Browsing by Subject "Medical imaging"
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Item Clinical photoacoustic imaging for detection and characterization of metal implants(2011-08) Su, Jimmy Li-Shin; Emelianov, Stanislav Y.; Dunn, Andrew; Karpiouk, Andrei; Smalling, Richard; Sokolov, KonstantinAccurate insertion and monitoring of metal implants in-vivo is essential for clinical diagnosis and therapy of various diseases. Clinical studies and examples have demonstrated that the misplacement errors of these metal devices can have dramatic consequences. This thesis focuses on three main metal devices that are in widespread use today: needles, coronary stents and brachytherapy seeds. Each application requires proper image-guidance for correct usage. For needles, image guidance is required to ensure correct local injection delivery or needle aspiration biopsy. Fine needle aspiration biopsies are performed in order to avoid major surgical excisions when obtaining tissue biopsy procedures. However, because of the small biopsy sample, the risk is that the sample is collected outside of the tumorigenic region, resulting in a false negative result. Implantation of stents requires that confirmation that proper stent apposition has been achieved due to balloon inflation. Furthermore, it is important to guide the stent to shield the vulnerable region of an atherosclerotic plaque. With prostate brachytherapy seeds, the ability to monitor seed placement is crucial because needle deflections or tissue deformation can result in seed misplacement errors, decreasing the efficacy of the pre-established treatment plan. For the described applications and other possible clinical practices involving the use of metallic implants, an imaging technology that can accurately depict the location of the metal objects, relative to their respective backgrounds, in real-time, is necessary to improve the safety and the efficacy of these procedures. Currently, ultrasound is used because of its real-time capabilities, non-ionizing radiation, and soft tissue contrast. However, due to high acoustic scattering from tissue, the contrast of metal implants can be low. Photoacoustic imaging can be used as an alternative, or complementary, imaging method to ultrasound for imaging metal. This thesis focuses on the benefits and the pitfalls of using photoacoustic imaging for detecting three different metal implants, each having unique requirements. Overall, the goal of this work is to develop a framework for clinical applications using combined ultrasound and photoacoustic imaging to help guide, detect and follow-up on clinical metal implants introduced in-vivo.Item Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis(2013-12) Lim, Liang; Tunnell, James W.The goal of this thesis is to study the potential of optical spectroscopy as a clinical diagnostic tool for melanoma and nonmelanoma skin cancer. Skin cancer is the most common cancer in the United States. Like most cancers, early diagnosis and treatment improves patient prognosis for both melanoma and nonmelanoma skin cancer. However, current “gold standard” for diagnosis is invasive, costly and time-consuming. A diagnostic procedure consists of a clinical examination of the suspicious lesion, followed by biopsy and histopathology, with an additional turnaround time of approximately one week. There is a need for an accurate, objective, noninvasive, and faster method to aid physician in diagnosing cancerous lesions, increasing diagnosis accuracy while preventing unnecessary biopsies. We propose Spectral Diagnosis, a system capable of noninvasive in vivo spectroscopic examination of human skin. The research objectives are: (1) Probe pressure effects on in vivo spectroscopy measurements of human skin, (2) Clinical trial of Spectral Diagnosis, (3) Design, construction, and characterization of a confocal Raman microspectroscope. Spectral Diagnosis utilizes an optical fiber probe that transmits and collects optical spectra in contact with the suspected lesion. We identified short term and light probe pressure effects to be minimal on diagnostic parameters, and should not negatively influence diagnostic performance. We conducted a clinical trial at the University of Texas MD Anderson Cancer Center, and our results show that principal components from three spectroscopy modalities (diffuse reflectance spectroscopy, laser induced fluorescence spectroscopy, and Raman spectroscopy) provide excellent melanoma and nonmelanoma skin cancer diagnosis. We also constructed and characterized a Raman microspectroscope, with the goal of developing a physiological-based fitting model to better understand the analysis of in vivo Raman spectroscopy data from human skin tissue.Item What lies beneath : medical imaging and the erotic in public culture(2012-08) Wise, Rebecca Louise; Wojciehowski, Hannah Chapelle, 1957-; Browne, Simone A.The anatomic human body is increasingly visible in public culture. Representations of the body sourced from or imitative of the images produced by medical imaging technology are bloodless depictions that highlight the body’s internal structures and elide its viscerality. Despite the deliberate exclusion of the flesh, many of these images are saturated in erotic potential, both implicitly and explicitly. These images emerge in a culture preoccupied with the visualization and control of women’s bodies and sexualities. Feminist scholars have long been critical of the ways in which popular media constructs the body as an object for erotic consumption;; the anatomic images I consider here go one step further. The mainstream gaze has previously been limited to the exterior surfaces of the body, with the penetrating gaze into the body’s interior restricted to the medical and legal establishments. The penetrating gaze is increasingly democratized as x-ray and other interior views of the body become more prevalent.The texts under discussion in this thesis traverse the opaque barrier of the skin and serve to construct the totality of the human body as an object to be examined and consumed. While X-rated x-rays can, sometimes, offer a potential site of resistance to gen- dered surveillance of the anatomic body, their increasing ubiquity demonstrates the escalation of a dominating surveillant regime intent on penetrating and controlling the anatomic body. The images’ uncritical public consumption provides an insidious route by which that regime may be normalized, furthered and even glorified.