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Journal of Biomedical Physics & Engineering

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https://www.readbyqxmd.com/read/29082222/online-estimation-of-elbow-joint-angle-using-upper-arm-acceleration-a-movement-partitioning-approach
#1
M Farokhzadi, A Maleki, A Fallah, S Rashidi
Estimating the elbow angle using shoulder data is very important and valuable in Functional Electrical Stimulation (FES) systems which can be useful in assisting C5/C6 SCI patients. Much research has been conducted based on the elbow-shoulder synergies. The aim of this study was the online estimation of elbow flexion/extension angle from the upper arm acceleration signals during ADLs. For this, a three-level hierarchical structure was proposed based on a new approach, i.e. 'the movement phases'. These levels include Clustering, Recognition using HMMs and Angle estimation using neural networks...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082221/uncertainty-analysis-in-mri-based-polymer-gel-dosimetry
#2
M Keshtkar, M H Zahmatkesh, A R Montazerabadi
BACKGROUND: Polymer gel dosimeters combined with magnetic resonance imaging (MRI) can be used for dose verification of advanced radiation therapy techniques. However, the uncertainty of dose map measured by gel dosimeter should be known. The purpose of this study is to investigate the uncertainty related to calibration curve and MRI protocol for MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) gel and finally ways of optimization MRI protocol is introduced. MATERIALS AND METHODS: MAGIC gel was prepared by the Fong et al...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082220/in-vitro-evaluation-of-the-relationship-between-gray-scales-in-digital-intraoral-radiographs-and-hounsfield-units-in-ct-scans
#3
L Khojastepour, S Mohammadzadeh, M Jazayeri, M Omidi
BACKGROUND: Jaw bone quality plays an essential role in treatment planning and prognosis of dental implants. Regarding several available methods for bone density measurements, they are not routinely used before implant surgery due to hard accessibility. OBJECTIVE: An in vitro investigation of correlation between average gray scale in direct digital radiographs and Hounsfield units in CT-Scan provides a feasible method for evaluating alveolar bone quality prior to implant surgery...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082219/an-update-of-couch-effect-on-the-attenuation-of-megavoltage-radiotherapy-beam-and-the-variation-of-absorbed-dose-in-the-build-up-region
#4
T Sedaghatian, M Momennezhad, S H Rasta, Y Makhdoomi, S Abdollahian
PURPOSE: Fiber carbon is the most common material used in treating couch as it causes less beam attenuation than other materials. Beam attenuation replaces build-up region, reduces skin-sparing effect and causes target volume under dosage. In this study, we aimed to evaluate beam attenuation and variation of build-up region in 550 TxT radiotherapy couch. MATERIALS AND METHODS: In this study, we utilized cylindrical PMMA Farmer chamber, DOSE-1 electrometer and set PMMA phantom in isocenter of gantry and the Farmer chamber on the phantom...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082218/evaluation-of-radiation-exposure-pattern-and-radiation-absorbed-dose-resulting-from-occupational-exposure-of-anesthesiologists-to-ionizing-radiation
#5
B Maghsoudi, S M J Mortazavi, S Khademi, P Vatankhah
INTRODUCTION: Little information is available concerning the radiation exposure of anesthesiologists, and no such data have previously been collected in Iran. This prospective study was performed to determine the amount of radiation exposure of anesthesiologists for the purpose of assessing whether or not dangerous levels of radiation exposures were being reached, and to identify factors that correlate with excessive risk. PARTICIPANTS AND METHODS: The radiation exposure of all anesthesiology residents and the attending of Shiraz University of Medical Sciences during a 3-month period (from June to August 2016) was measured using a film badge with monthly readings...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082217/the-optimization-of-magnetic-resonance-imaging-pulse-sequences-in-order-to-better-detection-of-multiple-sclerosis-plaques
#6
Z Farshidfar, F Faeghi, H R Haghighatkhah, J Abdolmohammadi
BACKGROUND AND OBJECTIVE: Magnetic resonance imaging (MRI) is the most sensitive technique to detect multiple sclerosis (MS) plaques in central nervous system. In some cases, the patients who were suspected to MS, Whereas MRI images are normal, but whether patients don't have MS plaques or MRI images are not enough optimized enough in order to show MS plaques? The aim of the current study is evaluating the efficiency of different MRI sequences in order to better detection of MS plaques...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082216/synergistic-effects-of-ndrg2-overexpression-and-radiotherapy-on-cell-death-of-human-prostate-lncap-cells
#7
M Alizadeh Zarei, M A Takhshid, A Behzad Behbahani, S Y Hosseini, M A Okhovat, Gh R Rafiee Dehbidi, M A Mosleh Shirazi
BACKGROUND: Radiation therapy is among the most conventional cancer therapeutic modalities with effective local tumor control. However, due to the development of radio-resistance, tumor recurrence and metastasis often occur following radiation therapy. In recent years, combination of radiotherapy and gene therapy has been suggested to overcome this problem. The aim of the current study was to explore the potential synergistic effects of N-Myc Downstream-Regulated Gene 2 (NDRG2) overexpression, a newly identified candidate tumor suppressor gene, with radiotherapy against proliferation of prostate LNCaP cell line...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082215/modelling-tumor-induced-angiogenesis-combination-of-stochastic-sprout-spacing-and-sprout-progression
#8
F Hosseini, N Naghavi
BACKGROUND: Angiogenesis initiated by cancerous cells is the process by which new blood vessels are formed to enhance oxygenation and growth of tumor. OBJECTIVE: In this paper, we present a new multiscale mathematical model for the formation of a vascular network in tumor angiogenesis process. METHODS: Our model couples an improved sprout spacing model as a stochastic mathematical model of sprouting along an existing parent blood vessel, with a mathematical model of sprout progression in the extracellular matrix (ECM) in response to some tumor angiogenic factors (TAFs)...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082214/an-analytical-empirical-calculation-of-linear-attenuation-coefficient-of-megavoltage-photon-beams
#9
F Seif, M J Tahmasebi-Birgani, M R Bayatiani
BACKGROUND: In this study, a method for linear attenuation coefficient calculation was introduced. METHODS: Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury. RESULTS: The values of calculated linear attenuation coefficient with this new method are in acceptable range...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082213/reducing-radiation-doses-in-female-breast-and-lung-during-ct-examinations-of-thorax-a-new-technique-in-two-scanners
#10
P Mehnati, M Ghavami, H Heidari
BACKGROUND: Chest CT is a commonly used examination for the diagnosis of lung diseases, but a breast within the scanned field is nearly never the organ of interest. OBJECTIVE: The purpose of this study is to compare the female breast and lung doses using split and standard protocols in chest CT scanning. MATERIALS AND METHODS: The sliced chest and breast female phantoms were used. CT exams were performed using a single-slice (SS)- and a 16 multi-slice (MS)- CT scanner at 100 kVp and 120 kVp...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082212/impact-of-prolonged-fraction-delivery-time-modelling-stereotactic-body-radiation-therapy-with-high-dose-hypofractionation-on-the-killing-of-cultured-achn-renal-cell-carcinoma-cell-line
#11
M Khorramizadeh, A Saberi, Ma Tahmasebi-Birgani, P Shokrani, A Amouhedari
INTRODUCTION: Stereotactic body radiotherapy delivers hypofractionated irradiation with high dose per fraction through complex treatment techniques. The increased complexity leads to longer dose delivery times for each fraction. The purpose of this study is to investigate the impact of prolonged fraction delivery time with high-dose hypofractionation on the killing of cultured ACHN cells. METHODS AND MATERIALS: The radiobiological characteristics and repair half-time of human ACHN renal cell carcinoma cell line were studied with clonogenic assays...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29082211/modification-of-source-strength-in-low-dose-rate-lung-brachytherapy-with-125-i-and-103-pd-seeds
#12
H Rezaei, H Mostaghimi, A R Mehdizadeh
BACKGROUND: A new treatment approach for most patients who have undergone early stage non-small-cell lung carcinoma (NSCLC) is wedge resection plus permanent implant brachytherapy. However, the specification of dose to medium at low energies especially in heterogeneous lung is unclear yet. OBJECTIVE: The present study aims to modify source strength for different configurations of 125I and 103Pd seeds used in lung permanent implant brachytherapy. METHODS: Different arrays of (125)I and (103)Pd seeds were simulated by MCNPX code in protocol-based water vs...
September 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580340/a-system-for-continuous-estimating-and-monitoring-cardiac-output-via-arterial-waveform-analysis
#13
A Vakily, H Parsaei, M M Movahhedi, M A Sahmeddini
BACKGROUND: Cardiac output (CO) is the total volume of blood pumped by the heart per minute and is a function of heart rate and stroke volume. CO is one of the most important parameters for monitoring cardiac function, estimating global oxygen delivery and understanding the causes of high blood pressure. Hence, measuring CO has always been a matter of interest to researchers and clinicians. Several methods have been developed for this purpose, but a majority of them are either invasive, too expensive or need special expertise and experience...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580339/can-evolutionary-based-brain-map-be-used-as-a-complementary-diagnostic-tool-with-fmri-ct-and-pet-for-schizophrenic-patients
#14
R Boostani, M Sabeti
OBJECTIVE: In this research, a new approach termed as "evolutionary-based brain map" is presented as a diagnostic tool to classify schizophrenic and control subjects by distinguishing their electroencephalogram (EEG) features. METHODS: Particle swarm optimization (PSO) is employed to find discriminative frequency bands from different EEG channels. By deploying the energy of those selected frequency bands from different channels within each time frame (window) on the scalp geometry, a sort of two dimensional points along with their values are created; by applying Lagrange interpolation, an image can be constructed...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580338/exposure-to-visible-light-emitted-from-smartphones-and-tablets-increases-the-proliferation-of-staphylococcus-aureus-can-this-be-linked-to-acne
#15
M Taheri, M Darabyan, E Izadbakhsh, F Nouri, M Haghani, S A R Mortazavi, G Mortazavi, S M J Mortazavi, M Moradi
BACKGROUND: Due to rapid advances in modern technologies such as telecommunication technology, the world has witnessed an exponential growth in the use of digital handheld devices (e.g. smartphones and tablets). This drastic growth has resulted in increased global concerns about the safety of these devices. Smartphones, tablets, laptops, and other digital screens emit high levels of short-wavelength visible light (i.e. blue color region in the visible light spectrum). MATERIAL AND METHODS: At a dark environment, Staphylococcus aureus bacteria were exposed to the light emitted from common tablets/smartphones...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580337/neural-network-based-learning-kernel-for-automatic-segmentation-of-multiple-sclerosis-lesions-on-magnetic-resonance-images
#16
H Khastavaneh, H Ebrahimpour-Komleh
BACKGROUND: Multiple Sclerosis (MS) is a degenerative disease of central nervous system. MS patients have some dead tissues in their brains called MS lesions. MRI is an imaging technique sensitive to soft tissues such as brain that shows MS lesions as hyper-intense or hypo-intense signals. Since manual segmentation of these lesions is a laborious and time consuming task, automatic segmentation is a need. MATERIALS AND METHODS: In order to segment MS lesions, a method based on learning kernels has been proposed...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580336/simulation-study-of-hemodynamic-in-bifurcations-for-cerebral-arteriovenous-malformation-using-electrical-analogy
#17
Y Kiran Kumar, S B Mehta, M Ramachandra
BACKGROUND AND OBJECTIVE: Cerebral Arteriovenous Malformation (CAVM) hemodynamic is disease condition, results changes in the flow and pressure level in cerebral blood vessels. Measuring flow and pressure without catheter intervention along the vessel is big challenge due to vessel bifurcations/complex bifurcations in Arteriovenous Malformation patients. The vessel geometry in CAVM patients are complex, composed of varying diameters, lengths, and bifurcations of various angles. The variations in the vessel diameter and bifurcation angle complicate the measurement and analysis of blood flow features invasively or non-invasively...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580335/adaptive-response-induced-by-pre-exposure-to-915-mhz-radiofrequency-a-possible-role-for-antioxidant-enzyme-activity
#18
S M J Mortazavi, Z Mostafavi-Pour, M Daneshmand, F Zal, R Zare, M A Mosleh-Shirazi
BACKGROUND: Over the past few years, the rapid use of high frequency electromagnetic fields like mobile phones has raised global concerns about the negative health effects of its use. Adaptive response is the ability of a cell or tissue to better resist stress damage by prior exposure to a lesser amount of stress. This study aimed to assess whether radiofrequency radiation can induce adaptive response by changing the antioxidant balance. MATERIALS AND METHODS: In order to assess RF-induced adaptive response in tissues, we evaluated the level of GSH and the activity of GR in liver...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580334/melatonin-role-in-ameliorating-radiation-induced-skin-damage-from-theory-to-practice-a-review-of-literature
#19
REVIEW
A Abbaszadeh, G H Haddadi, Z Haddadi
Normal skin is composed of epidermis and dermis. Skin is susceptible to radiation damage because it is a continuously renewing organ containing rapidly proliferating mature cells. Radiation burn is a damage to the skin or other biological tissues caused by exposure to radiofrequency energy or ionizing radiation. Acute skin reaction is the most frequently occurring side effect of radiation therapy. Generally, any chemical/biological agent given before or at the time of irradiation to prevent or ameliorate damage to normal tissues is called a radioprotector...
June 2017: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/28580333/oral-administration-of-vitamin-c-cimetidine-and-famotidine-on-micronuclei-induced-by-low-dose-radiation-in-mouse-bone-marrow-cells
#20
A Naeeji, H Mozdarani, A Shabestani Monfared, F Faeghi, A A Ahmadi, M Gholami, R Behzadi, M R Momtaz
BACKGROUND: In many studies, chemicals and natural materials were tested to reduce the harmful effects of radiation. It is known that Famotidine and vitamin C reduce DNA damage. OBJECTIVE: The aim of this study was to evaluate the radioprotective effect of vitamin C, Cimetidine and Famotidine on gamma-radiation-induced damage on mouse bone marrow. METHODS: Six-to-seven week male NMRI mice (28 g ±3) were randomly divided into fourteen groups: control, 2Gy irradiation, six group drugs without irradition (Famotidine, Cimetidine, vitaminC, Fam-Cim, Fam-Vit, Cim-Vit), six groups received drugs and 2Gy radiation with a 60Co |γ|-ray source at room temperature 22 ± 2 °C...
June 2017: Journal of Biomedical Physics & Engineering
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