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Measurement of Thyroid Iodine Uptake


Measurement of thyroid iodine uptake procedure is used to determine the fraction of an arbitrary quantity of (radioactive) iodide taken up by the thyroid, using a small test dose.


• This procedure requires an administration of a radioactive material.
• If there is a possibility that you are pregnant, please inform the Nuclear Medicine staff. Female patients and wives of male patients should avoid becoming pregnant for 3 – 6 months. Please consult your doctor before getting pregnant.
• If you are breast-feeding, please inform the Nuclear Medicine staff. Terminate breast-feeding permanently 3 weeks before dosing and discard the milk.
• Please inform the Nuclear Medicine staff if you had recent dose of radioiodine.
• Avoid the list of interfering materials on the other tab.
• Avoid the list of interfering drugs on the other tab.
• Do not stop other medications.
• This procedure requires fasting for 4 hours before and 2 hours after the radioiodine dose.
• For 3 days after dosing: take Laxative (Dulcolax) at bedtime.
• For 3 days after radioiodine dosing: Drink plenty of water and empty your bladder frequently.
• INSTRUCTIONS ON RADIATION SAFETY: will be given to you just before Iodine-131 dosing.
• Avoid the following for 7 days before and 3 days after radioiodine administration:
o Iodized table salt, sea salt and salted food.
o Dairy products: cheese, cream, butter, yogurt, milk and its products: chocolate, ice cream etc..
o Seafood and all seafood products, all seaweed derivatives and additives.
o Soy products (soy sauce, soymilk and tofu).
o Food & drinks that are artificially colored with pink or red (E127, Red dye no.3 (erythrosine B) such as canned & glace strawberries & cherries, spam, salami, cereals, candies, pastries, sweets & lemonade.
o Commercial bread and bread products.
o Eggs.
o Restaurant food.
o Processed food
o Cabbage, lettuce & turnips.
o Cured and corned meat
o Molasses.
Allowable food and drinks:
o Non- Iodized salt.
o Fresh and frozen vegetables and fruits (except cabbage, lettuce, and turnips).
o Rice and pasta.
o Fresh meat (NOT cured and corned meat).
o Food colored by spices.
o Tea and coffee (with NO milk).
o Homemade bread.
• Stop* the following drugs for the stated period:
Antithyroid medications (Carbimazole, Propylthiouracil, Methimazole.. etc.) 1 week
Salicylates 1 week
Steroids 1 week
Sodium nitroprusside 1 week
Antihistamines 1 week
Antiparasitics 1 week
Penicillin 1 week
Sulfonamides 1 week
Tolbutamide 1 week
Thiopental 1 week
Phenylbutazone 1 – 2 weeks
Expectorants, vitamins 2 weeks
Thyroid hormones (Levothyroxine, Tiratricol.. etc.) 3-4 weeks
Benzodiazepines 4 weeks
I.V. contrast agents 1 – 2 months
Topical iodide agents 1 – 9 months
Amiodarone 3 – 6 months
Oral cholecystographic agents 6 – 9 months
Bronchographic contrast oil-based iodinated agents 6 – 12 months
Mielographic contrast oil-based iodinated agents 2 – 10 years
* Check with your referral doctor if you can stop taking these drugs and use alternative ones.


Are Nuclear Medicine procedures safe?2020-12-08T10:21:58+03:00

Nuclear medicine diagnostic procedures are safe except for pregnant ladies, unless it is requested by the physician for exceptional cases. However, the procedure better to be discussed with the doctor to know the desired benefits of the test and the alternative procedures, or you can ask the the nuclear medicine specialist about the procedure.

Should I wear a lead apron?2020-11-25T14:38:49+03:00

No, you shouldn’t because nuclear medicine scans use high-energy radioisotopes, the radiation passes directly from the other person without interacting with tissues. In contrast, wearing a lead apron slows down the radiation beam, which allows it to deposit its energy in the body and interact with tissues.

Are there risks from radiation?2020-12-08T12:45:27+03:00

The risks from diagnostic doses are usually small compared to other lifetime risks to which the patient is exposed to and the amount of radiation dose in most diagnostic procedures is less than an x-ray, CT scan, or fluoroscopy.

What is the expected damage from radiation?2020-12-08T10:32:23+03:00

When the body is exposed to radiation, tissue damage may occur, which in turn may damage DNA or chromosomes, increasing the risk of genetic mutations. When a fetus is exposed to radiation doses, it may cause abnormalities in an organ or irreparable damage and if the radiation dose is too high, it may cause the death of the fetus.

The radioactive dose used in diagnostic procedures in nuclear medicine is very low, unlike radiation treatments in which the amount of radioactive dose is high and this gives the desired effect on the tissues or organs when radiotherapy. That is why the patient must undergo a pregnancy test in the event of suspicion or if the pregnancy is uncertain before starting the therapeutic doses.

Does the patient become a danger to his family?2020-12-08T10:51:15+03:00

In diagnostic procedures the radioactivity is very low. However, the patient may be asked to maintain a distance of approximately one meter between him and his family members for a period of time given by the nuclear medicine specialist to protect them from exposure to radiation.

One the other hand, in therapeutic procedures, the patients may present some slight risk to their family members if they do not follow the INSTRUCTIONS ON RADIATION SAFETY given to them by the nuclear medicine specialist.


Radiation Protection following Iodine-131 Administration
By |2021-07-30T14:02:31+03:00September 14th, 2020|Tumour and Endocrine Glands|

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About the Author:

Senior Nuclear Medicine Specialist at Hafar Al-Batin Central Hospital, Founder of NuclearMed Website. Member of SSNMMI Executive Committee.

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