RT Journal Article SR Electronic T1 Identification of a Shine-Through Artifact in the Trachea with 124I PET/CT JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 909 OP 911 DO 10.2967/jnumed.108.060442 VO 50 IS 6 A1 Sakar B. Abdul-Fatah A1 Mariangela Zamburlini A1 Servé G.E.A. Halders A1 Boudewijn Brans A1 Gerrit J.J. Teule A1 Gerrit J. Kemerink YR 2009 UL http://jnm.snmjournals.org/content/50/6/909.abstract AB The presence of 124I in tissue near the trachea can cause a phenomenon that might be called shine-through. The effect is due to high-energy positrons that cross the air-filled trachea and annihilate at the opposite tracheal wall, incorrectly suggesting uptake at that location. Methods: We investigated shine-through using 124I, 68Ga, and 18F PET/CT scans of a neck phantom. Additionally, we evaluated 124I studies of 29 patients with differentiated thyroid cancer who underwent imaging for postsurgical staging. Results: In the phantom studies with a 0.1-mL 124I source, the relative intensity of shine-through decreased from 7% to nearly zero when the thickness of the positron-stopping layer was increased from 0.3 to 3.85 mm. In patients, shine-through was observed in 5 of the 29 studies, with intensities between 0.7% and 14%. Conclusion: Shine-through appears rather common in differentiated thyroid cancer. Recognition is important for identification of real lesions, calculation of uptake, and dosimetry.