RT Journal Article SR Electronic T1 Initial Experience with Oral Contrast in PET/CT: Phantom and Clinical Studies JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 412 OP 416 VO 44 IS 3 A1 Cohade, Christian A1 Osman, Medhat A1 Nakamoto, Yuji A1 Marshall, Laura T. A1 Links, Jonathan M. A1 Fishman, Elliot K. A1 Wahl, Richard L. YR 2003 UL http://jnm.snmjournals.org/content/44/3/412.abstract AB The aims of the study were to evaluate the effects of oral contrast on apparent tracer activity measured with PET/CT when using CT attenuation correction and to report our initial experience in the use of oral contrast with PET/CT. Methods: Phantom studies with 18F activity and saline bags or syringes filled with barium or gastrografin of varying densities were performed using a PET/CT scanner (CT attenuation correction). In the study, 91 clinical patients received dilute oral contrast and were evaluated by whole-body 18F-FDG PET. Results: A phantom experiment with CT contrast (1.3% weight/volume [w/v] barium) showed a “cold” area in the cold stomach whereas a phantom with high-density barium (98% w/v) showed an artifactual focus of intense “activity” in the cold stomach. In clinical studies, stomach and right colon were opacified by CT contrast. Maximal measured contrast density was 239 Hounsfield units. Conclusion: High-density barium causes overestimation of tissue 18F-FDG concentration. Low-density barium does not cause significant artifacts and appears suitable for clinical use.