INTRODUÇÃO: A avaliação do mediastino quanto à presença de metástases linfonodais é importante na escolha do tratamento dos pacientes com câncer de pulmão de não pequenas células. Apesar da tomografia computadorizada ser o exame de imagem de escolha no estadiamento do câncer de pulmão, tem limitações conhecidas quanto à avaliação dos linfonodos regionais. O objetivo deste trabalho é avaliar a acurácia do SPECT/TC utilizando o radiofármaco 99mTc-sestamibi no estadiamento linfonodal do mediastino em pacientes com diagnóstico de carcinoma de pulmão de não pequenas células e candidatos a tratamento cirúrgico. MÉTODOS: Foi realizada coleta prospectiva de dados de 41 pacientes entre dezembro de 2006 a fevereiro de 2009. Os pacientes foram submetidos à tomografia computadorizada de tórax e ao SPECT/TC com 99mTc-sestamibi no prazo máximo de 30 dias antes da cirurgia. O SPECT/TC foi considerado positivo quando havia captação no mediastino e a tomografia de tórax, quando havia linfonodos maiores do que 10 mm no menor eixo. Os resultados da interpretação do SPECT/TC com sestamibi e da TC de tórax foram comparados aos encontrados na patologia, definido como método padrão ouro. RESULTADOS: O SPECT/TC identificou de maneira correta seis dos 19 casos com envolvimento dos linfonodos hilares e um dos sete casos com metástases ganglionares no mediastino pela patologia. Os valores de sensibilidade, especificidade, valores de predição positivo e negativo para o 99mTc-sestamibi SPECT/TC na avaliação do hilo foram respectivamente de: 31,6%, 95,5%, 85,7% e 61,8% e para o mediastino de 14,3%, 97,1%, 50% e 84,6%. A tomografia de tórax encontrou sensibilidade para a análise dos linfonodos hilares e mediastinais de 47,4% e 57,1%, especificidade de 95,5%, e 91,2%, valores de predição positivo de 90% e 57,1% e negativo de 67,7% e 91,2%, respectivamente. CONCLUSÃO: Nos pacientes com câncer de pulmão de não pequenas células com doença inicial e ressecável o SPECT/TC com 99mTc-sestamibi no estadiamento linfonodal do mediastino apresentou baixa sensibilidade e acurácia, apesar da alta especificidade. O SPECT/TC não adicionou informações relevantes à TC de tórax, que poderiam justificar o seu emprego no estadiamento pré-operatório do carcinoma de pulmão de não pequenas células / INTRODUCTION: The proper nodal staging of non-small cell lung cancer is important to choose the best treatment modality. Although CT is the first-line imaging test for primary staging of lung cancer, it is well known its limitations on mediastinum nodal staging. The aim was to evaluate the accuracy of SPECT/CT using 99mTc-sestamibi in the nodal staging of patients with non-small cell lung cancer and potential candidates towards surgical treatment. METHODS: A prospective data collection of 41 patients was conducted from December 2006 to February 2009. The patients underwent chest CT and SPECT/CT with 99mTc-sestamibi within 30 days interval before surgery. SPECT/CT was considered positive when there was focal uptake of sestamibi in the mediastinum and CT scan when there was lymph nodes larger than 10 mm in short axis. The results of SPECT/CT and CT were correlated with pathology findings after surgery. RESULTS: SPECT/CT correctly identified six of 19 cases with involvement of hilar lymph nodes and one of seven cases with nodal metastases in the mediastinum. The sensitivity, specificity, positive and negative predictive value for 99mTc-sestamibi SPECT/CT in the assessment of the hilum were respectively: 31.6%, 95.5%, 85.7% and 61.8% and for the mediastinum 14.3%, 97.1%, 50% and 84.6%. Chest tomography showed a sensitivity of hilar and mediastinal lymph nodes of 47.4% and 57.1%, specificity of 95.5% and 91.2%, positive predictive value of 90% and 57.1% and negative predictive value of 67.7% and 91.2%, respectively. CONCLUSION: SPECT/CT with 99mTc-sestamibi showed very low sensitivity and accuracy for nodal staging of patients with non-small cell cancer despite its high specificity. Moreover, the performance of SPECT/CT added no relevant information compared to CT that could justify its use in the routine preoperative staging of non-small cell lung carcinoma

INTRODUÇÃO: A avaliação do mediastino quanto à presença de metástases linfonodais é importante na escolha do tratamento dos pacientes com câncer de pulmão de não pequenas células. Apesar da tomografia computadorizada ser o exame de imagem de escolha no estadiamento do câncer de pulmão, tem limitações conhecidas quanto à avaliação dos linfonodos regionais. O objetivo deste trabalho é avaliar a acurácia do SPECT/TC utilizando o radiofármaco 99mTc-sestamibi no estadiamento linfonodal do mediastino em pacientes com diagnóstico de carcinoma de pulmão de não pequenas células e candidatos a tratamento cirúrgico. MÉTODOS: Foi realizada coleta prospectiva de dados de 41 pacientes entre dezembro de 2006 a fevereiro de 2009. Os pacientes foram submetidos à tomografia computadorizada de tórax e ao SPECT/TC com 99mTc-sestamibi no prazo máximo de 30 dias antes da cirurgia. O SPECT/TC foi considerado positivo quando havia captação no mediastino e a tomografia de tórax, quando havia linfonodos maiores do que 10 mm no menor eixo. Os resultados da interpretação do SPECT/TC com sestamibi e da TC de tórax foram comparados aos encontrados na patologia, definido como método padrão ouro. RESULTADOS: O SPECT/TC identificou de maneira correta seis dos 19 casos com envolvimento dos linfonodos hilares e um dos sete casos com metástases ganglionares no mediastino pela patologia. Os valores de sensibilidade, especificidade, valores de predição positivo e negativo para o 99mTc-sestamibi SPECT/TC na avaliação do hilo foram respectivamente de: 31,6%, 95,5%, 85,7% e 61,8% e para o mediastino de 14,3%, 97,1%, 50% e 84,6%. A tomografia de tórax encontrou sensibilidade para a análise dos linfonodos hilares e mediastinais de 47,4% e 57,1%, especificidade de 95,5%, e 91,2%, valores de predição positivo de 90% e 57,1% e negativo de 67,7% e 91,2%, respectivamente. CONCLUSÃO: Nos pacientes com câncer de pulmão de não pequenas células com doença inicial e ressecável o SPECT/TC com 99mTc-sestamibi no estadiamento linfonodal do mediastino apresentou baixa sensibilidade e acurácia, apesar da alta especificidade. O SPECT/TC não adicionou informações relevantes à TC de tórax, que poderiam justificar o seu emprego no estadiamento pré-operatório do carcinoma de pulmão de não pequenas células / INTRODUCTION: The proper nodal staging of non-small cell lung cancer is important to choose the best treatment modality. Although CT is the first-line imaging test for primary staging of lung cancer, it is well known its limitations on mediastinum nodal staging. The aim was to evaluate the accuracy of SPECT/CT using 99mTc-sestamibi in the nodal staging of patients with non-small cell lung cancer and potential candidates towards surgical treatment. METHODS: A prospective data collection of 41 patients was conducted from December 2006 to February 2009. The patients underwent chest CT and SPECT/CT with 99mTc-sestamibi within 30 days interval before surgery. SPECT/CT was considered positive when there was focal uptake of sestamibi in the mediastinum and CT scan when there was lymph nodes larger than 10 mm in short axis. The results of SPECT/CT and CT were correlated with pathology findings after surgery. RESULTS: SPECT/CT correctly identified six of 19 cases with involvement of hilar lymph nodes and one of seven cases with nodal metastases in the mediastinum. The sensitivity, specificity, positive and negative predictive value for 99mTc-sestamibi SPECT/CT in the assessment of the hilum were respectively: 31.6%, 95.5%, 85.7% and 61.8% and for the mediastinum 14.3%, 97.1%, 50% and 84.6%. Chest tomography showed a sensitivity of hilar and mediastinal lymph nodes of 47.4% and 57.1%, specificity of 95.5% and 91.2%, positive predictive value of 90% and 57.1% and negative predictive value of 67.7% and 91.2%, respectively. CONCLUSION: SPECT/CT with 99mTc-sestamibi showed very low sensitivity and accuracy for nodal staging of patients with non-small cell cancer despite its high specificity. Moreover, the performance of SPECT/CT added no relevant information compared to CT that could justify its use in the routine preoperative staging of non-small cell lung carcinoma

<p>The most important aspects of nuclear medicine imaging systems such as Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) are the spatial resolution and the sensitivity (detector efficiency in combination with the geometric efficiency). Considerable efforts have been spent during the last two decades in improving the resolution and the efficiency by developing new detectors. Our proposed improvement technique is focused on the readout and electronics. Instead of using traditional pulse height analysis techniques we propose using free running digital sampling by replacing the analog readout and acquisition electronics with fully digital programmable systems.</p><p>This thesis describes a fully digital data acquisition system for KS/SU SPECT, new algorithms for high resolution timing for PET, and modular FPGA based decentralized data acquisition system with optimal timing and energy. The necessary signal processing algorithms for energy assessment and high resolution timing are developed and evaluated. The implementation of the algorithms in field programmable gate arrays (FPGAs) and digital signal processors (DSP) is also covered. Finally, modular decentralized digital data acquisition systems based on FPGAs and Ethernet are described.</p>

The capability to resolve the contributions from spectroscopically overlapping fluorophores has enabled significant breakthroughs in cellular imaging. However, commercial microscopes for this purpose use analog light detection with least squares curve-fitting analysis and improvements in sensitivity are needed. To this end, a microscope has been constructed with high throughput and single-photon detection capability. The fluorescence is separated through use of a prism spectrometer or a series of dichroic mirrors into four spectral bands and detected using four single-photon avalanche diode (SPAD) detectors, which provide high-quantum efficiency in the red spectral region. The detectors are connected to a time-correlated single photon counting module to provide sub-nanosecond temporal resolution for distinguishing fluorophores with different fluorescence lifetimes. Maximum-likelihood (ML) methods have been developed for analyzing the temporally and spectrally resolved photon count data from the SPADs to find the contributions from different fluorescent species and from background. Commercially available SPADs exhibit a count-rate dependent time shift in the impulse response function, and hence the instrument incorporates custom modified SPADs with improved timing stability. Nevertheless, there is still some time shift, and hence the ML-analysis has been extended to include this as an adjustable parameter for each individual SPAD. Monte Carlo simulations have also been developed to enable studies of the number of photons needed to resolve specific fluorophores.

Thesis (Ph. D.)--Ohio State University, 2006. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 Jun 16

The most important aspects of nuclear medicine imaging systems such as Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) are the spatial resolution and the sensitivity (detector efficiency in combination with the geometric efficiency). Considerable efforts have been spent during the last two decades in improving the resolution and the efficiency by developing new detectors. Our proposed improvement technique is focused on the readout and electronics. Instead of using traditional pulse height analysis techniques we propose using free running digital sampling by replacing the analog readout and acquisition electronics with fully digital programmable systems. This thesis describes a fully digital data acquisition system for KS/SU SPECT, new algorithms for high resolution timing for PET, and modular FPGA based decentralized data acquisition system with optimal timing and energy. The necessary signal processing algorithms for energy assessment and high resolution timing are developed and evaluated. The implementation of the algorithms in field programmable gate arrays (FPGAs) and digital signal processors (DSP) is also covered. Finally, modular decentralized digital data acquisition systems based on FPGAs and Ethernet are described.

An extended Förster theory (EFT), previously derived (L. B.-Å. Johansson et al. J. Chem. Phys., 1996,105) has theoretically been adapted and used in simulations of donor-acceptor energy transfer (DAET), which is a process often referred to as FRET. It was shown that the classical Förster theory is only valid in the initial part of the fluorescence decay. In this thesis an EFT is derived and outlined for electronic energy transport between two fluorescent molecules which are chemically identical, but photophysically non-identical. The energy migration within such asymmetric pairs is partially reversible and therefore referred to as partial donor-donor energy migration (PDDEM). The previously derived model of PDDEM (S. V. Kalinin et al. Spectrochim Acta Part A, 2002,58) is an approximation of the EFT. In particular, the EFT accounts for the time-dependent reorientations as well as the distance that influence the rate of electronic energy migration. The reorientation of the fluorophores transition dipole moments has been simulated using Brownian dynamics. As a result, the related “k2-problem” has been solved. The EFT of PDDEM has also been studied regarding the effect of PDDEM on experimental observables e.g. quantum yield of fluorescence and steady-state anisotropies

The capability to resolve the contributions from spectroscopically overlapping fluorophores has enabled significant breakthroughs in cellular imaging. However, commercial microscopes for this purpose use analog light detection with least squares curve-fitting analysis and improvements in sensitivity are needed. To this end, a microscope has been constructed with high throughput and single-photon detection capability. The fluorescence is separated through use of a prism spectrometer or a series of dichroic mirrors into four spectral bands and detected using four single-photon avalanche diode (SPAD) detectors, which provide high-quantum efficiency in the red spectral region. The detectors are connected to a time-correlated single photon counting module to provide sub-nanosecond temporal resolution for distinguishing fluorophores with different fluorescence lifetimes. Maximum-likelihood (ML) methods have been developed for analyzing the temporally and spectrally resolved photon count data from the SPADs to find the contributions from different fluorescent species and from background. Commercially available SPADs exhibit a count-rate dependent time shift in the impulse response function, and hence the instrument incorporates custom modified SPADs with improved timing stability. Nevertheless, there is still some time shift, and hence the ML-analysis has been extended to include this as an adjustable parameter for each individual SPAD. Monte Carlo simulations have also been developed to enable studies of the number of photons needed to resolve specific fluorophores.

Thesis (D.Tech.: Radiography)-Dept. of Radiography, Durban Institute of Technology, 2006 xxiii, 166 leaves / The purpose of this study was to evaluate 99mTc- methoxyisobutylisonitrile (MIBI) imaging, in terms of sensitivity and specificity, for non invasively detecting extracutaneous involvement of Kaposi’s sarcoma (KS) and for differentiating pulmonary infection from malignancy in acquired immunodeficiency syndrome (AIDS) patients before and after treatment. Current investigations are invasive.

Thesis (D.Tech.: Radiography)-Dept. of Radiography, Durban Institute of Technology, 2006 xxiii, 166 leaves / The purpose of this study was to evaluate 99mTc- methoxyisobutylisonitrile (MIBI) imaging, in terms of sensitivity and specificity, for non invasively detecting extracutaneous involvement of Kaposi’s sarcoma (KS) and for differentiating pulmonary infection from malignancy in acquired immunodeficiency syndrome (AIDS) patients before and after treatment. Current investigations are invasive.