Physical Sciences and Mathematics Commons^™

X Ray Phase And Coherent Scatter Imaging Measurements, Pikting Cheung

Legacy Theses & Dissertations (2009 - 2024)

Traditional x-ray images are good for distinguishing between materials with very different absorption coefficients. However, detecting breast cancer using conventional x-ray imaging is hard because cancer tissue has similar absorption coefficients as normal tissue. Annually 43,600 women will die from breast cancer. The odds of survival are better if the cancer is diagnosed at an early stage, but mammography tends to have high rates of missed cancers. Mammography also tends to have a high false-positive rate, which leads to unnecessary biopsies. Two techniques with potential to add additional information to breast imaging have been investigated. X-ray phase imaging has been …

A Novel Phase And Spectroscopic Imaging Technique To Evaluate Cellular Functions, Ting Chean Khoo

Legacy Theses & Dissertations (2009 - 2024)

This thesis presents the application of Raman spectroscopy, digital holographic microscope (DHM) and transport intensity equation (TIE) in imaging biological samples. Raman spectroscopy is a non-destructive technique that can provide chemical structure, concentration, temperature, and molecular interactions. On the other hand, DHM and TIE provide physical measurements such as height, width, area and volume.We applied Raman spectroscopy to study iron-bound transferrin (Tf) in intact human breast cancer cells. Iron is an essential element required for human life and is highly regulated in the body. As the exact mechanisms of iron-bound Tf in cells are not well known, we developed a …

X Ray Phase And Coherent Scatter Imaging Measurements, Mahboob Ur Rehman

Legacy Theses & Dissertations (2009 - 2024)

In conventional radiography, anatomical information of the patients can be obtained, distinguishing different tissue types, e.g. bone and soft tissue. However, it is difficult to obtain appreciable contrast between two different types of soft tissues. Instead, coherent x-ray scattering can be utilized to obtain images which can differentiate between normal and cancerous cells of breast. An x-ray system using a conventional source and simple slot apertures was tested. Materials with scatter signatures that mimic breast cancer were buried in layers of fat of increasing thickness and imaged. The result showed that the contrast and signal to noise ratio (SNR) remained …

System Measurements For X-Ray Phase And Diffraction Imaging, Erik Wolfgang Tripi

Legacy Theses & Dissertations (2009 - 2024)

In medical imaging, X rays are used to look inside the body to find fractures in bones, abnormal masses, cavities in teeth, and so on. What makes X rays so good at looking at these types of structures is the X ray’s penetration power. When imaging soft tissue to search for tumors, X-ray images tend to have difficulty performing well. The reason for this is that the background structures, such as fat or fibro glandular tissue have similar absorption coefficients as the tumor. Mammography tends to have a high false positive rate and can miss tumors entirely as well. There …

Coherent Scatter And Grid-Based Phase Imaging For Materials Discrimination, Sean Niccholas Starr-Baier

Legacy Theses & Dissertations (2009 - 2024)

Traditional X-Ray images provide a meaningful way to differentiate between materials with differing attenuation coefficients. The low contrast provided by this method for materials of low electron density or similar attenuation is a limitation of traditional radiography. Two alternatives have presented themselves as viable candidates for widening the viability of X-Ray imaging, Coherent scatter, and phase contrast imaging provide a means to distinguish between objects of both low absorption and similar attenuation.

Coherent Scattering Imaging Monte Carlo Simulation, Laila Hassan

Legacy Theses & Dissertations (2009 - 2024)

Conventional mammography has poor contrast between healthy and cancerous tissues due to the small difference in attenuation properties. Coherent scatter potentially provides more information because interference of coherently scattered radiation depends on the average intermolecular spacing, and can be used to characterize tissue types. However, typical coherent scatter analysis techniques are not compatible with rapid low dose screening techniques. Coherent scatter slot scan imaging is a novel imaging technique which provides new information with higher contrast. In this work a simulation of coherent scatter was performed for slot scan imaging to assess its performance and provide system optimization. In coherent …

Grid-Based Fourier Transform Phase Contrast Imaging, Sajjad Tahir

Legacy Theses & Dissertations (2009 - 2024)

Low contrast in x-ray attenuation imaging between different materials of low electron density is a limitation of traditional x-ray radiography. Phase contrast imaging offers the potential to improve the contrast between such materials, but due to the requirements on the spatial coherence of the x-ray beam, practical implementation of such systems with tabletop (i.e. non-synchrotron) sources has been limited. One recently developed phase imaging technique employs multiple fine-pitched gratings. However, the strict manufacturing tolerances and precise alignment requirements have limited the widespread adoption of grating-based techniques. In this work, we have investigated a technique recently demonstrated by Bennett et al.1 …

Diffraction-Based Techniques For High Contrast X-Ray Imaging, Lubna Naseem Peerzada

Legacy Theses & Dissertations (2009 - 2024)

Two X-ray diffraction based techniques for high contrast were explored to improve contrast in radiology: diffraction enhanced imaging (DEI) and coherent scatter imaging.

Coherent Scatter Imaging For Mammography, Katie Kern

Legacy Theses & Dissertations (2009 - 2024)

Traditional x-ray images are good at distinguishing between materials with different absorption coefficients. The problem with mammography stems from the fact that there is very low contrast between cancerous and normal tissue types. Since cancerous and normal tissue have similar absorption coefficients, using conventional x-ray imaging to distinguish between the two is difficult. Coherent scatter is an alternative method to detect cancerous material within human breast tissue. Coherent scatter can distinguish between tissue types, if the intermolecular spacing of the tissues differ.

Innovative Acoustic Reflection Imaging Techniques And Application To Clinical Breast Tomography, Steve Phillip Schmidt

Wayne State University Dissertations

Conventional ultrasound techniques use beam-formed, constant sound speed ray models for fast image reconstruction. However, these techniques are inadequate for the emerging new field of ultrasound tomography (UST). We present a new technique for reconstruction of reflection images from UST data. We have extended the planar Kirchhoff migration method used in geophysics, and combined it with sound speed and attenuation data obtained from the transmission signals to create reflection ultrasound images that are corrected for refractive and attenuative effects.

The resulting techniques were applied to simulated numerical phantom data, physical phantom data and in-vivo breast data obtained with an experimental …

Application Of X-Ray Diffraction To Material Analysis And Medical Imaging, Wei Zhou

Legacy Theses & Dissertations (2009 - 2024)

Powder diffraction is commonly used to determine the structures of both inorganic and organic materials. The angle and intensity of the diffraction (also called coherent scatter) peak depends on the nanostructure of the material. When no x-ray optic is used, the peak width broadens, and hence the resolution worsens, as the sample area is increased. However, a small sample area gives low diffracted signal intensity, particularly for thin films and for organic materials, which have low diffraction cross sections. X-ray optics can be used in x-ray powder diffraction to increase the diffraction intensity, thus decreasing exposure times. For a small …