Coded-aperture system for planar imaging of volumetric sources

A method of reconstructing a two-dimensional image produced by a collimator using a coded-aperture system wherein photon flux from an object is received by a detector after passing through a coded aperture, comprising the following steps:

• (a) recording a plurality of detector measurements of said photon flux, wherein at least some of the measurements are taken varying a spacing between the coded aperture and the object;
• (b) calculating a volumetric distribution of the photon flux from the object on the basis of said plurality of detector measurements;
• and
• (c) integrating the photon flux from the object over parallel cylindrical projections of said coded aperture through the object using the volumetric distribution calculated in step (b).

Apparatus for reconstructing a two-dimensional image produced by a collimator using a coded-aperture system wherein photon flux from an object is received by a detector after passing through a coded aperture, comprising the following components:

• a stage for supporting an object to be imaged;
• a detector for recording measurements of photon flux by said object;
• a coded aperture positioned between said object and said detector;
• means for varying a spacing between the coded aperture and the detector;
• means for calculating a volumetric distribution of the photon flux from the object on the basis of a plurality of detector measurements taken varying said spacing between the coded aperture and the detector;
• and
• means for integrating the photon flux from the object over parallel cylindrical projections of said coded aperture through the object using said volumetric distribution of the photon flux from the object.

Apparatus for reconstructing a two-dimensional image produced by a collimator using a coded-aperture system wherein photon flux from an object is received by a detector after passing through a coded aperture, comprising the following components:

• a stage for supporting an object to be imaged;
• a detector for recording measurements of photon flux from said object;
• a coded aperture positioned between said object and said detector;
• means for varying a spacing between the coded aperture and the object;
• means for calculating a volumetric distribution of the photon flux from the object on the basis of a plurality of detector measurements taken varying said spacing between the coded aperture and the object;
• and
• means for integrating the photon flux from the object over parallel cylindrical projections of said coded aperture through the object using said volumetric distribution of the photon flux from the object.