Constrained IntraSPECT reconstruction from SPECT projections

A new method is presented for tomographic image reconstruction, called "Intrinsic Transmission SPECT" or just "IntraSPECT". It simultaneously reconstructs both the attenuation map (/spl mu/) and an attenuation-compensated activity map (A), using only the SPECT projections. A modified ART-algorithm (ART-IntraSPECT) was developed and tested with a simulated thorax. The /spl mu/-image reconstructed with ART-IntraSPECT clearly exhibited all relevant anatomical structure, such as lungs and spine vs soft tissue. However, both A and /spl mu/-images were quantitatively inaccurate. The accuracy was considerably improved by applying reasonable tissue-type constraints to the /spl mu/-image.<>