Answer to Question #7785 Submitted to "Ask the Experts"

Category: Nuclear Medicine Patient Issues — Therapeutic Nuclear Medicine

The following question was answered by an expert in the appropriate field:

A family member, a 36-year-old female, had thyroid surgery followed by iodine-131 therapy three years ago. Recently she had a whole-body PET (positron-emission tomography) scan, which came out clear. She wants to have a baseline mammogram done, and she would like to know how long she should wait after her PET. She is concerned with the added radiation dose/risk.

She needs to wait until the next day, when all the fluorine-18 has decayed away. But besides that, there is no reason to wait to have a mammogram. The radiation doses from mammograms are small and unimportant as far as risk.

Diagnostic exams should not be a concern following iodine-131 therapy. It is important to have screening scans for cancer and any other diagnostic exams that her physician feels are needed for her ongoing post-therapy care.

Carol S. Marcus, PhD, MD
Professor of Radiation Oncology and of Radiological Sciences, UCLA

Marcia Hartman

Answer posted on 29 August 2008. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.