Simona Avramova-Cholakova

Simona Avramova-Cholakova
Imperial College Healthcare NHS Trust · Radiological Sciences Unit

PhD

About

52
Publications
13,702
Reads
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184
Citations
Citations since 2017
18 Research Items
118 Citations
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2017201820192020202120222023051015202530
2017201820192020202120222023051015202530
Additional affiliations
August 2019 - present
Imperial College London
Position
  • Lecturer
Description
  • Provide lectures for the MSc Biomedical Engineering programme, module Ionising Tissue & Flow Imaging
October 2018 - present
Imperial College Healthcare NHS Trust
Position
  • Senior Radiological Physicist
March 2016 - February 2018
University Hospital Acibadem City Clinic
Position
  • Principal Investigator
Education
November 2008 - December 2013
Medical University of Sofia
Field of study
  • Medical Radiological Physics specialty, post graduate education
November 2008 - March 2010
September 2002 - December 2003
Plovdiv University "Paisii Hilendarski"
Field of study
  • Medical Physics

Publications

Publications (52)
Article
The aim of this study is to compare effective dose (E) estimations based on different methods for patients with recurrent computed tomography (CT) examinations. Seventeen methods were used to determine the E of each phase as well as the total E of the CT examination. These included three groups of estimations: based on the use of published E, calcu...
Article
The purpose is to compare full-field digital mammography (FFDM), digital breast tomosynthesis (DBT) and contrast-enhanced spectral mammography (CESM) technologies on three mammography systems in terms of image quality and patient dose. Two Senographe Essential with DBT and CESM (denoted S1 and S2) and one Selenia Dimensions (S3) with FFDM and DBT w...
Conference Paper
Purpose: Phantom study was performed aimed to assess the effectiveness of RADPAD® in reducing staff exposure during Cerebral Embolisation procedures. Methods and Materials: A biplane suite Azurion Clarity IQ (Philips) was used. Three cylindrically shaped PMMA phantoms of increasing size simulated patient body. Standard 20 cm PMMA plates were positi...
Conference Paper
Purpose. This study was initiated as part of the UK national patient dose survey in Computed Tomography. The purpose is to determine typical patient doses from seven CT scanners in three hospitals, to compare the protocols and to establish local diagnostic reference levels (LDRLs) according to the new ICRP recommendations. Materials and Methods. Fo...
Article
Purpose Patients with hematuria and renal colic often undergo CT scanning. The purpose of our study was to assess variations in CT protocols and radiation doses for evaluation of hematuria and urinary stones in 20 countries. Method The International Atomic Energy Agency (IAEA) surveyed practices in 51 hospitals from 20 countries in the European re...
Article
Full-text available
Purpose To assess the frequency, appropriateness, and radiation doses associated with multiphase computed tomography (CT) protocols for routine chest and abdomen–pelvis examinations in 18 countries. Materials and Methods In collaboration with the International Atomic Energy Agency, multi-institutional data on clinical indications, number of scan p...
Conference Paper
The Council Directive 2013/59/EURATOM requires medical physics experts (MPE) to be recognized at governmental level and their continuity of expertise to be ensured. In 2014 European Guidelines on Medical Physics Expert, Radiation Protection No 174 (RP174) was published. This document provides comprehensive description of educational and training sc...
Article
Full-text available
The first national survey of patient exposures from hybrid imaging in Nuclear Medicine, performed in Bulgaria in 2014, revealed that SPECT/CT imaging of either thyroid or parathyroid glands was performed by applying a CT scan of the whole anatomical region, neck and chest, subject to SPECT. In most cases it was not necessary to perform a CT scan ma...
Conference Paper
Full-text available
Eur J Nucl Med Mol Imaging (2018) 45 (Suppl 1): S738. Introduction: A national survey of patient exposures from hybrid imaging in Nuclear Medicine, performed in Bulgaria in 2014, revealed that single photon emission computed tomography/ computed tomography (SPECT/CT) imaging of either thyroid or parathyroid glands was performed by applying a CT sca...
Article
Full-text available
This article aims to present the protocol on Quality Controls in Digital Mammography published online in 2015 by the European Federation of Organisations for Medical Physics (EFOMP) which was developed by a Task Force under the Mammo Working Group. The main objective of this protocol was to define a minimum set of easily implemented quality control...
Conference Paper
Full-text available
The first national survey of patient doses from PET/CT was performed in Bulgaria in 2013-2014. It included both systems available in the country. New equipment was installed in recent years prompting the Bulgarian Society of Nuclear Medicine to initiate a second national survey. The aim of the paper is to estimate patient exposures from all six PET...
Conference Paper
Full-text available
Introduction The number of fluoroscopically guided invasive diagnostic and interventional urology procedures is increasing during the last few years. This leads to higher staff doses in comparison with other radiology procedures. Purpose The aim of this study is to evaluate staff doses in fluoroscopically guided invasive diagnostic and interventio...
Conference Paper
Full-text available
First national survey of patient doses from hybrid imaging in nuclear medicine in Bulgaria was performed in 2013-2014. Afterwards new equipment was installed in the country. The purpose of this study is to supplement the information from the national survey by estimating radiation exposure of patients from the new positron emission tomography-compu...
Conference Paper
Full-text available
After the first national survey of patient exposures from hybrid imaging in nuclear medicine was performed in Bulgaria, a new single-photon emission computed tomography and computed tomography (SPECT-CT) system was installed. The purpose of this study is to estimate patient doses received from procedures on this system and to supplement data from t...
Conference Paper
Full-text available
The first systems for Digital Breast Tomosynthesis (DBT) were installed in Bulgaria in 2015. This study aims to perform pilot estimation of patient doses from examinations on two DBT systems – GE Senograph Essential and IMS Giotto Tomo. Incident air kerma (IAK) and mean glandular dose (MGD) were determined applying the method proposed in the Protoc...
Article
Full-text available
The aim of this study is to compare four dosimetry methods for wide-beam multi-detector computed tomography (MDCT) in terms of computed tomography dose index free in air (CTDIfree-in-air) and CTDI measured in phantom (CTDIphantom). The study was performed with Aquilion One 320-detector row CT (Toshiba), Ingenuity 64-detector row CT (Philips) and Aq...
Article
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 pro...
Article
Positron emission tomography (PET) was installed for the first time in Bulgaria in 2009, and nowadays two hybrid PET-computed tomography (CT) systems are in operation. The aim of this work is to estimate patient doses from PET-CT procedures and to explore potential for optimisation. Data were retrospectively collected for 50 patients examined with...
Article
The requirements for quality control (QC) in diagnostic radiology were introduced in Bulgarian legislation in 2005. Hospital medical physicists and several private medical physics groups provide QC services to radiology departments. The aim of this study was to analyse data from QC tests in mammography and to investigate the impact of QC introducti...
Article
According to the Bulgarian regulation for radiation protection at medical exposure, the National Centre of Radiobiology and Radiation Protection (NCRRP) is responsible for performing national dose surveys in diagnostic and interventional radiology and nuclear medicine and for establishing of national diagnostic reference levels (DRLs). The next nat...
Article
Full-text available
Recent years two types of hybrid systems were installed in Bulgaria - Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET), combined with an X-ray computed tomography (CT) system. The aim of this work is to perform national survey of patient doses from SPECT-CT and PET-CT procedures, to explore potential for opt...
Article
Full-text available
The purpose of this work is to develop a protocol with recommended values of tube voltage for manual exposure in semiautomatic mode depending on compressed breast thickness and glandular content of the breast. The protocol was developed based on literature data and on our own measurements. The values were tested on one mammography unit for 54 patie...
Article
The purpose of this work is to compare the state of a representative number of mammography systems in Bulgaria in terms of incident air kerma (IAK) and film optical density (OD) and to propose the optimisation measures where appropriate. IAK with a standard phantom and OD of the exposed films were measured on 22 % of all units in the country. IAK v...
Article
The objective is to study mammography practice from an optimisation point of view by assessing the impact of simple and immediately implementable corrective actions on image quality. This prospective multinational study included 54 mammography units in 17 countries. More than 21,000 mammography images were evaluated using a three-level image qualit...
Article
Full-text available
The purpose of this work is to explore the influence of different parameters, including viewing conditions, on image quality in X-ray mammography. Images of Barts and ACR mammography phantoms, obtained at different tube voltage (kV) and optical density (OD) values were estimated on 3 viewing boxes with different luminance by 2 observers. Subjective...
Article
Full-text available
The paper presents the current status of Diagnostic Radiology in Bulgaria. The total number of X-ray systems in 2009 is 2490, with 55.8 % contribution of conventional radiography and fluoroscopy systems, 25.5 % of dental, 7.8 % of computed tomography and 6.9 % of mammography systems. Old X-ray equipment still constitutes a considerable part of the...
Article
Full-text available
Pilot study of patient and phantom breast dose measurements in Bulgaria A pilot study of breast dose measurements on two mammography units in Bulgaria was conducted. The mean glandular doses (MGDs) to samples of approximately 60 women per unit were measured. MGD with a standard PMMA phantom was measured as well. The MGDs were calculated according t...
Article
This work is aimed to study the variability of dosimetry results owing to various measurement methodologies for breast dosimetry. This is performed in the frame of the development of a national protocol for breast dosimetry. Doses for standard phantom and group of patients were calculated for two mammography systems from the tube output measured wi...
Article
Full-text available
National protocol for quality assurance in DXA-bone densitometry Osteoporosis becomes largely one of the most important socially significant and costly diseases. Modern techniques (DXA, US) are applied for bone densitometry. The paper presents a protocol for quality assurance especially of DXA-bone densitometers including quality control made in co...
Article
The results from the national pilot project on implementation of the European protocol for the quality control (QC) of the technical aspects of mammography screening as well as the European protocol for dosimetry in mammography in Bulgaria are presented. A QC programme for mammography equipment and a standardised measurement protocol were created....

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