Department of Medical Physics (1999 - Present)
Medical Physics
, Tarbiat Modares University,
Medical Physics
, Tarbiat Modares University,
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Purpose:This study was to evaluate the accuracy of the reconstructed models from ultrasound image processing by comparing the radial displacement waveforms of the subject-specific artery model and to find the stress changes in the proximal shoulder, throat, and distal shoulder of the plaques depending on the degree of carotid artery stenosis.Methods:Three groups of subjects including healthy, less, and more than 50% carotid stenosis were evaluated with ultrasonography. 2D transverse imaging of the common carotid artery was carried to reconstruct geometry. A longitudinal view of the same region was recorded to extract the Kelvin viscoelastic model parameters. Pulse pressure waveform and the effective pressure of perivascular tissue was loade
Ultraviolet (UV) radiation causes direct and indirect damage to the cell structure, thereby increasing the aging process. Ultraviolet B-rays (UVB)(with 280-320 nm wavelengths) cause direct damage to the skin, and the portion that reaches the epidermal cells induces biological damage [1] and the most important biological damage is inflicted by DNA damage. With UVB absorption, thymine bases in the DNA bind to adjacent thymine [2]. This evidence can affect protein synthesis. The accumulation of unrepaired damages can disrupt the cell cycle and create cell death. Moreover, these damages can sometimes destroy the cell apoptotic ability and increase the malignancies. The results depend on the type of tissue, UV dose, and its wavelength [3]. UV ra
In this study, a method for non-invasive estimation of stress on the heart wall in the diastole phase is presented using ultrasound echocardiography and tissue Doppler imaging. The aim of this study was to evaluate the stress on the heart wall as a pre-diagnosis to identify people with coronary artery stenosis. 29 patients with stenosis of more than 70%, 30 patients with stenosis of 50 to 70% and 35 healthy human participated in this study as a control group. the average stress of anterior and intraventicular septum was estimated non-invasively by considering wall thickness, left ventricular dimensions, and end-diastolic pressure by Using 2D echocardiography, tissue Doppler and Doppler ultrasound imaging techniques. The statistical analysis
Background:Left ventricular torsion is one of the most important biomechanical parameters of heart that routinely is measured in short axis view. A review of the literature has indicated that assessment of left ventricular torsion in short axis view has some limitations. In the present study, we evaluated whether torsion angle assessment in long axis view can be used as a diagnostic biomechanical marker in patients with coronary artery disease (CAD).Methods:We assessed 20 males and 15 females who suffered from CAD and 24 healthy males and females. Two dimensional echocardiography images were scanned in cine loop format position throughout four cardiac cycles at basal and apical levels in the long axis view (4CH). Peak torsion angle in long
The purpose of this study was to evaluate the possible synergistic effect of gold nano-therapy (Au-NPs) on Y79 cells treated with ultrasonic hyperthermia. The cells in the presence and absence of gold nanoparticles were subjected to ultrasonic irradiation (3 MHz, 1 W/cm2, 40% pulse mode). Gold nanoparticles with an average diameter of 60 nm were synthesized. The cell viability of the Y79 cells was evaluated 48 h after performing 0.5–11 min hyperthermia with and without Au-NPs using the MTT assay. There was no cytotoxicity with 1.7 μg/mL Au-NP concentration. Moreover, the results revealed a significant difference in the cell viability between the control group and the groups with a hyperthermia period of more than 4 min. The results indic
Introduction: Ultraviolet (UV) radiation to the skin causes oxidative damage and causes cancer in the epidermis. There seems to be a relationship between the thickening of the skin layer and the carcinogenicity. The aim of this study was to establish a rare benign skin lesion of Trichoepithelioma in an animal model and to investigate the relationship between the radiation dose of ultraviolet waves with thickening of the skin layer resulting from high-frequency ultrasound images.Materials and Methods: To investigate the skin damage process, 25 C57BL6 mice were irradiated with UVB (5 times a week for 9 weeks) with an energy density of 135, 270, 405, 540, 675, 810, 945, 1080 and 1215 J/m2, from the first week to the ninth week, respectively. T
Introduction The effect of fullerene nanoemulsion on skin wrinkle repair in an animal model was evaluated using ultrasonic images processing. Methods Wrinkles were created in C57BL6 mice during 35?days of UVB radiation. Then, to investigate the therapeutic effect of fullerene nanoemulsions, mice were divided into three groups of control, UVB radiation, and treatment with fullerene nanoemulsion. Stable fullerene nanoemulsions were prepared using shear equalization. The therapeutic effect of fullerene nanoemulsion was investigated by extracting the skin thickness and mechanical parameters. Histology studies were performed to confirm the reliability of the treatment. Results A significant decrease was observed in the thickness of the epi
Purpose This study purposed to evaluate the efficacy of brachytherapy with the modality of ultrasonic hyperthermia in the presence of gold nanoparticles (GNPs) on an ocular retinoblastoma tumor in an animal model of the rabbit. Materials and Methods Gold nanoparticles (GNPs) were synthesized and confirmed by UV-vis spectroscopy, scanning electron microscopy and dynamic light scattering. Rabbit eyes were exposed to an ultrasonic continuous mode to reach 42 ?C, and then turned into a pulse mode (40%) to maintain in the hyperthermia range (42-45 ?C) for 30 min. For in vivo experiments, a retinoblastoma tumor was induced by the injection
Ultrasound hyperthermia is a new way to treat cancerous tumors. Retinoblastoma is one of the most common malignant ocular tumors in children. Since hyperthermia is an effective treatment for cancer cells, the effect of hyperthermia on retinoblastoma cells was investigated in this study. The purpose of this study was to determine the effect of duration of 3 MHz ultrasound hyperthermia on Y79 cell death after 48 hours using MTT assay. In this study, the percentage of cell viability after 48 hours in treatment groups with a duration of hyperthermia more than 4 minutes was significantly different from the control group and in the treatment group with hyperthermia time of 9 minutes and 11 minutes, 50% and 69% of cells were killed, respectively.
Objectives The mechanical index has long been one of the main criteria used to assess the safety limits for therapeutic medical applications. However, the safety of the mechanical index parameter is considered to be unknown in male fertility, which has a very significant role in vitro conditions. In this study, the effect of cavitation interactions due to mechanical index regions was evaluated on spermatogonial stem cells. Methods The acoustic pressure and mechanical index equations at the low intensities and the intended frequency were modeled and solved. The mechanical index average of 40 kHz frequency was selected as subthreshold, 0.70, and above the cavitation threshold. Neonatal spermatogonial stem cells were cultured. Spermatogon
The publication of this article unfortunately contained a mistake.
Ultrasonic imaging is able to detect structural changes due to chemical reactions occurring due to ionizing irradiation. The purpose of this study to create a gel phantom dosimeter (developed MAGIC gel), which has ultrasonic properties equivalent to human tissue for readout with ultrasonic imaging. The speed of sound and the attenuation coefficient were determined as a function of the absorbed dose in the range of 0–50 Gy by using this dosimeter. A gel phantom was prepared by adding MAGIC polymer gel proprietary combinations in ultrasonic soft tissue-mimicking gel. Then, the ultrasonic parameters (response) of the samples, including the propagation speed of sound (SOS) and the attenuation coefficient (BUA) were measured in the absorbed d
Mesenchymal stem cells are mechano-sensitive cells with the potential to restore the function of damaged tissues. Low-intensity ultrasound has been increasingly considered as a bioactive therapeutic apparatus. Optimizing transplantation conditions is a critical aim for radiation-induced skin tissue injury. Therefore, the therapeutic function of adipose-derived mesenchymal stem cells to ultrasound stimulus was examined based on the mechanical index (MI). Mesenchymal stem cells were isolated from the adipose tissues of mature guinea pigs. An ultrasound system (US) was constructed with a 40 kHz frequency. The radiation-induced skin injury model was produced on the abdominal skin of guinea pigs by 60 Gy of radiation. Then, they were divided to
BackgroundIn this study, physical parameters of the strain of left ventricle (LV), wall stress with a thick-walled ellipsoidal model, and elastic modulus of LV were extracted for distinguishing patients who were stent candidates.
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