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

Quantitative PET studies require the computation of the attenuation correction factors (ACFs) for compensating the body attenuation effect in the emission data. Short acquisition times for transmission are desired, because of patient comfort and movement elimination. In practice, long acquisition times are used, due to the statistical noise of count-limited scans. In order to reduce the noise, the median root prior (MRP) iterative reconstruction method was used for reconstruction of short-acquisition-time transmission images. 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 desirable for quantitative whole-body PET studies. The new method is object-independent and robust, because no smoothing of the scan data or segmentation of the images are used.