Patient organ dose assessment during radioactive iodine treatments of benign thyroid diseases

Introduction

Radioactive iodine is commonly used to treat thyroid benign cases and differentiated thyroid tumors. Two approaches are used in the treatment: fixed and calculated activities. In the fixed activity approach, iodine doses are given based on medical indications, while the calculated approach requires proper dosimetry.

Methods

This study was conducted at Mount Lebanon University Hospital Medical Center (MLHUMC), and included all radioactive iodine treated patients over a period of five consecutive years. The study examined the distribution of patients in terms of gender, age and the administered activities during treatment. Additionally, organ doses were calculated for seven different administered activities using IDAC-Iodine software, specifically for the treatment of benign thyroid cases. Doses were calculated for both female and male patients.

Results

The results revealed higher effective, and organ absorbed doses in female when compared to male patients. Particularly high absorbed doses were observed for thymus, salivary glands, endotracheal region, esophagus, lymphatic nodes. Ratios for organ dose per administered activity were calculated and compared to those from the International Commission on Radiological Protection (ICRP).

Conclusion

These ratios can be used to estimate organ doses in clinical practice and reduce the organ dose with a good clinical outcome.

Implications for practice

This study highlights the value of using personalized dosimetry in iodine-131 treatments to optimize therapeutic effectiveness. Estimating organ-specific doses, especially in female patients, can help reduce radiation exposure to sensitive tissues while maintaining clinical outcomes.