Nucl Med Mol Imaging.  2015 Jun;49(2):122-126. 10.1007/s13139-014-0317-x.

Does 131I Radioactivity Interfere with Thyroglobulin Measurement in Patients Undergoing Radioactive Iodine Therapy with Recombinant Human TSH?

• Park S
• Bang JI
• Lee HY
• Kim SE

• KMID: 2313258
• DOI: http://doi.org/10.1007/s13139-014-0317-x

Abstract

OBJECTIVES
Recombinant human thyroid-stimulating hormone (rhTSH) is widely used in radioactive iodine therapy (RIT) to avoid side effects caused by hypothyroidism during the therapy. Owing to RIT with rhTSH, serum thyroglobulin (Tg) is measured with high 131I concentrations. It is of concern that the relatively high energy of 131I could interfere with Tg measurement using the immunoradiometric assay (IRMA). We investigated the effect of 131I administration on Tg measurement with IRMA after RIT.
METHODS
A total of 67 patients with thyroid cancer were analysed retrospectively. All patients had undergone rhTSH stimulation for RIT. The patients' sera were sampled 2 days after 131I administration and divided into two portions: for Tg measurements on days 2 and 32 after 131I administration. The count per minute (CPM) of whole serum (200 microl) was also measured at each time point. Student's paired t-test and Pearson's correlation analyses were performed for statistical analysis.
RESULTS
Serum Tg levels were significantly concordant between days 2 and 32, irrespective of the serum CPM. Subgroup analysis was performed by classification based on the 131I dose. No difference was noted between the results of the two groups.
CONCLUSIONS
IRMA using 125I did not show interference from 131I in the serum of patients stimulated by rhTSH.

Keyword

Immunoradiometric assay; Thyroglobulin; Radioactive iodine therapy; Recombinant human TSH

MeSH Terms

Classification
Humans
Hypothyroidism
Immunoradiometric Assay
Iodine*
Radioactivity*
Retrospective Studies
Thyroglobulin*
Thyroid Neoplasms
Thyrotropin
Thyrotropin Alfa*
Iodine
Thyroglobulin
Thyrotropin
Thyrotropin Alfa