Patent ID: 8456164

Claim:
A method of reconstructing a 3D image f(r1) that specifies a spatial density distribution of magnetic dipoles in an object in a 3D volume space V1 at each point r1, said method comprising the steps of: (a) applying a known polarizing magnetic field p(r) for a short time period of about 0.00001 second to 100 seconds in said 3D volume space V1 occupied by said object thus magnetically polarizing or magnetizing said object with magnetic dipole density distribution f(r1) and turning off said known polarizing magnetic field p(r); (b) measuring data that includes at least one component of magnetic field intensity characteristics generated by magnetic dipoles in said object, measurement being made in a 3D volume space V2 that in particular extends substantially along a radial direction pointing away from the approximate center of said object thereby obtaining information that includes variation of magnetic field at multiple points along said direction for 3D image reconstruction, and recording this measured data as a function of position r2 of points in said 3D volume space V2 as g(r2); (c) determining a system matrix H(r1,r2) that specifies magnetic field intensity characteristics at point r2 produced by a magnetic dipole source of unit strength located at point r1; (d) setting up a vector-matrix equation g(r2)=H(r1,r2) f(r1)+n(r2) where n(r2) represents noise in measured data at point r2; and (e) solving said vector-matrix equation g(r2)=H(r1,r2) f(r1)+n(r2) and obtaining a solution for said 3D image f(r1).