Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica) /shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex-vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by enhanced permeability and retention (EPR) effect. Ex-Vivo NBI of tumor xenografts demonstrated tumor specific heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of the present study demonstrate the feasibility of using GNS as contrast agents to visualize tumor tissues using NBI technique. / text

We consider the problem of narrow-band signal detection in a passive sonar environment. The collected signals are passed to a fast Fourier Transform (FFT) delay-sum beamformer. In classical signal detection, the output of the FFT spectrum analyser in each frequency bin is the signal power spectrum which is used as the signal feature for detection. The observed signal power is compared to a locally estimated mean noise power and a log likelihood ratio test (LLRT) can then be established. In this thesis, we propose the use of the power spectral density (PSD) matrix of the spectrum analyser output as the feature for detection due to the additional cross-correlation information contained in such matrices. However, PSD matrices are structurally constrained and therefore form a manifold in the signal space. Thus, to find the distance between two matrices, the measurement must be carried out using Riemannian distance (RD) along the tangent of the manifold, instead of using the common Euclidean distance (ED). In this thesis, we develop methods for measuring the Frechet mean of noise PSD matrices using the RD and weighted RD. Further, we develop an optimum weighting matrix for use in signal detection by RD so as to further enhance the detection performance. These concepts and properties are then used to develop a decision rule for the detection of narrow-band sonar signals using PSD matrices. The results yielded by the new detection method are very encouraging. / Thesis / Master of Applied Science (MASc)

No description available.

A significant challenge in the surgical resection of tumors is accurate identification of tumor margins. Current methods for margin detection are time-intensive and often result in incomplete tumor excision and recurrence of disease. The objective of this project was to develop a near-infrared narrowband imaging (NIR NBI) system to image tumor and its margins in real-time during surgery utilizing the contrast provided by gold nanoparticles (GNPs). NIR NBI images narrow wavelength bands to enhance contrast from plasmonic particles in a widefield, portable and non-contact device that is clinically compatible for real-time tumor margin demarcation. GNPs have recently gained significant traction as nanovectors for combined imaging and photothermal therapy of tumors. Delivered systemically, GNPs preferentially accumulate at the tumor site via the enhanced permeability and retention effect, and when irradiated with NIR light, produce sufficient heat to treat tumor tissue. The NIR NBI system consists of 1) two LED's: green (530 nm) and NIR (780 nm) LED for illuminating the blood vessels and GNP, respectively, 2) a filter wheel for wavelength selection, and 3) a CCD to collect reflected light from the sample. The NIR NBI system acquires and processes images at a rate of at least 6 frames per second. We have developed custom control software with a graphical user interface that handles both image acquisition and processing/display in real-time. We used mice with a subcutaneous tumor xenograft model that received intravenous administration and topical administration of gold nanoshells and gold nanorods. We determined the GNP's distribution and accumulation pattern within tumors using NIR NBI. Ex vivo NIR NBI of tumor xenografts accumulated with GNPs delivered systemically, demonstrated a highly heterogeneous distribution of GNP within the tumor with higher accumulation at the cortex. GNPs were observed in unique patterns surrounding the perivascular region. The GNPs clearly defined the tumor while surrounding normal tissue did not indicate the presence of particles. In addition, we present results from NBI of tumors that received topical delivery of conjugated GNPs. We determined that tumor labeling using topical delivery approach resulted in a more homogenous distribution of GNPs compared to the systemic delivery approach. Finally, we present results from the on-going in vivo tumor margin imaging studies using NIR NBI. Our results demonstrate the feasibility of NIR NBI in demarcating tumor margins during surgical resection and potentially guiding photo-thermal ablation of tumors. / text

Orientador: René Aloísio da Costa Vieira / Banca: Jair Cortez Montovani / Banca: José Magrin / Resumo: O câncer de boca e orofaringe apresentam incidência elevada em nosso meio, sendo o diagnóstico realizado em estádio avançado, onde a sobrevida é limitada. Neste sentido, faz-se importante avaliar e aprimorar métodos que visem ao diagnóstico precoce destas lesões. O uso do lugol ou do azul de toluidina tem limitações, e o exame clínico de rotina não é realizado rotineiramente na prática clínica, mesmo em populações de alto risco. A pesquisa neoplasia primária em pacientes de risco constitui um bom modelo na avaliação de novas metodologias de diagnóstico precoce do câncer de boca e orofaringe, sendo que a taxa de segunda neoplasia primária varia de 1 a 40%. Recentemente, o aparecimento de endoscópios com o recurso do Narrow-band imaging (NBI) tem demonstrado uma elevação na acurácia do diagnóstico de lesões neoplásicas, porém o número de trabalhos é limitado, havendo pouca experiência em nosso meio. Estudo prospectivo de pacientes portadores de carcinoma espinocelular de boca, orofaringe e esôfago, sem tratamento prévio, atendidos no Hospital de Câncer de Barretos no período de janeiro a agosto de 2010. Procurou-se avaliar a pesquisa de lesões préneoplásicas e segunda tumor primário (STP) na boca e orofaringe, utilizando-se o exame físico, associado a endoscopia com luz branca e a endoscopia com o recurso do NBI. As lesões visualizadas foram biopsiadas e as imagens digitalizadas. Utilizou-se a classificação patológica de WHO. Procurou-se avaliar a sensibilidade, especificidade, acurácia valores preditivos positivos e negativos e teste kappa da técnica do NBI em relação à técnica tradicional avaliando em as lesões pré-neoplásicas e neoplásicas. Foram avaliados 144 pacientes, sendo a maioria homens (86,8%), portadores de CEC de boca (44,4%), fumantes (80,6%) e etilistas (58,3%), com tumores em estádio STP em cabeça e pescoço... (resumo completo, clicar acesso eletrônico abaixo) / Abstract: Oral and oralpharyngeal cancer have high incidence in our country, being diagnosed at advanced stages, where survival is limited. In this sense is important to evaluate and improve methods aimed at early diagnosis, such as lugol's solution and toluidine, but both have limitations, and clinical evaluation, not always used in clinical practice, even in high risks population.The research of second primary tumor in high risks pacients is a good way to evaluate new methods of earlier diagnosis of oral and oralpharyngeal cancers. It's important to remember that the rate of second primary tumor varies between 1 to 40%. Recently, advent of endoscopes with the NBI feature (narrow band imaging) in endoscopy has demonstrated an increase in accuracy in cancer diagnosis, but the number of publications are still limited, with little experience in our midst. Cross-sectional, prospective, study of patients with oral carcinoma, pharynx and esophagus, untreated, in Cancer Hospital of Barretos, between january and august in 2010. Second primary tumor (SPT) in oral and oropharynx was searching using the association between clinical evaluation with white light endoscopy and NBI endoscopy. When lesions were presented it was biopsied and images digitalized. WHO pathologic classification was performed. The results of the both methods were compared regarding sensitivity, specificity, accuracy, positive predictive value and negative predictive value and kappa test. We evaluated 144 patients, being the majority men (86.8%) with OSCC (oral squamous cell carcinomas) (44.4%), smokers (80.6%) and alcoholics (58.3%), clinical stage neoplasia III and IV (77.0%). We identified nine neoplastic lesions and 16 dysplasia lesions. Head and neck SPT rate was 6,3%, but the rate of premalignant lesions and malignant in oral cavity and oropharynx was 17.4% and 30.0% when the primary site was oral cavity, 25.0% for esophagus... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:23:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-16Bitstream added on 2014-06-13T18:50:21Z : No. of bitstreams: 1 boldrinijunior_d_me_botfm.pdf: 512291 bytes, checksum: 8823a68fb6704d2438a0ce58e025b019 (MD5) / Fundação Pio Xii - Barretos / O câncer de boca e orofaringe apresentam incidência elevada em nosso meio, sendo o diagnóstico realizado em estádio avançado, onde a sobrevida é limitada. Neste sentido, faz-se importante avaliar e aprimorar métodos que visem ao diagnóstico precoce destas lesões. O uso do lugol ou do azul de toluidina tem limitações, e o exame clínico de rotina não é realizado rotineiramente na prática clínica, mesmo em populações de alto risco. A pesquisa neoplasia primária em pacientes de risco constitui um bom modelo na avaliação de novas metodologias de diagnóstico precoce do câncer de boca e orofaringe, sendo que a taxa de segunda neoplasia primária varia de 1 a 40%. Recentemente, o aparecimento de endoscópios com o recurso do Narrow-band imaging (NBI) tem demonstrado uma elevação na acurácia do diagnóstico de lesões neoplásicas, porém o número de trabalhos é limitado, havendo pouca experiência em nosso meio. Estudo prospectivo de pacientes portadores de carcinoma espinocelular de boca, orofaringe e esôfago, sem tratamento prévio, atendidos no Hospital de Câncer de Barretos no período de janeiro a agosto de 2010. Procurou-se avaliar a pesquisa de lesões préneoplásicas e segunda tumor primário (STP) na boca e orofaringe, utilizando-se o exame físico, associado a endoscopia com luz branca e a endoscopia com o recurso do NBI. As lesões visualizadas foram biopsiadas e as imagens digitalizadas. Utilizou-se a classificação patológica de WHO. Procurou-se avaliar a sensibilidade, especificidade, acurácia valores preditivos positivos e negativos e teste kappa da técnica do NBI em relação à técnica tradicional avaliando em as lesões pré-neoplásicas e neoplásicas. Foram avaliados 144 pacientes, sendo a maioria homens (86,8%), portadores de CEC de boca (44,4%), fumantes (80,6%) e etilistas (58,3%), com tumores em estádio STP em cabeça e pescoço... / Oral and oralpharyngeal cancer have high incidence in our country, being diagnosed at advanced stages, where survival is limited. In this sense is important to evaluate and improve methods aimed at early diagnosis, such as lugol´s solution and toluidine, but both have limitations, and clinical evaluation, not always used in clinical practice, even in high risks population.The research of second primary tumor in high risks pacients is a good way to evaluate new methods of earlier diagnosis of oral and oralpharyngeal cancers. It’s important to remember that the rate of second primary tumor varies between 1 to 40%. Recently, advent of endoscopes with the NBI feature (narrow band imaging) in endoscopy has demonstrated an increase in accuracy in cancer diagnosis, but the number of publications are still limited, with little experience in our midst. Cross-sectional, prospective, study of patients with oral carcinoma, pharynx and esophagus, untreated, in Cancer Hospital of Barretos, between january and august in 2010. Second primary tumor (SPT) in oral and oropharynx was searching using the association between clinical evaluation with white light endoscopy and NBI endoscopy. When lesions were presented it was biopsied and images digitalized. WHO pathologic classification was performed. The results of the both methods were compared regarding sensitivity, specificity, accuracy, positive predictive value and negative predictive value and kappa test. We evaluated 144 patients, being the majority men (86.8%) with OSCC (oral squamous cell carcinomas) (44.4%), smokers (80.6%) and alcoholics (58.3%), clinical stage neoplasia III and IV (77.0%). We identified nine neoplastic lesions and 16 dysplasia lesions. Head and neck SPT rate was 6,3%, but the rate of premalignant lesions and malignant in oral cavity and oropharynx was 17.4% and 30.0% when the primary site was oral cavity, 25.0% for esophagus... (Complete abstract click electronic access below)

No description available.

Cross correlator systems, analog and clipped input channels, with correlated random narrow band Gaussian noise as inputs are computer simulated. The performance of each system is evaluated on the basis of the output signal-to-noise ratio. The output SNR of each system is compared with theoretical asymptotic approximations computed as a function of the SNR of the input channels. The output of the simulation compares within 3 dB of the asymptotic approximations for the analog correlator for all values of the correlation coefficient tested and for the systems with clipped input channels with uncorrelated inputs. For the systems with clipped input channels, certain combinations of the input SNR with non-zero correlation cause the output SNR to be zero. This causes discontinuities in the dB plot. For the systems with clippers and non-zero correlation of the input channels, the output of the simulation compares within 3 dB of the results of the asymptotic approximations when no discontinuities occur in the output plot.

This dissertation is concerned with the development and performance analysis of non-linear receivers for detection of weak narrow-band signals in multivariate non-Gaussian clutter. The novelty of the detection scheme lies in the utilization of both the complex measurement and the multivariate non-Gaussian character of the clutter. Two clutter models are developed based on the available partial information. Model (I) is based on the a priori knowledge of the first-order density, correlation structure of the amplitude, and the circular symmetric assumption of the in-phase and quadrature phase components. Model (II) is based on the first-order in-phase and quadrature phase densities and the complex correlation structure. These models completely specify a multivariate complex nonGaussian density and can be used for clutter generation. A class of optimum non-linear receiver structures based on weak signal level, canonically known as Locally Optimum Detectors (LOD) are derived under clutter Model (I). This can be considered to be a generalization of the LOD for the independent and identically distributed (i.i.d) clutter. The detectors utilize complex measurements and their structures depend on whether the underlying hypothesis testing model is real or complex. The performance of each of the proposed detector structures, based on the concept of Efficacy, is formulated. Then, the performance of the detectors are evaluated with respect to a reference detector using Asymptotic Relative Efficiency (ARE) criterion. Numerical evaluation of the performance expression is carried out for constant signal in Weibull distribution for various density parameters. Simulation results indicate that the performance of the developed detectors, based on ARE, is superior to (i.i.d) LOD detector and matched filter. Finally, the sensitivity of the detector performance to parameter variation of the structural non-linearities is investigated. / Ph. D.

Approved for public release, distribution is unlimited / In this study, the use of multi narrow-band filters was explored to correlate or fuse information to improve detection and recognition for specific targets of interest. To fully understand the viability and limitations of narrow band filters in thermal imaging, laboratory test procedures were first designed to characterize thermal images using common performance parameters, particularly the Noise Equivalent Temperature Difference (NETD), the Modulation Transfer Function (MTF) and the Minimum Resolvable Temperature (MRT). An available thermal imager, the Cincinnati Electronics IRRIS-256LN, and a newly purchased thermal imager, the Indigo Systems Merlin InSb Laboratory Camera, were investigated and compared. The MRT measurement showed a superior cut-off spatial frequency of 1.33 cycle/mrad for the Merlin camera, compared with 1.18 cycle/mrad for the Cincinnati, with similar sensitivity of about 0.1 ʻC for both cameras. Below cut-off the Modulation Transfer for the Merlin was approximately twice that of the Cincinnati. NETD measurements for both systems were inhibited by excess noise in the measurement system. The Merlin camera was consequently employed for further research on narrow band images. Three commercially available narrow band filters, 4110/4720 nm, 4540/4720 nm and 3750/4020 nm, were selected to isolate the "red" and "blue" spike signatures of plume emission and aerodynamic heating found in the signature of fast moving air targets. Similar sensor characterization was carried out with these filters, however, quantitative performance parameter measurements were hindered by excessive measurement system noise. As a preliminary study in multi-spectral image analysis, spectral features of hydrocarbon combustion were extracted from correlated narrow-band images of a laboratory propane flame. Digital analysis using software statistical tools showed potential for discrimination of hydrocarbon emission from other thermal sources by correlating pixel number and pixel radiant intensity. / Captain, Singapore Armed Forces