Optimal Imaging Time for Diagnostic I-123 Whole Body Scan in the Follow-up of Patients with Differentiated Thyroid Cancer: Comparison between 6- and 24-Hour Images of the Same Subjects.
- Author:
Hong Je LEE
1
;
Sang Woo LEE
;
Bong Il SONG
;
Sung Min KANG
;
Ji Hyoung SEO
;
Jeongsoo YOO
;
Byeong Cheol AHN
;
Jaetae LEE
Author Information
1. Department of Nuclear Medicine, Kyungpook National University School of Medicine, Daegu, Korea. jaetae@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Differentiated thyroid cancer;
diagnostic I-123 scan;
post-therapy I-131 scan
- MeSH:
Eating;
Follow-Up Studies;
Humans;
Lymph Nodes;
Neck;
Neoplasm Metastasis;
Thyroglobulin;
Thyroid Gland;
Thyroid Neoplasms;
Thyroidectomy;
Whole Body Imaging
- From:Nuclear Medicine and Molecular Imaging
2009;43(2):129-136
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: To determine optimal imaging time for diagnostic I-123 whole body scan in the follow-up of patients with differentiated thyroid cancer (DTC), we compared the image quality of 6- and 24-hour images of the same subjects. MATERIALS AND METHODS: Four hundred ninety-eight patients (M:F=55:443, Age 47.6+/-12.9 years) with DTC who had undergone total thyroidectomy and I-131 ablation therapy underwent diagnostic whole body scanning 6 hour and 24 hour after oral ingestion of 185 MBq (5 mCi) of I-123. Serum thyroglobulin measurement and ultrasonography of the neck were performed at the time of imaging. In 40 patients underwent additional I-131 therapy, post-therapy I-131 images were obtained and compared with diagnostic I-123 images. RESULTS: In 440 patients (88.4%), 6- and 24-hour diagnostic I-123 images were concordant, and 58 patients (11.6%) showed discordant findings. Among 58 discordant patients, 31 patients showed abnormal tracer uptake on only 6-hour image, which turned out false-positive findings in all cases. In 12 patients with positive findings on only 24-hour image, remnant thyroid tissue (4 patients) and cervical lymph node metastasis (3 patients) were presented. Among 40 patients underwent additional I-131 therapy, 6-hour and 24-hour images were discordant in 13 patients. All 5 patients with abnormal uptake on only 6-hour image revealed false-positive results, whereas most of 24-hour images were concordant with post-therapy I-131 images. CONCLUSION: I-123 imaging at 24-hour could reduce false-positive findings and improve diagnostic accuracy, compared with 6-hour image in the follow-up of patient with DTC.
