Sharif Digital Repository

In recent years there has been a great effort to enhance the computer-aided diagnosis systems, Since expertise elicited from past resolved cases plays an important role in medical applications, and images acquired from various cases have a great contribution to diagnosis of the abnormalities, Content based medical image retrieval has become an active research area for many scientists. In this project we proposed a new framework to retrieve visually similar images from a large database, in which visual similarity is regarded as much as the semantic category relevance, we used optimized wavelet transform as the multi-resolution analysis of the images and extracted various statistical SGLDM... 

Computer-Aided Diagnosis (CAD) systems are widely used for detection of various kinds of abnormalities in mammography images. In this work, mass classification is investigated and its steps are explained in detail, for each step a main method is presented and other methods are also discussed. For mass segmentation a relatively new method based on level set and Morphological Component Analysis (MCA) is used.After this step, various kinds of features such as shape, geometrical, and textural ones are introduced. Moreover, a set of proposed features based on wavelet transformation,for this application are presented. The proposed features can describe margin and texture characterizations of a... 

Computer Aided Diagnosis (CAD) systems are widely used in different medical tasks. Radiology is a branch of medicine which takes advantage of image processing techniques to help radiologists, analyse complicated radiologic images. Among all kind of medical imagingprocedures, utilization of screening mammographyisgetting very popularin detection of breast abnormalities. A typical CAD system for mammogram analysis uses image enhancement and segmentation as pre-processing phase, and feature extraction and classification for detection phase. In this thesis, we have studied different approaches in each level of image processing required in a mammogram mass classification systems, and introduced a... 

The Scattered radiation is the principal factor affecting the quality of the digital and screen-film mammography images. The contrast improvement factor and bucky factor which are also referred to as the benefit and risk of the anti-scattered grid cannot be properly assessed without a detailed knowledge of the scattered radiation. In this work the scatter to primary ratio has been calculated and an anti-scatter grid has been designed based on the reduction of the scattered radiation to reduce the patient dose to a minimum level and to improve the image quality simultaneously.The MCNPX 2.6.0 Monte Carlo code has been used to improve the geometry of the anti-scatter grid to both reduce the... 

Breast cancer is the second leading cause of cancer death among women. Mammography is considered the “gold standard” in the evaluation of the breast lesions from an imaging perspective. But this modality has limitations. Completed studies are used to overcome these limitations. The Positron Emission Mammography (PEM) is the one of these complementary methods. PEM imaging is a molecular imaging modality for the diagnosis of breast cancer. In this thesis, a commercial PEM system as Naviscan PEM has been simulated using the GATE program. This system consists of two parallel planes of detectors, each detector consists of 12 blocks with 6 × 2 array and each block consists of 169 crystals with 13... 

One of the most important factors that make breast cancer such a dangerous and deadly disease is its hidden. One of the most important methods of revealing this disease is imaging. There are different types of imaging to reveal cancerous tissues (tumors), such as ultrasound, mammography, X-ray, etc. Ultrasound imaging is a cheap, convenient and accessible imaging. The aim of this project is to provide a breast cancer detection system that uses the images taken with this method according to the characteristics of ultrasonic imaging. Regarding cancer diagnosis, doctors identify the tumor with the help of their personal experience, which is based on the characteristics of the tumor image. In...