@article {Lopresti1496, author = {Brian Lopresti and Teresa Coleman and Charles Laymon and Lonnie Frye and Jamie Tomko and Joanne Flynn and Jonathan Carney}, title = {CT-based attenuation correction for a pre-clinical PET/CT imaging platform}, volume = {50}, number = {supplement 2}, pages = {1496--1496}, year = {2009}, publisher = {Society of Nuclear Medicine}, abstract = {1496 Objectives A preclinical PET/CT imaging platform based on the microPET Focus 220 and the CereTom neuro CT allows larger animals, here a non-human primate model of tuberculosis, to be scanned on a common imaging pallet. Whereas initially transmission (TX) images acquired on the microPET using a Co-57 source were used for attenuation correction, we have recently implemented a CT-based attenuation correction (CTAC) procedure. Methods The CT images are assembled into a 511 keV mu-map volume based on measurements using reference tissue-like materials. This is registered with the non-attenuation corrected PET volume, and broken up into constituent volumes for each acquired PET bed position, which are reprojected to give the attenuation correction factors (ACFs). Results CTAC [F-18] FDG PET images are comparable with those obtained using segmented TX images, except for higher observed uptake in the lung. This is expected as the TX images are segmented into solid tissue or air, with normal lung tissue being treated as air, whereas the CTAC method does not underestimate ACFs passing through the lungs. The higher values using CTAC are more in keeping with expected values based on clinical FDG PET/CT scans. Conclusions Using the CT images from the CereTom scanner gives more accurate ACFs than the standard method using the Co-57 source, which necessitates lengthy transmission scans. Additionally, the ability to remove the microPET point source mechanism allows the bore opening to be increased from 22cm to 26cm, accommodating larger subjects, though at the expense of reduced side-shielding of the detectors.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/50/supplement_2/1496}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }