RecruitingBehavioural interventionTesting a Web-based Intervention for Radioactive Iodine Symptom Management to Improve Health-related Quality of Life Among Differentiated Thyroid Cancer PatientsThe goal of this clinical trial is to learn if adult patients diagnosed with differentiated thyroid cancer can easily use and benefit from an online tool aimed to provide patients with educational resources and symptom management strategies to improve their quality of life after radioactive iodine (RAI) treatment. The main questions it aims to answer are: 1. Can patients easily use and benefit from the RAI Support intervention? 2. Does RAI Support improve health-related quality of life (overall well-being) compared to usual care? This research will help test better digital tools to support thyroid cancer survivors in managing their health after RAI treatment. Researchers will compare RAI Support to treatment as usual (a publicly available informational website about thyroid cancer) to see if RAI Support works to improve patients' overall well-being. Participants will: 1. Receive access to RAI Support or an informational website (treatment as usual) for four weeks. 2. Use the assigned website once a week for up to four weeks. 3. Complete two online questionnaires (an initial questionnaire and a final questionnaire after four weeks of using the assigned website) about symptoms related to RAI treatment, mood, and confidence in managing symptoms. 4. Complete an optional 60 minute virtual interview about your experiencing using the assigned website.