PT - JOURNAL ARTICLE AU - Christian Cohade AU - Medhat Osman AU - Yuji Nakamoto AU - Laura T. Marshall AU - Jonathan M. Links AU - Elliot K. Fishman AU - Richard L. Wahl TI - Initial Experience with Oral Contrast in PET/CT: Phantom and Clinical Studies DP - 2003 Mar 01 TA - Journal of Nuclear Medicine PG - 412--416 VI - 44 IP - 3 4099 - http://jnm.snmjournals.org/content/44/3/412.short 4100 - http://jnm.snmjournals.org/content/44/3/412.full SO - J Nucl Med2003 Mar 01; 44 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.