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Damianov D.,Sofia University | Asenov Y.,Sofia University | Kurtev P.,Specialized Hospital for Active Treatment in Oncology | Penkov N.,Sofia University | And 4 more authors.
Chirurgia (Romania)

Retroperitoneal soft-tissue sarcomas remain a serious therapeutic problem. The aim of the study is to define the optimal treatment strategy of patients with locally recurrent or metastatic retroperitoneal soft-tissue sarcomas. Material and methods: A retrospective study was performed. Between 2001 and 2013, 89 patients with retroperitoneal soft-tissue sarcomas were surgically treated in the University Hospital "Queen Joanna - ISUL" and the Specialized Hospital for Active Treatment in Oncology - Sofia. Clinicopathological data were investigated with SPSS-19. Results: The mean time of onset of the first and second relapse of sarcomas was 23 and 13 months, respectively. Over 40% of the studied patients underwent more than one operation because of recurrence. Ability of radical extirpation of the tumour decreased with each subsequent relapse. The 5-year survival rate was 60% for patients with primary combined radical resection versus 28% for patients with partial resection. In the presence of metastatic lesions the 3-year survival rate was only 22%. Conclusion: Local recurrences, the presence of distant metastases and the ability of radical extirpation are the main long-term prognostic factors. Copyright© Celsius. Source

Gerganov G.,Sofia University | Papucharov A.,Specialized Hospital for Active Treatment in Oncology | Kawrakow I.,Viewray Inc. | Mitev K.,Sofia University
IEEE Nuclear Science Symposium Conference Record

The precise patient positioning is a very important step in radiotherapy. The positioning of the patient for treatment with a LINAC is usually performed by aligning a radiograph to a reference image and the obtained alignment parameters are used to move the patient to the required position. To automate the positioning process, a fast and accurate image registration technique is usually required. In this work we investigate the performance of the phase correlation method (PCM) as a registration tool for Electronic Portal Imaging Device (EPID) images. We propose the usage of the PCM method for fast and accurate rigid registration of misaligned EPID images. To illustrate the concept, EPID images are obtained on a Siemens PRIMUS Linear Accelerator by irradiating two different phantoms - a standardised contrast and spatial resolution phantom ('Las Vegas' phantom) and a realistic phantom of a human pelvis area. Each of the phantoms is placed at the patient table and several images at different table positions are acquired. The position of the table at each image acquisition provides information about the true displacements between the obtained images with a millimeter-level precision. In order to evaluate the accuracy of the PCM registration, the obtained translational parameters using the method are compared with the true displacements known from the table positions. The obtained results show that the method provides very accurate shift estimation with a millimeter-level precision. The method can find potential applications in the calibration and quality assurance procedures of this type of linear accelerator systems. The authors anticipate that the PCM can find application for patient positioning not only by registration of EPID images, but with images from other projection-based imaging modalities as well. © 2013 IEEE. Source

Dimcheva M.,Sofia City Cancer Center | Petrova E.,Sofia University | Garcheva M.,Sofia University | Dimitrova M.,Specialized Hospital for Active Treatment in Oncology | Palashev Y.,Sofia University
Radiation Protection Dosimetry

The aim of this work is to estimate patient doses from hybrid single-photon emission computed tomography (SPECT) and computed tomography (CT) procedures. The study involved all four SPECT-CT systems in Bulgaria. Effective dose was estimated for about 100 patients per system. Ten types of examinations were considered, representing all diagnostic procedures performed in the SPECT-CT systems. Effective doses from the SPECT component were calculated applying the ICRP 53 and ICRP 80 conversion coefficients. Computed tomography dose index and dose length product were retrospectively obtained from the archives of the systems, and effective doses from the CT component were calculated with CT-Expo software. Parallel estimation of CT component contribution with the National Radiological Protection Board (NRPB) conversion coefficients was performed where applicable. Large variations were found in the current practice of SPECT-CT imaging. Optimisation actions and diagnostic reference levels were proposed. © The Author 2015. Published by Oxford University Press. Source

Jassem J.,Medical University of Gdansk | Ozmen V.,Istanbul University | Bacanu F.,Sf. Maria Hospital | Drobniene M.,Vilnius University | And 11 more authors.
European Journal of Public Health

Background: Reducing treatment delay improves outcomes in breast cancer. The aim of this study was to determine factors influencing patient- and system-related delays in commencing breast cancer treatment in different countries. Methods: A total of 6588 female breast cancer patients from 12 countries were surveyed. Total delay time was determined as the sum of the patient-related delay time (time between onset of the first symptoms and the first medical visit) and system-related delay time (time between the first medical visit and the start of therapy). Results: The average patient-related delay time and total delay time were 4.7 (range: 3.4-6.2) weeks and 14.4 (range: 11.5-29.4) weeks, respectively. Longer patient-related delay times were associated with distrust and disregard, and shorter patient-related delay times were associated with fear of breast cancer, practicing self-examination, higher education level, being employed, having support from friends and family and living in big cities. The average system-related delay time was 11.1 (range: 8.3-24.7) weeks. Cancer diagnosis made by an oncologist versus another physician, higher education level, older age, family history of female cancers and having a breast lump as the first cancer sign were associated with shorter system-related delay times. Longer patient-related delay times and higher levels of distrust and disregard were predictors of longer system-related delay times. Conclusions: The delay in diagnosis and treatment of breast cancer remains a serious problem. Several psychological and behavioural patient attributes strongly determine both patient-related delay time and system-related delay time, but their strength is different in particular countries. © 2013 © The Author 2013. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved. Source

Marinova L.,Medical University-Varna | Hristozova I.,Specialized Hospital for Active Treatment | Mihaylova I.,Specialized Hospital for Active Treatment in Oncology | Perenovska P.,Sofia University
Radiation Protection Dosimetry

Ewing's sarcoma in childhood is a disease from family of the peripheral primitive neuroectodermal tumours. For a period of 16 y (1984-2000), 34 children with Ewing's sarcoma were treated and followed in our department. Twenty-seven of these patients were without distant metastases. Complex treatment was applied to all these patients-chemotherapy VACA (vincristine, actinomycin D, cyclophosphamide, adriamycin), local radiotherapy to a total dose of 50-56 Gy 1/2 surgery. After, a local tumour control was achieved in 11 children with non-metastatic Ewing's sarcoma, elective whole lung irradiation to a total dose of 12-15 Gy was applied. Our experience in these 11 patients with non-metastatic Ewing's sarcoma, in whom elective lung irradiation was applied, showed significant reduction in the lung metastases, improved free of disease survival and overall survival. The achieved good treatment results necessitate extending this treatment approach through defining the risk groups of patients, suitable for elective lung radiotherapy combined with chemotherapy in non-metastatic Ewing's sarcoma. © The Author 2015. Source

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