Systematic evaluation of salivary gland damage following I-131 therapy in differentiated thyroid cancer patients by quantitative scintigraphy and clinical follow-up

Nucl Med Commun. 2015 Aug;36(8):819-26. doi: 10.1097/MNM.0000000000000325.


Objectives: Radioiodine therapy is a common adjunct to thyroidectomy in papillary thyroid cancer treatment. However, a variety of associated adverse effects have been reported. In this study, we assessed radioiodine-induced salivary gland dysfunction using quantitative scintigraphy, and evaluated the associated complications.

Methods: Patients were divided into five groups on the basis of the cumulative I-131 dosage received. Scintigraphic dynamic images of the salivary glands were obtained and converted into clinically relevant parameters: uptake index (UI), maximum secretion rate (%SR), and combined gland function scores. Patients were followed up for 3-66 months and interviewed for side effects including xerostomia, taste alteration, bitter taste, dental caries, xerophthalmia, and pain/swelling.

Results: An increase in I-131 doses resulted in a reduction in the UI and %SR and an increase in the combined scintigraphy score. Parotid glands were more affected than submandibular glands. A cumulative dosage of greater than 600 mCi resulted in complete loss of %SR in the parotid glands. No significant difference in either the UI or the %SR was observed between nontreated patients and patients receiving an I-131 dosage of up to 150 mCi. The occurrence of xerostomia was significantly correlated with the gland scintigraphic score, the number of treatment cycles, and I-131 dosage. The occurrence of pain and swelling was extremely low and only lasted for a short time.

Conclusion: Although the side effects associated with radioiodine treatment were apparent, they were usually small and temporary. Nevertheless, more consideration should be placed on careful dosing of I-131.

MeSH terms

  • Adult
  • Female
  • Follow-Up Studies
  • Humans
  • Iodine Radioisotopes / adverse effects*
  • Iodine Radioisotopes / therapeutic use*
  • Male
  • Middle Aged
  • Radiation Injuries / diagnostic imaging
  • Radiation Injuries / etiology
  • Radionuclide Imaging
  • Salivary Glands / diagnostic imaging
  • Salivary Glands / radiation effects*
  • Sodium Pertechnetate Tc 99m
  • Thyroid Neoplasms / pathology
  • Thyroid Neoplasms / radiotherapy*
  • Xerostomia / diagnostic imaging
  • Xerostomia / etiology


  • Iodine Radioisotopes
  • Sodium Pertechnetate Tc 99m