The role of iodine-131 and thallium-201 imaging and serum thyroglobulin in the management of differentiated thyroid carcinoma.
BACKGROUND
A prospective study was conducted to evaluate the use of iodine-131 sodium scintigraphy, thallium-201 chloride scintigraphy, and quantitative serum thyroglobulin estimation in the detection of differentiated thyroid carcinoma after thyroidectomy and iodine-131 sodium ablative therapy.


METHODS
Thirty-one patients with a median age of 45.6 years (range, 20-73 years) were included in the study. After optimal endogenous thyroid-stimulating hormone stimulation (> 50 mU/ml), 53 pairs of iodine-131 and thallium-201 scans were performed. Concomitant serum thyroglobulin levels were available for 32 pairs of scans. The presence or absence of thyroid cancer was established by clinical, radiologic, and/or biopsy findings.


RESULTS
The concordance between iodine-131 and thallium-201 scan findings in the presence of disease (25 scan sets) was 36%. The concordance in the absence of disease (28 scan sets) was 82%. Iodine-131 scanning was found to be significantly better (P < 0.05) than thallium-201 scanning, in terms of sensitivity (0.8 versus 0.6), specificity (0.96 versus 0.82), accuracy (0.89 versus 0.72), and the predictive value of a positive test (0.95 versus 0.75). The measurement of serum thyroglobulin had a low sensitivity (0.3) in the study but had a specificity of 1.0.


CONCLUSIONS
It was concluded that iodine-131 sodium scintigraphy is superior to thallium-201 scintigraphy and serum thyroglobulin estimation for the detection of residual or metastatic differentiated thyroid carcinoma. However, the use of combined modalities provides a higher diagnostic yield. Thallium-201 scintigraphy was especially useful in cases in which iodine-131 scintigraphy was negative and quantitative thyroglobulin levels were elevated.
Department of Radiation Oncology and Nuclear Medicine, Hahnemann University Hospital, Philadelphia, PA 19102.
S
S
Dadparvar
L
L
Krishna
L W
LW
Brady
W J
WJ
Slizofski
S J
SJ
Brown
A
A
Chevres
B
B
Micaily
D000230:Adenocarcinoma / Q000097:blood* / Q000000981:diagnostic imaging* / Q000556:secondary; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D002291:Carcinoma, Papillary / Q000097:blood* / Q000000981:diagnostic imaging* / Q000556:secondary; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000601:surgery
D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D013794:Thallium Radioisotopes; D013954:Thyroglobulin