Development of a combined microPET and microCT system for mouse imaging.

摘要

The mouse has become the laboratory mammal of choice in many areas of biomedical research. Mice are widely used for studying the basic biology of mammalian systems, to create models of human disease and for testing new therapeutic approaches in these models. The physiologic similarity and genetic homology with man, combined with the availability of sophisticated methods for genetic manipulation, their rapid breeding cycle and relatively low maintenance costs, have all contributed to the success of the mouse in the biomedical research laboratory. The completion of the mouse genome will only add to the opportunities for improving our understanding of mammalian biology and for creating new and improved models of human disease.; It has been widely recognized that non-invasive imaging technologies can provide a window into the biology of the living mouse. In this project we have developed a prototype bench-top combined x-ray computed tomography (CT) and positron emission tomography (PET) system designed specifically for mouse imaging. The x-ray system consists of a compact mini-focal x-ray tube and an amorphous selenium (a-Se) flat panel x-ray detector. The PET system uses planar arrays of lutetium oxyorthosilicate (LSO) scintillator coupled to position-sensitive photomultiplier tubes. PET and CT images of both phantoms and mice were acquired simultaneously on this system.; The effect of the x-ray detector on the microCT system was investigated by comparing the performance of an a-Se detector, an amorphous silicon (a-Si) detector coupled to a gadolinium oxysulfide (GOS) screen, and a charge coupled device (CCD) detector coupled via to a GOS screen. The a-Se detector had the best performance as measured by the detective quantum efficiency (DQE), however reconstructed CT images acquired with the a-Si detector had lower noise. The effects of the x-ray spectrum on image contrast and radiation dose to the mouse were investigated, with the results showing that little contrast is lost through using a harder x-ray spectrum while dose is reduced significantly.; The goal of the bench-top PET-CT system was to study the effects of operating the two systems simultaneously and to optimize the microCT system for the specific task of mouse imaging.