Attenuation correction for PET using count-limited transmission images reconstructed with median root prior

Quantitative PET studies require the computation of the attenuation correct ion factors (ACF) for compensating the body attenuation effect in the emiss ion data. Short acquisition times for transmission are desired, because of patient comfort and movement elimination. In practice, long acquisition tim es are used due to the statistical noise of count-limited scans. In order t o reduce the noise, the median root prior (MRP) iterative reconstruction me thod was used for reconstruction of short acquisition time transmission ima ges. Using these images, the ACFs were generated for correction of emission data. The new approach allows for scan times of 2 min or less, which is de sirable for quantitative whole body PET studies. The new method is object i ndependent and robust, because no smoothing of scan data or segmentation of the image are used.