ELECTROMAGNETIC PHANTOM DESIGN FOR MEASUREMENT AND IMAGING QUALITY TESTING USING NMR IMAGING METHODS

摘要

Electromagnetic phantom design for measurement and imaging quality testing using NMR imaging has been performed. First attempts of electromagnetic phantom computation and testing on an experimental NMR 0,1 T imager were accomplished. The existing geometrical and chemical phantoms are generally used for testing of NMR imaging systems. They are simple cylindrical or rectangular objects with different dimensions and shapes with holes filled with specially prepared water solutions. In our experiments a homogeneous phantom (reference medium) was used - a container filled with water - as a standard. The resultant image represents the magnetic field distribution in the homogeneous phantom. For detection a standard gradient-echo imaging method, susceptible to magnetic field homogeneity, was used. An image acquired by this method is actually a projection of the sample properties onto the homogeneous phantom. The goal of the paper is to map and image the magnetic field deformation using NMR imaging methods. In our experiments we are using a slender rectangular vessel with constant thickness filled with specially prepared water. A carefully tailored gradient-echo NMR measuring sequence was used.