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

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

Long term results of PDR brachytherapy for lip cancer

Purpose: To evaluate the long time outcome with regard to local tumour control and side effects of a pulsed dose rate (PDR) monobrachytherapy of primary or recurrent cancer of the lip. Material and methods: Between 1995 and 2007 we treated 43 patients with primary or recurrent clinical T1-T3N0 lip cancers. There were 22 T1 patients (51%), 16 T2 (37%) and 5 T3 cases (12%). A median dose of 60 (55-66) Gy was given, depending on the tumour volume. The PDR treatment was delivered with 0.83 Gy/pulse every second hour for 5.5-6.5 days. The patients were followed for a median of 55 (1-158) months. Results: The 2-, 5- and 10-year rates of actuarial local control were 97.6%, 94.5% and 94.5%, overall survival 88.0%, 58.9% and 39.1%, disease free survival 92.7%, 86.4% and 86.4% respectively. The regional control rate was 93%. One patient (2%) developed distant metastases. A dosimetrical analysis showed a mean treated volume of 14.9 (3.0-56.2) cm3. Long-term side effects were mild and the cosmetic outcome excellent, except for 1 case (2%) of soft tissue necrosis and 1 case (2%) of osteoradionecrosis. Conclusions: Local outcome is excellent and similar to other published studies of continuous low dose rate (cLDR) brachytherapy

+Department of Medical Physics The Royal Marsden Hospital

Institutionen för medicin och vår

The choice of anti-scatter grids in diagnostic radiology : the optimization of image quality and absorbed dose

A Monte Carlo model is developed to study and optimise the design of antiscatter grids in diagnostic radiology. The imaging chain including X-ray energy spectra, phantom (representing the patient), grid and image receptor is simulated. Image quality is quantified in terms of contrast (conventionai screen-film imaging) and signal-to-noise ratio, SNR (digital imaging) and the radiation detriment to the patient (risk) by the mean absorbed dose in the phantom. The advantages of using fibre instead of aluminium for grid interspaces and covers are quantified. Compared to aluminium grids, the absorbed dose is reduced by 10-50%, contrast is improved by 0-10% and SNR by 10-40% (digital radiography). The advantages are larger at low tube potentials and for grids with high ratio and low strip density. Commercial grids, with different interspace materials, strip density, strip width and grid ratio, are compared in paediatric, lumbar spine and chest examinations. The differences in dose increase and contrast improvement factors obtained with these grids are mainly due to the use of different materials in the grid interspaces, but the strip design is also important. In a global optimisation of grid design and tube potential at fixed contrast, it is found that grids of different strip density and ratio all can have good performances provided that they are used with appropriate strip width and tube potential. In the paediatric examination, low ratio grids need thinner strips than used today to be optimal. A small air gap could alternatively be used. In examinations with more scatter (adult AP), present commercial grids are optimal (r=12-16, d=30-50µm). In the lateral view (even more scatter), grids with ratios larger than 16 are optimal provided the grid can be accurately aligned in the beam. The optimization is performed with grids with fibre interspaces and covers since low atomic number materials should preferably be used for materials between the patient and the receptor. Optimal grids with aluminium for these components have lower grid ratio and higher strip densities than optimal fibre grids

Pulsed dose rate brachytherapy as the boost in combination with external beam irradiation in base of tongue cancer. Long-term results from a uniform clinical series

Purpose: To evaluate long time outcome with regard to local tumour control, side effects and quality of life of combined pulsed dose rate (PDR) boost and hyperfractionated accelerated external beam radiotherapy (EBRT) for primary base of tongue (BOT) cancers. Material and methods: Between 1994 and 2007, the number of 83 patients were treated with primary T1-T4 BOT cancers. Seven patients (8%) were T1-2N0 (AJCC stage I-II) and 76 (92%) patients were T1-2N+ or T3-4N0-2 (AJCC stage III-IV). The mean estimated primary tumour volume was 15.4 (1-75) cm3. EBRT was given with 1.7 Gy bid to 40.8 Gy to primary tumour and bilateral neck lymph nodes in 2.5 weeks. PDR boost of 35 Gy and a neck dissection in clinical node positive case was performed 2-3 weeks later. The patients were followed for a median of 54 (2-168) months. Results: The 2-, 5- and 10-years rates of actuarial local control were 91%, 89% and 85%, overall survival 85%, 65% and 44%, disease free survival 86%, 80% and 76%, respectively. The regional control rate was 95%. Six patients (7%) developed distant metastases. A dosimetric analysis showed a mean of 100% isodose volume of 58.2 (16.7-134) cm3. In a review of late complications 11 cases of minor (13%) and 5 of major soft tissue necroses (6%), as well as 6 cases of osteoradionecroses (7%) were found. The patients median subjective SOMA/LENT scoring at last follow up was as follow: grade 0 for pain and trismus, grade 1 for dysphagia and taste alteration, and grade 2 for xerostomia. Global visual- analogue-scale (VAS) scoring of quality of life was 8. Conclusion: Local and regional tumour control rate was excellent in this treatment protocol. The data shows the PDR boost as at least as effective as published continuous low dose rate (CLDR) results