Single Photon Emission Computed Tomography 167
Estimated
image
Calculated
projections
of estimated
image
Compare A & B projections Measured
Reconstructed
image
Correct for
differences
Create new
estimated image
Initial
guess
Unfold
projections
A B
Maximum
agreement
Discrepancy
Fig. 12.12. Conceptual scheme of iterative reconstruction.
C
qi
j
Fig. 12.13. A projection qiin the estimated image is the sum of counts in all pixels
Cjand is compared with the measured projection pi.