Some practitioners recommend that patients who will be undergoing a body scan looking for thyroid cancer recurrence should go on a low-iodine diet, in order to reduce the total body iodine levels. Researchers tested a stringent self-managed low iodine diet compared to typical use of a conventional restricted iodine diet. They measured urinary iodine to evaluate effectiveness of the diet at reducing body iodine levels. What they found was:
- The one-week stringent low-iodine diet adequately prepared 26% of the patients -- reducing iodine ratios to less than 100 µg/gCr
- Two weeks on the stringent low-iodine diet adequately prepared 70% of the patients.
- At two weeks, none of the stringent diet patients had levels above I/Cr above 150 µg/gCr, but 19% of the one-week patients did
Generally, the researchers recommended that a two week minimum, stringent low-iodine diet be used to prepare for a radioiodine scan or radioiodine treatment for thyroid cancer.
Source: Chisato Tomada, et. al. "Reevaluation of Stringent Low Iodine Diet in Outpatient Preparation for Radioiodine Examination and Therapy" Endocr J Vol. 52: 237-240, (2005).