1.Indications
(1) All differentiated thyroid cancer with residual thyroid tissue after surgery with a 131I uptake rate greater than 1%.
(2) Thyroid imaging with thyroid tissue visualization (with or without functional metastases).
(3) The patient is in good general condition and the white blood cell is not less than 3.0×109/L. 131I should be applied to remove the residual thyroid tissue after surgery.
2. Contraindications
(1) Pregnancy and lactation.
(2) Those whose postoperative thyroid wounds are not completely healed.
(3) Those whose white blood cells are below 3.0×109/L or those with severe liver or kidney dysfunction.
Step 1 Method of removing residual thyroid tissue
1. Patient preparation
(1) Discontinue thyroid tablets (or T4) before 131I treatment and switch to T3 for 3 weeks, then discontinue all thyroid hormones for 2 weeks to raise TSH levels in the serum. If you have been taking thyroid tablets (T4), you must stop taking them for 4 to 6 weeks; for those who have recently undergone thyroid surgery, give adequate thyroid tablet replacement therapy for 4 to 6 weeks immediately after surgery (to facilitate wound healing and avoid post-surgical complications) before stopping the medication as described above.
(2) Avoid iodine for 4 weeks.
(3) Measure serum FT3, FT4, TSH, Tg and check thyroid uptake rate of 131I and whole body 131I imaging.
(4) If there is residual cancer in the neck, 131I removal should be performed after surgery if possible.
2.Treatment of taking 131I to remove residual thyroid tissue
After taking 131I, let patients drink more water and empty urine on time, and often take vitamin tablets by mouth to promote saliva secretion.
Step 2 131I treatment for differentiated thyroid cancer
1. Patient preparation
(1) Surgery to remove the primary focus and 131I to remove the residual thyroid tissue.
(2) Discontinue thyroid hormone (T4 for 4-6 weeks, T3 for 2 weeks).
(3) Iodine abstinence for four weeks.
(4) Measurement of serum FT3, FT4, TSH and Tg.
2. Take 131I to treat differentiated thyroid cancer
Take 131I to let patients drink more water to empty urine on time, and often take vitamin tablets by mouth to promote saliva secretion.
Safety protection
(1) Patients must be hospitalized in a ward with special protective conditions.
(2) The patient’s urine and other excreta should be disposed of according to the requirements of radiation protection.
(3) Patients can be discharged when the amount of 131I stored in their bodies drops below 1.11 GBq (30 mCi), and avoid going to public places for a week, and cannot come into contact with pregnant women and children.
(4) During the treatment process, medical personnel should pay attention to their own safety protection according to the protection requirements.