Ozcan Gundogdu

Ozcan Gundogdu
Kocaeli University · Department of Biomedical Engineering

Professor

About

95
Publications
19,048
Reads
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965
Citations
Citations since 2017
29 Research Items
480 Citations
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
Additional affiliations
August 2007 - January 2009
Royal Surrey County NHS Foundation Trust
Position
  • R&D Physicist
January 2003 - August 2007
University of Surrey
Position
  • Senior Researcher
January 2001 - July 2003
Kingston University
Position
  • Senior Researcher

Publications

Publications (95)
Article
Full-text available
The articular cartilage overlying subchondral bone consists of variously oriented collagen fibres, the detailed organisation of which is essential for cartilage integrity that has suffered damage in degenerative joint disease such as osteoarthritis (OA). A technique attracting particular interest is that of coherent small-angle X-ray scattering map...
Article
Digital mammography equipment should operate at a high-performance level for detecting breast cancer over the lifetime of the systems. This study investigates the performance of the Fujifilm Amulet Innovality full-field digital mammography system in relation to the number of exposures. The performance of twelve systems, from new and up to 17 000 ex...
Preprint
Full-text available
Background The objectives of this study were to compare the cumulative incidence, hospitalizations and mortality, by country and age group, in child and young people (CYP) from the beginning of the pandemic to January 2022, and to describe the differences and similarities and justification in the measures adopted in relation to CYP vaccination agai...
Article
Full-text available
Multipl Skleroz (MS), vücudun bağışıklık sistemi hücreleri tarafından beyindeki sinir hücrelerinin dış kısmında bulunan miyelin kılıfların zarar görmesi sonucu lezyon veya plak oluşmasına bağlı nörolojik bir hastalıktır. Bu makalenin amacı Sekonder Progresif MS (SPMS) için tıp ve biyomedikal mühendisliği alanında çözüm önerileri üreterek yapılan ça...
Article
Background: The radiobiological effect of high dose rate FFF beams on the DU-145 cells was investigated with SBRT plans which have >10 Gy. Methods and Materials: To compare the radiobiological effect on DU-145 cell line four experiments designed: (1) the constant dose rate of 6 MV and 6 MV FFF with increased dose per pulse (2) the effect of dose pe...
Article
Full-text available
The present work, with its interest focusing on the elastic scattering of energetic electrons, provides a novel formulation that is demonstrated to give accurate values of the screening parameter. This is a matter considered vital in obtaining transport cross-sections, the work herein covering not only a wide range of electron energies popular in a...
Article
Full-text available
Radiation therapy is widely used as a treatment tool for malignancies. However, radiation-related complications are still unavoidable risks for off-target cells. Little is known about radiation therapy's possible effects on mechanical features of the off-target cells such as human red blood cells (RBCs). RBCs are nucleus-free circulating cells that...
Article
Full-text available
Objective: In this study, we retrospectively reviewed and statistically analyzed the Cyberknife SBRT outcomes in terms of local control and survival times for the patients with primer lung tumors treated at Anadolu Medical Center. Methods: We included 135 patients who were treated between 2005 and 2016 and diagnosed primary lung cancer who were ju...
Article
Objective: To evaluate Peak Expiratory Flow (PEF) values in Turkish children between the ages 6 and 14 years old according to height, gender and age. Methods: Data was obtained from public health screening days in primary care practice on 1439 children. Peak expiratory flow (PEF) was measured for each child with a Mini Wright Peak Flow Meter. The s...
Article
Background The Very Early Diagnosis Of Systemic Sclerosis (VEDOSS) study has shown that 82% of patients with Raynaud’s Phenomenon, specific ANA positivity and scleroderma pattern at nail fold videocapillaroscopy will fulfil classification criteria within 5 years. This is suggesting that there is a subclinical window of opportunity to diagnose syste...
Article
Background Previous studies have shown that Optical Coherence Tomography (OCT) is a reliable biomarker of skin fibrosis and significantly correlates with the severity of the skin involvement in Systemic Sclerosis (SSc) 1,2 . Objectives Aim of this cross-sectional study was to evaluate the performance of skin OCT to discriminate between SSc and hea...
Article
Full-text available
Background The modified Rodnan skin score (mRSS) is the current gold standard for skin assessment in systemic sclerosis (SSc) both in clinical trials and practice. Several studies have reported that skin high frequency ultrasound (HFUS) and, more recently, optical coherence tomography (OCT) are able to reflect the severity of the skin disease in SS...
Article
Full-text available
Background The Very Early Diagnosis Of Systemic Sclerosis (VEDOSS) study has shown that 82% of patients with Raynaud’s phenomenon, specific ANA positivity and scleroderma pattern at nailfold video capillaroscopy will fulfill classification criteria within 5 years. This is suggesting that there is a sub-clinical window of opportunity to diagnose sys...
Article
This study reports structural, charge transport and antibacterial properties of Poly(N-methylpyrrole) (PNMPy) and its composites. Optical studies indicated that both indium(III) oxide (In2O3) and tungsten(VI) oxide (WO3) nanoparticles increased the optical band gap of PNMPy. Furthermore, it was determined that the filling process increased the fluo...
Article
Full-text available
Objectives: To investigate diffusional changes in multiple sclerosis (MS) plaques and non-Gaussian behavior of water diffusion by using diffusional kurtosis imaging (DKI). Methods: 31 MS patients and 21 controls underwent MRI on a 3T scanner. Mean kurtosis (MK) parametric maps were computed. Region of interest (ROI) was delineated as white matte...
Article
Full-text available
Objective: In this study, we aimed to establish a standard protocol of measurements by taking quality control tests belonging to digital mammography devices widely used in our country. Breast cancer occurs in glandular tissue. For this reason, it is necessary to measure the mean glandular tissue value and follow the standard values. The accuracy of...
Article
Full-text available
This study reports the synthesis of polyfuran/tin(IV) oxide (PFU/SnO2) composite by the chemical polymerization method. Characterization studies indicated that the filling process mostly affected the C=C and C=O functional groups in the PFU rings and as well as increased the degree of crystallinity of PFU from 2.93 to 6.97%. Furthermore, tin oxide...
Article
Full-text available
Introduction: According to international quality control testing standards, image quality determination in mammography systems is based on measuring contrast-detail measurements with contrast-detail for mammography (CDMAM) phantom. It is therefore important to evaluate the CDMAM phantom images correctly. The purpose of this study is to compare the...
Article
Full-text available
Lasers are used in industry in a large variety of applications. These applications can mainly be divided into two categories: one specifically being materials processing. Material processing includes cutting, drilling, welding,etc., and generally involves the use of high-powered lasers. Laser applications such as rust/dye removal and surface cleani...
Article
A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi2O3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experiment...
Conference Paper
Full-text available
In this study, we present comparison of human and software reading of contrast-detail mammography (CDMAM) phantom images for a digital mammography system. The human readings were conducted through CDMAM images using 3 Megapixel and 5 Megapixel medical monitors. The phantom was positioned between Poly methyl methacrylate (PMMA) blocks of 20mm thickn...
Article
A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compto...
Article
This paper reports a process by which two copper plates are welded together by using a millisecond pulse Nd:YAG laser with the addition of stellite 6 powder which increases the absorption of laser energy. It also reports an interesting application of Laser Induced Breakdown Spectroscopy (LIBS) in order to determine the elemental composition and dif...
Article
Full-text available
Kidney stones were analyzed using laser-induced breakdown spectroscopy (LIBS), utilizing a high resolution multi-channel charge-coupled device (CCD) spectrometer and a nanosecond-pulse Nd : YAG laser. The kidney stones were also characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques for comparative analysis. It was foun...
Article
Investigation is made on the energy spectrum of photons originating from interactions of 662 keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm×19 cm×24 cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed usin...
Article
Alumina ceramics have found wide range of applications from semiconductors, communication technologies, medical devices, automotive to aerospace industries. Processing of alumina ceramics is rather difficult due to its high degree of brittleness, hardness, low thermal diffusivity and conductivity. Rapid improvements in laser technologies in recent...
Article
The techniques μProton-Induced X-and γ-ray Emission, μ-PIXE and μ-PIGE, were used to investigate trace and essential element distributions in sections of normal and osteoarthritic (OA) human femoral head. μ-PIGE yielded 2-D mappings of Na and F while Ca, Z, P and S were mapped by μ-PIXE. The concentration of chondroitin sulphate supporting function...
Article
Full-text available
Concentration of (222)Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measuremen...
Article
(222)Rn measurements in water samples collected from 27 wells and 19 taps that were supplied from the investigated wells were conducted using the AlphaGUARD PQ 2000PRO radon gas analyser at sites across several geologic formations within the city of Bursa, Turkey. The measured radon concentrations ranged from 1.46 to 53.64 Bq l(-1) for well water a...
Article
Micro-Proton Induced X-ray Emission (μ-PIXE) and Proton Induced Gamma-ray Emission (PIGE) techniques were employed in the investigation of trace and essential elements distribution in normal and diseased human femoral head sections affected by osteoarthritis (OA). PIGE was exploited in the determination of elements of low atomic number z15 viz Ca,...
Article
The effect of varying object to detector separation at constant and varying magnification has been investigated at an accelerating potential of 30kVp. Edge-contrast enhancement provided by phase effects was investigated for a drinking straw and found to provide up to 2.52±0.02× the contrast for a PVC Heaviside step function. An optimum magnificatio...
Article
The energy spectra of beta rays emitted from 90Sr and 204Tl radioisotopes were obtained by using a silicon surface barrier detector with a 1000 μm depleted layer and 50 mm2 effective area. The detector response function is interpreted by making use of range distributions of mono-energetic electrons in matter and by assuming a linear energy loss alo...
Article
This paper discusses a method to determine the thickness of an absorber using the energy distribution of beta particles. An empirical relationship was obtained between the absorber thickness and the energy distribution of beta particles transmitted through. The thickness of a polyethylene radioactive source cover was determined by exploiting this r...
Article
To explore what factors influence Turkish parents' decision whether to have their children immunised or not and compare them with other internationally published studies. Data from 300 parents were gathered via a survey completed by the parents during their policlinic visit between January 2009 and March 2010 in Kocaeli, Turkey. The survey content...
Article
Full-text available
Drinking water may contain varying levels of radioactivity. It is therefore important to determine the radium levels in drinking waters for public health and radiation protection. This paper presents results of 226Ra concentrations in bottled spring waters. The concentration of radium has been assessed in the bottled natural spring water samples co...
Conference Paper
The divalent cations Ca, P and Zn have been reported to play an important role in the normal growth and remodelling of articular cartilage and subchondral bone and in the degenerative and inflammatory processes associated with osteoarthritis (OA). In particular, they act as co-factors of a class of enzymes known as metalloproteinases, believed to b...
Article
Full-text available
In this paper, results from an optical technique for measuring surface roughness using image analysis of speckle pattern images are presented. The technique coined as statistical properties of binary images (SPBI) utilizes the combined effects of speckle and scattering phenomena. The speckle patterns obtained with a He–Ne laser were binarized and e...
Article
The investigations reported herein link tissue structure and elemental presence with issues of environmental health and disease, exemplified by uptake and storage of potentially toxic elements in the body, the osteoarthritic condition and malignancy in the breast and other soft tissues. Focus is placed on application of state-of-the-art ionizing ra...
Article
Radon ((222)Rn) is a tasteless, colourless and odourless radioactive noble gas, responsible for approximately 50% of radiation from natural sources. Being highly soluble in water, radon in water sources is also a major public health concern and is still an active research area. This paper presents the results of radon concentration measurements in...
Conference Paper
Full-text available
When a surface is illuminated with a highly coherent light such as a laser beam, the speckle pattern of bright and dark regions is observed. It depends on the surface parameters and carries important information about the roughness of the surface. Various methods and techniques are employed for the determination of surface roughness parameters from...
Article
Micro Proton Induced X-ray Emission (micro-PIXE) analysis has been employed herein in investigating and quantifying the distribution of a number of essential elements in thin human diseased articular cartilage sections affected by osteoarthritis (OA). Various cations Ca, P and Zn have been reported to play an important role both in the normal growt...
Article
Synovial joints articulate in a lubricating environment, the system providing for smooth articulation. The articular cartilage overlying the bone consists of a network of collagen fibres. This network is essential to cartilage integrity, suffering damage in degenerative joint disease such as osteoarthritis. At Surrey and also in work conducted by t...
Article
This paper presents results on the angular distribution of Compton scattering of 662 keV gamma photons in both forward and backward hemispheres in copper medium. The number of scattered events graph has been determined for scattered gamma photons in both the forward and backward hemispheres and theoretical saturation thicknesses have been obtained...
Article
A wide range of materials of interest in the sciences and medicine can exhibit weak X-ray attenuation but yet still produce significant phase shifts at the same X-ray wavelengths. The use of phase information for imaging purposes therefore represents an attractive prospect. Images formed from differences in phase produced by an object manifest from...
Article
Full-text available
CDMAM phantoms are widely used in the Europe to assess the performance of mammography systems utilising small size and low contrast disc details. However, the assessment of CDMAM images by human observers is slow and tedious. An automated method for scoring CDMAM images (CDCOM) is widely available to address this issue. We have developed an alterna...
Article
The main objective of the present study is to determine the type of environmental contamination in lichens in Gökçeada Island in the Northern Aegean Sea in Turkey. We used two different lichen species Cladonia foliacea and Ramalina pollinaria. In the first part of the investigation, the beta activities of lichens have been measured by using a TENNE...
Article
European Guidelines for quality control in digital mammography specify minimum and achievable standards of image quality in terms of threshold contrast, based on readings of images of the CDMAM test object by human observers. However the methodology is time-consuming and has large inter- and intra-observer error. To overcome these problems a softwa...
Article
The LB 1000-PW detector is mainly used for determining total alpha, beta and gamma activity of low activity natural sources such as water, soil, air filters and any other environmental sources. Detector efficiency needs to be known in order to measure the absolute activity of such samples. This paper presents results on the total gamma counting eff...
Article
Nanoparticles do not like to be alone. They like to be part of a group from the moment they are created due to their extremely large surface area. It is their "nature." In order to have nano-intensive products with exciting properties, one has to understand a great deal about this, often overlooked, nano-agglomeration behaviour.
Article
The mass energy absorption, the mass energy transfer and mass absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass en...
Article
To create advanced nano-structured materials and fluid media with unique tailored properties, it is often necessary to form nanocomposites or nano-dispersions, which may include homogenous and heterogeneous mixtures of nanoparticles dispersed in a matrix or medium of another compound such as a polymer. Recent and ongoing research on polymer/inorgan...
Conference Paper
The performance of a wide range of digital mammography systems has been compared in terms of the dose required to achieve the image quality standards in the European guidelines at different detail sizes. This paper considers how these results relate to measurements of detector performance on these systems. The dose to meet the minimum requirements...
Conference Paper
Dose and image quality have been evaluated for two types of digital mammography system which have X-ray tubes with tungsten anodes, the Siemens Novation and the Hologic Selenia. For each system, contrast-to-noise ratio and threshold contrast measurements were made. The results were used to determine the optimum exposure settings for each system to...
Article
There is a growing interest being shown in the changes occurring in elemental distribution at the bone-cartilage interface, the changes either being a result of mechanical damage or disease. In particular, such investigations have tended to concern the elemental alterations associated with the osteoarthritic wear and tear damage occurring to the ca...
Article
In articular cartilage, Ca, P, K and S are among some of the well known co‐factors of the metalloproteinases enzymatic family, the latter playing a pivotal role in the growth and degeneration of the collagenous bone‐cartilage interface of articulating joints. Current study forms part of a larger investigation concerning the distribution of these an...
Article
A microbeam synchrotron x-ray fluorescence (µ-SXRF) technique has been employed in investigating the localisation of metals in two biological systems, soft and calcified tissue. Breast carcinoma is the focus of the former investigations, and osteoarthritis, that of the latter. Copper has been the metal of particular interest in breast tissue work,...
Article
Clinical radiography has traditionally been based on contrast obtained from absorption when X-rays pass through the body. The contrast obtained from traditional radiography can be rather poor, particularly when it comes to soft tissue. A wide range of media of interest in materials science, biology and medicine exhibit very weak absorption contrast...
Article
This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid...
Article
Polyviologens (PVs) are used as potential templating agents. They were prepared and then incorporated into a silica matrix via base-catalyzed hydrolytic sol-gel reaction. The resultant polymer hybrid material is amorphous aggregates of roughly spherical silica nanoparticles. In this article, we describe an experimental system designed to examine an...
Article
Nanoparticles and nanocomposites have become a major focus of interest in science and technology due to exceptional properties they provide. However, handling and processing of ultra-fine powders is very challenging because they are extremely cohesive. Fluidization is one of techniques available to process powders. It has become increasingly import...
Article
Polyviologen polymers are potential template agents for hydrolytic sol–gel processing of silica particles. The resultant polyviologen-silica hybrid nanopowders are amorphous aggregates of roughly spherical shape, which can be harvested from the sol–gel solution and processed to green body products under different environmental conditions. A bench-t...
Article
In this Letter, an expression is presented to calculate elastic scattering cross sections for incident electrons as a function of both energy and atomic number in the energy range between 1 keV and 1 MeV for materials with effective atomic number between 3 and 18. The expression we present has a rather simple analytical form which gives accurate re...
Article
The absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy absorption coefficients for gamma rays with an incide...