RESUMO
The results of studies conducted with a small field of view tomographic gamma camera based on a Position Sensitive Photomultiplier Tube are reported. The system has been used for the evaluation of radiopharmaceuticals in small animals. Phantom studies have shown a spatial resolution of 2mm in planar and 2-3mm in tomographic imaging. Imaging studies in mice have been carried out both in 2D and 3D. Conventional radiopharmaceuticals have been used and the results have been compared with images from a clinically used system.
Assuntos
Bombesina/farmacocinética , Neoplasias Experimentais/diagnóstico por imagem , Compostos Radiofarmacêuticos/farmacocinética , Tecnécio/farmacocinética , Algoritmos , Animais , Câmaras gama , Processamento de Imagem Assistida por Computador/instrumentação , Rim/diagnóstico por imagem , Camundongos , Camundongos Nus , Cintilografia , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador/instrumentação , Tecnécio/químicaRESUMO
This paper investigates the possibility of developing a SPECT system that combines the high spatial resolution of position sensitive photomultiplier tubes (PSPMTs) with the excellent performance of iterative reconstruction algorithms. A small field of view (FOV) camera based on a PSPMT and a pixelized scintillation crystal made of CsI(Tl) have been used for the acquisition of the projections. With the use of maximum likelihood expectation maximization (ML-EM) and ordered subsets expectation maximization (OSEM) slices of the object are obtained while three-dimensional (3D) reconstruction of the object is carried out using a modified marching cubes (MMC) algorithm. The spatial resolution of tomographic images obtained with the system was 2-3mm. The spatial resolution of a conventional system that uses filtered backprojection (FBP) for slices reconstruction was more than 9 mm.
