Detection for Residual Thyroid Tissue and Metastatic Lesion after Total Thyroidectomy in Patients with Differentiated Thyroid Cancer: Comparison between Tc-99m Pertechnetate Scan and High Dose I-131 Therapy Scan.
- Author:
Joo Ryung LEE
1
;
Byeong Cheol AHN
;
Shin Young JEONG
;
Jaetae LEE
;
Kyu Bo LEE
Author Information
1. Department of Nuclear Medicine, Kyungpook National University Hospital, Kyungpook National Unversity Medical School, Daegu, Korea. kyubo@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Tc-99m pertechnetate scan;
I-131 iodide scan;
thyroid cancer;
thyroid remnant;
metastasis
- MeSH:
Humans;
Neck;
Neoplasm Metastasis;
Sodium Pertechnetate Tc 99m*;
Thyroid Gland*;
Thyroid Neoplasms*;
Thyroidectomy*
- From:Korean Journal of Nuclear Medicine
2003;37(2):120-127
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: To evaluate diagnostic sensitivity of nuclear imaging in the detection of residual thyroid tissue and metastatic lesion, we have compared neck scintigrams with Tc-99m pertechnetate (Tc-99m scan) and high dose I-131 iodide (I-131 scan) in patients with differentiated thyroid cancer. SUBJECTS AND METHODS: One hundred thirty-five thyroidectomized patients for differentiated thyroid cancer were enrolled in this study. Twenty-three had a previous history of radioiodine therapy. Planar and pin-hole images of anterior neck with Tc-99m were acquired at 20 minutes after injection, followed by I-131 scan three days after high-dose radioiodine therapy within 7 days interval. Patients were asked to discontinue thyroid hormone replacement more than 4 weeks. RESULTS: All subjects were in hypothyroid state. Seventy out of 135 patients (51.9%) showed concordant findings between Tc-99m and I-131 scans. I-131 scan showed higher number of uptake foci in all of 65 patients showing discordant finding. Tc-99m scan showed no thyroid bed uptake in 34 patients, whereas 23 of them (67.6%) showed bed uptake in I-131 scan. Tc-99m scan did not show any uptake in thyroid bed in 11 of 112 patients without previous history of radioiodine therapy, but 9 of them showed bed uptake in I-131 scan. Tc-99m scan showed no bed uptake in all of the 23 patients with previous history of radioiodine therapy, in contrast 14 of them (60.9%) showed bed uptake in I-131 scan. CONCLUSION: These results suggest that Tc-99m scan has poor detectability for residual thyroid tissue or metastatic lesion in thyroidectomized differentiated thyroid cancer patients, compared to high dose I-131 therapy scan. Tc-99m scan could not detect any remnant tissue or metastatic lesion in patients with previous history of radioiodine treatment, especially.
