntos
Praguicidas/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Micro-Ondas , Compostos Orgânicos/análise , Petróleo , Solo/análise , Poluentes do Solo/análise
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