Sharif Digital Repository

Medical images contain information about vital organic tissues inside of the human body and are widely used for diagnoses of diseases or for surgical purposes. Image Reconstruction is essential for medical imaging for medical systems like suppression of noise or de-blurring from projections in order to have images with better quality and contrast. Due to the vital role of image reconstruction in medical sciences the corresponding algorithms with better efficiency and higher speed is preferable. Most algorithms in the field of image reconstruction are operated in frequency domain such as the filtered back projection which is a popular algorithm for the reconstruction of the medical images. In... 

Tomography offers a unique opportunity to unravel the complexities of the internal structure of an object without the need to invade it. There are various methods for this reason, in which all of them occupy wave or energy,ffiduction for imaging inside an object. Since the tomography plays a vital role in medicine and industry and present methods have limitation and difficulties to operate, the necessity for developing it has been inevitable. In this thesis a new tomography method has been presented in which uses inverse heat conduction for estimating unknown object with heat conductivity k2 inside a known domain with heat conductivity k 1 • For this purpose temperature is measured at... 

Introduction: Today, backward and forward scattering tomography of dispersive medium is of great interest because of its broad applications, especially in medical imaging, of breast cancer, Distinguishing different tissues of the body from each other is one of the necessities. Increasing the quality of the image by just a few percents has great improvement on the tomography resolution.
Materials and Methods: In this project we made phantom of the tissue and tumor from Intralipid 10% plus Agarose and Indian ink for soft tissue and plastic fibers as tumor having birefringence factor of 0.001.After putting the plastic tumor in soft tissue phantom, the polarized white light and a digital... 

Electrical Impedance Tomography, (EIT), is one of the medical imaging technologies, similar to CT-Scan or X-Ray. It can also be used in industrial process monitoring. In this technique a reconstructed image of the inner part of a conductive subject can be made with an array of external electrodes which are connected to the boundary of the subject (e.g., body). It is inexpensive, fast, small and portable. In this imaging method, the image of electrical conductivity (or impedance) distribution of the internal part of a typical subject is reconstructed. The Image reconstruction process is done by injecting an accurate current into the boundary of the subject, measuring voltages around the... 

Radar is a type of active remote sensing instrument that is used to create images of an object, such as a landscape. Synthetic Aperture Radar or SAR is another type of radar which is typically mounted on a moving platform such as an aircraft or a spacecraft and uses the motion of the antenna over the target region to provide finer spatial resolution than is possible with conventional beam-scanning radars. In fact SAR is an advanced form of Side-Looking Airborne Radar (SLAR). The movement of SAR antenna acts as another form of aperture; this aperture combined with the physical aperture of the antenna creates a large "synthetic" antenna aperture (the "size" of the antenna) which enables higher... 

Lung cancer is one of the most common types of cancers, and its early diagnosis can save many lives. Due to the high number of computed tomography (CT) images used to detect lung cancer, it is difficult to accurately and rapidly diagnose this disease. Doing so requires high expertise by radiologists. Therefore the demand for computer aided diagnosis systems in this area has been increased. The core of all lung cancer detection systems is the distinction between cancer and non-cancerous tissues. The main objective of this study is to present a new method based on 3D convolutional neural networks (CNN) that can perform false positives reduction operations while providing high sensitivity. In... 

In recent years, optical biomedical imaging techniques show great potential in noninvasive imaging. Although these methods have many advantages over other biomedical imaging methods (such as Computerized Tomography (CT), Magnetic Resonance Imaging (MRI) and etc.), these techniques confront with some problems such as optical scattering, light absorption and etc. For in vivo imaging, the short-wavelength infrared region (SWIR; 1,000–2,000 nm) provides several advantages over the visible and near-infrared regions: general lack of auto-fluorescence, low light absorption by blood and tissue, and reduced scattering. In this thesis we want to analyze the traditional IR imaging techniques and...