Sung M. Kim MD, Presenter: Nothing to Disclose

Gunsel Acikgoz MD, Abstract Co-Author: Nothing to Disclose

Charles Michael Intenzo MD, Abstract Co-Author: Nothing to Disclose

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

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

The objective of a diagnostic iodine scan after total thyroidectomy is to assess amount of residual thyroid remnant and a possible metastatic lesion. Recently, utility of diagnostic iodine whole body scan during the immediate post thyroidectomy has been questioned by the efficacy of serum thyroglobulin (Tg)level, especially for a fixed-dose method of radioablation. To investigate whether a diagnostic whole body iodine scan after immediate total thyroidectomy has an added benefit.

A total of 30 patients who had a diagnostic scan after total thyroidectomy were analyzed whether a scan finding changes a clinical decision for the radioablation based on a fixed-dose method. A whole body iodine scan was obtained 48 hrs after an oral administration of 5 mCi of I-131. Percent uptake of residual/remnant iodine uptake was calculated on the anterior and posterior whole body imaging. The % iodine uptake values were correlated with post thyroidectomy serum Tg level. The patient age ranges from 21 to 81 yr-old with a mean age of 51.4. There were 24 women and 6 men. There were 12 in stage 1, 10 in stage 2, 7 in stage 3 and 1 in stage 4.

All 30 patients demonstrated thyroid bed uptake. Six patients showed cervical lymph node uptake. Of these, three patients showed unexpected lymph nodes uptake when compared topost-operative pathologic reports. Percent iodine uptake after thyroidectomy ranges from 0.5 % to 17.8%(Background uptake was 0.4%). Two patients has less than 1% uptake, 15 patients has between 1-3% (the median % uptake value of 2.4% (95% confidence interval: 1.6 to 3.8% )). Tg levels ranged from 0.3 to 9230 with a median value of 12.6 ng (95% CI: 4.7-28.6%). Tg-antibody is noted in 4 patients.

A diagnostic iodine scan during the immediate thyroidectomy period has added benefits in identifying unexpected cervical lymph node metastases in 3 of 30 patients and 2 patients with less than 1% which would change subsequent clinical decision making for radioiodine treatment dose.

Kim, S, Acikgoz, G, Intenzo, C, Jabbour, S, Miller, J, Is It Necessary to Perform a Diagnostic Whole Body Iodine Scan after Immediate Total Thyroidectomy?.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4418316.html