Patent ID: 8264222
Filing Date: 2012-09-11
Classification: A61B

Abstract:
1. A magnetic tomographic imaging method configured for magnetic particle imaging (MPI), the method configured for localizing magnetic particles using a plurality of magnetic fields, the magnetic particles being nanoparticles used as biomedical markers, and the plurality of magnetic fields having associated different frequencies generated using two or more generators, the method comprising: generating, by a first generator, a first frequency; generating, by a first auxiliary coil, a first magnetic field of the plurality of magnetic fields based on the first frequency, the first generator being associated with the first auxiliary coil; generating, by a second generator, a second frequency, the second frequency being different than the first frequency; generating, by a second auxiliary coil, a second magnetic field of the plurality of magnetic fields based on the second frequency, the second generator being associated with the second auxiliary coil; applying the plurality of magnetic fields to a system with structures to be examined, the structures to be examined including the magnetic particles; scanning points where a time independent magnetic field vanishes as field-free points, the field free points being points defining a free field space in one of the plurality of magnetic fields where a magnetic particle material produces a signal including higher order harmonics as induction signals; detecting the induction signals generated by the magnetic particles inside the field-free space; amplifying, by a lock-in amplifier, the signal and the induction signals; localizing the magnetic particles by superposing an alternating field on a static gradient field of the system; obtaining an image of the position of the magnetic particles at the field-free points, using harmonics of a fundamental frequency associated with the first frequency and the second frequency, the magnetic particles being excited using the auxiliary coils of the prescribed frequencies; detecting frequencies that differ from at least one of the first frequency and the second frequency, wherein