Simultaneous Attenuation and Scatter Corrections in Small Animal PET Imaging

Abstract

The aim of this work is to simultaneously correct for attenuation and scatter in positron emission tomography (PET) by analytically assessing the distribution of the scattered photons using the emission images, the probability of scatter interactions and the detection efficiency. Above the usual lower energy threshold of 300 keV, the attenuated photons are dominantly those which have undergone a Compton scattering. A simple equation is established by considering that each voxel in the image is the measurement of the transmitted photons through the subject, added to the contribution from the other sources by means of their scatter. The solution of this equation allows to correct from scatter and attenuation simultaneously. This new method was applied for data measured with the Sherbrooke small animal PET scanner in line sources, hot spot phantoms, and in rat hearts and tumors.

A comparison between GATE4 results and MCNP4B published data for internal radiation dosimetry

“…Such effects have a large impact on quantitative accuracy of images and all have to be corrected for, in order to obtain optimal images (37). Fortunately, there has been considerable progress in correction for the image degrading factors that eventually will lead to provide quantitative images suitable for accurate dose estimation (3,26,37).…”