Radioiodine Therapy: Tracking Radiation in Salivary Glands and Thyroid Lesions Using SPECT/CT

What is it about?

The study aimed to estimate the uptake and radiation doses to salivary glands (SG) and pathologic lesions in differentiated thyroid cancer (DTC) patients following radioiodine therapy (RIT). Twenty-five DTC patients underwent RIT with varying therapeutic activities, and sequential SPECT/CT scans were acquired. The absorbed doses to parotid and submandibular glands, thyroid residues, and distal lesions were calculated using IDAC-Dose 2.1. Results showed a broad dose range for thyroid residues and distal lesions, with significant SG uptake in early hours potentially affecting thyroid uptake accuracy. The methodology used for dose estimation proved feasible and consistent with other studies, suggesting its utility in establishing dose-effect relationships and assessing radiation-induced SG damage. Calibration experiments and corrections for count loss and partial volume effect were also conducted to ensure accuracy in the dosimetry.

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Photo by Ozkan Guner on Unsplash

Photo by Ozkan Guner on Unsplash

Why is it important?

This research is important because it provides critical insights and dose estimates for salivary glands and pathological lesions in differentiated thyroid cancer (DTC) patients undergoing radioiodine therapy (RIT). Accurate dosimetry is essential for optimizing therapeutic outcomes, minimizing side effects, and establishing a dose-effect relationship for better management of DTC. The study's methodology and findings can help refine treatment protocols and improve patient care by targeting the right dose to effectively treat cancer while reducing radiation-induced damage to healthy tissues, such as the salivary glands. Key Takeaways: • Feasibility of Dosimetry Method: The study demonstrates that dose estimation using SPECT/CT scans is feasible and aligns well with previously published dose estimates using 124 I PET/CT. This suggests its potential for broader clinical application. • Broad Dose Range: The research identifies a broad and often sub-effective dose range for thyroid residues and distal lesions, highlighting the need for personalized dosimetry rather than standardized therapeutic activities. • Salivary Glands Uptake: Significant uptake of radioiodine by the salivary glands in the early hours post-administration was observed, which could impact the accuracy of thyroid uptake measurements and underscores the importance of considering salivary gland exposure in treatment planning.