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Iodine-131 Whole Body Imaging with Thyrogen


  • You have been referred for Iodine-131 Whole Body (I-131 WB) Imaging and is performed after you have had your thyroid removed due to thyroid carcinoma.

  • Since you have previously had severe side-effects from being off your Thyroid medications, your doctor has decided to administer "Thyrogen".

  • "Thyrogen" is a synthetic drug called "recombinant human TSH alpha" (rhTSHα or simply rhTSH) . It is very similar to the naturally released TSH (Thyroid Stimulating Hormone) that our body produces every day.

  • For this study, you remain on all your medications.

  • Important Note: If you are of child bearing age, we require you to have a pregnancy blood test (betaHCG) prior to the Thyrogen injections and I-131 capsule.

  • You will be given two Thyrogen injections into the muscle of your buttock on two separate days.

  • This usually occurs on MONDAY and TUESDAY morning between approximately 9am - 10 am.

  • You must NOT be pregnant or breast-feeding.

  • You will only feel a small pinprick with the injections. Most patients do not experience any side-effects from the Thyrogen injections.

  • Even though side-effects to the Thyrogen are uncommon, you should still be aware that they may occur (see below).

  • On WEDNESDAY, you shall be asked to swallow a small radioactive Iodine-131 capsule. This has NO harmful side effects and has no taste to it. It is similar to taking a headache capsule.

  • The dose of Iodine is very small and is designed to not have a therapeutic effect on you.

  • On THURSDAY, you will have your I-131 WB images done using a Gamma Camera (1).

  • Once you have swallowed the Iodine capsule, you may go about your daily routine as normal.

  • You will need to stand 1 - 2 meters away from people for at least 24 hours after swallowing the Iodine capsule.

  • You may eat and drink as normal throughout the course of the day. Please avoid products that contain Iodine in them (e.g. Sushi, Seaweed, Seafood, Cough syrups, some multi-vitamins. etc)

  • During the day and in the evening, you should suck on some lemon and drink copious amounts of water. Iodine is naturally taken up by the salivary glands, so to release this Iodine back into your gastro-intestinal system, you need to suck on lemon (or anything that is sour).

  • This should be repeated in the morning, before breakfast.

  • Before the images on THURSDAY, you need to shower or wash your head and neck area. This is essential so as to wash any possible salivary contamination (which may have occurred overnight).

  • On the day of imaging, please try and wear clothing that does not have any metal on it. This is so that the images can be done with your clothes on. Any necklaces, chains, belts, wallets, earrings, watches, pens, etc. need to be removed prior to imaging.

  • Before imaging, you will be asked to empty your bladder.

  • You will then be given two glasses of water to wash down any residual salivary activity from the oesophagus.

  • You then simply lie on a bed (without a pillow) whilst the Gamma Camera takes images of your whole body. This takes approximately 40 minutes to complete.

  • At the end of your whole body scan, we take 3D images (called SPECT/CT (2)) using the same Gamma Camera. This also takes 40 minutes to complete.

  • At the end of the test, you must wait until we explain to you what we have found on the scan and if you require treatment or can go back on your medications.

  • On FRIDAY, you need to have a blood test to correctly measure your Thyroglobulin (Tg) and Thyroglobulin Antibody (TgAb) levels. These results need to be faxed to us as soon as possible on (02) 9550 5293.

  • You should NOT have this procedure if you are pregnant.

  • If you are planning further children, this should be postponed for at least THREE (3) MONTHS after the administration of Iodine-131 (this applies for males & females).

  • Breast-feeding should be stopped completely for this period.

  • With this procedure, you will for a short time, be more radioactive than normal.

  • Some simple precautions should be followed to minimise the radiation received by members of your family and the public.

  • The dose family members and others receive is very small and has never been shown to be harmful but it is sensible to minimise this if we can.

  • The majority of Iodine is excreted via the saliva, urine and bowel matter.

  • You receive a slight radiation dose by having a Whole Body Iodine-131 Study plus SPECT/CT ~ up to 3.3 times your yearly background radiation (3).








  • Nausea

  • Headache.

  • Fatigue

  • Vomiting

  • Dizziness

  • Paraesthesia (pins-and-needles)

  • Asthenia (lack of energy)

  • Diarrhoea.


Precautions for the first THREE DAYS (for I-131):

  • Use separate eating utensils.

  • No lip kisses or sexual intercourse.

  • Sleep alone.

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

  • No long cinema visits.

  • Double flush the toilet and wash your hands well.

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

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


Patient Preparation (for I-131):

  • If you are pregnant, trying to fall pregnant or breast feeding, you must inform our staff. You will NOT be able to have this test.

  • TAKE all your medications (especially your Thyroxine (Levothyroxine Sodium T4)) as normal.

  • You must NOT EAT or DRINK any IODINE related products (e.g. 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...) for 2 weeks prior the test.

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

  • You must NOT TAKE Neo-Mercazole (Carbimazole) or Propylthiouracil (PTU) 5 days prior the test.

  • Amiodarone can effect Whole Body Iodine uptake for up to 2 years after cessation. Please seek advise from your doctor or call us to discuss.

  • You are allowed to EAT and DRINK on the days of the test (excluding Iodine products).

  • 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.

  • Bring a list of any medications you are taking.

  • Wear comfortable clothing and minimise the amount of metal jewellery you have on (all metal objects will need to be removed prior to imaging).

  • Important Note: You cannot have this test if you have had a PET or Nuclear Scan within 24 hours prior to this test. If you have had Iodine-131 ablative therapy, allow 4-weeks before having this test. Please ring to discuss booking options.​


Breast-Feeding Mothers: Once you have been given the Iodine-131 tracer, you need to stop breast-feeding completely.


For Patients: Download "I-131 Imaging with Thyrogen" patient handout...


For Doctors: Download "Thyrogen Medical Benefits Scheme Checklist"...



(1) A Gamma Camera is a device that detects gamma-rays (gamma-rays are very similar to x-rays) and does not emit any radiation..

(2) SPECT/CT means Single Photon Emission Computer Tomography/Computer Tomography. CT does emit radiation.

(3) We all receive a yearly background radiation dose ~ 2.4mSv. Whole Body Iodine-131 Study plus SPECT/CT ~ 7.8mSv = 3.25 times yearly background dose.

value. quality care. convenience.

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