Biyomedikal Mühendisliği Enstitüsü

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Micro-processor based automated arrhythmia monitoring system
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1984., 1984.) Gemicioğlu, Cüneyt.; Tan, Yusuf P.
Heart disease is a major cause of death; therefore patients with heart problems, i.e. those who had myocardial infarction are kept under medical observation. Most commonly used method for such observations is the Holter method, which is a 24 hour continuous recording of the electrocardiogram. These recordings are later analyzed by cardiologists or computers , and the results obtained guide therapy applied to the patient. In this thesis a micro-processor based system which analyses electrocardiogram continuously, and records only the cardiac arrhythmias detected. This system supplies immediate information to the cardiologist, as well as being less expensive than other methods.
Inventory control in clinical engineering
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Göbelek, H. Derya.; Tanyolaç, Necmi,; Denker, Ahmet.
The purpose of the Equipment Control Program in Biomedical Engineering is to optimize the safety, effectiveness, efficiency and economy of diagnostic, therapeutic and support equipment used for patient care. In this study, the concept of the Inventory Control, a subprogram of the Equipment Control Program, is investigated. An Inventory tontrol method, to be applied to the Ministry of Health and Social Aid ( S.S.VuB ) hospital, is determined. Finally, this method has been applied to Sisli Etfal Hastahanesi, Istanbul.
Standards for biomedical devices in foreign countries and Turkey
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Eryolalan, Korhan.; Tanyolaç, Necmi,
In this study, the standards and standardizing organizations of biomedical devices which are very important in healthcare are investigated. The regulations of biomedical devices in U.S.A, Canada and Europe countries are described briefly. In Turkey, T.S.E (Turkish Standards Institute) which is the only organization in standardization is described. The topics for Health Preparatory Group in 1985-1986 of T.S.E and the relevant standards until 1984 are investigated. The biomedical devices and the hospital equipment manufacturers are investigated. T.S.E Standards related to medical devices are given in tables. Finally, testing procedure on medical devices produced in Turkey and for imported ones are recommended.
A database management system for nuclear medicine
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 199., 1985.) Dentes, Selim.; Miller, Neil,
The purpose of this thesis is to develop a databank of Nuclear Medicine activities in Turkey. Until recently, no databanks existed in any field in Turkey. This was because the available technology was insufficient to establish such databanks. As a result, obtaining specific information about a subject in any field was time consuming and expensive. However, today, the facilities exist to construct databanks and extensive work has been done to computerize and establish databanks of birth certificates, police records and other information. The purpose of this thesis is to establish such a databank in Nuclear Medicine. This system is meant to be used by all physicians (both Nuclear Medicine physicians and non- Nuclear Medicine ones), Nuclear Physicists, chemists, University Biomedical students and staff, equipment suppliers and government agencies. Primarily, it will be most helpful to physicians in the eastern part of Turkey, where Nuclear Medicine centers are not available and for physicians who can not follow the recent developments taking place in this field in Turkey. This thesis consists of two parts. The first describes the field of Nuclear Medicine. It has three sections. The first is a detailed description of the gamma camera, the second describes the isotopes and radiopharmaceuticals used in Nuclear Medicine imaging, and the third, Nuclear Medicine studies. The second part of the thesis describes the database manager program, PC-FILE III, used to organize the data collected from Nuclear Medicine centers. It also has three sections. The first section describes how the database was designed, i.e. file definitions, data collection and distribution between them are given. The second section discusses the use of the database manager, and the last provides a detailed report derived from the database. The thesis is concluded with examples of how the system is used, how it can be extended for future needs and the advantages and disadvantages of the system.
Magnetic resonance in medicine and possibilities in Turkey
(Thesis (M.A.)- Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Zeytinoğlu, Hakan.; Tanyolaç, Necmi,
Biotelemetry systems and the design of a low cost microprocessor controlled radiotelemetry system
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Çolgar, M. Fatih.; Morgül, Avni,
In this thesis, Biotelemetry systems are presented in general, with various coding systems that send different physiological signals. After that, a special Biotelemetry system is designed, to demonstrate how different methods are employed to solve problems, and the implementation of different blocks of a Biotelemetry system. As it can be seen on the following pages, the system designed for demonstration has different approaches to some well known subjects.
Design and instrumentation of a coronary care unit
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Kireçyan, Ari.; Istefanopulos, Yorgo.
In this study, the main principles that must be obeyed in the design and equipment selection of a coronary care unit are investigated along with the architectural steps which could be used in the establishment of such a unit. Information is given about the bedside monitors, central console monitors and other assisting devices which must be present in an optimal coronary care unit (CCU). The operation principles of these devices are explained by means of block diagrams. The computerized forms of these units which are widespread in developed countries and their advantages are also explained. The characteristics that the hospital's electrical network must have in order for the desired CCU to be realized and the precautions to ensure patient, user and visitor safety are described. The coronary care unit in the Etfal Hospital, the Cerrahpasa, a Hospital, the Haydarpaşa Gogus Cerrahisi Hospital and in the Medical University of Istanbul Çapa Hospital which are functioning in Istanbul are investigated. Information is given about the existing design and some suggestions to solve the problems that arise are offered. In short, the major purpose of this thesis is to built up a source of information on how to realize a CCU design at optimal usefullness and efficiency, taking the economy and technical conditions of the country into consideration.
Establishing biomedical equipment maintenance programs for hospitals in Turkey
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Erdim, Gülsün.; Miller, Neil,
The function of a hospital is to meet the acute health needs of the community it serves. Biomedical instrumentation maintenance programs have been established to help hosp-itals meet these needs through the effective use of technology. These programs can be provided by both outside and inhos pital service organizations. In this study, the elements of an effective biomedical instrumentation maintenance program are presented, and various service options are discussed. In addition, data from surveys carried out in selected hospitals and original equipment manufacturer's representatives in Turkey are provided. In Turkey, there are fewer engineers and technicians in biomedical engineering discipline than are presently needed. There is only one Biomedical Engineering Institute at Bogazici University graduating Biomedical Engineers. Keeping this fact and the findings of the survey in account, 'modeI' biomedical instrumentation maintenance programs for small, medium-sized and large hospitals in Turkey are developed. A case study related to establishing an in-hospital biomedical engineering department Şişli Etfal Hospital is also presented. The proposed 'model' biomedical equipment maintenance programs will help to provide safe, high quality medical care, and effective cost control of this care.
Mechanoelectric transduction: |a review and a methodologic approach to explain the phenomena
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1985., 1985.) Karamanoğlu, Mustafa.; Tan, Yusuf P.
The phenomena of mechanical to electrical transduction is a common response of nervous tissue. In gathering information from environment these tissues are specialized to respond in a fashion like mechanical to electrical transducer. However, it has been demonstrated that this phenomena is related with the intrinsic behavior of membrane itself and observed in different membrane preparations. In this thesis a review of the phenomena and models proposed by other investigators is made and a model which seems to explain it is proposed. In order to test the predictions of model, an experimental setup and a methodological approach to conduct the experiment is presented and suggestions are made for future work on this subject.
Improving medical diagnostic information through better usage of film technology
(Thesis (M.S.)- Bogazici University. Institute of Biomedical Engineering, 1986., 1986.) Kongur, Vahit.; Güveniş, Albert.
Photographic Quality Assurance is an important element of the quality assurance programs as applied in medical diagnostic imaging centers. This thesis addresses the problem of optimizing image quality in Turkey with respect to X-ray film management procedures. First a sensitometric study has been conducted in 32 diagnostic centers in Istanbul. in order to find out the major problems encountered in darkrooms and processors. Then a quality assurance prograrnme has been implemented in a private clinic for a period of one month. Both studies indicate a need for quality assurance programmes in Turkey in order to increase diagnostic image quality and decrease unnecessary radiation dose to the patient. Film purchasing policy in Turkey and its potential effects on film quality have also been discussed in this thesis.
Basic standards of radiation protection in nuclear medicine
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1986., 1986.) Sayman, Haluk B.; Tanyolaç, Necmi,
In this study, the basic standards of radiation protection during routine examinations of Nuclear Medicine or in case of any accident that can happen are explained . The precautions in safe handling of radioisotopes and methods of use of radioactive sources and as well as their storage and transportation are outlined to lower the exposure of radiation toa minimum. The specifications of Radiopharmaceuticals used in Nuclear Medicine practice and their standards are overwieved in the next section. As a case study, a performance test of a scintillation camera approved by AAPM is added to emphasize the importancy of quality control in Nuclear Medicine.
EMG pattern classification based on AR modeling
(Thesis (M.S.)-Bogazici University. Institute of Biomedical Engineering, 1986., 1986.) Erim, Zeynep.; Sankur, Bülent.
Myoelectric control of powered prostheses is a field of rehabilitation engineering that has received wide attention in the recent decades. In this thesis a historical perspective of the studies in the field is given. The physiological properties of muscles are reviewed. The linear models, algorithms for identifying model parameters, and basic pattern recognition considerations are outlined. A scheme to extract motion information from a single surface EMG channel is discussed. The results obtained in performance tests are given. Suggestions for future research topics are made. Major computer programs used are given in the appendix.
A computer aided biofeedback system
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1986., 1986.) Aybey, İ. Melih.; Güveniş, Albert.
Biofeedback devices, unlike other medical devices, are not used in order to monitor a disordered physiological function. They are aimed to be used in training work to gain control over any physiological variable which may have no direct relation with the symptoms of the illness. This thesis reviews the theory and applications of biofeedback and presents an original design of a computerized biofeedback system (DBMl. The digital biofeedback monitor is a system which enables the therapist to analyze the data obtained during and after a biofeedback session by means of a digital computer. It can also be used by the patient for any kind of biofeedback treatment. Collected data related to the session can be stored onto a floppy disk for future references and analyses.
3 D display of organs using CT data implementation on an IBM PC
(Thesis (M.S.)- Bogazici University. Institute of Biomedical Engineering, 1987., 1987.) Hüner, Mutlu.; Güveniş, Albert.
This thesis presents a low cost software package for the three dimensional display of organs using an IBM microcomputer.First existing 3D display techniques and their application in medicine are given. Then the particular algorithm selected for implementation is described and explanations pertinent to this specific implementation are discussed. The boundary detection algorithm used is the one developed by G.T. Herman et,al, Standard computer graphics methods displaying 3D objects. A grid technique is are used introduced for when performing the scan conversion in orter to increase image quality. Some of the results obtained by using mathematical phantoms are presented and discussed. The results indicate that this package can display high resolution images withoul antialiasing effect that is typically encountered in similer packages. It is shown that low pass filtering is only needed in extreme cases.
Analysis of tracheal sounds acquired from patients with lung cancer
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1995., 1995.) Karaaslan, Fatih.; Gülçür, Halil Özcan.
In this study an attempt has been made to determine the quantitative characteristics of the sounds which are caused by the presence of a tumor in the bronchial tree. For this purpose, a special instrumentation system consisting of a PC equipped with an A/D converter, a water-sealed spirometer and amplifiers for tracheal sounds, environmental sounds and a flow potentiometer have been used. Using this system the tracheal sounds of the subject, environmental noise and flow rate of the breathing of the subject were recorded simultaneously. Although vocal cords and oral cavity produce interfering sound signals, trachea was selected as the precise location to acquire the diagnostic lung sounds. This is because the malign tumors of the lung are mostly found in the large bronchi, respiratory sounds measured at the trachea undergo very little filtering, andcharacteristics of the tracheal lung sounds do not depend on subject's morphology to a great extend.The sound signals were filtered using high pass filters having cut-off frequencies at 100 Hz and 2500 Hz, respectively. A sampling frequency of 5 Hz was selected. 1024 data points were extracted from the proper inspiration and expiration phases of each subject. Using a Hanning window and DFFT, the Welch periodogram was estimated.Because patients with lung cancer and chronic obstructive pulmonary disease (COPD) are usually heavy smokers, they have similar symptoms. Therefore, COPD patients were also included to this study. Regions of diagnostic significance in the frequency spectra of subjects studies have been identified and confirmed using the statistical t-test. The area of such a region in the frequency spectra above 633.8 Hz in the inspiration phase of patients with lung cancer and COPD was determined as a distinctive feature with a possibility of less than 18% error.
Comparative studies of ultrasonography in orthopaedics
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1996., 1996.) Eren, T. Ufuk.; Üçışık, A. Hikmet.
In this study ultrasonographic images of different musculoskeletal parts of human body have been examined to see whether they can be used for orthopaedic applications. In some of the examinations, comparisons of the ultrasonographic images with X-Ray films have also been performed. Due to the wide difference between the characteristic impedances of soft tissue and bone, it is very difficult to obtain a clear bone image; only an echogen band and behind it an acoustic shadow can be obtained with ultrasonography. As the results of the 47 examinations on the patients which have been performed in the Orthopaedics and Traumatology, and Radiology Departments of the Istanbul Medical Faculty with the help of the high frequency transducers, some results are obtained. Ultrasonography may reveal components of cartilage which may be obscure in some X-Ray films. Moreover, it can be used to study bone metastasis. Being a safe technique, ultrasonography may be used in "real-time" mode on moving joint parts like shoulder, hip, knee, wrist, ankle and elbow, to obtain valuable diagnostic information. It is shown that ultrasound may be used as an adjunct to radiography in the diagnosis of lesions of bone. The impermeability of bone tissue to ultrasound may be used to analyze the effects of bony lesions on adjacent soft tissue. This approach could make it possible to diagnose bony destruction, inflammation, and new bone formation. It is demonstrated that, in the diagnosis of these kind of pathological changed bone-related parts, ultrason is a excellent adjunct modality to radiography.
Biocompatability of hemodialysis membranes
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1996., 1996.) Aksoy, M. Emin.; Üçışık, A. Hikmet.
With the development of biomaterials the term biocompatability was required to classify these materials in regard to their biological interaction. Biocompatability in extracorporeal blood treatments like hemodialysis is especially important, because all the pathways to bioincompatability become active, when the blood interacts with the membranes used for hemodialysis. The objective of this thesis was to have a better knowledge about the membranes used for hemodialysis and the blood-membrane interactions. In this study, stereomicroscopic evaluation, scanning electron microscopic (SEM) evaluation and tensile testing of the dialysis membranes have been performed. Besides these experiments, patient monitorisation and blood tests consisting of the determination of blood fibrinogen levels, complement 3 levels and white blood cell count during hemodialysis using four different membranes (Polysulfone, Cuprophan, Hemophan and Cellulose- diacetate). Depending on the experiments performed, it can be concluded that polysulfone membranes were the best ones in terms of biocompatability, while cellulose-acetate was the worst one.
A user-friendly sofware for generating patient-specific masking noise in relieving the incurable tinnitus
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1996., 1996.) Fırat, Murat.; Gülçür, Halil Özcan.
Tinnitus is a widely suffered complaint concerning the human auditory system. The tinnitus-stricken patient is generally characterized with hearing loss and suffers from an almost never-ending sound in his ears. These whistle, wind, water fowl, water flow, hissing, etc.-like sounds are always subjective and thus, their detection is quite difficult. Masking the tinnitus sound is one of the most successful non-invasive methods of coping with the tinnitus. In order for the masking method to be acceptable and successful, the masking sound should be individually tailored for the patient. In this thesis, a special computer software has been improved which will enable the physician to detect the tinnitus frequency necessary for masking and which will especially be learnt and conducted easily by the patients. Such a system, consisting of a PC, equipped with a sound card and specially developed software has been proposed and its cost-effectiveness has been demonstrated. The system will for sure speed up the tedious work needed for the determination of the tinnitus frequencies and for the generation of the matching masking sound which is a time-consuming process for both the physician and the patient. A small clinical testing and experience proved that this time-consuming detection of pitch-frequency is much more shorter and simpler with this new software. This software, first of all, applies a simple audiometric test between 125-8000 Hz. The main stage in which the tinnitus frequency is detected, has an algorithm based on the Newton-Rhapson method. This process begins with the application of pure sinusoidal tone at 860 Hz that will change eventually according to the patient's trials to find the relieving sound for him. The scanning of tinnitus frequencies between 125 and 8000 Hz is repeated three times respectively. When this process is completed, a narrow-band white noise with a pure tone at the pitch frequency is synthesized. The software also includes a database for the personal information and the measurement data of the patients.
Correlation dimension computation of EEG time series
(Thesis (M.A.) - Bogazici University. Institute of Biomedical Engineering, 1997., 1997.) Taşkın, Ersin.; Gülçür, Halil Özcan.; Denizhan, Yağmur.
In this thesis, a software package, to be used in correlation dimension (D2) computation of human electroencephalograms (EEG), is developed. The main algorithm calculating the D2 is based on the Grassberger Procaccia (G-P) theorem. Rigorous algorithms are developed to speed up the process without a loss in accuracy. The package is developed under Windows 95 in Delphi 2.0 environment, which enables the program to be a natural part of the contemporary 32 bit environments, and provides the user with a user friendly graphical user interface. The software developed is applied to two groups of signals. 1) Signals, whose D2's are known a priori- a sinusoidal, a Henon map, and a segment of white noise. 2) EEG samples recorded (whose D2's have to be calculated from experimental measurements) under various experimental conditions, from various groups of individuals, which comprise steady state responses of flash driven subjects, alpha dominant waves, beta dominant waves, and beta dominant waves from subjects having minor epilepsy. The numerical results obtained are analyzed, and compared with those in literature.
Electromagnetic compatibility of hearing aids with digital mobile phones
(Thesis (M.S.) - Bogazici University. Institute of Biomedical Engineering, 1997., 1997.) Yürekli, Ali İhsan.; Özkan, Mehmed.
When the intensity of emissions from a radio transmitter varies at an audible rate, it causes interference on sensitive electronic equipment. Hearing aid user complaints caused by this kind of interference were increased by the introduction of digital mobile phones in recent years. Interference reveals itself as a disturbing "buzzing" sound in the hearing aid output. The electromagnetic compatibility of 16 different hearing aid types was measured for high-frequency electromagnetic fields, particularly for those emitted by digital mobile phones. An automated test setup was developed for testing. Setup consisted of a GTEM cell where high frequency fields were generated. Draft version of IEC 118-13 standard was utilized as a basis for the test methodology. All of the hearing aids showed susceptibility to some degree. Interference levels up to 140 dB SPL was measured in 800-960 MHz range of the carrier frequency. Six of the hearing aids were found to produce levels above the level (55 dB SPL Input Related Interference Level) proposed by the standard. Increasing levels of the electric field strength resulted in a quadratic increase in sound pressure levels produced by the hearing aid. This 1:2 dB ratio proves to be a helpful tool in interpolating for any field strength level that was not tested. Setup developed, methodology followed and results obtained in this study can be used to evaluate the electromagnetic compatibility of hearing aids.

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