До проблеми міжетнічних контактів сарматських племен Північного Причорномор’я перших століть нашої ери (за матеріалами ліпної кераміки)

(uk) Стаття присвячена дослідженню проблем трансформації сарматського ліпного керамічного комплексу як вияву міжетнічної взаємодії племен Північного Причорномор’я І – ІV ст. н.е.(en) The article investigates the problems of transformation of Sarmatian ceramic plastic complex as a manifestation of interethnic interaction of the tribes of Northern Prychornomorya in the I – IV centuries A.D

Patient dose reduction during voiding cystourethrography

Voiding cystourethrography (VCUG) is a commonly performed examination in a pediatric uroradiology practice. This article contains suggestions on how the radiation dose to a child from VCUG can be made ‘as low as reasonably achievable–(ALARA). The pediatric radiologist should consider the appropriateness of the clinical indication before performing VCUG and utilize radiation exposure techniques and parameters during VCUG to reduce radiation exposure to a child. The medical physicist and fluoroscope manufacturer can also work together to optimize a pulsed-fluoroscopy unit and further reduce the radiation exposure. Laboratory and clinical research is necessary to investigate methods that reduce radiation exposures during VCUG, and current research is presented here

Applying the ALARA concept to the evaluation of vesicoureteric reflux

The voiding cystourethrogram (VCUG) is a widely used study to define lower urinary tract anatomy and to diagnose vesicoureteric reflux (VUR) in children. We examine the technical advances in the VCUG and other examinations for reflux that have reduced radiation exposure of children, and we give recommendations for the use of imaging studies in four groups of children: (1) children with urinary tract infection, (2) siblings of patients with VUR, (3) infants with antenatal hydronephrosis (ANH), and (4) children with a solitary functioning kidney. By performing examinations with little to no radiation, carefully selecting only the children who need imaging studies and judiciously timing follow-up examinations, we can reduce the radiation exposure of children being studied for reflux

The change of radiation doses to the patient when switching from conventional technique to digital technique without films in barium enema and IVU examinations. Final report SSI research project P933

X-ray examinations of the colon (barium enema) and the kidneys (IVU) are combined with rather high radiation doses to the patients when using analogue technique with film-screen systems. It is therefore of great interest to see if the change from analogue to digital technique involves a reduction of doses. Barium enema and IVU examinations were monitored with DAP-meters before and after the X-ray department changed to digital techniques. For IVU also the change from storage phosphor plates to a Direct Digital detector is included. The study comprises between 53 and 87 patients for each modality of the two examinations. A considerable dose reduction was observed. In barium enema the overview images with large field sizes were omitted when using digital technique. On the other hand the number of spot images was increased from 6 to 22. The fluoroscopy time was increased from 4 minutes to 6 minutes. The DAP value was reduced from 54,3 Gy cm sup 2 to 21,9 Gy cm sup 2. For IVU a dose reduction from 44,5 Gy cm sup 2 to 32,5 Gy cm sup 2 was achieved in the first step when storage phosphor plates replaced the film-screen system. In the next step one exposure was omitted and the storage phosphor plates were replaced with a flat panel detector. This step resulted in a dose reduction from 32,5 Gy cm sup 2 to 12,5 Gy cm sup 2. The main dose reduction in barium enema was a result of omitting the overview images and the use of pulsed fluoroscopy. In IVU the introduction of the flat panel detector was the main reason for the dose reductio

Modulationsöverföringsfunktionen (MTF) : De matematiska grunderna med exempel

Vid överföring av information kan man karakterisera ett överföringssystem på olika sätt. Man kan t.ex. ange hur en signal förstärks, hur den förvr~ngs (distorderas), hur mycket brus systemet innehåller etc. Ett bildgivande system kan i princip karakteriseras av ett objekt som ger en insignal till en detektor vars utsignal antagligen innehåller signal + brus. För att beskriva hur utsignalen ser ut i jämförelse med insignalen används flera begrepp som: Punktspridningsfunktionen (PSF) Linjespridningsfunktionen (LSF) Halvvärdesbredden (FWHM) Inom bildöverförande system använder man sig av begreppet MTF (MTF= Modulation Transfer Eunction) . Vi skall i det följande gå igenom grunderna för MTF och även ge exempel på hur man beräknar MTF. Genom att införa Fourier-transformen kan man lättare beräkna MTF och vi kommer därför att beskriva denna. För mätning av MTF för olika system inom röntgendiagnostiken hänvisas-till litteraturen

POSSÍVEIS CONTRIBUIÇÕES DA TEORIA E DA CRÍTICA LITERÁRIA PARA AULAS DE LITERATURA

Resumo: O artigo busca demonstrar possíveis contribuições da teoria e da crítica literária para aulas de literatura. Para tanto, parte-se da análise de textos literários de diferentes fases da literatura brasileira, tendo como fundamentação teórica pressupostos da Estética da Recepção da Escola de Constança, na Alemanha, a fim de que se possa refletir sobre o reconhecimento da teoria literária e da crítica literária para a formação de professores e para a elaboração de propostas práticas relacionadas ao ensino e à aprendizagem da literatura. Essas propostas envolvem poemas de Carlos Drummond de Andrade e de Antonio Cícero e a importância da relação texto e contexto para ampliar os sentidos de compreensão das obras. Palavras-chave: Teoria literária. Crítica literária. Formação de professores de literatura. Ensino e aprendizagem de literatura