The value of I-131 SPECT in the detection of recurrent differentiated thyroid cancer

Abstract

The aim of this study is to assess the additional value of radioiodine-131 (I-131) single-photon emission computed tomography (SPECT) to whole-body scintigraphy (WBS) in the detection of recurrent differentiated thyroid cancer. Eighty-seven consecutive patients with differentiated thyroid cancer, who had undergone a diagnostic SPECT WBS study, were included. In all patients, posttreatment scans, computed tomography scanning or ultrasonography were used to assess positive results, whereas follow-up was used in patients with a negative scan result. General data, such as primary tumor, histology and biochemical parameters were also gathered. In this study cohort, nine positive diagnostic WBS were found compared with 31 positive SPECT scans. In eight of the nine (89%) positive WBS, recurrent thyroid cancer was found at the same location on the SPECT scan. In 56 patients SPECT and WBS were negative. Moreover, eight patients with a positive SPECT study had a serum thyroglobulin level less than 1 microg/l, which, in our hospital, was the cut-off level for treatment. On the basis of the serum thyroglobulin measurements and the WBS, 9% of the patients would not have been treated. I-131 SPECT of the head and neck region and chest has a complementary role for planar imaging in the follow-up of patients treated for differentiated thyroid cancer. Therefore, its use in addition to WBS is strongly recommended in clinical practice.