131I for Graves’ hyperthyroidism
【Rationale】.
Graves’ disease has a diffusely enlarged thyroid gland that overexpresses the sodium-iodine transporter (NIS). After oral administration of 131I, the thyroid gland takes up a large amount of 131I from the blood through the NIS. 131I emits beta radiation with a range of only 2-4 mm, which has little effect on the surrounding tissues, resulting in a shrinking of the thyroid gland and the disappearance of hyperthyroid symptoms.
Indications
1. Patients with Graves’ hyperthyroidism, allergic to antithyroid drugs, poor efficacy of antithyroid drugs, multiple relapses after antithyroid treatment drugs;
2.Recurrence after surgery;
3.Graves hyperthyroidism with leukocytopenia or thrombocytopenia;
4. Graves’ hyperthyroidism with atrial fibrillation.
Contraindications
1.Pregnancy, lactation;
2.Severe renal insufficiency;
3.Acute myocardial infarction.
Method and procedure
1.First of all, the diagnosis of Graves’ disease should be confirmed.
2.Stop taking antithyroid drugs such as methimazole or propylthiouracil for 2~4 weeks.
3.Patients can continue to take oral β-receptor inhibitors, whitening drugs and hepatoprotective drugs.
4.Low iodine diet for 2~4 weeks.
5.Check blood routine, liver and kidney function, thyroid function, TRAb, TGAb, TPOAb.
6.Measure thyroid 2, 4, 6 and 24-hour iodine uptake rates to rule out destructive thyrotoxicosis such as subacute thyroiditis. Use the 24-hour iodine uptake rate to calculate the patient’s required 131I dose.
7. Determine the effective half-life of 131I and adjust the dose to be administered.
8.Inform the patient of the possible efficacy of the method and the possibility of hypothyroidism (any treatment can lead to hypothyroidism), and sign a written informed consent.
9.Record the present medical history, the relevant departments for physical examination and writing the complete case.
10. Determine the planned dose per gram of thyroid tissue based on the length of the history, size and texture of the thyroid gland, presence or absence of nodules, presence or absence of thyroid medication, age, and other factors. The planned dose per gram of thyroid tissue is 2.4~4.4 MBq.
11.Estimated weight of thyroid ECT.
12.Calculate the dose taken for each patient by using the following formula. Dose (MBq) = [planned dose MBq/g thyroid tissue * weight of thyroid gland] / % iodine uptake in 24 hours, corrected if valid for less than 5 days using the following formula.
Dose (MBq) = [planned dose MBq/g thyroid tissue * thyroid weight] / % iodine uptake rate in 24 hours * 5 / effective half-life.
13. Two people calculate the dose and review and sign before taking the medication, and dispense it according to the 131I dose taken by the patient using the automatic nuclide dispenser.
14. Instruct patients to learn how to take 131I orally, conduct safety education, inform them of the precautions to take after taking the drug, such as diet, taking other drugs and review, tell them to stay away from pregnant women and infants, and minimize contact with social workers.
15.Patients need to give the drug on an empty stomach.
16.Verify the patient’s name, drug name, dose, medication time and usage according to the doctor’s prescription. The water cup after medication is thrown in the red garbage bag container, and the whole process is managed by video, and real-time guidance is given when necessary.
17.Radioactive waste is placed in the lead canister to decay.
18.Leaving from the special channel for patients after taking medication.
[Complications
1.Common adverse reactions are weakness, dizziness, lack of appetite, nausea, vomiting, skin pruritus, and localized swelling and pain of the thyroid gland.
2, the most common is hypothyroidism, divided into early-onset hypothyroidism and late-onset hypothyroidism, thyroid crisis is less common.
Efficacy test]
After taking 131I, the thyroid function will be reviewed regularly at 3, 6, 9 months and 1 year to determine the patient’s recovery, and replace the treatment timely for hypothyroidism, and repeat the treatment if the hyperthyroidism is not completely relieved at 3-6 months. After one year, the thyroid function will be reviewed regularly every year, and hypothyroid patients will be instructed to carry out reasonable replacement therapy.