Patient specific clinical dosimetry in radioiodine therapy for thyroid cancer: Refining approaches to treatment of patients

Learning Objectives 1. Become familiar with the dosimetry procedure. 2. Considerations in selecting patients for dosimetry. 3. Added clinical information the procedure could provide that could alter treatment and follow-up approaches to select patients treated with radioiodine (I-131).

Dosimetry prior to radioiodine treatment is performed in very few institutions and in selected patients. These are most frequently very high risk patients with thyroid cancer who are being considered for very high treatment dosages, approaching 2 Gy to marrow radiation dose limits. Nevertheless, clinical dosimetry can often provide added information that could be useful in other situations such as in patients with renal impairment as well as in pediatric and elderly patients. Cases will be presented where dosimetric analysis impacted patient treatment, as well as post-treatment follow-up after therapy in certain cases to monitor possible side-effects. Methods: Some examples will be shown illustrating how dosimetry implemented for clinical use in select patients can assist in better treatment planning of the patient. Cases used will be those with advanced disease, pediatric and renally impaired patients, and novel developments in this area will be discussed, which may be the next step in the clinical use of dosimetry. Conclusion: Use of patient specific clinical dosimetry may help guide and provide insight in the treatment and management of select patients undergoing radioiodine therapy for Thyroid Cancer