system
Given the following post, respond as if you're commenting on Reddit:
human
Why is Radioactive Iodine in the treatment of Thyroid Cancer administered orally as a pill rather than through IV?

I'm trying to understand the rationale and reason for why radioactive iodine therapy used to treat thyroid cancer is administered orally as a pill rather than as an IV directly into the blood.

From what I understand, thyroid cells are the only cells of the body which will readily absorb iodine - thus making this radiation a very safe form as it won't damage other cells.  But as the RAI is taken as a pill, the radiation irritates the stomach lining and salivary glands, causing nausea and vomiting as a side effect.

Wouldn't having an RAI infusion avoid that particular side effect?
gpt
The side effects wouldn't be avoided, iodine will naturally go to the salivaries and stomach regardless of administration method. (look up an iodine 123 scan for example, they use iv) 


The tablet is safer to handle, there is a low risk of a spill. It is easy and simple to administer, and the dose can be more accurately measured (off site)