Source: Dissertation Abstracts International, Volume: 38-04, Section: B, page: 1598. / Thesis (Ph.D.)--The Florida State University, 1976.

Source: Dissertation Abstracts International, Volume: 39-06, Section: B, page: 2691. / Thesis (Ph.D.)--The Florida State University, 1978.

CHO cells were pulse-labeled with $\rm\sp{125}I$-iododeoxyuridine during early-S phase, harvested 30 min or 5 h after labeling for accumulation of $\rm\sp{125}I$ decays. Cells harvested 30 min after labeling yielded low-LET survival curves (large shoulder, $\rm D\sb0$ 136 decays/cell); cells harvested at hour 5 showed a high-LET pattern of cell killing (no shoulder, $\rm D\sb0$ 45 decays/cell). Surprisingly, the low-LET to high-LET shift in $\rm\sp{125}I$ action was abolished in cells previously exposed to HAT medium; both 30 min and 5 h groups exhibited high-LET-type cell killing (no shoulder, $\rm D\sb0$ 52 decays/cell). The striking difference in cell death was not accompanied by any change in the induction or repair of DNA DSBs as measured by neutral filter elution. These findings suggest that cell killing may not be directly linked to DNA DSBs, and support our earlier conclusion that damage to higher-order genome structures may be important in radiation-induced cell death. / In related experiments, synchronized CHO cells were pulse-labeled with $\rm\sp{125}IUdR$ in S phase and harvested for decay accumulation at the $\rm G\sb2$ phases of two successive cell cycles. When decays were accumulated during the first $\rm G\sb2$ phase after labeling, cell survival followed a high-LET-type pattern characteristic of single-hit kinetics of cell killing (N = 1, $\rm D\sb0$ 40 decays/cell). In contrast, decays during the second $\rm G\sb2$ phase induced cell death with dual-hit kinetics (N = 2, $\rm D\sb0$ 80 decays/cell). A similar divergence in $\rm\sp{125}I$ action was also observed for micronucleus formation and HGPRT mutations. In short, $\rm\sp{125}I$-induced cellular damage can vary depending on whether the decays occur in daughter (first $\rm G\sb2)$ or parental (second $\rm G\sb2)$ DNA. These results imply that parental and daughter DNA strands show different spatial organization in the mammalian genome. / Source: Dissertation Abstracts International, Volume: 56-07, Section: B, page: 3633. / Major Professor: Kurt G. Holer. / Thesis (Ph.D.)--The Florida State University, 1995.

<p>There are two Gadolinium-based liver-specific contrast media for Magnetic Resonance Imaging on the market, Gd-BOPTA (MultiHance®, Bracco Imaging, Milan, Italy) and Gd-EOB-DTPA (Primovist®, Bayer Schering Pharma, Berlin, Germany). The aim of this study in two parts was to evaluate the dynamics of biliary, parenchymal and vascular enhancement using these contrast media in healthy subjects. Ten healthy volunteers were examined in a 1.5 T magnetic resonance system using three-dimensional Volumetric Interpolated Breath-Hold (VIBE) sequences for dynamic imaging with both contrast media – at two different occasions – until five hours after injection. The doses given were 0.025 mmol/kg for Gd-EOB-DTPA and 0.1 mmol/kg for Gd-BOPTA. The enhancement over time of the common biliary duct in contrast to the liver parenchyma was analyzed in the first study. This was followed by a study of the image contrasts of the hepatic artery, portal vein and middle hepatic vein versus the liver parenchyma.While Gd-EOB-DTPA gave an earlier and more prolonged enhancement of the biliary duct, Gd-BOPTA achieved higher image contrast for all vessels studied, during the arterial and portal venous phases. There was no significant difference in the maximal enhancement obtained in the liver parenchyma.At the obtained time-points and at the dosage used, the high contrast between the common biliary duct and liver parenchyma had an earlier onset and longer duration for Gd-EOB-DTPA, while Gd-BOPTA achieved higher maximal enhancement of the hepatic artery, portal vein and middle hepatic vein than Gd-EOB-DTPA. Diseases of the liver and biliary system may affect the vasculature, parenchyma, biliary excretion or a combination of these. The clinical context regarding the relative importance of vascular, hepatic parenchymal and biliary processes should determine the choice of contrast media for each patient and examination.</p><p> </p>

<p>Deep vein thrombosis (DVT) and pulmonary embolism (PE) are different aspects of a single condition, venous thrombo-embolic disease (VTE), a major cause of morbidity and mortality in the western world. Rapid diagnosis is critical, as timely medical intervention can have a substantial beneficial effect on the mortality rate.</p><p>Irrespective of its presentation, VTE is a difficult disease to diagnose. Pathologies unrelated to VTE can give rise to a clinical presentation similar to DVT or PE, resulting in a false positive diagnosis. This raises the risk of a patient being treated inappropriately. Therefore, there is a need for an agent that has high specificity and sensitivity for the detection of active blood clots, which are amenable to treatment by anticoagulant and/or thrombolytic therapy. </p><p>This work describes the pre-clinical efficacy studies performed on one such agent, ^99mTc-NC100668. ^99mTc-NC100668 is a substrate for factor XIIIa and as a potential physiological, rather than anatomical, marker of VTE it is hoped it will not give rise to the false negative and positive diagnoses that are inherent in the currently available diagnostic techniques, such as the ventilation perfusion (V/Q) scan, multidetector computer tomography or ultrasound.</p><p>It is reported in this work that ^99mTc-NC100668 uptake and retention in blood clot was rapid and maintained over at least a 4 hour period in a rat model of DVT. Anticoagulant and thrombolytic therapies commonly used to treat thrombosis did not seriously impair the ability of ^99mTc-NC100668 to detect thrombi. No significant tissue retention, which could interfere with the ability to image thrombi <i>in vivo</i>, was observed. Biodistribution and plasma clot uptake studies showed that ^99mTc complex of gly-NC100194, the major metabolite of ^99mTc-NC100668, would be unlikely to affect adversely the clinical utility of the test substance.</p><p>The <i>in vitro</i> uptake of ^99mTc-NC100668 into forming plasma clots indicated that retention into human blood clots would be comparable with the observations made in the rat preclinical models. </p><p>The uptake of ^99mTc-NC100668 <i>in vitro</i> and <i>in vivo</i> was much greater than could be accounted for by physical entrapment into the forming blood clots. The reduced uptake of a biologically inactive analogue of ^99mTc-NC100668 both<i> in vitro</i> and <i>in vivo</i> indicated that the blood clot uptake and retention of ^99mTc-NC100668 was mediated by factor XIIIa.</p><p>In conclusion, ^99mTc-NC100668 might be useful in the detection of thrombo embolism.</p>

No description available.

Radiation dermatitis is a common side effect of external beam radiation therapy. The purpose of this study was to evaluate the effectiveness of applying an aloe vera based skin gel to the target area skin in preventing the development of radiation dermatitis to postlumpectomy/ mastectomy patients receiving external beam radiation therapy in an ambulatory radiation-oncology clinic in the southeastern region of the United States. In this descriptive correlational study, a convenience sample of willing participants (n=18) was followed from initial treatment through the one-month follow-up examination to assess the intensity of their skin reaction. Five research questions were examined pertaining to the relationship between prognostic indicators and the development of radiation dermatitis when RadiacareR gel was used before and throughout external beam radiation therapy post-mastectomy or post-lumpectomy. The prognostic indicators used in this study were: Breast size > C-cup, prior chemotherapeutic exposure, length of incision, age of client, and weight changes since diagnosis. Analysis of Variance (ANOVA) and Pearson's Correlation Coefficients were used in the data analysis with a confidence of p=0.05. This study indicated that breast size and weight changes were the most prognostic of the factors studied. The small sample size and lack of randomization or control group limit the generalizability of these findings to clinical practice; however, it does support the need for continued research in this area. Recommendations for future studies include comparing Body Mass Index (BMI) to incidence and determining a relationship between gel use and treatment breaks and if there is a difference in the length of time until the skin is restored to baseline upon completion of therapy.

Breast cancer is the most common and the second lethal cancer among women in the United States. Our group is constructing a dedicated cone beam breast CT (CBCT) system to provide true 3D image to improve the screening and diagnostic of breast cancer. Our result shows that dedicated CBCT out-perform a lot than conventional CT when detecting micro-calcification which is essential to the detection of early stage breast cancer. I also explored the possibility of using the super parallel computing power of GPU with CUDA environment to deal with data-immense and computationally-intensive image reconstruction process of CBCT. My results show that FDK algorithm image reconstruction with GPU is over 10 times faster than that with our PC cluster system. The faster and accurate image reconstruction implies potential new applications in diagnostic and therapy technology.

<p>X-ray mammography is the most widely used breast cancer imaging technique. However, over 400,000 women newly diagnosed each year are misdiagnosed and undergo a biopsy. Current mammography techniques are limited by: (1) low image contrast, especially in women with dense breasts; (2) difficulty in diagnosing and detecting lesions close to the chest wall and in women with radiographically dense breasts; (3) structural overlap onto a two-dimensional (2D) image plane; and (4) patient discomfort due to breast compression. Therefore, three-dimensional (3D) tomographic breast imaging approaches for pendant, uncompressed breasts have been explored to overcome these limitations and improve the detection of breast lesions. The goal of this thesis is to characterize and implement a dual-modality SPECT-CT dedicated breast imaging system that can overcome these limitations and integrate both metabolic and anatomical information to further improve the visual quality and quantitative accuracy over independent systems alone.</p><p>Initial work on this thesis started out with characterizing the modulation transfer function (MTF) in 3D for the independent dedicated SPECT and CT systems. Using a novel phantom to measure the MTF at different locations in a 3D reconstructed volume, results show that acquiring images with a step-and-shoot mode and with trajectories that meet the sampling criteria, uniform resolution throughout a 3D reconstructed volume is obtained. </p><p>The effects of sampling and system geometry on the reconstructed CT images are investigated. As expected, constraining the x-ray source and detector to a circular tilt yields insufficiently sampled reconstructed images, which contain geometric distortions, reconstruction inaccuracies, and cupping artifacts. Although beam hardening and scatter are considered to be the main causes of cupping artifacts in the reconstructed CT images, this study suggests that insufficient sampling might be a third cause to cupping artifacts in the reconstructed images. An additional finding in this study is that despite the insufficient sampling in the reconstructed CT images, high frequency objects (small size) are preserved more than low frequency objects (large size). </p><p>Using a lateral offset geometry (i.e. the entire system shifted such that the central ray of the cone-beam is at an offset with respect to the COR) in CT has also been shown previously to introduce circular and cylindrical artifacts in the reconstructed coronal and sagittal CT slices, respectively. Monte Carlo studies show that these artifacts are due to mechanical detector misalignment. However, cropping the projections, such that there is less of an overlap between conjugate projections, or placing the system in a centered geometry can eliminate these artifacts.</p><p>Next, the dual-modality SPECT-CT scanner is designed and built. The performance of this scanner is evaluated with geometric and anthropomorphic phantoms. Despite only nearly complete sampling from both systems, results illustrate that SPECT and CT images can be registered and fused with minimal error.</p><p>The feasibility of using the reconstructed CT images to quantify different tissue components is also investigated by using different materials (acrylic, delrin, polyethylene, and fat-equivalent and glandular-equivalent plastics) and a cadaver human breast. By implementing scatter correction using the beam stop approach, scatter corrected reconstructed images yield attenuation coefficient values to within 11% of their actual values.</p><p>Finally, few clinical studies are done to evaluate the effectiveness of the dual-modality scanner. Although the CT is currently limited in the amount of breast volume that can be imaged, reconstructed images appear to have minimal distortion and reconstruction inaccuracy. Fused SPECT-CT images also show the significance of using functional information from SPECT to help localize the lesion in the anatomical CT images. </p><p>The dual-modality SPECT-CT scanner has successfully demonstrated its capability to uniformly sample an uncompressed breast with 3D complex trajectories that meet the sampling criteria and provide tissue quantification and localization information. This system will be a clinically useful imaging tool in detecting cancer, especially in women with high risk of breast cancer, monitoring treatment therapies, and improving surgical biopsy guidance.</p> / Dissertation

There are two Gadolinium-based liver-specific contrast media for Magnetic Resonance Imaging on the market, Gd-BOPTA (MultiHance®, Bracco Imaging, Milan, Italy) and Gd-EOB-DTPA (Primovist®, Bayer Schering Pharma, Berlin, Germany). The aim of this study in two parts was to evaluate the dynamics of biliary, parenchymal and vascular enhancement using these contrast media in healthy subjects. Ten healthy volunteers were examined in a 1.5 T magnetic resonance system using three-dimensional Volumetric Interpolated Breath-Hold (VIBE) sequences for dynamic imaging with both contrast media – at two different occasions – until five hours after injection. The doses given were 0.025 mmol/kg for Gd-EOB-DTPA and 0.1 mmol/kg for Gd-BOPTA. The enhancement over time of the common biliary duct in contrast to the liver parenchyma was analyzed in the first study. This was followed by a study of the image contrasts of the hepatic artery, portal vein and middle hepatic vein versus the liver parenchyma.While Gd-EOB-DTPA gave an earlier and more prolonged enhancement of the biliary duct, Gd-BOPTA achieved higher image contrast for all vessels studied, during the arterial and portal venous phases. There was no significant difference in the maximal enhancement obtained in the liver parenchyma.At the obtained time-points and at the dosage used, the high contrast between the common biliary duct and liver parenchyma had an earlier onset and longer duration for Gd-EOB-DTPA, while Gd-BOPTA achieved higher maximal enhancement of the hepatic artery, portal vein and middle hepatic vein than Gd-EOB-DTPA. Diseases of the liver and biliary system may affect the vasculature, parenchyma, biliary excretion or a combination of these. The clinical context regarding the relative importance of vascular, hepatic parenchymal and biliary processes should determine the choice of contrast media for each patient and examination.