Publications by authors named "Anna Simeonova"

The sources of marine litter (ML) pollution along the Bulgarian Black Sea coast in 2019 were identified and categorized to: Public litter, Fishing, Shipping, Sanitary and sewage, Fly tipped, Medical and Non-sourced, following Veiga et al., 2016 approach. Largest was the contribution of Public litter - 48.

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Quantitative assessment of marine litter (ML) along the Bulgarian Black Sea coastline was presented. ML surveys were conducted every season in a total of 8 beach monitoring sites during 2015-2016. Eight main categories of material were determined, based on standard OSPAR monitoring protocol.

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In this study marine litter (ML) surveys were conducted in 8 beaches along the Bulgarian Black Sea coastline within 4 seasons for 2015-2016. The monitoring applied OSPAR guideline, classifying ML in eight categories and 167 types. The results exhibited predominance of artificial polymer materials - 84.

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Background: Experimental data demonstrated that concurrent anti-angiogenic treatment with sunitinib may improve the efficacy of radiation therapy (RT). Here we report the results of a phase I trial performed within the German Interdisciplinary Sarcoma Group (GISG-03) of combined sunitinib and RT for neoadjuvant treatment of locally advanced soft tissue sarcoma (STS).

Methods: The primary endpoint of the study was to explore the recommended dose of sunitinib combined with RT for subsequent trials.

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Background: Antiangiogenic substances and radiation therapy (RT) may have synergistic effects and improve irradiation efficacy. We present a cohort study evaluating the toxicity of combined sunitinib and RT as neoadjuvant treatment of extremity and retroperitoneal soft tissue sarcoma (STS).

Methods: Sixteen patients with locally advanced extremity (6/16) or retroperitoneal (10/16) STS were treated with continuous-dosing sunitinib (15/16: 37.

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Background And Purpose: Flattening-filter-free (FFF) beams are increasingly used in radiotherapy as delivery times can be substantially reduced. However, the relative biologic effectiveness (RBE) of FFF may be increased relative to conventional flattened (FLAT) beams due to differences in energy spectra. Therefore, we investigated the effects of FFF and FLAT beams on the clonogenic survival of astrocytoma cells.

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Volumetric-modulated arc radiotherapy (VMAT) is an iteration of intensity-modulated radiotherapy (IMRT), both of which deliver highly conformal dose distributions. Studies have shown the superiority of VMAT and IMRT in comparison with 3-dimensional conformal radiotherapy (3D-CRT) in planning target volume (PTV) coverage and organs-at-risk (OARs) sparing. This is the first study examining the benefits of VMAT in pancreatic cancer for doses more than 55.

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Background: Stereotactic Ablative RadioTherapy (SABR) of lung tumors/metastases has been shown to be an effective treatment modality with low toxicity. Outcome and toxicity were retrospectively evaluated in a unique single-institution cohort treated with intensity-modulated image-guided breath-hold SABR (igSABR) without external immobilization. The dose-response relationship is analyzed based on Biologically Equivalent Dose (BED).

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Purpose: Flattening filter free (FFF) irradiation potentially reduces treatment delivery time in radiosurgery thus eliminating intrafraction motion and increasing patient comfort. We compared plan quality and efficiency of VMAT and IMRT plans for FFF- and standard delivery for brain metastases with single fraction doses of 20 Gy and validated the dosimetric accuracy of the FFF delivery.

Material And Methods: CT data of 15 patients with brain metastases were included in this study.

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Hypofractionated image-guided stereotactic ablative radiotherapy (igSABR) is effective in small lung/liver lesions. Computer-assisted breath-hold reduces intrafraction motion but, as every gating/triggering strategy, reduces the duty cycle, resulting in long fraction times if combined with intensity-modulated radiotherapy (IMRT). 10 MV flattening-filter-free IMRT reduces daily fraction duration to <10 min for single doses of 5-20 Gy.

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Purpose/objectives: Standard 3D-CRT after BCS may cause skin toxicity with a wide range of intensity including acute effects like erythema or late effects. In order to reduce these side effects it is mandatory to identify potential factors of influence in breast cancer patients undergoing standard three-dimensional conformal radiation therapy (3D-CRT) of the breast and modern systemic therapy.

Materials/methods: Between 2006 and 2010 a total of 211 breast cancer patients (median age 52,4 years, range 24-77) after BCS consecutively treated in our institution with 3D-CRT (50 Gy whole breast photon radiotherapy followed by 16 Gy electron boost to the tumorbed) were evaluated with special focus on documented skin toxicity at the end of the 50 Gy-course.

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In early stage non-small cell lung cancer (NSCLC) definitive radiation therapy is an appropriate alternative to surgery. Recent studies show, that in such patients hypofractionation schedules (for example 3 times 18 Gy or 5 times 12 Gy), can be safely applied, without causing severe toxicities and achieving high local control rates of up to 90% and more. In the last couple of years a lot of knowledge about the cancer biology, technical aspects, clinical outcomes and toxicities has been accumulated from different clinical trials.

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Purpose/objective(s): IMRT allows dose escalation for large lung tumors, but respiratory motion may compromise delivery. A treatment plan that modulates fluence predominantly in the transversal direction and leaves the fluence identical in the direction of the breathing motion may reduce this problem.

Materials/methods: Planning-CT-datasets of 20 patients with Stage I-IV non small cell lung cancer (NSCLC) formed the basis of this study.

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Background: Therapy possibilities are limited in patients with cervix carcinoma and thrombocytopenia.

Case Report: We describe a 50-year-old woman with inoperable cervical carcinoma and chronic lymphatic B cell leukemia (B-CLL). Due to thrombocytopenia, a combined radiochemotherapy could not be performed.

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