Abstract
The main approach to differentiated thyroid cancer (DTC) therapy is still empiric, consisting of the administration of fixed activities. Repeated treatments, however, may have a stunning effect. An individualized dosimetric study may represent an important tool to determine the best activity to prescribe, in particular for patients with distant metastases or when therapy with recombinant human thyroid-stimulating hormone (rhTSH) stimulation is deemed necessary. This study provides a practical operational example for carrying out a dosimetric study, according to the European Directive EURATOM/59/13. Starting from the case of a patient who underwent rhTSH stimulation before radioiodine ablation, we illustrate the necessity of measuring both red marrow (RM) and blood (BL) absorbed dose during the treatment in order to not exceed the dose limit of 2 Gy to the RM, so as to avoid repeating radioiodine treatment several times. Dosimetry to the RM and BL was performed during the treatments, after administration of therapeutic activity without modifying the fixed activity schema, using different approaches. The results suggest the possibility of restricting the number of treatments, reducing thus the risk of stunning effect and, where possible, eliminating an additional source of stress and dejection for patients.
Highlights
Radioiodine therapy is a standard procedure in the treatment of differentiated thyroid cancer (DTC)
Iodine choice is justified by the specific irradiation of the cancerous tissue due to the metabolic capacity to simulate the behavior of iodine in the thyroid hormone synthesis
The method usually employed to estimate the internal dose was developed by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine, that provides a systematic approach of calculation, called the “MIRD schema” [12]
Summary
Radioiodine therapy is a standard procedure in the treatment of differentiated thyroid cancer (DTC). Dosimetric study is rarely performed, and in most care centers the therapy is based on the administration of the empirical fixed activity of 131 I. The choice of empiric activity quantity should depend on patient classification. Two groups of patients can be identified as follows [1]: (1) (2). High-risk group, patients with documented persistent disease or at high risk of persistent or recurrent disease. A high activity of radioiodine is indicated, following the prolonged withdrawal of thyroid hormone treatment, since the use of recombinant human thyroid-stimulating hormone (rhTSH) stimulation has not yet been approved for this indication; low-risk group, includes all other patients. Benefits are controversial and there are still uncertainties as to whether it should be administered to all patients or only to selected patients
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
