Thyroid Cancer Treatment Radioactive Iodine
Radioactive iodine (RAI) is a type of radioisotope treatment. Radioisotopes are radioactive substances given as capsules. Cancer cells absorb more radioisotope than normal cells, which causes the cancer cells to die. Radioactive iodine is also known as I131 or radioactive iodine ablation treatment. RAI is usually given to destroy tiny amounts of remaining cancer cells or healthy thyroid tissue left behind after surgery.
Radioactive iodine treatment is suitable for people diagnosed with papillary or follicular thyroid cancer. RAI doesn’t work for medullary or anaplastic thyroid cancer because these types do not take up iodine. The radioactive iodine treatment often starts 4– 5 weeks or more after surgery.
If you are pregnant, you can’t have RAI. If you are breastfeeding, you will have to stop nursing before starting treatment. Ask your doctor for more information.
Preparing for radioactive iodine treatment
Limit foods high in iodine
Two weeks before treatment you will need to start avoiding high-iodine foods as these make RAI treatment less effective.
- iodised table salt
- some dairy products
- soy beans
- soy-containing products and foods with E127 colouring.
Raising TSH levels
For RAI treatment to work, you need a high level of TSH. This is done in two ways, and the option recommended for you will depend on availability at your hospital and what is suitable for you.
Recombinant human thyroid-stimulating hormone (rhTSH) injections– You will be prescribed an injection of recombinant human thyroid-stimulating hormone (rhTSH) or Thyrogen ®. You will need an injection once a day for the two days before you start RAI treatment.
Thyroid hormone replacement– You stop taking your thyroid hormone replacement medicine for a few weeks. This often causes the side effects of hypothyroidism, and some people find it difficult to cope with this, while others don’t notice any side effects.