Methods and apparatuses for 3D magnetic density imaging and magnetic resonance imaging

Methods and apparatuses for 3D tomographic imaging of objects such as soft-tissues in humans are disclosed. They are similar to the Magnetic Resonance Imaging (MRI) methods and apparatuses but they are based on the new Field Paradigm founded on the principle that the field intensity distribution in a 3D volume space uniquely determines the 3D density distribution of the field emission source and vice versa. The object to be imaged is first magnetized by a polarizing magnetic field pulse. The magnetization of the object is specified by a 3D spatial Magnetic Density Image (MDI) that needs to be determined. The magnetic field due to the magnetized object is measured in a 3D volume space that extends in all directions and in particular substantially along the radial direction from the center of the object being imaged. Further, magnetic field intensity may be measured along multiple directions at each point. This measured data captures all the available information and facilitates fast and accurate 3D image reconstruction. This is unlike prior art where measurements are made only on a surface at a nearly constant radial distance from the center of the target object. Therefore useful and available data is ignored and not measured in prior art. Consequently, prior art does not provide a fast and accurate solution to 3D imaging. The methods and apparatuses of the present invention are combined with frequency and phase encoding techniques of MRI in prior art to achieve different trade-offs.