Spatial linear recovery coefficients for quantitative evaluations in SPECT

Spatial linear recovery coefficient functions (LRCs) are defined for each of the three Cartesian axes to recover the true dimensions of 3D activity distributions in SPECT data. These are measured using a dedicated GE Infinia Hawkeye 4 SPECT/CT system and, in terms of the ratio of a source size to overall spatial scanner resolution, are found to be independent of the radiotracer energy, collimator, radius of rotation, background and attenuator, or whether the object is cold or hot. The LRCs so defined are reproduced by a single Gaussian error function. It is demonstrated that by using these LRCs to compensate for limited system resolution effects, one recovers functional volumes and activity concentrations of any 3D radiotracer distribution irrespective of its shape or geometry, reliably.