RT Journal Article SR Electronic T1 Impact of Contamination from Scattered Photons in Singles-Mode Transmission Data on Quantitative Small-Animal PET Imaging JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1852 OP 1861 DO 10.2967/jnumed.108.051193 VO 49 IS 11 A1 Vandervoort, Eric A1 Sossi, Vesna YR 2008 UL http://jnm.snmjournals.org/content/49/11/1852.abstract AB In previous work, we described and validated a method of scatter correction for singles-mode transmission data using experimental preinjection data acquired with a dedicated rodent PET scanner. In the current work, we investigated the impact that our method has on the quantitative accuracy of small-animal PET. Methods: This investigation had 3 stages. We first confirmed the general validity of our method by applying it to preinjection transmission data from a different imaging system (a larger dedicated primate scanner). For these data, we evaluated the accuracy of the reconstructed distributions of linear attenuation coefficients (μ-values). In the second stage, we applied our attenuation-map reconstruction and scatter correction procedure for postinjection transmission data acquired with the dedicated rodent scanner. For these studies, we investigated the quantitative accuracy of reconstructed emission images that use attenuation correction derived from postinjection transmission data. In the third stage, we compared our scatter correction method with 2 more commonly used alternatives (automated rescaling and segmentation of the attenuation-map images). Results: For the primate scanner data, the average reconstructed μ-values with scatter correction were within 3% of the expected values for water and soft tissue, whereas uncorrected values were 19%–26% lower than their expected values. For the postinjection transmission studies, we found that the correct average μ-values and reconstructed activity concentrations consistent with well-counter measurements were obtained only when scatter correction and emission contamination correction were applied to the transmission data. We also found that our transmission scatter correction provides more accurate μ-values and better image quantification than either rescaling or segmentation. Conclusion: Using different imaging systems (primate and rodent) and different scanning protocols (before and after injection), we found that our transmission scatter correction is more accurate (for both reconstructed μ-values and activity concentrations) than the existing alternatives.