Sung M. Kim MD, Abstract Co-Author: Nothing to Disclose

Charles M. Intenzo MD, Presenter: Nothing to Disclose

Jeffrey Miller MD, Abstract Co-Author: Nothing to Disclose

Serge Jabbour MD, Abstract Co-Author: Nothing to Disclose

To evaluate the characteristics of F-18 FDG PET positive scan in detecting a recurrent metastatic thyroid cancer in relation to the serum TG level, post therapy iodine scan and other diagnostic scan such as ultrasound.

We evaluated retrospectively 47 patients who had FDG PET scan with clinical suspicion of recurrent thyroid cancer. 33 of the patients had a negative radioactive whole body iodine scan with an elevated thyroglobulin level. The patients were divided into two groups: Group A (n = 17) with PET positive and group B (n = 30) with PET negative for recurrent thyroid cancer. Outcome of PET scan was correlated with serum thyroglobulin (TG) level at the time of imaging, outcome of post-iodine therapy whole body scan, thyroid staging and other diagnostic test, namely neck US if the patient had any of these study.

Median TG level of group A is 740 ng/ml (95%CI: 3-2300) and median TG level of group B is 182 ng/ml (95% CI: 2.3 to 1209). Diagnostic US is positive in 7/10 in the group A than in 11/25 in the group A. Post therapy iodine scan is positive in 8/15 in the group A than in group the B. PET positive finding is in the more advance staging than in negative group (stage 1 and II vs. stage III and IV.)

FDG PET positive group has a tendency of having higher thyroglobulin level, higher posive scan rate in post therapy iodine scan and high resolution US.

Higher the serum TG level and higher the cancer staging,  higher incidence of the FDG PET positive for recurrent thyroid cancer is noted.

Kim, S, Intenzo, C, Miller, J, Jabbour, S, Characteristics of F-18 FDG PET Positive Scan in the Patient with Recurrent Thyroid Cancer.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6016650.html