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Simulating Light Propagation and Photoplethysmography Signal Generation over the Radial Artery
, M.Sc. Thesis Sharif University of Technology ; Zahedi, Edmond (Supervisor)
Abstract
Measuring the human brachial arterial diameter has significant applications in medical research. This is conventionally carried out using ultrasonography which is costly and operator-skill dependent. The objective of this project is to come up with substitute solutions based on optical measurement. Reflectance photoplethysmography (PPG) over the radial artery has been considered to this end. Monte Carlo method has been employed to simulate light propagation in the wrist area, along with a model comprising tissue, artery and bone, made of simple solid geometries. Functions of optical parameters such as refractive index, absorption coefficient, scattering coefficient and anisotropy factor have...
Toward a computer aided diagnosis system for lumbar disc herniation disease based on MR images analysis
, Article Biomedical Engineering - Applications, Basis and Communications ; Volume 28, Issue 6 , 2016 ; 10162372 (ISSN) ; Ebrahimzadeh, E ; Izadi, M. R ; Mikaeili, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
Abstract
Lumbar disc diseases are the commonest complaint of Lower Back Pain (LBP). In this paper, a new method for automatic diagnosis of lumbar disc herniation is proposed which is based on clinical Magnetic Resonance Images (MRI) data. We use T2-W sagittal and myelograph images. Our method uses Otsu thresholding method to extract the spinal cord from MR images of Lumbar disc. In the next step, a third-order polynomial is aligned on the extracted spinal cords, and in the end of preprocessing step all the T2-W sagittal images are prepared for extracting disc boundary and labeling. After labeling and extracting a ROI for each disc, intensity and shape features are used for classification. The...
A meshless method to simulate interactions between large soft tissue and a surgical grasper
, Article Scientia Iranica ; Volume 23, Issue 1 , 2016 , Pages 295-300 ; 10263098 (ISSN) ; Abdi, E ; Farahmand, F ; Narimani, R ; Chizari, M ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
Realistic simulation of tool-tissue interactions can help to develop more effective surgical training systems and simulators. This study uses a finite element and meshless modeling approach to simulate the grasping procedure of a large intra-abdominal organ, i.e. a kidney, during laparoscopic surgery. Results indicate that the accuracy of the meshless method is comparable with that of the finite element method, with root mean square errors in the range of 0.8 to 2.3 mm in different directions. For the model presented in this study, the computational cost of the meshless method was much less than that of the finite element model
Microfluidic-based multi-organ platforms for drug discovery
, Article Micromachines ; Volume 7, Issue 9 , 2016 ; 2072666X (ISSN) ; Khadem Mohtaram, N ; Pezeshgi Modarres, H ; Mohammadi, M. H ; Geraili, A ; Jafari, P ; Akbari, M ; Sanati Nezhad, A ; Sharif University of Technology
MDPI AG
Abstract
Development of predictive multi-organ models before implementing costly clinical trials is central for screening the toxicity, efficacy, and side effects of new therapeutic agents. Despite significant efforts that have been recently made to develop biomimetic in vitro tissue models, the clinical application of such platforms is still far from reality. Recent advances in physiologically-based pharmacokinetic and pharmacodynamic (PBPK-PD) modeling, micro- and nanotechnology, and in silico modeling have enabled single- and multi-organ platforms for investigation of new chemical agents and tissue-tissue interactions. This review provides an overview of the principles of designing...
Phenomenological contact model characterization and haptic simulation of an endoscopic sinus and skull base surgery virtual system
, Article 4th RSI International Conference on Robotics and Mechatronics, ICRoM 2016, 26 October 2016 through 28 October 2016 ; 2017 , Pages 84-89 ; 9781509032228 (ISBN) ; Esfandiari, M ; Farahmand, F ; Vossoughi, G ; Sharif University of Technology
Abstract
During the endoscopic sinus and skull base training surgeries, the haptic perception of tool-tissue interaction and even transitions and ruptures in the tissues are fundamental which should be taken into account in a robotic control scheme. However, this problem is extremely complex given the nature and the variety of tissues involved in an ESS procedures. In this article, ex-vivo indentation and relaxation experiments associated with an offline model estimation of the interaction between tissues and a surgical tool are presented. The estimated parameters of the modified Kelvin-Voigt model are then used to provide a realistic tool-tissue interaction dynamic model. Finally, the principle of a...
Thermal Relaxation Time Of Healthy and Cancerous Tissue In Pulsed Laser Using Monte Carlo Simulation
, M.Sc. Thesis Sharif University of Technology ; Amjadi, Ahmad (Supervisor)
Abstract
Thermal relaxation time is the time when maximum temperature of a particle get to 1/e of it’s initial value. The destruction of a tissue depends to this important parameter. This parameter has studied by Monte Carlo simulation of pulsed laser in to environment as healthy and cancerous tissue. The main goal of this method is providing proper temperature in a special area so that minimize thermal destruction around that area. In this thesis, temperature distribution of tissue that is caused by pulsed laser, has solved by new method;in this new method the pulse duration uses for Monte Carlo simulation. Also using the solution of radiation transfer equation by Discretes Ordinate Method, new...
Constitutive Modeling of Nonlinear Tumor Growth; A Finite Element Approach
,
M.Sc. Thesis
Sharif University of Technology
;
Naghdabadi, Reza
(Supervisor)
Abstract
Mechanical forces play a crucial role in tumor patho-physiology. Compression of cancer cells inhibits their proliferation rate and induces apoptosis. Additionally, compression of intratumor blood vessels has negative impacts on drug delivery system. Despite the great importance of the mechanical forces on the pathology of cancer, there are limited studies on the constitutive modeling of tumors. In this study, first, the tumor growth inside a rigid cylinder with an exponential growth function is represented, a model mimicking the growth of ductal carcinoma. Then, a mathematical model of a spherical tumor growth with a Gompertz growth function is represented. Using the notion of multiple...
Discrimination of Malignant Melanoma by Light-Tissue Interaction Model and Optical Properties Extraction using Optical Coherence Tomography”
, Ph.D. Dissertation Sharif University of Technology ; Fatemizadeh, Emadeddin (Supervisor) ; Nasiri Avanaki, Mohammad Reza (Co-Supervisor)
Abstract
The current gold standard for clinical diagnosis of melanoma is excisional biopsy and histopathologic analysis. Approximately 15–30 benign lesions are biopsied to diagnose each melanoma. In addition, biopsies are invasive and result in pain, anxiety, scarring, and disfigurement of patients, which can add additional burden to the health care system. Among several imaging techniques developed to enhance melanoma diagnosis, optical coherence tomography (OCT), with its highresolution and intermediate penetration depth, can potentially provide required diagnostic information noninvasively.
an image analysis algorithm, "optical radiomic melanoma detection (ORMD)" has been presented which...
an image analysis algorithm, "optical radiomic melanoma detection (ORMD)" has been presented which...
Towards an automatic diagnosis system for lumbar disc herniation: the significance of local subset feature selection
, Article Biomedical Engineering - Applications, Basis and Communications ; 2018 ; 10162372 (ISSN) ; Fayaz, F ; Nikravan, M ; Ahmadi, F ; Dolatabad, M. R ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2018
Abstract
Herniation in the lumbar area is one of the most common diseases which results in lower back pain (LBP) causing discomfort and inconvenience in the patients' daily lives. A computer aided diagnosis (CAD) system can be of immense benefit as it generates diagnostic results within a short time while increasing precision of diagnosis and eliminating human errors. We have proposed a new method for automatic diagnosis of lumbar disc herniation based on clinical MRI data. We use T2-W sagittal and myelograph images. The presented method has been applied on 30 clinical cases, each containing 7 discs (210 lumbar discs) for the herniation diagnosis. We employ Otsu thresholding method to extract the...
Integrative Utilization of Microenvironments, Biomaterials and Computational Techniques for Advanced Tissue Engineering
, Article Journal of Biotechnology ; Volume 212 , 2015 , Pages 71-89 ; 01681656 (ISSN) ; Mohammadaliha, N ; Mohseni, M ; Sharif University of Technology
Elsevier
2015
Abstract
This review aims to propose the integrative implementation of microfluidic devices, biomaterials, and computational methods that can lead to a significant progress in tissue engineering and regenerative medicine researches. Simultaneous implementation of multiple techniques can be very helpful in addressing biological processes. Providing controllable biochemical and biomechanical cues within artificial extracellular matrix similar to in vivo conditions is crucial in tissue engineering and regenerative medicine researches. Microfluidic devices provide precise spatial and temporal control over cell microenvironment. Moreover, generation of accurate and controllable spatial and temporal...