Ionization Radiation
Mostrando 13-24 de 42 artigos, teses e dissertações.
-
13. Avaliação dos efeitos da radiação ionizante em materiais utilizados em restaurações dentárias / EVALUATION OF EFFECTS OF IONIZING RADIATION ON MATERIALS USER IN DENTAL RESTORATIONS.
This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were su
Publicado em: 2009
-
14. DEVELOPING A VERSATILE MONOCHROMATIZATION SYSTEM FOR X-RAYS / DESENVOLVIMENTO DE UM SISTEMA DE MONOCROMATIZAÇÃO VERSÁTIL PARA RAIOS-X
The investigation of the dynamics of the interaction of high-energy X-rays and molecules of biological interest requires the energy of the X-rays to be well defined, so that one can establish the dependence of the molecular ionization and fragmentation patterns as functions of the incident beam energy. For this purpose, a versatile system for the monochromat
Publicado em: 2009
-
15. Degradação de substâncias de relevância ambiental por processos oxidativos e redutivos com monitoramento por espectrometria de massas com ionização electrospray
Firstly, the degradation of the insecticides Thiamethoxam, Imidacloprid and Methomyl in aqueous solutions by a number of processes was studied. It was verified that although the UV radiation was highly efficient in promoting the degradation of Thiamethoxam, the combined systems, i. e. UV/catalyst and UV/US/catalyst (catalyst = Fe2O3 or Fe3O4), showed to be m
Publicado em: 2008
-
16. AvaliaÃÃo dos parÃmetros dosimÃtricos em feixes de FÃtons de Radioterapia usando fototransistor SMT
One of the biggest challenges in radiotherapy dosimetry is to certify that the prescribed dose is given to the patient. For this, it is necessary to use small detectors to evaluate the beam parameters. Current dosimetry is realized with detectors that highlight problems: high cost, difficulty in handling, absence of real time readout, complex and delayed obt
Publicado em: 2008
-
17. Estudo de processos alternativos para a degradação de compostos de relevância ambiental com monitoramento dos produtos formados por espectometria de massas com fonte de ionização electrospray (ESI-MS)
Over the last decades, the growth of population and industrial activities has contributed to the aggravation of environmental problems, especially the contamination of superficial and underground waters. This is mainly caused by the enormous amounts of domestic or industrial wastes that are many times discarded directly into these bodies with no previous tre
Publicado em: 2008
-
18. Avaliação de dispositivos de proteção individual utilizados em radiologia diagnóstica / Evaluation of personal protective devices used in diagnostic radiology
Neste trabalho foram avaliados aventais de proteção e blindagens de ovário de cinco fabricantes segundo as normas NBR / IEC 61331-1 e NBR / IEC 61331-3 de 2004. Para a determinação da espessura equivalente de atenuação foram aplicadas três metodologias diferentes (interpolação linear, modelo de Archer e somatório de exponenciais), uma vez que a no
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/10/2006
-
19. Intercomparação de colimadores de múltiplas lâminas para implementação de terapia de feixes de intensidade modulada / Multileaf collimator intercomparison for intensity modulated radiation therapy implementation
Neste trabalho é apresentada uma intercomparaçào das características dosimétricas entre três sistemas de colimadores multi-lâminas: Varian Millenium com 120 lâminas, mMLC m3 Brainlab e Varian Mark II ambos com 52 lâminas. A largura da projeção das lâminas no isocentro e na região central do campo é de 0,5 cm; 0,35 cm e 1,0 cm respectivamente. F
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/01/2006
-
20. Projectile electron loss in nitrogen
The projectile electron loss channel plays an important role in modeling several processes connected to the penetration of swift ions in gases, such as radiation damage, energy loss, upper atmosphere studies, storage lifetimes of low-charge state heavy ions, etc. In this paper we have used recent measurements of projectile electron loss of He+ ions in N2 tog
Brazilian Journal of Physics. Publicado em: 2006-06
-
21. UtilizaÃÃo do dosÃmetro Fricke para dosimetria de mÃquinas teleterapÃuticas, irradiadores gammacel e aparelhos de raios-X superficiais
The chemical dosimetry has been used as a reference in the measurement of the absorbed dose, with the Fricke dosimeter, at standardization laboratories. This dosimeter is considered an absolute dosimetric standard for measurements of radiation doses ranging from 20 to 400 Gy, covering a wide energy spectrum, from X-ray, g-ray to fast electron beam. The objec
Publicado em: 2006
-
22. Caracterização e dosimetria de feixes de raios-x de 100 e 140kVp usados em radioterapia
Radiotherapy is the modality used in the treatment of malignant neoplasias that aims the deposition of a controlled amount of ionizing radiation in a limited area of the patient body. In order to provide a well-known and as accurate as possible absorbed dose for controlling a lesion, all characteristics of the treatment radiation beam must be known. For this
Publicado em: 2006
-
23. Doses e risco de radiação em estudo tomográfico computadorizado do tórax com tecnologia de quatro cortes
The computerized tomography (CT) is an important method for studying chest pathologies to provide its morphological and functional analysis and to allow a specific therapeutic approach of signs or symptoms resulting from diseases. Since CT uses ionizing radiation, it should be considered that a precise balance between risks and benefits must be achieved in o
Publicado em: 2006
-
24. Dependence of transition probabilities for non-linear photo-ionization of He atoms on the structure of the exciting radiation pulses
We discuss the expected dependence of the probability transitions for 2-photon and 3-photon absorption in Helium gas on the spatial and temporal structure of the exciting radiation pulses. Regarding spatial structure, we assumed a Gaussian radial intensity distribution; we find, as expected, that the 2-photon and 3-photon processes become negligible at dista
Brazilian Journal of Physics. Publicado em: 2005-09