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Therapy: Iodine-131 for Thyroid Cancer


  • Your treating doctor has asked us to give you radioactive Iodine-131 treatment for your thyroid cancer.

  • To have this treatment, admission into hospital for 2-3 days is required, whereby you will be cared for in a private room i.e. visitors and other patients have limited access into your room (Medical staff are excluded).

  • The first dose of Iodine-131 following surgery, is given to completely eradicate any residual thyroid tissue that may still be present in the body.

  • The Iodine-131 destroys any functioning thyroid tissue by releasing radiation (electrons or beta particles). Remnant thyroid tissue takes up most of the Iodine-131 and the rest is excreted in the urine, saliva, sweat and the bowels.

  • You cannot have this therapy if you are pregnant, breast feeding or attempting to fall pregnant.

  • If you are planning further children, this should be postponed for at least 6 months after the Iodine-131 treatment (males & females).

  • Breast-feeding should be stopped completely.

  • The Iodine-131 is colourless and tasteless and is given in capsule form.

  • Note: ​For people who have difficulty swallowing capsules, there is a liquid alternative and this information should be conveyed to your doctor.

  • After you have had the capsule, you will be given something to eat and drink.

  • This helps in breaking up the capsule in the stomach and allows for rapid absorption of the Iodine-131.

  • Sucking on sweet and sour lollies helps increase salivary production to minimise the radiation dose to the salivary glands.

  • Iodine-131 treatment has been given successfully for more than 35 years and is very safe.

  • After swallowing the capsule, you will remain in your room alone for 2 to 3 days.

  • Visits by nursing staff and visitors are kept to a minimum to reduce their exposure to the radiation.

  • A doctor or scientist will return on the third day of your hospital stay to monitor if you are ready for discharge.

  • On the day of your release from hospital, you will have a Whole Body Iodine Scan at Alfred Nuclear Medicine and Ultrasound, RPAH Medical Centre, Level 2, Suite 206, 100 Carillon Ave, Newtown, 2042.

  • Once your scan is complete, you may need to see your referring doctor for the last time before going home.

  • This will be organised when you are discharged from hospital.

  • You receive a radiation dose by having an Iodine-131 therapy but the benefits from this treatment far outweigh any radiation risks.  

Some simple precautions should be followed:

  • For the first THREE days after leaving the hospital:

    • Use separate eating utensils.

    • No lip kisses.

    • No sexual intercourse.

    • Need to sleep alone.

    • Do not undertake long trips on planes or other public transport.

    • Do not attend the cinema.

    • If you have young children in your house, have them stay elsewhere with relatives if possible.

    • Double flush the toilet and wash your hands well.

  • For the first WEEK:

    • Spend as little time as possible close up to people.

    • When in the same room, step back a meter or two (since the radiation is absorbed in air).

    • Do not undertake long trips on planes.


​​Important Note:

  • It has been found that for a period of 12 weeks, some very sensitive airport & security alarms may be triggered off by the small amount of radioactivity remaining in your body.

  • A letter outlining your treatment will be given to you and should be kept with your travel documents if you plan international travel during this period.


Patient Preparation:

  • You can not be pregnant, trying to fall pregnant or breast feeding to have this treatment.

  • If you are of child-bearing age, we require a beta-HCG blood test stating you are not pregnant before we can proceed with the treatment. This should be undertaken less than three days prior the therapy.

  • You must not take your Thyroxine (T4) for 5 weeks prior to your I-131 capsule.

  • You will be placed on Triiodothyronine (T3) for 3 weeks then you need to stop this 2 weeks prior to your I-131 capsule.

  • A blood test will be arranged 2 - 3 days before your treatment to assess your eligibility for I-131 therapy.

  • Your doctor will give you all the relevant dates, instructions, referrals prior your consultation with us.

  • Bring a list of any medications you are taking.

  • A low Iodine diet is ideal for 2 weeks prior your test i.e. Avoid: Seaweed and Kelp products, Agar, Carrageen, Sushi, Seafood, Multivitamins, Skin products with Iodine, Iodized Salt, Milk/Dairy products, Eggs, FDC Red dye #3, Chocolate, Commercial Bread with Iodine, cough syrups, etc...

  • Investigations with Iodine contrast media should be avoided for at least 8 weeks prior your treatment.

  • Amiodarone can effect the treatment of your thyroid for up to 2 years after cessation. Please seek advise from your doctor or call us to discuss.

  • If you are taking Neo-Mercazole (Carbimazole) or Propylthiouracil (PTU), you need to stop these one week prior treatment.

  • If you have had prior imaging e.g. PET, Nuclear Scan, CT, MRI, X-Ray, Ultrasound, etc... please bring these with you.

  • Please also bring your referral and any blood results that you may have had done.


Breast-Feeding Mothers: Once you have been given the tracer, you need to stop breast-feeding completely.

value. quality care. convenience.

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