I131 Treatment

This information has been designed to provide you with some useful information regarding your admission to the Northern Centre for Cancer Care (NCCC) for Radioiodine (I131) treatment. It explains / includes:

  • Where you will have your treatment
  • How your treatment is given
  • Special precautions that will need to be taken
  • Possible side effects
  • Discharge arrangements

Please Note: a printer-friendly version of this guide is available.

Information produced 2011 by Nicola Armstrong, Thyroid Cancer Nurse Specialist and Butterfly Cancer Trust, Northern Centre for Cancer Care (NCCC).

Be sure to also read our information about the Low Iodine Diet.

Why am I having I131?

Your consultant will have discussed the reasons why you have been advised to have I131; including what would happen if you chose not to have this treatment.

You will also have been given an information pack in clinic and provided with an opportunity to visit the Nuclear Medicine department and Ward 35 where you will be having your treatment.

If you have any further questions then you should discuss these with your consultant, or one of their team, before you come into hospital for your treatment.

I131 is often used to destroy any remaining normal thyroid tissue or microscopic deposits of thyroid cancer after surgery to the thyroid gland.

In many studies this has been shown to reduce the risk of the cancer returning and improve survival (Mazzaferri 1997, Mazzaferri & Kloose 2001).

I131 can also be used to treat cancer that has returned and still achieve a cure. It is important to remember that the long-term survival for most patients with papillary or follicular thyroid cancer is excellent.

Where will I have my treatment?

After deciding on the date for your admission, you will receive a letter from Nuclear Medicine Department regarding your admission and whole body scan. On the day of admission you will need to attend Nuclear Medicine Department for blood samples. For females with childbearing capacity a sample of blood will be taken to exclude pregnancy.

Pregnant women and those who are currently breast feeding must not be administered radioiodine treatment.

After you are reviewed in nuclear medicine you can make your way to Ward 35.

You will be met by the ward clerk or one of the nursing staff and then shown to the radioiodine suite.The nurses and doctor will then admit you to the ward, taking blood pressure, pulse and temperature.

Am I nursed in a special room?

Yes, you will usually be nursed in a cubicle that has been specially adapted to care for patients receiving I131.


Why do I need to be nursed in a special room?

I131 is a form of internal radiation therapy and once you receive your treatment special precautions must be taken.

This is because your bodily fluids will contain the radioactive material and radiation, similar to x-rays, will be emitted from your body.

The levels of radioactivity in your body will decrease quickly over a period of days as most of the material is eliminated from the body in your urine.

For a few days we care for you in the radioiodine suite to reduce other people’s exposure to radiation.

Regulations state that members of the public should not receive radiation doses greater than one millisievert (1mSv) in any year as a result of medical exposure to others (Statutory Instrument 1999).

To put these risks into context a person living in Newcastle is exposed to two millisieverts (2mSv) of background radiation a year.

What is in the radioiodine suite?

The suite has the following facilities:

An en-suite bathroom, which includes a toilet, bath and shower.

Although a small bag of toiletries is provided eg soap, shampoo, bath gel, bath gel, toothpaste, toothbrush and shower cap you may prefer to bring your own.

We would advise that you bring travel size toiletries (eg soap, shampoo, bath gel, bath gel, toothpaste, tooth brush and make-up) as these can be discarded, with minimal wastage, when you are discharged from hospital.

Disposable razors, sanitary items and top-up items are available on request. Towels are also available but you may wish to bring your own. We are happy for you to use hospital towels as bath mats.

While you are in hospital we would advise that you undertake the following measures in order to help remove unwanted radioactive iodine from your body:

  • Have a shower each day.
  • Drink between two to three litres of fluid a day (after your capsule)
  • Empty your bladder regularly, eg every three to four hours, while also being careful not to splash urine outside the toilet basin.
  • Empty your bowels each day.

A small kitchen area. You may be asked to share your kitchen facilities with another patient, of the same sex, who is having the same or similar treatment.

Meals will be placed on the bench in the entrance of your cubicle. A sink, washing up liquid and bowl are provided in the kitchen to enable you to wash your own cutlery and crockery, as this needs to remain in your room. Unwanted food should be disposed of using the waste disposal unit in the kitchen sink.

There is a small refrigerator in your cubicle and you may wish to bring a supply of mineral water, squash or fruit and other items that you are able to eat while on a low Iodine diet.

Although tea and coffee making facilities are available in the kitchen, including a kettle, please advise the ward staff if you require any additional supplies of tea, coffee, milk or sugar.

You will have been advised by your Consultant to eat a low Iodine diet for three weeks before and 48 hours after you treatment. Although in most cases you will be able to select your meals from the ward menu this may be influenced by any additional special dietary requirements you may have eg vegetarian.

Please contact the ward before your admission if you have any additional dietary requirements which they will need to take into account during your stay.

Unfortunately Patient line is not available in your cubicle. There is however a TV and DVD player in your cubicle which you do not need to pay to view. There is no telephone service.

Loan equipment: a hairdryer and CD player are available for you to use while you are in hospital. Please feel free to bring your own CDs from home.

When will I have my treatment?

Your treatment will be given to you in your room on the afternoon of your admission, usually at about 3 pm.

How is I131 treatment given?

The nurses will ask you to eat and drink nothing for two hours before and after your treatment.

The Nuclear Medicine staff will give you a capsule, similar in size to an antibiotic capsule and ask you to swallow it with a drink. It is very important not to bite it.

What will happen after I have had my treatment?

You must stay in the radioiodine suite. The usual stay is three days and each day the Nuclear Medicine staff will take a radiation measurement, using a hand held monitor, to help us to determine how much radioactive iodine is left in your body.

These measurements are used to help us decide when you can leave hospital.

Due to the possible long-term risks associated with being regularly exposed to patients receiving radiation therapy, the nursing staff will reduce the amount of time they spend with you after you have received your treatment.

On the day of your admission the nurse will discuss ways in which we can provide 24-hour surveillance and establish how regularly you would like us to check on your condition, during the day and night.

We will however try to ensure that one nurse is responsible for your care each day.

What are the visiting arrangements?

Visiting hours are usually between 2 pm and 4 pm or 6 pm and 8 pm. However, Ward 35 Sister has agreed to open visiting for radioiodine treatments due to the restrictions set.

Under 18s and pregnant women should not visit as they are more sensitive to the effects of radiation.

The daily radiation dose rate measurements, recorded by the Nuclear Medicine staff, are used to calculate how long your visitors may stay each day.

Visiting is usually restricted to about 30 minutes per visitor on the first day of treatment but this will increase during the period of your stay.

The Nuclear Medicine staff will provide you with information regarding daily restriction and this will be recorded on a white board outside your room.

Although visitors may enter your suite they must stay in the blue area marked on the floor which is inside the first door leading to your suite. It is important that you do not give your visitors anything to take out of your room.

Will I experience any side effects with I131 treatment?

When you stop your thyroid hormone you can feel lethargic, weak and tired and we would advise that you take sufficient rest.

We would also advise that you do not drive or operate machinery when you stop taking your thyroid hormone replacement (T3 & T4) and for the first two or three weeks after your I131 treatment as it takes a few weeks for your thyroxine levels to return to normal.

When your thyroxine levels are low (hypothyroid) you can feel very cold, particularly at night, and it is worth bringing some warm clothes into hospital with you, including bed socks.

Although side effects with I131 are uncommon, patients can say that their mouth, throat or neck feels swollen or sore.

If this happens it usually occurs on the second or third day of your stay. Please tell the nursing staff if you experience any side effects as they can provide advice and may give you some medication to ease any discomfort.

Sometimes people find that their sense of taste is slightly altered but this usually improves several days or weeks after your treatment.

Citrus fruit sweets, which encourage the production of saliva, can often help but these should only be used 24 hours after you have taken your I131 capsule.

How can I prevent myself from becoming bored?

You or your visitors can bring in items from home eg books (not library books), magazines, newspapers games and jigsaws.

Although sewing and knitting are permitted, items should not be passed on to anyone else for several weeks.

What will happen on the day I am due to leave hospital?

Iodine Suite: Scanning the abdomen
You will be asked to return to the hospital a week after your treatment to have a body scan which will take approximately 50 minutes to complete.
Your follow up will be approximately eight weeks later and will be arranged prior to your discharge.

On the day you are due to leave hospital, we will ask you to take a shower and place hospital towels into the laundry bag provided. You can take your own clothes and towels home with you.

Just wash them separately when you get home in order to remove any traces of radioactive iodine.

A member of staff from the Nuclear Medicine department will visit you on the ward in the morning to record your radiation dose rate measurement.

As you will still have a small amount of radioactive iodine in your body this measurement will be used to provide you with personalised information which will be given to you in the form of a yellow card.

You will probably be advised to avoid close, prolonged, contact with other people for another day or two (eg sleep in a separate bed from a partner) and avoid close, prolonged, contact with small children and pregnant women for a few days.

You will also be advised to avoid having any blood samples taken for four weeks after your treatment, unless they are absolutely necessary. You will be given a letter containing this information which you must give to your GP.

If you are planning any long distance travel, especially by air, in the next month or so, please discuss this with your Nuclear Medicine team.

The nursing staff will give you some thyroid hormone replacement tablets that have been prescribed by your consultant. As these should be started 48 hours after you take your I131 capsule, you will need to begin taking them on the day that you go home.

They will also give you a letter for your GP with information regarding your treatment and contact details.

Going back to work

If you’re planning on going back to work it is important to discuss this with Nuclear Medicine department to establish when you will be safe to do so.

You may also still feel very tired after radioiodine treatment if you have stopped taking you thyroid hormones. You will need to discuss with your GP to assess how you feel and whether you are fit for work.

What if I experience any problems when I go home?

If you experience any problems within seven days of leaving the hospital then we would advise that you contact either the Thyroid Nurse Specialist or your consultant’s secretary during normal working hours. At all other times please contact your GP.

You can contact Thyroid Cancer Specialist Nurse, your Consultant’ secretary, Hospital Ward by calling the hospital switchboard: 0191 2336161

Family planning


If you are considering have a family in the future please tell your doctor as this treatment can sometimes make some men infertile.

If your partner is of childbearing age we would advise that you use contraceptives for four months after your treatment as I131 may harm a developing baby.


As I131 may harm a developing baby, if you are of childbearing age we would advise that you use contraceptives before and for six months after your treatment.

You should inform your hospital doctor if your period is late and you think you may be pregnant either before or within six months of having had your treatment.


  • Mazzaferri E.L. (1997) Thyroid remnant I131 ablation for papillary and follicular thyroid carcinoma. ‘Thyroid’ 7, p265-271.
  • Mazzaferri E.L. & Kloose R.T. (2001) Current approaches to primary therapy for papillary and follicular thyroid cancer. ‘Journal of Clinical Endocrinology and Metabolism’ 86, p1447-1463.
  • Statutory Instrument (1999) No 3232 The Ionising Radiation Regulations 1999. London. HMSO.

If you have any further questions regarding your forthcoming admission please do not hesitate to contact your Thyroid Nurse Specialist or your consultant’s secretary or the staff on the ward.