289 research outputs found

    Krull Dimension of Tame Generalized Multicoil Algebras

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    We determine the Krull dimension of the module category of finite dimensional tame generalized multicoil algebras over an algebraically closed field, which are domestic

    Cycle-finite module categories

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    We describe the structure of module categories of finite dimensional algebras over an algebraically closed field for which the cycles of nonzero nonisomorphisms between indecomposable finite dimensional modules are finite (do not belong to the infinite Jacobson radical of the module category). Moreover, geometric and homological properties of these module categories are exhibited

    Doses in critical organs as limits of the total dose in the treatment of women with inoperable endometrial carcinoma

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    Surgery is the cornerstone of the treatments for endometrial carcinoma. However, about 20% of women must be treated with radiotherapy alone. They are patients in III FIGO stage and women in stage I and II with coexisting medical problems. The primary treatment of endometrial carcinoma is a combination of brachy-and teletherapy. During teletherapy the patients receive the total dose of 40–44 Gy to the treatment volume in pelvis with the use of the 4 beams-box technique. The second part of the treatment is intracavitary brachytherapy using two curved intrauterine applicators. The placing of the applicators in both corners of the uterus and individualized distribution of active sources in catheters make it possible to approximate the shape of isodoses to the size and shape of the uterus. On the basis of the AP and lateral radiographs with the parameters of the uterus we are able to plan the treatment according to the ICRU 38. The 50–55 Gy dose is distributed in two series with weekly intervals. We do not have much influence on the doses in the limiting organs (rectum, bladder) achived during teletherapy. Only the doses from brachytherapy can be modifed during treatment planning.Doses in critical organs are limiting factors for the administred total dose from brachy and teletherapy. Using the Target 2 Plus system enables to obtain combined isodoses from two parts of the treatment. This approach makes it possible to determine the dose in the points in the limiting organs. The doses at points of maximum exposure, as well as the modification of that dose allow us to avoid the possible complications

    10. The comparison between the three – field and four-field techniques of planning of radiotherapy in prostate cancer

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    Purposeevaluation 3-field(3F) and 4-field(4F) planning techiniques for patients with localized prostate cancer. Materials/methods: Five patients with prostate cancer (T3N0M0) were evaluated. CT images were obtained at 5 mm increments and were transferred to CadPlan_planning_workstation. The planning target volume (PTV) was defined as prostate and seminal vesicles with 15mm margins around clinical target volume (CTV) except prostate-rectum interface where 5 mm margin was applied. CTV was defined as prostate and seminal vesicles. Following organs at risk (OAR) were outlined: rectum, bladder, right femoral head. Following 3F and 4F plans were performed: 3F with angles (0deg-120deg-240deg; 0deg-90deg-270deg) and 4F (Odeg-90deg-180deg-270deg). We also created two versions of treatment plans including of energy; 6 MV and 20 MV for Clinac2300CD. Total dose was 74 Gy. Mean total doses of thirty plans in irradiated organs at risk (rectum, bladder and righ femoral head) were compared. For PTV mean and minimum dose were criteria for comparision of treatment plans. Results: There were no significant dose differenes between evaluated plans of treatment in PTV (0.05). Because mean dose in femoral head in each treatment plan was below tolerance dose, main dose-limiting organ was rectum and bladder. Lowest mean dose 42.7 Gy in rectum was achived by application of 3F technique of 20 MV(0deg-90deg-270deg). Bladder was also spared with the same 3F technique of 20 MV, where mean dose was 45.2 Gy. Conclusions: This study showed that the, T” three-field technique (an anterior and two opposing lateral fields) provided with 20 MV is optimal and assures the lowest rectal dose

    Effect of irradiation on interleukin 6 and soluble interleukin 6 receptor modified melanoma genetic vaccine

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    We have designed phase I/II human melanoma gene therapy clinical protocol. The aim of the study was to actively immunize HLA-A1 and/or HLA-A2-positive patients with melanoma with an admixture of irradiated autologous tumor cells and allogeneic melanoma cells genetically engineered to secrete IL-6 and sIL-6R in order to elicit or enhance specific and nonspecific antimelanoma immune responses to autologous tumor cells to eradicate distant melanoma lesions. Irradiation of autologous and allogeneic tumor cells is a key step in preparation of cellular vaccine because of two major reasons, (i) it inhibits cell proliferation which is crucial in the case of autologous cells which may form a tumor; (ii) it increases melanoma vaccine immunogenicity. The aim of the study was to estimate the optimal dose of ionizing radiation which will provide sterilization of both autologous and allogeneic melanoma cells and will ensure cytokine secretion.Human melanoma cells (Mich-1) were transduced with IL-6 and sIL-6R cDNA using double copy bicistronic retroviral vector. Parental and transduced cells were seeded at in six-well tissue culture plates and were irradiated with 10, 50, 100 and 200 Gy. Secretion of both recombinant proteins into culture was analyzed before and 24, 48,72,96 h and 6, 7, 10 and 12 days following irradiation. At the same time adherent cells were enumerated, evaluated’ for viability and proliferation. At 24, 48, 72 and 96 h postirradiation specific IL-6 and sIL-6R mRNA levels were analyzed.Irradiation of gene modified cells inhibited their proliferation in the dose dependant manner. Dose of 50 Gy sufficiently affected cell proliferation, however, for safety reasons we decided to use the dose of 100 Gy for vaccine preparation. Irradiation did not inhibit secretion of IL-6 and sIL-6R. In contrary, on a per cell basis it significantly increased their secretion which lasted 12 days postirradiation. Interestingly, we did not observe dose or time dependent differences in specific mRNA cellular levels suggesting that increased secretion of both proteins is regulated not on the transcriptional but rather on the posttranscriptional level. Taking all these facts into account we concluded that irradiation of tumor cells may provide an effective and safe approach for gene-modified vaccine preparation

    Tilted algebras and short chains of modules

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    We provide an affirmative answer for the question raised almost twenty years ago concerning the characterization of tilted artin algebras by the existence of a sincere finitely generated module which is not the middle of a short chain

    ESTRO-HERO survey: Guidelines for equipment and staffing of radiotherapy facilities in the European countries: Final results of the ESTRO-HERO survey

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    Background and purpose: In planning to meet evidence based needs for radiotherapy, guidelines for the provision of capital and human resources are central if access, quality and safety are not to be compromised. A component of the ESTRO-HERO (Health Economics in Radiation Oncology) project is to document the current availability and content of guidelines for radiotherapy in Europe. Materials and methods: An 84 part questionnaire was distributed to the European countries through their national scientific and professional radiotherapy societies with 30 items relating to the availability of guidelines for equipment and staffing and selected operational issues. Twenty-nine countries provided full or partial evaluable responses. Results: The availability of guidelines across Europe is far from uniform. The metrics used for capital and human resources are variable. There seem to have been no major changes in the availability or specifics of guidelines over the ten-year period since the QUARTS study with the exception of the recent expansion of RTT staffing models. Where comparison is possible it appears that staffing for radiation oncologists, medical physicists and particularly RTTs tend to exceed guidelines suggesting developments in clinical radiotherapy are moving faster than guideline updating. Conclusion: The efficient provision of safe, high quality radiotherapy services would benefit from the availability of well-structured guidelines for capital and human resources, based on agreed upon metrics, which could be linked to detailed estimates of nee
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