Assessment of an attenuation correction for SPECT by means of PET images

The attenuation correction for single photon emission computed tomography (SPECT) data developed by Luig et al. was tested with positron emission tomography (PET) data. Since the PET attenuation correction is very precise, it may be used as a reliable measure of the functionality of the SPECT correction. It was found that, in the case of homogeneous attenuation and activity distribution, the results of Luig's correction are equivalent to those obtained with the PET correction. Inhomogeneous distributions of activity are corrected satisfactorily as long as the absorption of the medium is sufficiently homogeneous. Inhomogeneous absorption, however, leads to inadequate correction. In the case of sections through the lung, Luig's method might 'correct' the data in the wrong direction. (author)