فهرست مطالب

Journal of Biomedical Physics & Engineering
Volume:7 Issue: 1, Jan-Feb 2017

  • تاریخ انتشار: 1395/12/25
  • تعداد عناوین: 10
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  • S. Zargan_P. Ghafarian_A. Shabestani Monfared_A. A Sharafi_M. Bakhshayeshkaram_M. R Ay Page 1
    Background
    PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center.
    Materials And Methods
    80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger–Muller dosimeter were also utilized for measurement purpose.
    Results
    The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk.
    Conclusion
    In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.
    Keywords: PET-CT, Cyclotron, TLD, Radiation Dose, Environment Dose, Staff Dose, [18F]-FDG
  • M. M Firoozabadi_Gh Izadi Vasafi_K. Karimi_Sh_M. Ghorbani Page 13
    Background
    In neutron interaction with matter and reduction of neutron energy due to multiple scatterings to the thermal energy range, increasing the probability of thermal neutron capture by neutron captures makes dose enhancement in the tumors loaded with these materials.
    Objective
    The purpose of this study is to evaluate dose distribution in the presence of 10B, 157Gd and 33S neutron capturers and to determine the effect of these materials on dose enhancement rate for 252Cf brachytherapy source.
    Methods
    Neutron-ray flux and energy spectra, neutron and gamma dose rates and dose enhancement factor (DEF) are determined in the absence and presence of 10B, 157Gd and 33S using Monte Carlo simulation.
    Results
    The difference in the thermal neutron flux rate in the presence of 10B and 157Gd is significant, while the flux changes in the fast and epithermal energy ranges are insensible. The dose enhancement factor has increased with increasing distance from the source and reached its maximum amount equal to 258.3 and 476.1 cGy/h/µg for 157Gd and 10B, respectively at about 8 cm distance from the source center. DEF for 33S is equal to one.
    Conclusion
    Results show that the magnitude of dose augmentation in tumors containing 10B and 157Gd in brachytherapy with 252Cf source will depend not only on the capture product dose level, but also on the tumor distance from the source. 33S makes dose enhancement under specific conditions that these conditions depend on the neutron energy spectra of source, the 33S concentration in tumor and tumor distance from the source.
    Keywords: Brachytherapy, Neutron Capture, 252Cf, Dose, MCNP
  • P. Pishdad_G. R Pishdad_S. Tavanaa_R. Pishdad_R. Jalli Page 21
    Objective
    Graves’ disease and Hashimoto’s thyroiditis are the most common causes of hyper and hypothyroidism, respectively. Differentiation of these 2 diseases, if the patient is euthyroid, may sometimes be extremely difficult on the basis of clinical and laboratory findings. The purpose of this study was to determine the sensitivity and specificity of gray scale sonography in differentiation of Graves’ disease from Hashimoto’s thyroiditis.
    Methods
    This study included 149 patients divided into three groups, patients with Graves’ disease (34 patients, mean age = 36.8 ± 10.17 years), Patients with Hashimoto’s thyroiditis (62 patients, mean age = 33.4 ± 12.16 years) and control group (53 healthy people, mean age = 34.74 ± 16.87 years). Members of all groups were referred to a single radiologist for thyroid sonography for evaluation of thyroid echogenicity pattern.
    Results
    A total of 117 women and 32 men were examined by sonography. The most common sonographic pattern in Hashimoto and Graves’ was homogenous hypo-echogenicity which was observed in 45.2% and 47.1% of cases, respectively. Peripheral hypo-echogenicity pattern was seen in 40.3% of Hashimoto’s group with 100% specificity and 40.3% sensitivity. Central-hypoechogenic pattern was observed in 17.6% of Graves’ group with 100% and 17.6% specificity and sensitivity, respectively.
    Conclusion
    Our findings indicate that sonography has high specificity but low sensitivity in the diagnosis of either Graves’ disease or Hashimoto’s thyroiditis. It is therefore not possible to differentiate between these two diseases using sonography alone. Confirmation by laboratory data is also needed.
    Keywords: Hashimoto's thyroiditis, Grave's disease, thyroid sonography
  • M. Valizadeh, A. Shirazi, P. Izadi, J. Tavakkoly Bazzaz, H. Rezaeejam Page 27
    Background
    After radiation therapy (RT), some health hazards including DNA damages may occur where melatonin can play a protective role due to free radical generation. On the other hand, serious accidental overexposures may occur during RT due to nuclear accidents which necessitate the need for study on exposure to high-dose radiations during treatments.
    Objective
    The aim of this study was to study the expression level of two genes in non-homologous end joining (NHEJ) pathways named Xrcc4 and Xrcc6 (Ku70) in order to examine the effect of melatonin on repair of DNA double-strand breaks (BSBs) caused by 8Gy ionizing radiation.
    Methods
    One hundred eight male Wistar rats were irradiated with a whole body gamma radiation dose of 8Gy with or without melatonin pretreatments. They were divided into six different groups of control, 100 mg/kg melatonin alone, 8Gy irradiation alone, vehicle alone, vehicle plus 8Gy irradiation and 100 mg/kg melatonin plus 8Gy irradiation. Peripheral blood samples were collected at 8, 24 and 48 h after irradiation. Ku70 and Xrcc4 gene expression were evaluated by real-time quantitative polymerase chain reaction (qPCR) technique and analyzed by one-way ANOVA test.
    Results
    Expression of Ku70 and Xrcc4 genes normalized against Hprt gene showed significant difference in melatonin plus irradiation group at 8h compared to the control group (p
    Conclusion
    We concluded that, by increasing expression level of Ku70 and Xrcc4 genes, 100 mg/kg melatonin administration 8 and 24 h before 8 Gyionizing radiation can significantly affect the repair of DNA DSBs in NHEJ pathway.
    Keywords: Ionizing Radiation, Melatonin, Gene Expression Level, Ku70, Xrcc4
  • A. Karimi Rahmati_S. K Setarehdan_B. N Araabi Page 37
    Background
    Fetal electrocardiography is a developing field that provides valuable information on the fetal health during pregnancy. By early diagnosis and treatment of fetal heart problems, more survival chance is given to the infant.
    Objective
    Here, we extract fetal ECG from maternal abdominal recordings and detect R-peaks in order to recognize fetal heart rate. On the next step, we find a better and more qualified extracted fetal ECG by using a novel approach.
    Materials And Methods
    In this paper, a PCA/ICA-based algorithm is proposed for extracting fetal ECG, and fetal R-peaks are detected as well. The method validates the quality of extracted ECGs and selects the best candidate fetal ECG to provide the required morphological ECG features such as fetal heart rate and RR interval for more clinical examinations. The method was evaluated using the dataset which was provided by PhysioNet/Computing in Cardiology Challenge 2013. The dataset consists of 75 recordings of 4-channel ECGs each containing 1-minute length for training and 100 similar recordings for testing.
    Results
    When the proposed algorithm was applied to the test set, the scores of 85.853 bpm2 for fetal heart rate and an error of 9.725 ms RMS for fetal RR-interval estimation were obtained.
    Conclusion
    The results obtained with the mentioned algorithm shows the robustness of the research, and it is suggested to be used in practical fetal ECG monitoring systems.
    Keywords: Fetal Electrocardiography (fECG), Fetal Heart Rate (FHR), Abdominal Electrocardiography, Principal Component Analysis (PCA), Independent Component Analysis (ICA), Best Quality fECG
  • S. Nouri_S. M Hosseini Pooya_J. Soltani Nabipour Page 51
    Background
    The motions of body and tumor in some regions such as chest during radiotherapy treatments are one of the major concerns protecting normal tissues against high doses. By using real-time radiotherapy technique, it is possible to increase the accuracy of delivered dose to the tumor region by means of tracing markers on the body of patients.
    Objective
    This study evaluates the accuracy of some artificial intelligence methods including neural network and those of combination with genetic algorithm as well as particle swarm optimization (PSO) estimating tumor positions in real-time radiotherapy.
    Method
    One hundred recorded signals of three external markers were used as input data. The signals from 3 markers thorough 10 breathing cycles of a patient treated via a cyber-knife for a lung tumor were used as data input. Then, neural network method and its combination with genetic or PSO algorithms were applied determining the tumor locations using MATLAB© software program.
    Results
    The accuracies were obtained 0.8%, 12% and 14% in neural network, genetic and particle swarm optimization algorithms, respectively.
    Conclusion
    The internal target volume (ITV) should be determined based on the applied neural network algorithm on training steps.
    Keywords: Real, Time, Radiotherapy, Neural, Network, Error, Genetic, Particle Swarm, Algorithm
  • R. Boostani, F. Asadi, N. Mohammadi Page 59
    Background
    Since psychological tests such as questionnaire or drawing tests are almost qualitative, their results carry a degree of uncertainty and sometimes subjectivity. The deficiency of all drawing tests is that the assessment is carried out after drawing the objects and lots of information such as pen angle, speed, curvature and pressure are missed through the test. In other words, the psychologists cannot assess their patients while running the tests. One of the famous drawing tests to measure the degree of Obsession Compulsion Disorder (OCD) is the Bender Gestalt, though its reliability is not promising.
    Objective
    The main objective of this study is to make the Bender Gestalt test quantitative; therefore, an optical pen along with a digital tablet is utilized to preserve the key drawing features of OCD patients during the test.
    Materials And Methods
    Among a large population of patients who referred to a special clinic of OCD, 50 under therapy subjects voluntarily took part in this study. In contrast, 50 subjects with no sign of OCD performed the test as a control group. This test contains 9 shapes and the participants were not constraint to draw the shapes in a certain interval of time; consequently, to classify the stream of feature vectors (samples through drawing) Hidden Markov Model (HMM) is employed and its flexibility increased by incorporating the fuzzy technique into its learning scheme.
    Results
    Applying fuzzy HMM classifier to the data stream of subjects could classify two groups up to 95.2% accuracy, whereas the results by applying the standard HMM resulted in 94.5%. In addition, multi-layer perceptron (MLP), as a strong static classifier, is applied to the features and resulted in 86.6% accuracy.
    Conclusion
    Applying the pair of T-test to the results implies a significant supremacy of the fuzzy HMM to the standard HMM and MLP classifiers.
    Keywords: Bender Gestalt, Optical Pen, Fuzzy HMM, OCD, Psychology
  • H. Parsaei_A. Vakily_A. M Shafiei Page 69
    Background
    The basic requirements for monitoring anesthetized patients during surgery are assessing cardiac and respiratory function. Esophageal stethoscopes have been developed for this purpose, but these devices may not provide clear heart and lung sound due to existence of various noises in operating rooms. In addition, the stethoscope is not applicable for continues monitoring, and it is unsuitable for observing inaccessible patients in some conditions such as during CT scan.
    Objective
    A wireless electronic esophageal stethoscope is designed for continues auscultation of heart and lung sounds in anesthetized patients. The system consists of a transmitter and a receiver. The former acquires, amplifies and transmits the acquired sound signals to the latter via a frequency modulation transmitter. The receiver demodulates, amplifies, and delivers the received signal to a headphone to be heard by anesthesiologist.
    Results
    The usability and effectiveness of the designed system was qualitatively evaluated by 5 anesthesiologists in Namazi Hospital and Shahid Chamran Hospital, Shiraz, Iran on 30 patients in several operating rooms in different conditions; e.g., when electro surgery instruments are working. Fortunately, the experts on average ranked good quality for the heard heart and lung sounds and very good on the user friendly being of the instrument.
    Conclusion
    Evaluation results demonstrate that the developed system is capable of capturing and transmitting heart and lung sounds successfully. Therefore, it can be used to continuously monitor anesthetized patients’ cardiac and respiratory function. Since via the instrument wireless auscultation is possible, it could be suitable for observing inaccessible patients in several conditions such as during CT scan.
    Keywords: Anesthetic Monitoring, Anesthetic Monitoring Equipment, Bio instrument, esophageal stethoscope, Electronic stethoscope, Heart Sound, Lung Sound
  • P. Mokarram_M. Sheikhi_S. M J. Mortazavi_S. Saeb_N. Shokrpour Page 79
    Background
    Over the past several years, the rapidly increasing use of mobile phones has raised global concerns about the biological effects of exposure to radiofrequency (RF) radiation. Numerous studies have shown that exposure to electromagnetic fields (EMFs) can be associated with effects on the nervous, endocrine, immune, cardiovascular, hematopoietic and ocular systems. In spite of genetic diversity, the onset and progression of cancer can be controlled by epigenetic mechanisms such as gene promoter methylation. There are extensive studies on the epigenetic changes of the tumor suppressor genes as well as the identification of methylation biomarkers in colorectal cancer. Some studies have revealed that genetic changes can be induced by exposure to RF radiation. However, whether or not RF radiation is capable of inducing epigenetic alteration has not been clarified yet. To date, no study has been conducted on the effect of radiation on epigenetic alterations in colorectal cancer (CRC). Several studies have also shown that methylation of estrogen receptor α (ERα), MYOD, MGMT, SFRP2 and P16 play an important role in CRC. It can be hypothesized that RF exposure can be a reason for the high incidence of CRC in Iran. This study aimed to investigate whether epigenetic pattern of ERα is susceptible to RF radiation and if RF radiation can induce radioadaptive response as epigenetic changes after receiving the challenge dose (γ-ray).
    Material and
    Method
    40 male Sprague-Dawley rats were divided into 4 equal groups (Group I: exposure to RF radiation of a GSM cell phone for 4 hours and sacrificed after 24 hours; Group II: RF exposure for 4 hours, exposure to Co-60 gamma radiation (3 Gy) after 24 hours and sacrificed after 72 hrs; Group III: only 3Gy gamma radiation; Group 4: control group). DNA from colon tissues was extracted to evaluate the methylation status by methylation specific PCR.
    Results
    Our finding showed that exposure to GSM cell phone RF radiation was capable of altering the pattern of ERα gene methylation compared to that of non-exposed controls. Furthermore, no adaptive response phenomenon was induced in the pattern of ERα gene methylation after exposure to the challenging dose of Co-60 γ-rays.
    Conclusion
    It can be concluded that exposure to RF radiation emitted by GSM mobile phones can lead to epigenetic detrimental changes in ERα promoter methylation pattern.
    Keywords: Radiofrequency (RF), DNA Methylation, Colon Cancer, Mobile Phone, Microwave
  • M. Nematollahi, K. Faghiri, O. Barati, P. Bastani Page 87
    Background
    The present study aimed to determine attitudes and effective factors in the acceptance of smart phones by physicians of the largest University of Medical Sciences in the south of Iran.
    Methods
    This cross-sectional study was performed using Structural Equation Modelling (SEM) in 2014. Study participants included 200 physicians working in the hospitals of Shiraz University of Medical Sciences selected through two-stage stratified sampling, but 185 participants completed the study. The study data were collected using a researcher-made questionnaire completed through a 5-point Likert scale. The content validity of the questionnaire was confirmed by a panel of experts, its construct validity by confirmatory factor analysis, and its reliability by Cronbach’s alpha of 0.802. All data analyses were performed using SPSS (version 22) and LISREL (version 8.8).
    Results
    Results showed that most physicians had a desirable attitude towards using smart phones. Besides, the results of SEM indicated a significant relationship between attitude and compatibility, observability, personal experience, voluntariness of use and perceived usefulness. Moreover, some important fitness indices revealed appropriate fitness of the study model (p=0.26, X2/df=1.35, RMR=0.070, GFI=0.77, AGFI=0.71, NNFI=0.93, CFI=0.94).
    Conclusion
    The results revealed that compatibility, observability, personal experience, voluntariness of use and perceived usefulness were effective in the physicians’ attitude towards using smart phones. Thus, by preparation of the required infrastructures, policymakers in the field of health technology can enhance the utilization of smart phones in hospitals.
    Keywords: Health Information Management, Technology, Smart Phone, Structure Equation Modelling, Physician, Iran