Radioiodine Therapy of Thyroid Cancer Dosimetry

Abstract

Radioactive iodine therapy has been established in the management of patients with metastatic thyroid cancer therapy. The optimal activity to be administered has been under discussion since its first use. The activity can be determined using two approaches, empiric and dosimetry based. Administering an empirical activity is low cost and easy, and the rate and severity of side effects are well known and accepted. However, it can lead to undertreat or overtreat patients, due to the different specific characteristics of the iodine kinetics in each patient. Therefore, an individual dosimetry-based approach is advisable to determine the correct activity to be administered in order to be effective and, at the same time, to limit severe side effects. Here a simple method to perform individual dosimetry is proposed, based on the Committee on Medical Internal Radiation Dose schema. It can be applied both to perspective and peri-therapy dosimetry, depending on the goal and the available resources; since it improves awareness in taking a decision in patient’s management, it represents a powerful instrument to support clinical strategies aimed at improving safety and efficacy of treatments.